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  1. #1
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    Lightbulb Handmade Passive Preamplifier

    My very first handmade passive preamp!

    Lots of fun to make it successfully amplifying and tuning sound quality in thick bass or accurate positioning Hope to share with all of you.
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  2. #2
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    Re: Handmade Passive Preamplifier

    Welcome and really nice work.
    -----------------
    Brian

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    Secondary - OPPO 93 > VAC CLA 1 MKII Pre > Odyssey Stratos > JM Labs Tantal 509s > Tara Labs Cables


  3. #3
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    Re: Handmade Passive Preamplifier

    Looks great, well done.
    How does it sound?
    My System:
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  4. #4
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by jadedavid View Post
    Looks great, well done.
    How does it sound?
    Thanks! well, it depends on the gain options. Mainly accurate positioning in 1X, sweet in 3X, thick bass in 5X and 10X.

  5. #5
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    Re: Handmade Passive Preamplifier

    Thanks!

  6. #6
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    Re: Handmade Passive Preamplifier

    In fact, hope to know whether there are anymore similar types of passive preamp. Wanna try and improve my work.

    Does anyone know?

  7. #7
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    Re: Handmade Passive Preamplifier

    Well done and thank you for joining!
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  8. #8
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    Re: Handmade Passive Preamplifier

    I don't even begin to understand the schematic.

  9. #9
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    Re: Handmade Passive Preamplifier

    In fact, hope to know whether there are anymore similar types of passive preamp. Wanna try and improve my work. Does anyone know?
    There are quite a few transformer-based attenuators around, I have a Stevens & Billington one. Mine has switchable inputs using relays -- many of which no longer work, by the way
    Very clear, airy sound, but I get more dynamic impact with the regular active pre.
    Beautifully done, by the way!
    Digital: Musichi player on Minix; DAC: Ideon Audio Absolute (loan), MSB Select II, Ideon Audio Ayazi II, 2x Ideon 3R Master Time signal reclocking; Analogue: TT: Simon Yorke - Pluto 6 // Pro ject Xtension 12'΄; Preactive: Borbely Reference; Prepassive: Steven & Billington; Amplifier: Symphonic Line -- Kraft 250 class A; Speakers: Devore / vintage Etude; Cabling: homegrown, Bearlabs, Nordost Valhalla; Isolation: Neuance shelves, Nordost pulsars Rack: suspended devices

  10. #10
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    Re: Handmade Passive Preamplifier

    Awesome job...

    Arek Kallas offers an attenuator that is rated as one of the best and I know they are highly rated in the DIY community. Khozma Acoustic is his company where these are sold.

    High Quality Audio & Industrial Attenuators and Passive Preamplifiers

    I do not believe he offers full kits however.

    His higher level company is Hattor Audio. In my personal view they offer one of the finest passive pre-amplifiers on the market.

    Hattor Audio

    I really like my Hattor pre-amp and I have the addon Tube Active Stage on order, which will make my Hattor a true three box pre-amp!
    Amps: Hattor "The Big" w/AMRG Trans, Hattor Tube Active Stage, Bel Canto REF500S, McIntosh MC754
    Vinyl: Rega RP8 w/Rega Neo PSU, Technics SL-1500C, Moon by SimAudio NEO 310LP, Record Doctor VI, Hexmat Yellow Bird
    Cartridges: Rega Ania Pro, Ortofon 2M Red, Audio Technica VM740ML
    Digital: Falcon Northwest PC Server, T+A DAC 8 DSD, W4S Recovery, Roon & HQPlayer, Microsoft Surface Pro 6, Astell & Kern SE200
    Transducers: Magnepan MG .7's w/Magna Riser Stands, Rythmik L12's (x2), Abyss Diana Phi's
    Other: McIntosh MR7083, Oppo BDP105, AudioQuest Niagara 1000, Astell & Kern AK240 (for sale)

  11. #11
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    Re: Handmade Passive Preamplifier

    I could tell you more if you want to

  12. #12
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    Re: Handmade Passive Preamplifier

    Since you guys are talking about the attenuators, I might share more about the attenuator and transformer I used in this DIY passive preamp.

    The attenuator and transformer are handcrafted and bought from "design by mr.k", a local brand from my hometown Hong Kong.

    I've tried other attenuators and transformers from other brand before, sadly they didn't work/sound good. But for "design by mr.k", I could find 59 steps mechanical volume control and even 59 steps autotransformer - I think it might be probably the largest number of steps I've ever seen before. This transformer controls the volume step-up amplifying, that's why this passive preamp doesn't require any power sources.

    This brand also offers the whole set of passive preamp product on eBay. Not sure whether you guys would be interested, but just hope to share my experience and some reviews

    Very sorry that up to this moment I could not post up any links yet(since I'm new and don't have enough post counts). Once I could, I will post up the company and eBay link to you all.

  13. #13
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by AudioLover525 View Post
    I've tried other attenuators and transformers from other brand before, sadly they didn't work/sound good. But for "design by mr.k", I could find 59 steps mechanical volume control and even 59 steps autotransformer - I think it might be probably the largest number of steps I've ever seen before. This transformer controls the volume step-up amplifying, that's why this passive preamp doesn't require any power sources.
    The Khozma are 64 step and about as good as you get. In the Hattor model "The Big" he uses two of them in dual mono. Each channel has its own volume control. With the AMRG Trans resistors version these are the state of the industry in passive attenuators.
    Amps: Hattor "The Big" w/AMRG Trans, Hattor Tube Active Stage, Bel Canto REF500S, McIntosh MC754
    Vinyl: Rega RP8 w/Rega Neo PSU, Technics SL-1500C, Moon by SimAudio NEO 310LP, Record Doctor VI, Hexmat Yellow Bird
    Cartridges: Rega Ania Pro, Ortofon 2M Red, Audio Technica VM740ML
    Digital: Falcon Northwest PC Server, T+A DAC 8 DSD, W4S Recovery, Roon & HQPlayer, Microsoft Surface Pro 6, Astell & Kern SE200
    Transducers: Magnepan MG .7's w/Magna Riser Stands, Rythmik L12's (x2), Abyss Diana Phi's
    Other: McIntosh MR7083, Oppo BDP105, AudioQuest Niagara 1000, Astell & Kern AK240 (for sale)

  14. #14
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Randy Myers View Post
    The Khozma are 64 step and about as good as you get. In the Hattor model "The Big" he uses two of them in dual mono. Each channel has its own volume control. With the AMRG Trans resistors version these are the state of the industry in passive attenuators.
    I know that Khozma with 64 steps, but it is an electronic switch. In the Design by Mr.K model, the volume switch is controlled mechanically which makes the tuning experience super concrete and good.

  15. #15
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    Re: Handmade Passive Preamplifier

    That is cool. Of course you should use whichever is best for your purposes.

    Arek's attenuators are highly regarded as about the purest sounding available. I can tell you from comparing several preamplifiers, the Hattor is the best sounding I have ever heard, and is ranked with the best of the best passive preamplifiers anywhere in the world.

    One huge difference however is that Arek offers an optional top quality Active Gain Stage. Mine should be arriving some time this week. It can be used as pure passive or with a selectable level of gain, and some added tube goodness! The full three box preamplifier supposable can hold its own against many of the very highest preamps!
    Amps: Hattor "The Big" w/AMRG Trans, Hattor Tube Active Stage, Bel Canto REF500S, McIntosh MC754
    Vinyl: Rega RP8 w/Rega Neo PSU, Technics SL-1500C, Moon by SimAudio NEO 310LP, Record Doctor VI, Hexmat Yellow Bird
    Cartridges: Rega Ania Pro, Ortofon 2M Red, Audio Technica VM740ML
    Digital: Falcon Northwest PC Server, T+A DAC 8 DSD, W4S Recovery, Roon & HQPlayer, Microsoft Surface Pro 6, Astell & Kern SE200
    Transducers: Magnepan MG .7's w/Magna Riser Stands, Rythmik L12's (x2), Abyss Diana Phi's
    Other: McIntosh MR7083, Oppo BDP105, AudioQuest Niagara 1000, Astell & Kern AK240 (for sale)

  16. #16
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Gregm View Post
    There are quite a few transformer-based attenuators around, I have a Stevens & Billington one. Mine has switchable inputs using relays -- many of which no longer work, by the way
    Very clear, airy sound, but I get more dynamic impact with the regular active pre.
    Beautifully done, by the way!
    In what ways they didn't work? Although somehow switchable inputs using relays are differ from my mechanical control switch.

  17. #17
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Randy Myers View Post
    That is cool. Of course you should use whichever is best for your purposes.

    Arek's attenuators are highly regarded as about the purest sounding available. I can tell you from comparing several preamplifiers, the Hattor is the best sounding I have ever heard, and is ranked with the best of the best passive preamplifiers anywhere in the world.

    One huge difference however is that Arek offers an optional top quality Active Gain Stage. Mine should be arriving some time this week. It can be used as pure passive or with a selectable level of gain, and some added tube goodness! The full three box preamplifier supposable can hold its own against many of the very highest preamps!
    So how do they sound? For mine, different gain options(1X, 3X, 5X and 10X) are with different sound qualities, like sweet and thick. I'm curious about whether Arek offers this kind of variety of selectable gain choices and sound effects.

  18. #18
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    Re: Handmade Passive Preamplifier

    The base unit is a pure passive preamplifier. He offers a few different levels of resistors to choose from (with added cost of course). I originally purchased the base vishay version and it was very good. I then stepped up to the AMRG Trans version, his finest. It was considerably more open, more lush sounding. More air around the instruments, simply inviting and musical sounding.

    The Tube Active Stage unit has not arrived yet. Therefore I can not answer that yet. I know the unit has a switch between pure passive mode which should be nice for lower listening, late night sessions, etc. When switching in the active mode there is another switch for how much gain. Arek states that with the active stage the sound is more relaxed, more dynamic with deeper bass. Because I am using harder to drive speakers, 4 ohm and 86 dB efficiency, and I am also preferring my amplifier that is very sweet sounding and musical but lower power, this extra dynamics should be useful.
    Amps: Hattor "The Big" w/AMRG Trans, Hattor Tube Active Stage, Bel Canto REF500S, McIntosh MC754
    Vinyl: Rega RP8 w/Rega Neo PSU, Technics SL-1500C, Moon by SimAudio NEO 310LP, Record Doctor VI, Hexmat Yellow Bird
    Cartridges: Rega Ania Pro, Ortofon 2M Red, Audio Technica VM740ML
    Digital: Falcon Northwest PC Server, T+A DAC 8 DSD, W4S Recovery, Roon & HQPlayer, Microsoft Surface Pro 6, Astell & Kern SE200
    Transducers: Magnepan MG .7's w/Magna Riser Stands, Rythmik L12's (x2), Abyss Diana Phi's
    Other: McIntosh MR7083, Oppo BDP105, AudioQuest Niagara 1000, Astell & Kern AK240 (for sale)

  19. #19

    Re: Handmade Passive Preamplifier

    Very nice work! I bought a 64 step volume control years ago with the intent of building something similar. I got lazy and never attempted it. My first passive pre was a Mod Squad Line Drive, it replaced a Carver preamp that had a power supply about the size of your thumb. That Line Drive blew me away and played many years of pretty music for me. Congrats.

  20. #20
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by stereogeek View Post
    Very nice work! I bought a 64 step volume control years ago with the intent of building something similar. I got lazy and never attempted it. My first passive pre was a Mod Squad Line Drive, it replaced a Carver preamp that had a power supply about the size of your thumb. That Line Drive blew me away and played many years of pretty music for me. Congrats.
    Thank you so much! I think the 64 steps one you bought should be electronic switches with relays, but here we use mechanical switch for concrete volume control experience which is great for HiFi lovers. In fact, you may start trying to build your second passive preamp without any power supply. The attenuator and transformer I bought is from DesignbyMr.K, which also offers the whole kit of passive premaplifier from eBay, has no any power sources applied in the design. As there is no any active components, power lines or supply nor wall plugs needed, no noise and distortion added to the device even up to 10X gain option. If you're looking for a no power passive preamp option, I would recommend DesignbyMr.K to you.

  21. #21
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    Re: Handmade Passive Preamplifier

    Looks great. Without a remote, it becomes difficult for practical purpose, especially for folks who are streaming digital from the comfort of their listening chair


    I am big fan of Chapman's autofomer. It really brings out the weakness/greatness of your frontend.

  22. #22
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by AudioLover525 View Post
    Thank you so much! I think the 64 steps one you bought should be electronic switches with relays, but here we use mechanical switch for concrete volume control experience which is great for HiFi lovers. In fact, you may start trying to build your second passive preamp without any power supply. The attenuator and transformer I bought is from DesignbyMr.K, which also offers the whole kit of passive premaplifier from eBay, has no any power sources applied in the design. As there is no any active components, power lines or supply nor wall plugs needed, no noise and distortion added to the device even up to 10X gain option. If you're looking for a no power passive preamp option, I would recommend DesignbyMr.K to you.
    Where did you source the chassis from? It looks identical to Aavik.


    Sent from my iPhone using Tapatalk Pro
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  23. #23
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    Re: Handmade Passive Preamplifier

    Another question I have. How do you select between the different inputs or do you manual switch the cables? I could be missing it but I only see a volume control on the unit. Am I missing something?
    Amps: Hattor "The Big" w/AMRG Trans, Hattor Tube Active Stage, Bel Canto REF500S, McIntosh MC754
    Vinyl: Rega RP8 w/Rega Neo PSU, Technics SL-1500C, Moon by SimAudio NEO 310LP, Record Doctor VI, Hexmat Yellow Bird
    Cartridges: Rega Ania Pro, Ortofon 2M Red, Audio Technica VM740ML
    Digital: Falcon Northwest PC Server, T+A DAC 8 DSD, W4S Recovery, Roon & HQPlayer, Microsoft Surface Pro 6, Astell & Kern SE200
    Transducers: Magnepan MG .7's w/Magna Riser Stands, Rythmik L12's (x2), Abyss Diana Phi's
    Other: McIntosh MR7083, Oppo BDP105, AudioQuest Niagara 1000, Astell & Kern AK240 (for sale)

  24. #24
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Devg View Post
    Looks great. Without a remote, it becomes difficult for practical purpose, especially for folks who are streaming digital from the comfort of their listening chair


    I am big fan of Chapman's autofomer. It really brings out the weakness/greatness of your frontend.
    Depends on your preference. The feeling is concrete and great during tuning for this 59 steps mechanical volume control which I really enjoy it.

  25. #25
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by UltraFast69 View Post
    Where did you source the chassis from? It looks identical to Aavik.


    Sent from my iPhone using Tapatalk Pro
    Just bought it from Taobao. It is not surprising that different brands bought the case from similar source.

  26. #26
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Randy Myers View Post
    Another question I have. How do you select between the different inputs or do you manual switch the cables? I could be missing it but I only see a volume control on the unit. Am I missing something?
    I switch the RCA for different input selections.

  27. #27

    Re: Handmade Passive Preamplifier

    I only used one input on my Line Drive ( cd player ) so I bypassed the selector switch. My passive would have been the same as your "X1" setting. We controlled the sound by using putty to dampen the inside of the chassis. Again, very nice work.

  28. #28
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    Re: Handmade Passive Preamplifier

    So in essence it is simply a volume control. That is cool. Gives you what you need.

    I have four sources hooked to my Hattor. Three use XLR and one RCA. Two of these I use on a daily basis so having input switching is fairly important to me on my passive pre.
    Amps: Hattor "The Big" w/AMRG Trans, Hattor Tube Active Stage, Bel Canto REF500S, McIntosh MC754
    Vinyl: Rega RP8 w/Rega Neo PSU, Technics SL-1500C, Moon by SimAudio NEO 310LP, Record Doctor VI, Hexmat Yellow Bird
    Cartridges: Rega Ania Pro, Ortofon 2M Red, Audio Technica VM740ML
    Digital: Falcon Northwest PC Server, T+A DAC 8 DSD, W4S Recovery, Roon & HQPlayer, Microsoft Surface Pro 6, Astell & Kern SE200
    Transducers: Magnepan MG .7's w/Magna Riser Stands, Rythmik L12's (x2), Abyss Diana Phi's
    Other: McIntosh MR7083, Oppo BDP105, AudioQuest Niagara 1000, Astell & Kern AK240 (for sale)

  29. #29
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by AudioLover525 View Post
    In fact, hope to know whether there are anymore similar types of passive preamp. Wanna try and improve my work.

    Does anyone know?
    Peter Daniel of Audiosector used to produce the AudioZone Pre-T1 which featured Stevens & Billington xfmers, arguably the best of their kind. Peter has an eye for form as well as function and his products all sound wonderful. There is no free lunch with these types of devices as impedance changes with each volume step and can wreak havoc with capacitive cables and accompanying gear with high output/low input impedances.
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    Simon Yorke S10 | My Sonic Lab Eminent GL | B.M.C MCCI Signature ULN | Wadia X32 | Innuous ZEN Mini Mk II | Valvet Soulshine2 | LTA ZOTL10 MkII | Avantgarde Uno Fino XD

    "One of the great challenges of this world: Knowing enough about a subject to think you are right, but not enough about the subject to know you're wrong" - Neil deGrasse Tyson

  30. #30
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    Re: Handmade Passive Preamplifier

    Looks interesting.
    Amps: Hattor "The Big" w/AMRG Trans, Hattor Tube Active Stage, Bel Canto REF500S, McIntosh MC754
    Vinyl: Rega RP8 w/Rega Neo PSU, Technics SL-1500C, Moon by SimAudio NEO 310LP, Record Doctor VI, Hexmat Yellow Bird
    Cartridges: Rega Ania Pro, Ortofon 2M Red, Audio Technica VM740ML
    Digital: Falcon Northwest PC Server, T+A DAC 8 DSD, W4S Recovery, Roon & HQPlayer, Microsoft Surface Pro 6, Astell & Kern SE200
    Transducers: Magnepan MG .7's w/Magna Riser Stands, Rythmik L12's (x2), Abyss Diana Phi's
    Other: McIntosh MR7083, Oppo BDP105, AudioQuest Niagara 1000, Astell & Kern AK240 (for sale)

  31. #31
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by stereogeek View Post
    I only used one input on my Line Drive ( cd player ) so I bypassed the selector switch. My passive would have been the same as your "X1" setting. We controlled the sound by using putty to dampen the inside of the chassis. Again, very nice work.
    Thanks for your appreciation! I got four gain options here, from 1X up to 10X(+20dB) for sound quality controlling. Here you see only RCA switching is available for gain selections, however I could actually make a selector switch. It definitely could be a way more than that! But the sound, still, available from accurate positioning to sweet to super thick by selecting 1X, 3X, 5X and 10X gain.

  32. #32
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Randy Myers View Post
    So in essence it is simply a volume control. That is cool. Gives you what you need.

    I have four sources hooked to my Hattor. Three use XLR and one RCA. Two of these I use on a daily basis so having input switching is fairly important to me on my passive pre.
    This is a passive preamplifier but not a volume control.....

    A 59 steps autotransformer is used for voltage amplifying. Magnetic force is induced throughout this C Core transformer, with 1X, 3X, 5X and 10X gain options, sound qualities could vary from sweet to thick bass to super thick...You could see the gain options plugs on the back panel from the image. There is no need to use any power sources, meaning no active components or power line/supplies or wall plug are used, so no noise and distortion will be added to the passive preamp. Plus, a 59 steps mechanical volume switch is used(really not an electronic one!) which makes me feel concrete and great during tuning!

  33. #33
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by puroagave View Post
    Peter Daniel of Audiosector used to produce the AudioZone Pre-T1 which featured Stevens & Billington xfmers, arguably the best of their kind. Peter has an eye for form as well as function and his products all sound wonderful. There is no free lunch with these types of devices as impedance changes with each volume step and can wreak havoc with capacitive cables and accompanying gear with high output/low input impedances.
    Does it have any gain selections? It seems to have input selections and volume control only, correct me if I'm wrong.

  34. #34
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    Re: Handmade Passive Preamplifier

    Since you guys may not have a fully understanding about this passive preamp work, just feel free to discuss with me about it, especially for its core part (the attenuator and transformer) used here

  35. #35
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by AudioLover525 View Post
    Since you guys may not have a fully understanding about this passive preamp work, just feel free to discuss with me about it, especially for its core part (the attenuator and transformer) used here
    I know exactly what it is, I was a Sonic Euphoria PLC beta tester for Jeff Hagler of Sound Values back in the mid 90s before he ever brought it to market. I will say it again, PLCs are not a free lunch they will impact frequency response based on the 'gain' setting which is a misnomer since they are really nothing more than an attenuator. Here's a pic of the old girl, look familiar? (balanced vers)
    Attached Images Attached Images
    Simon Yorke S10 | My Sonic Lab Eminent GL | B.M.C MCCI Signature ULN | Wadia X32 | Innuous ZEN Mini Mk II | Valvet Soulshine2 | LTA ZOTL10 MkII | Avantgarde Uno Fino XD

    "One of the great challenges of this world: Knowing enough about a subject to think you are right, but not enough about the subject to know you're wrong" - Neil deGrasse Tyson

  36. #36
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by puroagave View Post
    I know exactly what it is, I was a Sonic Euphoria PLC beta tester for Jeff Hagler of Sound Values back in the mid 90s before he ever brought it to market. I will say it again, PLCs are not a free lunch they will impact frequency response based on the 'gain' setting which is a misnomer since they are really nothing more than an attenuator. Here's a pic of the old girl, look familiar? (balanced vers)
    Yes and that's a very similar design to mine! Yours also got the gain and volume selections right? But I think it should be only up to 24 steps for both mechanical volume control and transformer right?The only brand I know that could reach to more steps is this 59 steps one from designbymrk. I don't mean that 64 steps one as it is designed as an electronic switch but not a mechanical one.

    Has anybody checked out this Hong Kong brand website? I really recommend its design and that's why I used it in my work.

  37. #37
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    Re: Handmade Passive Preamplifier

    I of course understand what a passive pre-amp is, I currently use one and have had others. However, when you state that it adds gain, guess what, it is no longer a passive pre-amp. Any kind of gain stage makes it into a standard active pre-amp and no longer a passive. If you are using it without gain you are using it passive.

    To quote Arek Kallas, one of the true expert designers in the field, offering some of the best passive pre-amps and attenuators in the world, when you add a gain stage, "In fact it will be an active preamp".

    Further more, to add gain does require some type of power. It can't add gain (amplification) without it. So in passive mode it is basically an attenuator and to add gain requires some kind of power (it cannot get louder without a power source). Therefore what is being referred to as gain is in fact more attenuation. With a pure passive, at no attenuation the full input signal is being passed to the amplifier, attenuation actually cuts this signal back to control the volume you hear. Usually with some type of resistors put in line. Less volume equates to larger attenuation resistors. The volume control actually moves different resistors in and out of line with the source signal.

    To summarize, you cannot add gain (amplification) without power and adding true gain in fact changes the pre-amp to an active pre-amp, no longer a passive. This has been fully described to me by two of the foremost experts in the field; Arek Kallas, owner of Hattor Audio and Khozma Acoustic and my personal friend EJ Sarmento, owner of Wyred 4 Sound (designer and builder of the world renowned STP-SE Stage 2), SST, Carver and others.
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  38. #38
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    Re: Handmade Passive Preamplifier

    I thought that the schematic in post #1 looked strange.
    It seems that the unit is not a passive pre-amp, that is an input selector and volume control. But rather it's a euphoric effects generator.

  39. #39
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    Re: Handmade Passive Preamplifier

    Now I don't have any problems with the unit, it looks great!
    The problem I have is calling it a pre-amp.

  40. #40
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Speedskater View Post
    Now I don't have any problems with the unit, it looks great!
    The problem I have is calling it a pre-amp.
    Again, I agree. It looks like a nice unit but it certainly is not a passive pre-amp.

    "successfully amplifying and tuning sound quality", and "with 1X, 3X, 5X and 10X gain options", I also have an issue with this, it cannot amplify the sound without a power source. Passive pre-amps attenuate the sound by putting various resistors in the signal path. Adding "gain" amplifies the signal and this requires a power source, and also would make it not be a passive pre-amp. Maybe he is confusing a lesser amount of attenuation as being gain?

    "This is a passive preamplifier but not a volume control", excuse me.... to be a passive pre-amp it has to be a volume control... that is exactly what attenuation does.

    "Plus, a 59 steps mechanical volume switch is used", ok, so now I am very confused, not a volume control and a couple sentences later 59 step mechanical volume switch is used??? Huh?

    "Since you guys may not have a fully understanding about this passive preamp work, just feel free to discuss with me about it", ahhh yea, I think we do.
    Amps: Hattor "The Big" w/AMRG Trans, Hattor Tube Active Stage, Bel Canto REF500S, McIntosh MC754
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  41. #41
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Randy Myers View Post
    I of course understand what a passive pre-amp is, I currently use one and have had others. However, when you state that it adds gain, guess what, it is no longer a passive pre-amp. Any kind of gain stage makes it into a standard active pre-amp and no longer a passive. If you are using it without gain you are using it passive.

    To quote Arek Kallas, one of the true expert designers in the field, offering some of the best passive pre-amps and attenuators in the world, when you add a gain stage, "In fact it will be an active preamp".

    Further more, to add gain does require some type of power. It can't add gain (amplification) without it. So in passive mode it is basically an attenuator and to add gain requires some kind of power (it cannot get louder without a power source). Therefore what is being referred to as gain is in fact more attenuation. With a pure passive, at no attenuation the full input signal is being passed to the amplifier, attenuation actually cuts this signal back to control the volume you hear. Usually with some type of resistors put in line. Less volume equates to larger attenuation resistors. The volume control actually moves different resistors in and out of line with the source signal.

    To summarize, you cannot add gain (amplification) without power and adding true gain in fact changes the pre-amp to an active pre-amp, no longer a passive. This has been fully described to me by two of the foremost experts in the field; Arek Kallas, owner of Hattor Audio and Khozma Acoustic and my personal friend EJ Sarmento, owner of Wyred 4 Sound (designer and builder of the world renowned STP-SE Stage 2), SST, Carver and others.
    First of all, if we talk about the gain, I would like to stress that the gain mentioned in my work is VOLTAGE gain but not power gain. We have definitions to define whether this is active or passive. To quote, "A passive component, depending on field, may be either a component that consumes but does not produce energy (thermodynamic passivity) or a component that is incapable of power gain (incremental passivity).", see on wikipedia. No active component involved. This is definitely a passive preamplifier.

    Adding power gain does require power, while adding voltage or current gain might not. We could do energy transfer to add voltage or current gain without power, one of the examples is phono MC transformer preamplifier. It added voltage gain by using a MC transformer to do energy transfer, which does not require power. This is exactly what the case in my work.

  42. #42
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Speedskater View Post
    I thought that the schematic in post #1 looked strange.
    It seems that the unit is not a passive pre-amp, that is an input selector and volume control. But rather it's a euphoric effects generator.
    To be more accurate, I would say that this is a passive preamplifier with input selector and volume control. For the reasons, see my previous comments:

    "We have definitions to define whether this is active or passive. To quote, "A passive component, depending on field, may be either a component that consumes but does not produce energy (thermodynamic passivity) or a component that is incapable of power gain (incremental passivity).", see on wikipedia. No active component involved. This is definitely a passive preamplifier."

    Have you ever seen a euphoric effects generator could obtain voltage gain selections from 1X, 3X, 5X to 10X?

  43. #43
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Randy Myers View Post
    Again, I agree. It looks like a nice unit but it certainly is not a passive pre-amp.

    "successfully amplifying and tuning sound quality", and "with 1X, 3X, 5X and 10X gain options", I also have an issue with this, it cannot amplify the sound without a power source. Passive pre-amps attenuate the sound by putting various resistors in the signal path. Adding "gain" amplifies the signal and this requires a power source, and also would make it not be a passive pre-amp. Maybe he is confusing a lesser amount of attenuation as being gain?
    I think I've explained this part. We can amplify without a power source, if we talk about VOLTAGE amplifying.

    Quote Originally Posted by Randy Myers View Post
    "This is a passive preamplifier but not a volume control", excuse me.... to be a passive pre-amp it has to be a volume control... that is exactly what attenuation does.

    "Plus, a 59 steps mechanical volume switch is used", ok, so now I am very confused, not a volume control and a couple sentences later 59 step mechanical volume switch is used??? Huh?
    This is a passive preamplifier with 59 steps mechanical volume control, but not either one, to be a more accurate speaking.

    With 1V input, we have 10V output. With 0.1V input, we have 1V output. This is the fact. How could you say that this is not the case, huh?

  44. #44
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    Re: Handmade Passive Preamplifier

    Yes a transformer can increase output voltage, but at the cost of lowering it's input impedance. There are no free lunches with transformers.
    Not sure that lower impedance's are a good idea with passive components.

  45. #45
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    Re: Handmade Passive Preamplifier

    Also, we are talking about the accepted terms in the audio world. A preamplifier controls volume output to an amplifier and selects inputs from music sources. A passive preamplifier does not add any gain but instead passes the signal through and controls volume more often then not by utilizing some sort of inline resistors to attenuate the signal.

    When I added the tube stage to my preamplifier yesterday it was no longer a passive preamp but instead became an active pre. I can actually selected which manner I would like to run it, either passive or active from a switch on the front panel. To add gain/amplification to the signal does indeed require a power source.

    The device you built, which looks interesting and appears that you did a good job on it, does not seem to be a passive preamplifier as the terms are used in the audio world. There is not input selection, but instead you can switch connected sources to change the voltages (as you described it) which of course does change the impedance.

    Cool looking device but certainly not what I would refer to as a passive preamplifier.
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  46. #46
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Randy Myers View Post
    Also, we are talking about the accepted terms in the audio world. A preamplifier controls volume output to an amplifier and selects inputs from music sources. A passive preamplifier does not add any gain but instead passes the signal through and controls volume more often then not by utilizing some sort of inline resistors to attenuate the signal.

    When I added the tube stage to my preamplifier yesterday it was no longer a passive preamp but instead became an active pre. I can actually selected which manner I would like to run it, either passive or active from a switch on the front panel. To add gain/amplification to the signal does indeed require a power source.

    The device you built, which looks interesting and appears that you did a good job on it, does not seem to be a passive preamplifier as the terms are used in the audio world. There is not input selection, but instead you can switch connected sources to change the voltages (as you described it) which of course does change the impedance.

    Cool looking device but certainly not what I would refer to as a passive preamplifier.
    First of all, those accepted terms you stated are lack of concrete evidence, at least I don't agree. For mine is supported by the Wikipedia, which is accepted by the worldwide.

    Secondly, when we input 0.2V would output 2V(10 times gain, +20dB). That's why I called it an amplifier.

    Thirdly, our preamp does not require any power sources and uses all passive components. That's why I called it a passive preamp.

    Fourthly, all preamp are with volume. So according to your theory, all preamp should be called as volume right?

    Finally, what you previously argued so far is meaningless.

  47. #47
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Speedskater View Post
    Yes a transformer can increase output voltage, but at the cost of lowering it's input impedance. There are no free lunches with transformers.
    Not sure that lower impedance's are a good idea with passive components.
    Certainly. Input impedance will surely be lowered, however all CD network players and DAC support that.

  48. #48
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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by AudioLover525 View Post
    our preamp
    Hmmmm.....

    Quote Originally Posted by AudioLover525 View Post
    For mine is supported by the Wikipedia, which is accepted by the worldwide.
    Wikipedia is not an authoritative source and you do know you are posting on an Audio Forum where we discuss things in audio terms, right?

    Quote Originally Posted by AudioLover525 View Post
    Secondly, when we input 0.2V would output 2V(10 times gain, +20dB). That's why I called it an amplifier.
    An amplifier amplifies the audio signal and does not simply play with voltage.

    Quote Originally Posted by AudioLover525 View Post
    Thirdly, our preamp does not require any power sources and uses all passive components. That's why I called it a passive preamp.
    You can't really call it a preamp if if does not have an input source selector and a volume control can you?

    Quote Originally Posted by AudioLover525 View Post
    Fourthly, all preamp are with volume. So according to your theory, all preamp should be called as volume right?
    That is just plain putting words in my mouth. No one said a preamp should be called volume, however a volume control is a major function of any preamplifier. Besides being wrong it is also extremely rude. I know you are not used to a forum like Audio Shark where people are friendly and treat others respectfully, but that is how we operate here.

    Quote Originally Posted by AudioLover525 View Post
    Finally, what you previously argued so far is meaningless.
    And again another rude statement.


    And there you have it. A shill for a company trying to drum up business.

    Just give it up please...Your arguments makes no sense and it just goes round and round. With each post you are sounding less and less credible so please just stop.

    Definitely have had enough of this thread.
    Amps: Hattor "The Big" w/AMRG Trans, Hattor Tube Active Stage, Bel Canto REF500S, McIntosh MC754
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  49. #49
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    Re: Handmade Passive Preamplifier

    Your unit has qualities that are almost opposite of the qualities desired by audiophiles that chose passive pre-amps.
    Those audiophiles chose passive pre-amps because they feel that an active stage might change the signal in some small way.
    Your unit intentionally changes the signal.
    Why not call it "Not a Passive Pre-amp" ?

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    Re: Handmade Passive Preamplifier

    Quote Originally Posted by Randy Myers View Post
    Wikipedia is not an authoritative source and you do know you are posting on an Audio Forum where we discuss things in audio terms, right?
    Wikipedia is monitored by many professional and discerning people, which is trustful. Otherwise what other platforms could you provide?

    Quote Originally Posted by Randy Myers View Post
    An amplifier amplifies the audio signal and does not simply play with voltage.
    I'm talking about 20Hz - 20kHz audio signal from 0.2V to 2V. If I'm not talking about audio signal, what else could I refer to?

    Quote Originally Posted by Randy Myers View Post
    You can't really call it a preamp if if does not have an input source selector and a volume control can you?
    You're wrong again. So you're talking about those so-called "definitions" again right? We do have a volume control with 59 steps mechanical control. I intentionally not to put on the input selector as there is only need to use one sourcing which I aimed to ensure a more pure sound quality.

    Quote Originally Posted by Randy Myers View Post
    That is just plain putting words in my mouth. No one said a preamp should be called volume, however a volume control is a major function of any preamplifier. Besides being wrong it is also extremely rude. I know you are not used to a forum like Audio Shark where people are friendly and treat others respectfully, but that is how we operate here.

    And again another rude statement.

    And there you have it. A shill for a company trying to drum up business.

    Just give it up please...Your arguments makes no sense and it just goes round and round. With each post you are sounding less and less credible so please just stop.

    Definitely have had enough of this thread.
    I couldn't feel how nice or friendly you've been so far. From time to time you keep on arguing what a preamplifier is, what means by active or passive...What I've received are those rude saying either, that's why I talk to you in this way. I agree that this forum is a place with many good people, but you might not be one of them.

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