Thread: Attenuators

While I don't know anything about 'Rothwell attenuators', Markertek in the US has several other nice ones.
Markertek - Search Results for attenuator xlr

I have not used the Markertech attenuators, however, I have used the 12db Rothwell ones with a Cary SLP-05. I could barely turn it up to 9 o'clock as it would get too loud without the Rothwell's installed . I thought they took away a bit of detail but, as you know, sometimes it's really hard to tell. Good luck.

attenuators don't take away the detail, they reduce the background noise. It's about system 'Gain Structure' in getting each stage at it's optimum level.

Originally Posted by Speedskater

attenuators don't take away the detail, they reduce the background noise. It's about system 'Gain Structure' in getting each stage at it's optimum level.

Agree it helps to optimize gain drive , but the added RLC change with IC and connectors will change tone and details, if matched correctly gains can be posit, sometimes not ..




Regards

Originally Posted by MPW

I own a Pass X350.8 that is being fed by a Cary SLP-05 using balanced inputs and outputs. In this configuration, the gain from the Cary is 24 dB. I find that I rarely move the preamp volume past about 8:00 and can get 90+ dB peaks at the listening position at this volume level. As I lower the volume, things can get a little squirrelly. Bottom line is I would like to lower the gain of the preamp going into the Pass. The system sounds great at high volumes, not so good at low volumes and I think there should be some advantage by raising the volume control on the preamp from that low position. I was looking at Rothwell attenuators, but I am not sure what that will do to the sonics. Would love any thoughts you guys have on the matter.

I would lower the drive into the Pre amp not the Amp ...!

The Cary SLP-05's line stage gain drops from 24db balanced to 17db when going single ended, this might be your answer. It might also sound better particularly since the Cary--and probably the Pass as well--don't use 'fully' balanced circuits from input to output and employ additional circuitry to invert the signal for balanced operation which gets bypassed when you go SE.

Wow 8M ..!!

The additional db gain says balanced input structure IMO, many balanced designs are not full differential but still run a “balanced” gain structure at input for noise control. Balanced claims are now becoming like “ Full class A “claims all marketing play along gibberish really, their is no such device I’m aware of currently that is full class A ...



Regards

Originally Posted by MPW

Also, I have an 8 meter run from pre to amp which makes single ended problematic.

Or around 26 ft which ive done before going SE from a CJ tube preamp to a Krell SS amp with no issues. The SLP05 has an output impedance of 400 ohm which is great in your case, as long your ICs are low in capacitance you wouldn't have bass issues but if you have ground loop issues then going SE will exacerbate them.

Originally Posted by MPW

I have used this setup in a fully single ended configuration with great success. When I moved to Pass amps, I tried balanced again and there was no going back. Much improved sonics. Kent English at Pass Labs confirmed for me that the Cary and Pass combination is best as balanced. I had always found the reverse to be true with other amps, but not with the Pass. I have recently began experimenting with the balanced inputs to the Cary. I had tried this configuration in the past (prior to the Ultimate Upgrade on the Cary) and always preferred single ended. I recently tried it again and am preferring the balanced inputs which put another set of tubes in the signal path. This is when I have run into the gain issue as you have indicated. I think I am going to get a set of balanced attenuators (likely Rothwell) which I can experiment with on the amp input vs the preamp input to see which is best and if this is even a viable option. Investment isn’t that high to conduct the experiment.

Let us know how the Rothwell works out. The elephant in the room still remains, the Cary has too much line stage gain. I've owned several ol skool tube preamps when 24db of line stage gain was de rigueur to make up for the low-ish gain of their internal phono stages. With separate phono stages being more common today the utility of 24db line stages has all but disappeared.

Originally Posted by a.wayne

Agree it helps to optimize gain drive , but the added RLC change with IC and connectors will change tone and details, if matched correctly gains can be posit, sometimes not ..
Regards

As to tone and detail, in a word, no.

Now things are getting much more complicated.
With a setup like this, all bets are off.

@MPW sorry for being late to the thread. I have an extra pair of Rothwell XLR attenuators I can give you. My system has changed so I don’t need them anymore. Happy to help the Shark community. If you PM me your address I’ll ship them to you (from NY)

I use Rothwell attenuators, both balanced and unbalanced, and have nothing but good things to say about them. I use the -10dB units in the output paths to my 7.1 channels of amplification to lower the almost imperceptible level of AC hum being induced in my pre/pro in my system to below audible levels and I had to resort to this because I was never able to find and resolve the root cause of the hum in the first place. I have also used them for system balancing across the eight channels of amplification and varying speaker sensitivities in my system. I have not experienced any degradation in SQ with the XLR units connected in this manner.

As a side note, I once attempted to drop the output level of my Lumin X1 streamer via inserting attenuators at the output of the X1 while connecting it directly to the inputs of my mono front L/R amplifies. The output was definitely attenuated but the soundstage took on an almost diffuse and directionless quality that I can't understand. Yes, you could tell the sound was "stereo" but I could no longer pinpoint where the instruments were in the soundstage, etc. I suspect it may have been some unwanted interaction between the Lumin's output transformer stage and the different loading that it was presented with. Weird indeed!

I've also used attenuators from other manufacturers but prefer the build quality and the unit-to-unit attenuation accuracy of the Rothwell units.

True enough indeed. And, on another topic, I still have yet to be able to hear the difference between a $0.25 Buss line fuse or the $150 a "pop", no pun intended, esoteric line fuse but I know that there are those of you who can.

What brand are you using , some will be amp and speaker load dependent ...!

Originally Posted by BlueSky

I use Rothwell attenuators, both balanced and unbalanced, and have nothing but good things to say about them. I use the -10dB units in the output paths to my 7.1 channels of amplification to lower the almost imperceptible level of AC hum being induced in my pre/pro in my system to below audible levels and I had to resort to this because I was never able to find and resolve the root cause of the hum in the first place. I have also used them for system balancing across the eight channels of amplification and varying speaker sensitivities in my system. I have not experienced any degradation in SQ with the XLR units connected in this manner.

As a side note, I once attempted to drop the output level of my Lumin X1 streamer via inserting attenuators at the output of the X1 while connecting it directly to the inputs of my mono front L/R amplifies. The output was definitely attenuated but the soundstage took on an almost diffuse and directionless quality that I can't understand. Yes, you could tell the sound was "stereo" but I could no longer pinpoint where the instruments were in the soundstage, etc. I suspect it may have been some unwanted interaction between the Lumin's output transformer stage and the different loading that it was presented with. Weird indeed!

I've also used attenuators from other manufacturers but prefer the build quality and the unit-to-unit attenuation accuracy of the Rothwell units.

Best to use a pre amp when running attenuators , well best for all system to have a preamp instead of running streamer directly ..


Regards

Originally Posted by a.wayne

Best to use a pre amp when running attenuators , well best for all system to have a preamp instead of running streamer directly ..


Regards

One of the things I like most about the Lumin X1 is the unit's volume control capability coupled with Leedh volume processing and the ability that it affords me to bypass the AV processor completely and connect directly to the amplifiers making the connection as direct as possible. As I mentioned earlier, my system has a very low level but still objectionable amount of AC hum or ground loop noise that, for the life of me, I have been unable to isolate and resolve. The hum or ground loop appears to be caused by one or more of the HDMI connections but still it baffles me. Bypassing the AV processor completely eliminates the noise and this is why I prefer the direct connection.

Originally Posted by a.wayne

What brand are you using , some will be amp and speaker load dependent ...!

The brand of fuses that I auditioned were Synergistic Research Orange fuses.

Originally Posted by W9TR

I too have tried SR fuses. On two occasions. First the Blue fuses a few years ago, and earlier this year the Orange fuses. Gear was McIntosh C 1000 and MC 2301’s. No difference. Nada. Zip. Zero. I’m glad they were sold with a money back guarantee. That’s the way I buy all my tweaks, including cables. I’m sometime surprised at what I find.

Trying before you buy, or a money back guarantee, makes the best sense!

Originally Posted by MPW

The Rothwell attenuators have finally arrived from England. They are in the system now. I will report back shortly on my impressions. One thing is for sure, they definitely lower the noise floor. Dead silence with my ear at the tweeter. I know this is virtually meaningless, but just making the observation.

My finding exactly. Inaudible noise and nothing negative about putting some high quality resistors in the circuit path. Oh, and by the way, I am OCD when it comes to hiss and hum and these devices do the trick for me at least!

Originally Posted by MPW

I did try the attenuators in the signal path of my Marantz CD player/DAC. There was a lot missing in this configuration. It was very easy to hear and was not positive in any way. I settled on having them immediately in front of the amp.

Good to hear! I am assuming you got the XLR balanced version of the attenuators because they are non directional and can be placed at either the output of the preamp or the input of the power amp. The RCA unbalanced version of his attenuators, however, are directional and should be placed where they were designed to be placed. He has a version of the unbalanced that can go on the output of a device or the input of a device.

Also, FWIW, there is a stocking dealer in the US in North Carolina called brit audio dot com for those of us who live here. He also has an eBay presence as well.