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CDLehner
January 23, 2017, 10:27 PM
Guys...Randy, is purchasing my VT-50.

It's his first foray, into tubed power-amps.

I've suggested, he take full advantage of the wealth of glass knowledge...here at the Shark; as far as, setting it up...properly and safely :audiophile:

Thanks

CDLehner
January 24, 2017, 12:09 AM
:cryforjoy: :signhere: :congrats:

http://i229.photobucket.com/albums/ee136/CDLehner/P1010905_zpsidi4wvnr.jpg (http://s229.photobucket.com/user/CDLehner/media/P1010905_zpsidi4wvnr.jpg.html)

CPP
January 24, 2017, 10:34 AM
enjoy Randy :congrats:

joeinid
January 24, 2017, 10:43 AM
Congratulations Randy!

Mike
January 24, 2017, 12:41 PM
Nice Randy


Sent from my iPhone using Tapatalk

Randy Myers
January 25, 2017, 01:43 AM
Hey guys... and Chris :)... yes anxious to give this amp a listen... decided to keep the Ampzilla and add the ARC to switch back and forth. Not gonna mess with anything much to start. Chris has told me that this guy just came back from ARC with a fresh rebuild and retubing so I think it should be good to go for now.

My biggest issue now is deciding where to put it in my open sided glass rack. I was thinking that I could easily move it in and out with SST in the bottom slot. But I have been told that the 4" above the amp is probably not enough for proper cooling.

I could move the Mc tuner on top of the rack, leaving 13", plenty of space. But not sure I like the look of that big open space...

I could also put the ARC on top of rack. Then I would have to simply unhook the Richard Gray power cable, W4S XLRs, and Kimber Kables speaker cords from the lower amp and hook them onto the upper amp...

Joe likes the last option... so what do you guys think? Would an ARC sitting up on top of the rack be out of place or look like the crown of the system? :D

I think I am leaning towards putting the Mc up on top and keeping the amps on the bottom. The extra space will make it very easy to switch the amps out :)...

Jozua
January 25, 2017, 07:09 AM
Looking forward to reading your comments re the "valve experience"....
Enjoy !

CPP
January 25, 2017, 10:10 AM
Hey guys... and Chris :)... yes anxious to give this amp a listen... decided to keep the Ampzilla and add the ARC to switch back and forth. Not gonna mess with anything much to start. Chris has told me that this guy just came back from ARC with a fresh rebuild and retubing so I think it should be good to go for now.

My biggest issue now is deciding where to put it in my open sided glass rack. I was thinking that I could easily move it in and out with SST in the bottom slot. But I have been told that the 4" above the amp is probably not enough for proper cooling.

I could move the Mc tuner on top of the rack, leaving 13", plenty of space. But not sure I like the look of that big open space...

I could also put the ARC on top of rack. Then I would have to simply unhook the Richard Gray power cable, W4S XLRs, and Kimber Kables speaker cords from the lower amp and hook them onto the upper amp...

Joe likes the last option... so what do you guys think? Would an ARC sitting up on top of the rack be out of place or look like the crown of the system? :D

I think I am leaning towards putting the Mc up on top and keeping the amps on the bottom. The extra space will make it very easy to switch the amps out :)...

41 lbs there Randy. You know you can always upgrade your rack , or add an (amp) stand for your VT and let it reside right next to your existing rack. :scholar:

Randy Myers
January 25, 2017, 10:16 AM
Might eventually grab a amp stand to sit next to the rack. For now it is not so hard to switch in and out. The Ampzilla is also 40 pounds so I know what the weight is moving the amps around :)...

Ok, I just ordered an amp stand! Set it next to the rack... take care of all of the above :)....

RDSChicago
January 25, 2017, 11:56 AM
Sometimes I use two inch thick maple blocks which serve as amp stands very micely. Enjoy the tube sound, Randy. It's addicting. Still my favorite way to listen.

Randy Myers
January 25, 2017, 01:46 PM
Nice... Audio Adviser have some fairly in expensive amplifier stands. One comes with spike feet, lifts the amp about 7" off the floor and have coloring to match my rack. I re-positioned some of the other gear and measured it all out. Should be able to easily move the wiring between the two amps. I am planning on still using the Ampzilla as the primary, when people are over, listening to the tuner as back ground, etc.; and then hook up the ARC when I feel like sitting down for some serious listening. That is the plan anyway :)....

mep
January 25, 2017, 04:41 PM
Guys...Randy, is purchasing my VT-50.

It's his first foray, into tubed power-amps.

I've suggested, he take full advantage of the wealth of glass knowledge...here at the Shark; as far as, setting it up...properly and safely :audiophile:

Thanks

Did you tell him not to do what you did? :)

Randy Myers
January 25, 2017, 04:43 PM
Hehe... I have had more than one person tell me that :D...

CDLehner
January 25, 2017, 11:06 PM
Might eventually grab a amp stand to sit next to the rack. For now it is not so hard to switch in and out. The Ampzilla is also 40 pounds so I know what the weight is moving the amps around :)...

Ok, I just ordered an amp stand! Set it next to the rack... take care of all of the above :)....

Pics Randy!

So...let's just go over, some of the common-sense rules; I think you should follow for set-up.

Which tube goes where, is VERY important. The included chart is accurate; the tubes are clearly marked, but if there is any question...please check with me, before powering up.

Again...this is going to seem obvious; but better safe than sorry. Unpack, remove the lid; take the tubes out of their protective foam

http://i229.photobucket.com/albums/ee136/CDLehner/40138fa3-809f-4507-90be-909e09035d3f_zpsaginl9pf.jpg (http://s229.photobucket.com/user/CDLehner/media/40138fa3-809f-4507-90be-909e09035d3f_zpsaginl9pf.jpg.html)

Small, pre-stage tubes first; larger, power tubes last. DO NOT PLUG IN POWER!

Hook up your kit, speakers, and IMO...this is extremely important; a habit to get into...(if you're not already)

- Source and Pre-amp (in this case, your Benchmark, right?); on FIRST. Volume, all the way down.

- Then...plug in the VT-50, turn it on; and were it me...I would let it warm-up, at least 30 minutes. (if you can...do something constructive, in the room...while it warms up; so you can keep an eye for any malfunction).

- Volume up, and enjoy (this last part, is crucial ;))

As important as start up; is shut down. I do this...

- Volume down

- Amp off

- Pre-amp off

Of course...I'll defer, to any of the more-experienced glass-heads here; for contradictory or additional advice. That's why I started the thread :)

Randy Myers
January 25, 2017, 11:19 PM
Yea, I always turn pre-amp on first, volume down, source on and then the amplifier... turning off, amplifier first, then source and then pre-amplifier :)...

And Chris, thank you, I look forward to playing with this classic amplifier!

CDLehner
January 25, 2017, 11:28 PM
Did you tell him not to do what you did? :)

Yeah; if/when the time comes to bias...get ALLIGATOR CLIPS, for your Voltmeter leads!

http://i229.photobucket.com/albums/ee136/CDLehner/s-l1000_zpsbrilvbfi.jpg (http://s229.photobucket.com/user/CDLehner/media/s-l1000_zpsbrilvbfi.jpg.html)

Randy Myers
January 26, 2017, 12:19 AM
Yea, the instructions I found online all say to use clips :).... Hopefully I won't be playing with that for a while.

CDLehner
January 26, 2017, 09:24 PM
ETD-

Wednesday, 2/1?

Randy Myers
January 27, 2017, 12:07 AM
OMG... too funny :)... we going to track it across the country :exciting:....


:celebrate008_2::wave::oley::crackedout::fingers:

Jozua
January 27, 2017, 03:55 AM
I dying to know if the boytjie is happy with his purchase... ?

Randy Myers
January 27, 2017, 01:54 PM
boytjie ? What is a boytjie ? :)

jdandy
January 27, 2017, 02:10 PM
Randy.......South African slang for either a jock or jock oriented person. It is also used to mean bro or brother. It is pronounced boy-tee.

Thank you Google. :D

Randy Myers
January 27, 2017, 02:21 PM
Hehe.... ok... I thought it was a typo :).... thank you Mr. Dan!

Jozua
January 27, 2017, 05:43 PM
Randy esq

Google is not spot-on but the reference to a brother/friend/comrade is possibly the nearest to correct in my part of the woods. Definitely not a derogatory reference. Since I am a valve convert it could also be read as welcome to the (world-wide?) tube environment..

Now the big burning question on this side of the pond is, are you happy with the sound?

Pronounced as "boy-chi" in Cape Town.

Regards

J

Randy Myers
January 27, 2017, 06:10 PM
Well it has not arrived yet... is supposed to arrive next Wednesday. I have the setup ready for it. A amplifier stand will be arriving Tuesday so should be good to go when the ARC comes in :)... Thanks for asking!

Jozua
January 27, 2017, 06:41 PM
I am very keen to read about your impressions as I am playing with the idea of doing something similar

Randy Myers
January 27, 2017, 06:46 PM
Nice... I am anxious to listen to it. Fairly sure it will have plenty of power for me. Having the powerful SS to fall back on is a good thing also. I assumed from your avatar that you already had an ARC amplifier :)...

Jozua
January 28, 2017, 02:27 PM
Yip- Very impressed with my ARC equipment...

Randy Myers
February 1, 2017, 07:21 PM
We have lift off! Plenty of power, in fact the volume control is about in the same position as it is with the Ampzilla (the 220/350 WPC Ampzilla)...

It sounds very good so far, but obviously to soon to give an honest comparison...

A few marks, scratches, etc., but not terribly so. What would be expected from an amp of this age... definitely looks to be built like a tank....

Really nice connection, why doesn't everyone use this grade connections! 4, 8, and 16 ohm taps. I used the 4 ohm since the MC have 4 ohms listed on the back of the speakers!

joeinid
February 1, 2017, 07:25 PM
Awesome Randy! So happy for you.

Randy Myers
February 1, 2017, 08:39 PM
I can tell you one thing... it is already growing on me.... very tight is the best way I can describe it.... amazing definition... seems to have a very good sound stage and instrument placement....


Listening to Norah Jones... her voice never sounded so inviting (always sounded great but this is a whole new...... just wow)....

ELP... Lucky Man... From the Beginning... very very nice!

joeinid
February 1, 2017, 11:04 PM
When you get right down to it, tubes rule!

CDLehner
February 1, 2017, 11:29 PM
Randy...those who might have been pushing you toward this amp, and/or tubes in general; I think what they were doing...is trying to "f a t t e n up" your sound. :)

I'm not a fan, of the DAC-as-preamp approach. I've tried it, many times...and with many models; some, naturally, are better than other. But none of them, ever matched a really good pre-amp; for my taste.

IMO...the trade-off is this: DAC-as-preamp, and/or passive pre-amps, etc. Yes...the path is shorter, "cleaner", etc.; and that can result, in a very resolving sound. But it can end up being, what you might call...too clean; too "sterile", and a bit thin. Going that route, with your Benchmark...and then into an SS amp; that's kinda a "clean" on "clean" combo.

The VT-50, should be lending weight, body; meat...to the musical bones. The fact that you're finding that...and, don't feel a loss of resolution at all (in fact, maybe find it...to at least appear, even more resolving); is a home run...and why ARC was a great choice (I know you are new, to the wonderful, strange, and maddening world of glass...but ARC is considered to be pretty "linear" sounding, for tube kit. I know you're not one, for messing-around...at least just yet; but know that KT-88s...and I'd HIGHLY recommend Gold Lions here https://www.upscaleaudio.com/collections/power-tubes/products/gold-lion-kt88 ...would give a touch more warmth, body, and richness at a possible small sacrifice, of resolution. BTW...these are what you have now https://www.upscaleaudio.com/collections/power-tubes/products/svetlana-sed-winged-c-6550c , except the cream of the crop from ARC!).

About the "few marks, scratches, etc."; I hope you mean mostly confined, to the top? Those are from the previous owner...and yes; not egregious IMO, and to be expected as you said. But I really didn't notice much to anything, on the all-important face-plate?

Joe is right; TOOBS RULE! PICS!!

Randy Myers
February 2, 2017, 12:52 AM
Pics soon soon... just got home from grand daughters soccer game :).... and yes, the marks are pretty much contained to the top and to be expected, so no big deal at all :)....

Randy Myers
February 2, 2017, 03:27 AM
Here are some photos... members systems thread...

http://www.audioshark.org/showthread.php?t=9365&page=8&p=193219#post193219

Jozua
February 2, 2017, 07:00 AM
Randy

Very nice to know the amp sounds good in your system.

Welcome to the ARC family.

Enjoy !

J

Randy Myers
February 2, 2017, 09:52 AM
Thank you sir. A very impressive "little" amp. For 45 WPC it can really power my speakers with no issues! And the MC are 85 dB, 4 ohm speakers...

CDLehner
February 2, 2017, 09:23 PM
Randy...looks awesome! Enjoy that RLJ ;)

Randy Myers
February 2, 2017, 09:26 PM
Thanks Chris.... ahhh what is RLJ?

CDLehner
February 2, 2017, 10:23 PM
Rickie Lee Jones. Isn't that Pirates, I see in your easel? ;)

Randy Myers
February 2, 2017, 10:41 PM
Ahhh got ya... yes Pirates, Original Mater Recording SACD. Really good disk!

CDLehner
February 5, 2017, 11:47 PM
So...how's the amp settling in Randy?

Randy Myers
February 6, 2017, 12:26 AM
So far pretty nice. I like the sound and the feel quite a bit. I would love to get a clear top like what I see shown on the Ref 6 :)....

How do I know when tubes are in need of replacement? Just planning for down the road.... Does the amplifier require being sent to ARC for tube replacement? I see people talking about putting 88's, or something like that in it. Are they the larger output tubes? And, since ARC literally labeled them to which socket each tube goes in, if you replace tubes with something else is this not also important?

Just some thoughts. So far I have been pretty much playing it almost exclusively, but I think at some point I might want to switch in the Ampzilla for a change of pace.

Jack
February 6, 2017, 02:01 AM
Randy

Even if you play it a couple of hours a day you have several years before you have to worry about replacing the tubes. Just enjoy.

Randy Myers
February 6, 2017, 02:10 AM
Thanks Jack... I was thinking it would be quite some time, but I also love to understand my equipment. I do have to say though, this ARC is very impressive! Really enjoying it so far... I am also going to be adding a STP-SE back into the system!

CDLehner
February 6, 2017, 11:32 AM
Thanks Jack... I was thinking it would be quite some time, but I also love to understand my equipment. I do have to say though, this ARC is very impressive! Really enjoying it so far... I am also going to be adding a STP-SE back into the system!

Randy, Jack is right. I'm not an hour-counter...but I think if you assume these tubes, to have ~100 hours on them; you won't be far off, in one direction or another.

But...to answer your questions (and again...any of the hard-core experts, feel free to correct me): when a tube starts to go bad, the unit will start to sound "wrong"; maybe some distortion, maybe what they call "tube rush"...which is like an "windy" sound, along with the audio signal. Of course, if you have a complete failure; the unit probably won't play at all.

When/if, the time comes...to replace either a single bad tube or the quad; you don't need to worry about the numbering. Obviously...with a single, bad tube; that's where the replacement will go...and you'll likely need to re-bias. With a whole quad...doesn't matter, where the new tubes go; but...that will DEFINITELY require a re-bias, and that's when you'll want to take note...which tube is where.

That's what the numbering is about; it's in that position, that the unit has been biased. So if you ever have to remove the tubes...like I did, to ship it to you; it's important they go back in the same place :)

The unit does not have to be sent to ARC, just to roll or replace the tubes; but depending on what, and how often you're having it done...it might not be a bad idea. For example...let's say 6 months from now, you decide you want to try a quad of KT-88s (yes, the larger power tubes; your current ones, being 6550-Cs. Which, BTW; if you're not replacing because they're shot...you'll absolutely, want to keep around. You can switch in and out, to tinker with sound...which is what we are referring to, when we say rolling; although, unlike pre-amps...which don't require it...it's not as easy, because of the need to re-bias); no...I would not send that away, to ARC to have done. One...they most likely, won't even do it...lol. ARC doesn't believe in "rolling"; they believe they've picked the perfect tube, designed the circuit around that tube...and that you, the owner, are only serving your silly, audiophile, futzing nature...by messing with it. Not saying they're wrong...lol; but...it is your prerogative, which is why you'll need to do it.

Two...even if they would do it; it would be crazy expensive, if you were doing so...on any kind of "regular" basis (as I said...like 6 months from now). OTOH...if say, 3 years from now; you feel the tubes have a certain amount of hours on them...are going "bad"...and you would like to completely re-tube. While you still don't have to...that might be worthwhile, sending to Plymouth. I have heard, the input tubes (the smaller ones. 6922s in this case http://www.arcdb.ws/VT50/VT50.html...are a b*tch to re-bias. That you have to bias them first...then bias the power tubes; then go back, and re-check the input tubes again!).

But to reiterate: Jack is right; just enjoy for now. You actually do, have the "best" tube; and ones, you really can't even get anymore. Now...adding an STP-SE; that's a GREAT idea! It was an excellent pairing!!

http://i229.photobucket.com/albums/ee136/CDLehner/P1010535%20-%20Copy_zpsh6jgotrp.jpg (http://s229.photobucket.com/user/CDLehner/media/P1010535%20-%20Copy_zpsh6jgotrp.jpg.html)

Randy Myers
February 6, 2017, 12:00 PM
Hey Chris, as well as Jack, I very much appreciate your wonderful input! Like each phase in re-learning this crazy hobby, I want to understand not only what I am doing, but as important to me, I simply want to understand how this all works.

Back a long long time ago I had some tube McIntosh equipment and I do not recall ever hearing about biasing. Not to say it was not done, I am sure it was, but I just don't ever remember hearing about it.

At this point in time I have no interest in rolling tubes. I currently believe that ARC knows a whole lot more than I on what works best in their amplifier. I was just curious on how it is determined that tubes are getting close to needing replacement. I also believe that even with gear that counts hours on tubes there has to be a variance, meaning that just because they say tubes last about 2000 hours does not mean that all tubes are worn out at that point. I am sure that most probably last much longer than that.

If they last for years then I would probably be inclined to have ARC do the job for me... Assuming of course I stay with this amplifier for that long... but at this point I would certainly say that is a distinct possibility!

mep
February 6, 2017, 05:29 PM
The ARC VT-50 is one of the easiest amps to check and set bias in the VT product line. If memory serves me correctly based on a friend of mine who used to own one, the bias test points are at the top of each board with clearly marked test points. If you are handy with a DVM, it shouldn't be a big deal to check your bias settings periodically and make adjustments as necessary. If you are like the last owner of your amp, you may blow it up and have to send it back to ARC for repairs. :( Buying new output tubes or switching from 6550s to KT-88s will require knowing how to set the bias properly. If you can't do it or know someone who can do it for you, it's best to send it back to ARC.

Randy Myers
February 6, 2017, 06:25 PM
It seems easy enough. Using alligator clips on each side of the bias resistor. I will have to get a meter... pretty cheap... but setting the meter correct is something I have to learn.

mep
February 6, 2017, 06:34 PM
It seems easy enough. Using alligator clips on each side of the bias resistor. I will have to get a meter... pretty cheap... but setting the meter correct is something I have to learn.

You should be reading the bias on the milliamp scale (ma).

audio.bill
February 6, 2017, 08:02 PM
You should be reading the bias on the milliamp scale (ma).
I'm afraid that trying to directly read current with a mulimeter by tapping across a resistor as Randy mentioned will not work. To directly read current with a multimeter requires the circuit path to be open and flow through the meter. If the test points are across a resistor as Randy stated then voltage is actually being measured, and using Ohm's law (http://www.electronics-tutorials.ws/dccircuits/dcp_2.html) it's simple to determine the bias current if necessary. The resulting current (I, in amps) will equal the measured voltage (V, in volts) divided by resistance (R, in ohms). Setting the meter correctly isn't something to worry about since digital multimeters will clearly alert you if you're out of the set range which you can then easily reset accordingly. Hope this helps!

mep
February 6, 2017, 08:41 PM
Straight out of the horse's mouth:

www.audioresearch.com/ContentsFiles/VT50_BiasAdjust.pdf (http://http://www.audioresearch.com/ContentsFiles/VT50_BiasAdjust.pdf)

joeinid
February 6, 2017, 08:51 PM
18400

joeinid
February 6, 2017, 08:51 PM
Not sure why it's not opening Mark, but I posted above.


Straight out of the horse's mouth:

www.audioresearch.com/ContentsFiles/VT50_BiasAdjust.pdf (http://http://www.audioresearch.com/ContentsFiles/VT50_BiasAdjust.pdf)

audio.bill
February 6, 2017, 09:07 PM
Straight out of the horse's mouth:

www.audioresearch.com/ContentsFiles/VT50_BiasAdjust.pdf (http://http://www.audioresearch.com/ContentsFiles/VT50_BiasAdjust.pdf)
And ARC's instructions confirm exactly what I posted, that you're actually making voltage measurements and not current. Your initial direction to Randy was: "You should be reading the bias on the milliamp scale (ma)" which was the reason for my post, the meter should correctly be set to read voltage.

Randy Myers
February 6, 2017, 09:26 PM
Those instructions are for doing a full tube biasing when replacing all tubes. ARC suggest having them do this :).... in their manual they suggest doing the output tubes once in a while... here are some good instructions for this....

"I would strongly suggest that you contact ARC for an info sheet on
biasing and a lecture about being careful. Do you have your
instruction manual? Everything should be explained there. I have a
VT50, and I'm assuming the procedure is the same, only doubled for
the VT100 since there are 8 tubes vs 4. The test leads should be
placed one on each leg of the black resistors at the top of the
circuit boards on either side of the amp. Since there is one
resistor per side on the VT50 (one per pair of tubes), I'm assuming
there are two per side on the VT100. The key to this whole procedure
is that you spend $5 at Radio Shack to get multimeter test leads that
clip on to the resistor legs, rather than the pin type that you just
hold on the legs. ARC told me they have already received two or
three VT50s back for repair after people fried their circuit boards
(and potentially themselves) by slipping with the test leads and
touching either the chassis or some other part of the amp. BE
CAREFUL. Once the leads are clipped on to the resistor and you let
the amp settle for 20-30min under zero-signal conditions, read the
bias and make appropriate adjustments using the trimpot also located
up at the top of the circuit board on either side. Use a
plastic-handle adjusting device. ARC says that once a new tube set
is settled in, you should only have to check bias every 6 mos or so,
depending on usage.

1:yes the meter leads should be clamped on either side of the resistor
2:set your meter for dc mV 200mV range
3:turn the amp on and watch the bias if it goes higher than 65mv bring it back with the blue pot adjustment, both sides should be watched, it's good to have two meters.
4:Then after about 1/2hr of warm up check again and re-ajust and again after about 1hr. Then check again a few hours later."

audio.bill
February 6, 2017, 09:35 PM
Those instructions are for doing a full tube biasing when replacing all tubes. ARC suggest having them do this :).... in their manual they suggest doing the output tubes once in a while... here are some good instructions for this....

"I would strongly suggest that you contact ARC for an info sheet on
biasing and a lecture about being careful. Do you have your
instruction manual? Everything should be explained there. I have a
VT50, and I'm assuming the procedure is the same, only doubled for
the VT100 since there are 8 tubes vs 4. The test leads should be
placed one on each leg of the black resistors at the top of the
circuit boards on either side of the amp. Since there is one
resistor per side on the VT50 (one per pair of tubes), I'm assuming
there are two per side on the VT100. The key to this whole procedure
is that you spend $5 at Radio Shack to get multimeter test leads that
clip on to the resistor legs, rather than the pin type that you just
hold on the legs. ARC told me they have already received two or
three VT50s back for repair after people fried their circuit boards
(and potentially themselves) by slipping with the test leads and
touching either the chassis or some other part of the amp. BE
CAREFUL. Once the leads are clipped on to the resistor and you let
the amp settle for 20-30min under zero-signal conditions, read the
bias and make appropriate adjustments using the trimpot also located
up at the top of the circuit board on either side. Use a
plastic-handle adjusting device. ARC says that once a new tube set
is settled in, you should only have to check bias every 6 mos or so,
depending on usage.

1:yes the meter leads should be clamped on either side of the resistor
2:set your meter for dc mV 200mV range
3:turn the amp on and watch the bias if it goes higher than 65mv bring it back with the blue pot adjustment, both sides should be watched, it's good to have two meters.
4:Then after about 1/2hr of warm up check again and re-ajust and again after about 1hr. Then check again a few hours later."
Again this confirms exactly what I originally posted, that you are measuring voltage across the resistor and not current.

Randy Myers
February 6, 2017, 09:44 PM
Good good... I am very comfortable inside electronics, building Hager amps and many computers, etc. However I have never used a volt meter... therefore my wanting to understand exactly what I am doing... again thanks for all the input!

CDLehner
February 7, 2017, 12:30 AM
The key to this whole procedure is that you spend $5 at Radio Shack to get multimeter test leads that
clip on to the resistor legs, rather than the pin type that you just hold on the legs. ARC told me they have already received two or
three VT50s back for repair after people fried their circuit boards (and potentially themselves) by slipping with the test leads and touching either the chassis or some other part of the amp.

ALL good stuff; but I would just reiterate this part.

I know; everyone pokes fun, and likes to kid that I'm an idiot...for blowing up my unit. I can look back on it now, and while not exactly laugh; consider it a lesson learned.

However...I am not an idiot; and my point being, is that I could have sworn the leads never strayed. Yet...Sizzle, POP!!

So...laugh all you want; but it can happen, pretty easily. Get the f*cking clips! LOL

Randy Myers
February 7, 2017, 12:43 AM
Absolutely... warned from several sources on this one!

Randy Myers
February 7, 2017, 03:32 PM
I thought everyone might fine this interesting. I wrote ARC to ask them about tube replacements, etc. Here is their reply (oh by the way, they do have replacement case tops if I wanted to buy a new one because of the scratched, etc.).

"Summary: ARC recommends the entire tube set be replaced at 2000 hours. Since this is an older model that lacks an hour meter, we recommend either keeping a log of hours you run the amp, or just plan on replacing the tube set at 3 years of use, which appears to be about 2000 hours for most customers. An owner can replace and bias the output tubes. It is recommended a technician replace the input and driver tubes as shop test equipment is needed to set up the amp during this service."

Randy Myers
March 3, 2017, 03:28 PM
I successfully adjusted the bias today. I was very nervous doing it for the first time, ever...

The volt meter I got is a piece of cake to use. I also got an extra set of leads with clips on them (because of how you have to bias these classic little ARC amps).

ARC's manual states to let the amp settle for 15 minutes before checking. I gave it about 25 minutes. Both channels were reading at about 66.7. The adjustment pod is very sensitive. I set each as close to 65 that I could get without going over. I think one was 64.8 and the other channel was 64.9.

All hooked back in the system and playing fine!

joeinid
March 3, 2017, 03:58 PM
Awesome Randy! So proud of you.

Randy Myers
March 3, 2017, 04:44 PM
Thank you sir!

joeinid
March 3, 2017, 06:06 PM
Randy,

When you are ready for Triode M845 amps, let me know. 50 glorious watts and auto bias!

CDLehner
March 3, 2017, 06:50 PM
I was going to ask, how the VT-50 has been treating you?

Good enough, that you finally let go...of SOA II?

Randy Myers
March 3, 2017, 07:10 PM
Well no.... I still have the SOA II. I might consider letting it go... but dam it is a great amp...

Jack
March 3, 2017, 09:29 PM
Randy

Congrats on getting over the hurdle. Now all you need to do is check them about twice a year and you should be good to go for a long time with the VT-50. It will take considerably more money to do any better than it and it is all the power you need. If you change to a larger or much less efficient speaker then you can look around. The short time it takes to bias even new tubes keeps you involved and is more precise than auto-biasing.

Randy Myers
March 3, 2017, 09:58 PM
Thanks Jack... the little ARC is really nice... the Ampzilla does some things better also, such as a little deeper base and a tad more dynamic. The Ampzilla is better for rock and certainly better for high volume, but for my current taste the ARC fulfills most of my needs!