Conrad Johnson GAT Owner Problems?

[audiojem]

Just wondered If any fellow GAT owners have had problems with their units and had to send back to C-J for service?
I have a 4 week old unit that the volume has become lower or completely drops out on right channel on all inputs.
I replaced tubes but nothing changed, any Ideas what could be wrong?
Hooked up my Pass XP-20 and works like a champ!

Thanks In Advance

[Rayooo]

Is the level dropping also shown on the display? .. I'm presuming the audio level readout remains 20/20 or whatever it's set to.

I've not had any issues with mine other than the very rare failure of the "Standby" LED to illuminate when entering Standby. I replaced the "logic" board, and the issue continues. It's an extremely minor issue and doesn't affect normal operation at all.

If you're a "techy" type person there are a couple things you could have a look at by popping the top... if you have to think about it, it's not a good idea. :)

Sounds like you've tried all the normal checks..so the following may be useless:

be sure the GAT RCA-Out connectors are solid. I've seen cases where a given set of RCA interconnects work fine on product A, but are intermittent on Product B due to tolerance variations.

Pull the AC plug for a few minutes. (Re-Boot)
"exercise" all the relays by going through all inputs/mute/volume/balance etc.
I've never-ever had any issue with the relays CJ use..so it's highly unlikely this will accomplish anything.

Good Luck!

[Myles B. Astor]

I agree with Rayoo. Unplug the unit and reboot it. It has that quirk where for some reason every so often, one channel will go to 1 and can't be raised. Unplugging the unit, cures the issue. Must be some sort of static electricity or surge issue?

[audiojem]

I did unplug but it did not fix issue, I also had problem with being stuck on volume control number 1 and will not go up.
Thanks

[Rayooo]

There pretty much are: "no user serviceable parts inside"
But.....there is a connector supplying power to the logic board in front, and data from the logic board to the volume/input selection relays in back. if you decide to take the top off you could have a look to be sure that connector is firmly seated.

Typical logic problems of any kind, whether caused by static electricity or other, in my experience have always been cured by the re-boot.

[audiojem]

I will try again tonight after being unplugged for the day, will let you know the out come.
Thanks

[audiojem]

Ok so unit sat unplugged today, I just hooked up and both channels work can someone explain!
Maybe MR. Conrad or Johnson might chime in.
This is the 2nd time I have lost the right channel and right volume stuck on # 1 and would not move!
Should it be sent to CJ for a check up?
Thanks Gang

[Briz Vegaas]

I keep writing replies to this and then deleting them because they are too rude.

Of course you phone your dealer. Do it straight away. Don't start nattering to the Internet, most of us know nothing. We are just a bunch of mugs like you.

I would be on to the phone to the dealer and get him out of bed to fix it or have it replaced. You just spent a shed load on a very very very expensive preamp upon which the brands reputation rests. If they can't jump through hoops to keep you happy then what hope is there for the rest of us.

Sheesh!

[Myles B. Astor]

Don't you think that if there's quick fix and you don't have to be without the unit for a period of time is the better option? Or that there's something that one possibly forgot to do?

Of course the dealer should see then what can be done.

[Rayooo]

Don't you think that if there's quick fix and you don't have to be without the unit for a period of time is the better option? Or that there's something that one possibly forgot to do?

Of course the dealer should see then what can be done.

+1 ..I was dreading the thought of sending my GAT back to VA..and I'm in NJ. :yes:

[audiojem]

Spoke to CJ Service they think it had to do with the chip inside and rebooting it should have solved the problem.
They also said the GAT has been very, very reliable so I will keep my fingers crossed.
Yes the thought and expense in sending back troubled me!
Thanks

[Joe Appierto]

I think there are more than a couple of GAT owners on this forum. Just out of curiosity, has any one else experienced any problems?

[Rayooo]

I think there are more than a couple of GAT owners on this forum. Just out of curiosity, has any one else experienced any problems?

I do have an opinion on the matter...but risking being labeled as a Heretic, I'd best not comment further. suffice it to say that I absolutely love the SOUND of the GAT. :D

[Joe Appierto]

I do have an opinion on the matter...but risking being labeled as a Heretic, I'd best not comment further. suffice it to say that I absolutely love the SOUND of the GAT. :D

'Nuff said.

[tonytsui]

Hi,

My first post though I have been reading for some time.

I have had two GATs in my house for the last six months and both worked perfectly.

Tony

[Coppy]

My GAT is probably four years old and has been flawless save very rarely getting stuck on the 1 volume setting. Turning it off fixes that rare occurrence and unplugging it for a reboot always resets everything. Even the factory tubes have been reliable. Great product... knocking on wood.

Bob

[Sunnyboy1956]

The only issue and not particularly irksome, is that when i knock on the unit I can hear the sound through the speakers, this is with analog and the volume/gain is 65 on the display. Not discernible on cd playback coz the volume rarely crosses 35. OTW the GAT is performing flawlessly. Will contact the seller if he experienced something similar. Should I be concerned ?
Cheers

[jazzhead]

Sunnyboy more likely an issue of microphony , caused by the tubes in use ....

[Rayooo]

welcome Tony! :music:


Hi,

My first post though I have been reading for some time.

I have had two GATs in my house for the last six months and both worked perfectly.

Tony

[Sunnyboy1956]

Jazzhead
True but do all GAT owners experience the same microphonics?
Lloyd , our GAT owner friend from London says he gets zilch all sound when he taps on the top plate or even tube cage. Lloyd is into analog.
Curious...

[Rayooo]

I did have a couple sets of tubes over the ages that were EXTREMELY micro phonic. a very slight tap on the case, or even the rack that that GAT was on, came through the speakers. Changing volume, one could here the relays "tingling" in the speakers. Most tubes I've had are dead quiet. The GAT's tube socket boards are isolated (as on the ET5 also) so that helps a little. All tubes have some, 'just a matter of if it causes a real problem. i.e. speaker feedback.

Jazzhead
True but do all GAT owners experience the same microphonics?
Lloyd , our GAT owner friend from London says he gets zilch all sound when he taps on the top plate or even tube cage. Lloyd is into analog.
Curious...

[Coppy]

Jazzhead
True but do all GAT owners experience the same microphonics?
Lloyd , our GAT owner friend from London says he gets zilch all sound when he taps on the top plate or even tube cage. Lloyd is into analog.
Curious...

My guess is that this is your first tube preamp. The tubes are a bit microphonic... not an unusual issue at all. Tubes can become microphonic with age (and shipping). Even new tubes can be somewhat microphonic and most will be noisy if you gently tap the tube itself; which you should not do. Preventing vibration from entering the sound is what those nice red rubber rings are about. Sounds like it's time to replace the tubes, a normal maintenance issue. Suggest you get a new set from c-j or one of the suggested suppliers mentioned in the forum here. In the mean time, as the Dr. says... don't tap on the chassis.

You haven't mentioned it yet but doesn't your GAT sound wonderful?

Enjoy the music.

[Joe Appierto]

Tony, welcome. :)

Pradeep, the microphonics could be a function of the tubes being used and also whether the O-rings are in place, or not. :scratch2:

[turntable]

I think there are more than a couple of GAT owners on this forum. Just out of curiosity, has any one else experienced any problems?

I have had no mechanical issues.
I am less impressed with the number of hours I get on the 6922's before they become noisy and have to be replaced. A lot less than the prem16 and ART.

[Joe Appierto]

I have had no mechanical issues.
I am less impressed with the number of hours I get on the 6922's before they become noisy and have to be replaced. A lot less than the prem16 and ART.

It's difficult to tell, I guess, whether the earlier tube mortality is due to the GAT itself perhaps driving the tubes hard or whether the preamp is so resolving that tube aging is more apparent.

[Sunnyboy1956]

Coppy
...."My guess is that this is your first tube preamp. The tubes are a bit microphonic... not an unusual issue at all. Tubes can become microphonic with age (and shipping). Even new tubes can be somewhat microphonic and most will be noisy if you gently tap the tube itself; which you should not do. Preventing vibration from entering the sound is what those nice red rubber rings are about. Sounds like it's time to replace the tubes, a normal maintenance issue. Suggest you get a new set from c-j or one of the suggested suppliers mentioned in the forum here. In the mean time, as the Dr. says... don't tap on the chassis..."
Sensible comments but the newbie vibe is a wee bit misplaced. Have owned tube preamps for over a decade. Had a CJ CT 5 for 6 years before the GAT. If you scroll up this thread my comments and praise of the GAT are pretty clear to anyone who cares to read.
Actually, the problem was solved by removing the tubes and reinserting them. Using a pair of NOS Seimens CCa that are IMHO superior to the CJ supplied EH 6922s.

[rlw3]

I have read that the chryo treatment of tubes may in its process releave physical tensions within the tube. Would this reduce or eliminate microphonic problems? Has anyone compared a chryo and non chryo 6922, if so what did you hear??

[Rayooo]

I compared a pair of cyro tubes to a standard working pair. no discernible difference to me, and not necessarily any better sounding..to me.

I did not however try to measure the level of micro phonics with for instance an Oscilloscope, for all I know cryo tubes could be 2db better, but I don't need another science project... just ask the cryo folks, of course cryo tubes are better. :)

Severely micro-phonic tubes are micro-phonic with or without the rubber bumpers. I suspect the rubber dampers make some kind of difference, but, I've yet to be able to prove this myself. Quiet tubes are quiet with or without the bumpers. Audiophile lore says you need rubber bumpers, so I've got rubber bumpers, I mean tube dampers.

I spent months chasing NOS sound via several pairs of Mullards and Telefunkens. I can safely say after months and $1000 dollars or so, it was a waste. (for me) The tubes sound great for a day, week or maybe a month, but they either get noisy, crackly or are severely micro-phonic right out of the gate.

Yes, I do very lightly tap on new tubes just to see where the fall micro-phonically. Most are dead quiet and show now sign whatsoever of micro-phonics. Some have a tiny amount. Some you could talk-into and hear your voice in the speakers. I draw the line when I lay a remote down on the top of the rack and can hear it in the speakers.

I've since installed a pair of Gold Lions, they, as the stock CJ tubes, sound good and seem to last a long time.

JMHO YMMV

[pstrisik]

I've settled on Gold Lion 6922's in my 17LS. I find them more pleasing than the stock EH's.

[audiojem]

I don't know why CJ does not put better tubes in the GAT, they use the same tube in the base ET-3 a $2500.00 unit.
I know its all about money but a cheap EH tube in a $20,000.00 pre amp come on CJ!

[Coppy]

I don't know why CJ does not put better tubes in the GAT, they use the same tube in the base ET-3 a $2500.00 unit.
I know its all about money but a cheap EH tube in a $20,000.00 pre amp come on CJ!

Not sure that's a fair comment. To begin with, many people think the EH tubes are fine performers. c-j must have many tubes available for new equipment and for replacement stock and so must choose a brand that makes acceptable product that can be restocked. Certainly not any NOS. They then buy many hundreds of them before testing and rejecting a significant percentage, (a reason to buy your replacements from them). Their equipment at all levels is actually designed around this available tube stock. BTW, they would respectfully disagree with there being many benefits at all in tube rolling. On the other hand... love the sound of my Teles in Mr. GAT.

[Myles B. Astor]

I don't know why CJ does not put better tubes in the GAT, they use the same tube in the base ET-3 a $2500.00 unit.
I know its all about money but a cheap EH tube in a $20,000.00 pre amp come on CJ!

What tube, noting that it has to be available new and in quantities such that owners will have it easily available for many, many years down the road, do you suggest cj use? And I've had no trouble with the 6922s in my GAT since I owned it (now going on three or four years now?).

[Briz Vegaas]

I've had three GATs in my sock draw and my sisters kids found some under the house. Oh, hang on, those were gnats.

It's the beta issue of low volume gear me thinks. The customer becomes the beta testing person.

I had a couple of fuses go with my CA200 but then it settled down. My CT5 needed a grounding plate but now also seems fine and the LP70s has been good, touch wood.
All was done promptly and under warranty and with a loaner when required or requested. We get good backup here in Brisbane, Australia.

[Myles B. Astor]

I've had three GATs in my sock draw and my sisters kids found some under the house. Oh, hang on, those were gnats.

It's the beta issue of low volume gear me thinks. The customer becomes the beta testing person.

I had a couple of fuses go with my CA200 but then it settled down. My CT5 needed a grounding plate but now also seems fine and the LP70s has been good, touch wood.
All was done promptly and under warranty and with a loaner when required or requested. We get good backup here in Brisbane, Australia.

I've had three problems in owning cj gear for over 25 years. In fact that's a major reason I own cj. One-a resistor went in a 7 year old MV75A1. He'll even a seven year old Krell KSA100 was known to lose an output transistor on occasion. Show me any piece of electronics, be it a playstation, printer or amplifier, that doesn't have a failure rate be it 2% or 50%. You only hear of the latter like the failure rate of the new-and might I add very, very pricey, OLEDs. Two-II had an issue with a power transformer in a MV125. The transformer company screwed up the winding and it only became apparent after the part had been used and heated up for a while. Three-cj had a problem with the new Teflon caps they installed in the ART S III preamps. Again and despite Q/C these caps failed at around 500 hrs. Might I add cj replaced them right away. (And might I add that from experiences in another profession, Q/C misses a lot of problems). So I would consider with saving owned now over probably 15 cj pieces over the years pretty good reliability.

[Joe Appierto]

I've had three GATs in my sock draw and my sisters kids found some under the house. Oh, hang on, those were gnats.

It's the beta issue of low volume gear me thinks. The customer becomes the beta testing person.

I had a couple of fuses go with my CA200 but then it settled down. My CT5 needed a grounding plate but now also seems fine and the LP70s has been good, touch wood.
All was done promptly and under warranty and with a loaner when required or requested. We get good backup here in Brisbane, Australia.

I've found c-j gear to be reliable as well in the 20 years I've owned their products. Not counting a self-inflicted wound with the Premier 140, the only real issue I've had was the right channel going dead on my Pr. 16LS2. Once repaired, the issue never resurfaced.

Interesting that you mention fuses and the CA200. I've gone through more than a couple both stock and after market fuses on the mains connection. It would happen when I'd change power cords. When powering the unit back on, from the power conditioner, the fuse would often blow. I've since changed it to a HiFi-Tuning Gold XT fuse and, fingers crossed, it hasn't happened since. The XT is an extra slow blow type made specifically for units with a powerful transformer (such as an amp). It's exactly the value specified -- I learned that lesson with the 140. :yes:

[audiojem]

I was tired of listening to background tube noise on my 45 day old GAT so I popped in a pair of Genelex Russian 6922's WOW, WOW, dead quiet hope it lasts!
The thing that rubs me the wrong way with CJ and others is the fact that this is a $20,000.00 pre-amp and you use a $5.00 tube, why not pony up a few more bucks and give the customer a better tube?
Their statement piece and their lowest priced pre-amp ET-3 $2500.00 use the same tube!
I have a ET-3SE also and have had noise problems with it!
On Monday I going to send my 3 noisy tubes back to CJ.
Dead Quiet For Now.

[pstrisik]

Supposedly they choose the best sounding tubes for which they can have confidence in continuing supply. They supposedly are picky about quality control within a given lot of tubes. I don't know how true either of these are.

I like the Genelex 6922's also. I tried several brands and have settled on these for my 17LS (not withstanding the possible tube failure problem I'm having with it - still not sure it's a tube).

[Coppy]

Supposedly they choose the best sounding tubes for which they can have confidence in continuing supply. They supposedly are picky about quality control within a given lot of tubes. I don't know how true either of these are.

I like the Genelex 6922's also. I tried several brands and have settled on these for my 17LS (not withstanding the possible tube failure problem I'm having with it - still not sure it's a tube).

You are correct. I've been to the factory on a number of occasions and can verify your understanding is accurate. c-j must buy tubes that are available in large quantities now and to stockpile for the future replacement orders. Remember, they supply replacement tubes for many years for all their current and former products. The tubes they buy are all tested. Some tube mfgrs are not considered as the rejection ratio of the product is so high. When buying in quantity they usually can't send faulty tubes back for credit. Vacuum tubes are all hand made overseas from tiny, often marginally made parts, in factories that would scare you with their processes. Check it out on the internet. I understand that EAT tubes come from the same mfgrs. as some you can buy. They simply test, re-lable and repackage them for sale at high prices. You
could never make tubes in the US on a cost effective basis. It's a wonder any of them work well at all. Obviously, NOS tubes are not options.

[Myles B. Astor]

You are correct. I've been to the factory on a number of occasions and can verify your understanding is accurate. c-j must buy tubes that are available in large quantities now and to stockpile for the future replacement orders. Remember, they supply replacement tubes for many years for all their current and former products. The tubes they buy are all tested. Some tube mfgrs are not considered as the rejection ratio of the product is so high. When buying in quantity they usually can't send faulty tubes back for credit. Vacuum tubes are all hand made overseas from tiny, often marginally made parts, in factories that would scare you with their processes. Check it out on the internet. I understand that EAT tubes come from the same mfgrs. as some you can buy. They simply test, re-lable and repackage them for sale at high prices. You
could never make tubes in the US on a cost effective basis. It's a wonder any of them work well at all. Obviously, NOS tubes are not options.

Not to mention that cj doesn't just put their tubes in tube tester but burns them in and puts them a mini circuit so as to assess the equipment meets its stated distortion, etc.

I'm not sure about the currently used tubes but back a couple years, cj's tube reject rate was 30-40 pct. You know what happened to the rejects? They went back to the distributor who put them back on the shelf and sold them to other people. Biggest example was the old GE 6550s where after a while, all Richardson had on its shelves were quadruple rejects from companies. No worries because they continued to pass them off as good tubes.

[Puma Cat]

If you talk to C-J, their top requirements for selecting a tube is reliability and durability (which are different measures of quality).