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Ampeg SVT 7 Pro Club

#1,301
OK..got some time before I had to leave for gig..

Amp is REV C00.
Main PCB looks to be REV "G_00"!
Pre-amp PCB is REV "B_01"!
See pics below..

FWIW - EVERYTHING in this unit looks pristine. Other than possibly a dead preamp tube (I currently out of spares), there are no signs of burns, damage of any kind, and NO loose connectors. As I said looks perfect inside.

Hope this is useful.

20150206_173405_w.jpg


20150206_173811_w.jpg


20150206_173936_w.jpg
20150206_173821_w.jpg
 
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#1,303
s0c9 said:
OK..got some time before I had to leave for gig..

Amp is REV C00.
Main PCB looks to be REV "G_00"!
Pre-amp PCB is REV "B_01"!
See pics below..

FWIW - EVERYTHING in this unit looks pristine. Other than possibly a dead preamp tube (I currently out of spares), there are no signs of burns, damage of any kind, and NO loose connectors. As I said looks perfect inside.

Hope this is useful.

View attachment 554654

View attachment 554653

View attachment 554651 View attachment 554652
Click to expand...
Thanks for looking. The Rev G is the latest power board, and from what I understand, the power boards are what cause most of the failures. When mine went bad, the board also looked pristine. Again, thanks and I hope your replacement amp works great.
 
#1,304
MrBassman17 said:
If this helps anyone, I have been using my SVT-7 Pro for about a year now, no issues at all, both practice and gig's. No one posts any positive things about this fantastic head, just thought I'd put my two cents worth in...
Click to expand...

They're great amps. Mine worked flawlessly for 1½ years before it died. Fortunately I was at home practicing when it happened, and was able to use a backup amp for the gig. The thing is, you don't know when or where it will finally give up. Mine was in the shop for 9 weeks waiting for parts.

Again, beautiful tone and power, but very unpredictable.
 
#1,305
s0c9 said:
OK..got some time before I had to leave for gig..

Amp is REV C00.
Main PCB looks to be REV "G_00"!
Pre-amp PCB is REV "B_01"!
See pics below..

FWIW - EVERYTHING in this unit looks pristine. Other than possibly a dead preamp tube (I currently out of spares), there are no signs of burns, damage of any kind, and NO loose connectors. As I said looks perfect inside.
Click to expand...

Sigh - this amp seems kind of like a super hot crazy chick - awesome while it lasts, but probably untrustworthy and not the marrying kind unless you like grief and torment - well I signed up any way
 
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#1,307
Decided that I'm going to take my chances and order another when I return this one tomorrow... meanwhile, I found some AX7's (no clue if they are good or not) in a closet and will replace the one in the 7 to see if that's the issue... I got nothing to lose at this point.
 
#1,308
SickAura said:
Sigh - this amp seems kind of like a super hot crazy chick - awesome while it lasts, but probably untrustworthy and not the marrying kind unless you like grief and torment - well I signed up any way
Click to expand...
Maybe not.. the thot plickens.... I just replaced the [stock] JJ ECC83S pre-amp tube with a GT AX7R (ECC83/7025) that I found and the amp powers up and plays fine!!

CONCLUSION: bad pre-amp tube that crapped out after single use!!

Now.. do I return the 7 and order another unit, or do I suck it up and replace the pre-amp tube. If the latter, do I use the GT-AX7R or buy another JJ ECC83S or some other AX7??
I'm thinking that the JJ gain characteristics are part of what gives the 7 it's overall character.

Thoughts and advice appreciated guys..!
 
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#1,309
Interesting - so your gut feeling last night was right. If it was me I would check how long it would take to get the replacement unit first. If its 2 weeks or less - its worth the wait. If its back ordered (like mine) and won't come for 8+ weeks - I would suck it up and replace the tube. I would also stick with the JJ for now.
 
#1,310
SickAura said:
Interesting - so your gut feeling last night was right. If it was me I would check how long it would take to get the replacement unit first. If its 2 weeks or less - its worth the wait. If its back ordered (like mine) and won't come for 8+ weeks - I would suck it up and replace the tube. I would also stick with the JJ for now.
Click to expand...
Thanks on the JJ... but it's the dead one so I'd have to order a replacement... but I get where you are going.. I used to have lots of AX7's lying around in the days before I moved away from tube amps (another long topic). Always tinkering with AX7 combos, from Mullard to NOS, Sovtek, Chinese variants and so on, tweaking to get that "tone". I'm not a noob in that area [but no expert either], which is why I posed whether the JJ provided the pre-amp character of the 7 and whether a different AX7 model might impact that. Even 2 AX7's in same batch from same vendor are not identical, so the question becomes HOW MUCH change would replacing the JJ with a Mullard or NOS cause?

FWIW - I order this unit last Sunday (Feb 1) it arrived Wed (Feb 4th). 3 days!! Dead tube on Thurs :(
So-o-o if I return it (via local GC) tomorrow - my guy works Sun - and can get another delivered by Wed... then I'm thinking I'll go that route.

BTW - Thanks for the input!
 
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#1,312
B-string said:
New production tubes have a high early failure rate from any existing factory.
JIMHO if all that was wrong is the new production tube died early, I would keep that unit. Next one could have a much more serious problem? "The devil you know" thing?
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Point taken.. and the characteristics [with another AX7] versus the JJ should not be overly dramatic. I may not even notice the diff.. it's not like I gigged it for 2 yrs already and am intimately familiar with the tone.. LOL.

Thanks for the feedback.
 
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#1,315
svtb15 said:
question.. is the SVT7 a real 1000 watts?
Click to expand...
A guy called tekdiver (he seems to have changed his user name now) did some test and got close but not quite and not 1000 watts and not at 5% THD like stated in Ampegs specs

From that thread

f.c.geil said:
In an effort to give the amp the benefit of the doubt, I took my gear to my friend's house. As a bonus, his power tested at 118v, so somewhat better than mine. I assumed an active bass, and went with 2v as maximum allowable input. I maintained a steady input signal of .5v at 1 kHz while twiddling knobs until maximized output. I then ran the test into an 8ohm dummy load, I calculated (v*v/ohm) (70v*70v/8ohm) 612.5 watts. Into a 4ohm dummy load, I got (62v*62v/4ohm) 961 watts.

In my (limited) experience, I'd have to call the amp legit. The tone is amazing, and there's something to be said about being able to rackmount. I may have to think about picking one up for myself. Nah, I still like my Streamliner better.
Click to expand...

JGR said:
Do you know what the THD was?
Click to expand...

f.c.geil said:
Yes, sorry, I got these numbers at just under 6% THD.
Click to expand...
 
#1,317
s0c9 said:
Point taken.. and the characteristics [with another AX7] versus the JJ should not be overly dramatic. I may not even notice the diff.. it's not like I gigged it for 2 yrs already and am intimately familiar with the tone.. LOL.

Thanks for the feedback.
Click to expand...
So... decided to keep the amp as I played it for a couple of hours last night and all was fine..
Ended up leaving a Chinese (Shuguang) AX7-A in there.. sounded a bit better than the GT or EH/Sovtek tubes I found in the closet.
It was not a chinese re-brand (like the GT.. ) but a genuine factory AX7A :)
Shuguang-12AX7A-Audio-Vacuum-Tube.jpg

As was mentioned.... better the devil you know.
Guess I'll put the rack ears back on it now, and order up a rack case for it..

thanks for all the input guys!

PS: FWIW - this is the JJ tube that died - that was factory installed.
JJ-ECC803S-12AX7-Audio-Vacuum-Tube.jpg
 
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#1,320
DaveLS said:
I wonder if any of the many other people who had issues with this amp and returned it just had a dead preamp tube.
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idk, but I just received a replacement JJ ECC83S and a Preferred Series 7025 to try out. The 7025 had the highest ratings of the reviewed AX7's for "Microphonics, Noise(Hiss, Pop, Hum) and Musical Detail and Dynamics" at the tubestore.com.

"The Preferred Series 7025 is a high quality 12AX7 tube type. This tube is a reproduction of the highly regarded and sought after Mullards from the 1960s."

Preferred-Series-7025-12AX7-Tube.jpg


The Chinese AX7A has worked out fine since I installed it a couple of days ago, but I'll try out the Preferred Series tonight and compare it against the replacement JJ as well. I'll go with whichever sounds the best...will let you know how the outcome.
 
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