Ampeg svt issue

[jonday30]

Yes, that is V1. The numbers relate to matching each triode within the tube. They are considered matched with those numbers. Sounds like you got it all figured out. Good job.

BTW, don’t touch the tube with greasy fingers. Residue can cause a hot spot on the glass envelope.

Greasy fingers, those are clean!! I’m a journey mechanic for the last 20 or so years. It’s like baked into my skin. Thank for the help though, so that is v1 then. I barely pulled on it and fell out. The rest I had to tug in a circle motion and even then they were tight. Which is a good thing.

 

[beans-on-toast]

Greasy fingers, those are clean!! I’m a journey mechanic for the last 20 or so years. It’s like baked into my skin. Thank for the help though, so that is v1 then. I barely pulled on it and fell out. The rest I had to tug in a circle motion and even then they were tight. Which is a good thing.

Even a mechanic can wear thin gloves on occasion.

 

[JimmyM]

Ok well I’ll be saving this info right here, thank you!!

So I think I did find and fix the problem!! I removed the 4 screws on the top of the amp and slide the control portion out. Found the 2 12ax7 tubes. The one closest to the gain knob was barely seated!!!

I removed it and it looks brand new. All the preamp tubes do beside the power tubes. Anyway I put that tube back in and proper seated the tube. They have little stickers with numbers, not sure what that means. I’m pretty sure someone was in here before.

Anyway fired it up with my preferred settings and it just pounds. No speaker crackle or distorted farty noises. Just a huge difference. Even with the switches both in, EQ flat, master cranked and gain at 9 o’clock it pounds. I did turn the mids down about 9:30 and the frequency to 1 setting.

Got the amp hot and checked the bias. Control #2 was just slightly flickering the red LED. Turned it back so both green and good to go. So it was probably just a poorly seated tube. Maybe that’s V1? View attachment 4458549

LOL! That's usually one of the first things we suggest to check. We dropped the ball on you. OTOH I could have missed it when someone else said it, so I'll just take full blame for it.

 

[jonday30]

Well that’s the first thing I checked also. I checked one 12ax7. I didn’t know there was 2 more!

Just fired it up again. Still no issues. Even the master volume popping and crackling seems to be gone.

 

[JimmyM]

Well that’s the first thing I checked also. I checked one 12ax7. I didn’t know there was 2 more!

Just fired it up again. Still no issues. Even the master volume popping and crackling seems to be gone.

yeah, funny what putting in a tube where no tube was in previously can do

A very happy ending, though...not a lot of those SVT-AV's compared to black ones were made so it's cool you have one.

 

[jonday30]

Well the tube was there, just barely installed!!

So I really don’t know anything about this amp. I mean I know what it is and it seems most bass players on a large stage are using one. I always wanted one and had one. I wanted it back but not at full retail. I got a call saying a used one came in for dirt cheap. I bought it.

Anniversary model is it rare or special? I just thought maybe the faceplate was different because it was a anniversary model.

 

[JimmyM]

Well the tube was there, just barely installed!!

So I really don’t know anything about this amp. I mean I know what it is and it seems most bass players on a large stage are using one. I always wanted one and had one. I wanted it back but not at full retail. I got a call saying a used one came in for dirt cheap. I bought it.

Anniversary model is it rare or special? I just thought maybe the faceplate was different because it was a anniversary model.

I don't know if there was a special occasion for it or now many were made, but AV has a meaning that escapes me at the moment, but I'm pretty sure that the V stands for vintage, since it was made with blue/silver grill and a silver faceplate. But it was a little extra so the black SVT-CL always sold in higher number. They're the same amp other than cosmetics.

 

[Wasnex]

I don't know if there was a special occasion for it or now many were made, but AV has a meaning that escapes me at the moment, but I'm pretty sure that the V stands for vintage, since it was made with blue/silver grill and a silver faceplate. But it was a little extra so the black SVT-CL always sold in higher number. They're the same amp other than cosmetics.

I thought AV meant anniversary?

"V" means vintage when it's VR...vintage reissue.

 

[jonday30]

Yeah I thought it just meant it was a 50th anniversary model. Limited numbers maybe and only made in 98 or so? Like I said I didn’t really look into it.

 

[Wasnex]

Yeah I thought it just meant it was a 50th anniversary model. Limited numbers maybe and only made in 98 or so? Like I said I didn’t really look into it.

The SVT was introduced in 1969, so not 50th...AFAIK they intended to release the 50th AV in 2019. I found a thread that suggested 25th AV, which would have been 1994.

 

[JimmyM]

I thought AV meant anniversary?
View attachment 4458762

"V" means vintage when it's VR...vintage reissue.

Well they do still use it for cabs of that design, so I don't know. But Dino's got a video up on AmpegTV, their Youtube channel that goes through what the abbreviations stand for, and I believe it's covered in it. I'd link you but I don't have much time left before I pass out.

 

[rodl2005]

Ok well I’ll be saving this info right here, thank you!!

So I think I did find and fix the problem!! I removed the 4 screws on the top of the amp and slide the control portion out. Found the 2 12ax7 tubes. The one closest to the gain knob was barely seated!!!

I removed it and it looks brand new. All the preamp tubes do beside the power tubes. Anyway I put that tube back in and proper seated the tube. They have little stickers with numbers, not sure what that means. I’m pretty sure someone was in here before.

Anyway fired it up with my preferred settings and it just pounds. No speaker crackle or distorted farty noises. Just a huge difference. Even with the switches both in, EQ flat, master cranked and gain at 9 o’clock it pounds. I did turn the mids down about 9:30 and the frequency to 1 setting.

Got the amp hot and checked the bias. Control #2 was just slightly flickering the red LED. Turned it back so both green and good to go. So it was probably just a poorly seated tube. Maybe that’s V1? View attachment 4458549

That'll do it!

Glad you got it sorted

 

[jonday30]

Well they do still use it for cabs of that design, so I don't know. But Dino's got a video up on AmpegTV, their Youtube channel that goes through what the abbreviations stand for, and I believe it's covered in it. I'd link you but I don't have much time left before I pass out.

I couldn’t find any video on this particular model. All kinds of info on the heritage 50th anniversary but nothing on this one. The guy at the store just said it’s a USA made anniversary model. Limited numbers.

 

[Old Fart]

Excellent! A healthy SVT is a very fine-sounding amp with what feels like a thousand watts of power.

 

[jonday30]

Hey guys just a update for anyone interested or anyone that may google and come across this thread.

So I fired this beast up again tonight to verify my previous V1 tube issue. Well 15 minutes into my jam it was actually worse. It was almost a heavier gritty distortion noise at nowhere new tube break up volumes. Weird.

I pulled the top chassis out, bottom chassis out and start looking for broken solder joints. Well I found a few.

Top chassis I think was the actual problem. 2 white connectors pretty much slide right off the pins, not a real solid connection and may have just been barely on. I removed the circuit board and sure enough 2 of those 4 pins were cracked. On the 2 white wires I can actually pull one of the pins out of the board.

The bottom chassis I didn’t really find any broken solder joints. Did solder a few questionable joints though just to be safe. Anyway put it back together and fired it up. So far so good. I also noticed a my master volume knob isn’t crackling the speakers when I turn it up or down now.

 

[JimmyM]

Yeah I thought it just meant it was a 50th anniversary model. Limited numbers maybe and only made in 98 or so? Like I said I didn’t really look into it.

Well that was the 50th anniversary of Ampeg as a company. Hard to believe they started in 1948.