Ampeg SVT-3 Pro Tube Gain Question

[Groover]

I have a 2001 SVT3. All original valves when I got it. Chap I got it from complained of low volume and I suspected the valves. Opened it up and found a Grove tube in pot VI which is usually the first valve after the input. The AU7 was Chinese and the rest were Russian and all looked pretty cooked. I tried a a couple different valves/tubes and all were an improvement of the original commie crud. Finally I put in a NOS GE AU7 for the phase splitter that feeds the slave. AU's apparently have a lower gain and are a bit cleaner. The Rest are now NOS RCA and the power just poured on. So much bottom I had to turn down the bass on my JB and that has never happened. And, a big increase in overall volume. But the richness is amazing, it is just not the same amp.
At the very least get a NOS AU in the splitter and NOS RCS for V1 which is where the Groove tube is.

So you replaced the existing 12AU7 with a GE 12AU7, or are you using a 12AU7 in place of a 12AX7 somewhere?

 

[dubcut]

I have a peavey classic 50/50 with the same loud fan. Yes, the pc fans are as good, and less noisey. Some reason, I dont know why exactly, but the larger fans are quieter, so If you have a little xtra room....

You may have to do like I did on my peavey, and take a terminal connector to ground it out, no biggie there.....good luck.

Hey everyone, thanks for the replies! ? It's a DC fan, so I'm wondering if an ultra-quiet PC fan with similar specs can be substituted. There are fans out there that can move just as much air but are much more quiet. It is definitely an issue in a small home studio.

 

[warnergt]

You folks with noisy fans in your SVT-3 PRO should check out this link:
Replacement SVT-3 PRO fan with ball bearings

 

[FresnoKiwi]

FYI the Groove Tube is likely also "commie crud" - as are some of the finest tubes available.

Maybe so, I've read they have improved, but all the amps I have had that had Chinese and to a lesser extent, new Russian tubes (can't vouch for the old ones have never seen them) were lifeless, and, FYI, I was including the Groove Tube in with that.
When replaced with NOS US and Brit tubes, big improvements, even some Dutch ones were nice. Not so impressed with GE's, Rathyon and HP's in V1, but this is all pretty subjective.
I have two 1990's Blues Jrs., both arrived with new JJ's and Groove Tubes and I didn't like them. Our harp player used both as well and didn't like them either. Especially the recent Groove tube loaded one. It fed back, was very shrill and just not very user friendly. Replaced V1 with NOS Mullard and the other two with NOS RCAs and it's a new amp, the older JR has the same setup with the same result. Same experience with the Ampeg and a Bassman 70.
Tubes don't last for ever, including NOS, but if you can get them they are worth the effort I feel. I sent a couple sets out to my brother in NZ for a newer Epi amp, same reaction.
The commie units maybe some of the finest available but IMHO that doesn't say to much for what is available. Additionally, availability may act as a greater determinative factor depending on where you are.

 

[FresnoKiwi]

I wasn't to clear. I meant to say "NOS RCA for V1, which is where the Groove tube WAS" I made it sound like the GT was still in place and it is not. Also, the GE AU replaced the existing AU. I did try putting an AU in different places, including V1, but the results weren't stellar; but worth the time playing around with just see how things work.