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Tubes for my SVT?!

#21
What tubes come with the SVTs from the factory? I just recently picked up a used Vietnam one and was curious as to if the tubes have been changed since it was purchased new.

The power tubes are all Sovtek 6550we's
Preamp is a Sovtek 12ax7wa and two EH 12au7a's.

I'm assuming the EH's are not factory. Are the Sovteks?
 
#22
Lazarus.Bird said:
What tubes come with the SVTs from the factory? I just recently picked up a used Vietnam one and was curious as to if the tubes have been changed since it was purchased new.

The power tubes are all Sovtek 6550we's
Preamp is a Sovtek 12ax7wa and two EH 12au7a's.

I'm assuming the EH's are not factory. Are the Sovteks?
Click to expand...


You should have more preamp tubes than that, are you only counting the phase splitter and driver tubes? Anyways, back in the day (ok like four or five years ago) when I bought my SVT-CL it came with Svetlanas, and as far as I knew that's still what came with it, but those are the sovtek made svetlanas anyhow, maybe they just switched to a different series of tube in the amp and those are stock. I don't think they were buying EH tubes, everything I've seen stock in SLM-current ampeg products was either sovtek or chinese manufacture (apeg "hot rods" for example).
 
#24
Lazarus.Bird said:
Oh, right. I think I was just looking at the driver tubes and didn't see the preamp tubes. I was on the phone while checking them. Also new to the tube game. The preamps must have been hiding from me.
Click to expand...

They're hidden up behind the faceplate so kind of a PITA to get to. You have to unscrew the top and pull it out. Those are probably still stock unless you had a really intrepid former owner who liked to tube roll.
 
#27
JimmyM said:
i'm almost positive those sovtek and ehx tubes are stock, since sovtek/new sensor is owned by ehx.
Click to expand...

Yup, you're right. I was under the impression that ehx tubes were made under license but it's really two companies owned by the same guy.

That said, I think all the tubes that were stock in my 2005/6ish SVT-CL were sovtek/svetlana, but that doesn't mean they didn't switch to EHX.
 
#28
Lazarus.Bird said:
What tubes come with the SVTs from the factory? I just recently picked up a used Vietnam one and was curious as to if the tubes have been changed since it was purchased new.

The power tubes are all Sovtek 6550we's
Preamp is a Sovtek 12ax7wa and two EH 12au7a's.

I'm assuming the EH's are not factory. Are the Sovteks?
Click to expand...

Yeah, currently stock non-Heritage Ampeg uses Sovtek.
 
#30
johnk_10 said:
my '07 nam VR came with sovtek 6550's and EH preamp and driver tubes. i'm running NOS tubes in the preamp, but i'm still using the stock output tubes in it and it sounds great.
Click to expand...

You're more pertinent to the OP, John. My '08 early Korea unit had all Sovtek. I went NOS V1 and drivers, and Tung Sol output, not because I didn't like the Sovtek 6550s, just because one of them was cracked. :D
 
#31
As a heads up for any Europeans retubing an SVT, the TAD 6550s are great sounding and durable.

I had had a matched set of (expensive, even though bought over 8 years ago) NOS GEs in mine that I had ordered from Watford valve, but a few of them drifted heavily over a year so i ended up swapping them for the TADs when I had the amp serviced at the Tube Amp Doctor. AFAIK they are tested and burned in Chinese tubes, strictly controlled for quality. In any case the amp sounds better than ever and is going strong after a few years with them.

I have the old GEs still, with the tested specs from TAD. I should get around to selling them, though obviously not as a matched set anymore...
 
#32
Ruby's suck, IMHO. I had them in my 1981 Ampeg SVT MTI when I bought it, and in my Bassman 100 when I bought it too. I changed the SVT to Electro Harmonix 6550 winged C's, (which is the same as Sovek), and my Bassman 100 to Sovtek 6550WE's. Both have plenty of that mid growl.

My Bassman 300 Pro have GrooveTube 6550's, which sound good, but I will be putting Svetlana 6550C's in real soon.
 
#33
Thumpking said:
Ruby's suck, IMHO. I had them in my 1981 Ampeg SVT MTI when I bought it, and in my Bassman 100 when I bought it too. I changed the SVT to Electro Harmonix 6550 winged C's, (which is the same as Sovek), and my Bassman 100 to Sovtek 6550WE's. Both have plenty of that mid growl.

My Bassman 300 Pro have GrooveTube 6550's, which sound good, but I will be putting Svetlana 6550C's in real soon.
Click to expand...

EH 6550s and Svetlana 6550s are made in the same factory to different specs AFAIK and both are different from SED Winged C 6550s. The Ruby and GT 6550s are just rebranded tubes from various suppliers - their russian tubes are (again, as far as I know/can find info for/have heard) made in the same factory as EH/Sovtek/Svetlana and their chinese tubes are made in the Shuguang factory by Samsung. (sourcing)
 
#35
Lazarus.Bird said:
What tubes come with the SVTs from the factory? I just recently picked up a used Vietnam one and was curious as to if the tubes have been changed since it was purchased new.

The power tubes are all Sovtek 6550we's
Preamp is a Sovtek 12ax7wa and two EH 12au7a's.

I'm assuming the EH's are not factory. Are the Sovteks?
Click to expand...

The Sovtek 6550s are damn good tubes. They should love you long time.

As for the "preamp" tubes you listed, those are probably the splitter and driver tubes (visible from the back of the amp) and they should be fine.

But for the actual preamp tubes (unscrew the four screws on the top of the amp, and slide the faceplate out) I'd suggest a pair of the new Tung-Sol 12ax7 tubes. They sound much better than the Sovtek tubes that are probably in there now.
 
#37
In terms of reliability, and for what it's worth, my tech swears by winged C brand. He tells me he's seen an unusually high number of failures of EH 6550s in SVTs.

My USA built SVT-VR came with Sovtek tubes. They sounded good, but I pulled the Winged C set from another amp and put those in. The Sovteks are now a backup set. I should be fixed for power tubes for the next 500 years.

I'm currently running Tung Sol 12ax7 and EH 12au7 preamp/driver tubes in my VR. Very pleased the plush sound.
 
#39
All of the current manufacturers of tubes have some degree of spotty quality (some runs are better than others) compared to the big manufacturers of what are now vintage tubes. New old stock GE 6550A tubes would be my #1 recommendation for power tubes in an SVT.

Among current production, I say =C= (Winged Cs). These are manufactured at the same factory in St Petersburg, Russia where Svetlana tubes were once manufactured. Supposedly, they're very similar, but I'd want real Svetlanas over the new =C= tubes.

I won't argue with Lord Valve though, Sovtek 6550WE are worth a shot if he says so.

Ruby is a distributor of many brands, not a manufacturer.
 

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