What's the worst tube amp you've ever heard?

[Enzo]

The Super Vacuum Tube amplifier - SVT - came out in June 1969. Fortunately for Ampeg, the Rolling Stones were preparing for a major tour at the time, and after checking out the SVT decided to take the SVTs on tour. DOn't blame the SVT on McCartney.

[drewl]

I got an early one on the bench now.
The front end is ringing like crazy, had to order new 12DW7's and 6C4....who the heck designed this thing?

[mykey]

I got an early one on the bench now.
The front end is ringing like crazy, had to order new 12DW7's and 6C4....who the heck designed this thing?

the 6C4 does have a problem with ringing however by installing a silver mica 7 pf 1000V cap between plate and grid this usually stops the ringing.
the old 6C4 was not prone to this problem but all the new ones are.
it is all but impossible to find a new 6C4 that does not ring.
but really with some experienced tweeking the SVT is not such a bad amp,
although the heater traces on the preamp circuit board introduce 60 cycle
into the audio path, the traces can be bypassed with twisted wire, the 60 cycle can be routed away from the audio.
I also like to set it up for KT 88s. At the time Magnavox made this amp there was nothing that could touch it, and therefore has some admirable qualities.
please don't confuse "SVT" with the Crate (fake) SVT, there are no similarities except the name plate.

[Brock Little]

In all honesty, any tube amp that I can't afford, is a POS.

If I can't have it, I'm not going to sit here and listen to you harp on about how good the damn thing is!

[tubeswell]

And same to the PV remark. ...within their tube line, the little Classic 30, a cool amp, .....

I'm with you Enzo, the Classic 30 is the coolest little amp, especially when you've done the Blue Guitar mods IMHO

[mykey]

if you don't mind the sound of the transistors buggering up your tube purity.

[Enzo]

What transistors, Mykey? The only transistor in a C30 is the effects send. Don't use the loop, no transistors in the signal path. COnsult the schematic.

[mykey]

What transistors, Mykey? The only transistor in a C30 is the effects send. Don't use the loop, no transistors in the signal path. COnsult the schematic.

The PV schematic (No. 81501580) I'm looking at has U1A, U1B 4558 op amps (in case you had not noticed, op amps contain LOTS of transistors), Q1 the FET, Q2 5534, which are ALL in the signal path using effects loop or not. It's JUST like PV to spoil the sound of a tube amp with (yuck) telephone parts.
Maybe Enzo needs glasses.

[Alex R]

The opamps and the switching FET are in the reverb circuit; call that the signal path if you like but you can dial it right out of the sound. Q2 is in the effects send circuit only, what I'd call the effects send buffer; have another look, the signal bypasses it when the effects loop is out of use, which I'm afraid is contrary to your assertion. I'd definitely call this an amp with a valve-only signal path.

Although this amp doesn't have them in the (non-reverb) signal path I wouldn't count switching FETs and transistors as doing anything at all to the sound of the amp, as when used as switches they simply either conduct or not. Or am I wrong?

Interesting driver circuit - maybe that relatively simple and unbalanced splitter is the reason these amps sound so good? I think I recall that the Superchamp uses the same kind of splitter - I'm used to calling this a 'concertina' type, apologies if this demonstrates my ignorance, something I do try to avoid as it is embarrassing.

[mykey]

Although this amp doesn't have them in the (non-reverb) signal path I wouldn't count switching FETs and transistors as doing anything at all to the sound of the amp, as when used as switches they simply either conduct or not. Or am I wrong?

Take the transistors out, and listen. Transistors are for wimps.

[Alex R]

Most of your last post, mykey, is my words. The last ten are yours, and you're very welcome to them.

I thought your post addressed to Enzo was kind of patronising, as he is a knowledgeable person. The assertions you made in it were wrong. How about owning up to that? Otherwise it all seems a bit shrill.

And then how about answering me properly? I listen to many amps, with and without transistors, so asking me to do more listening tests isn't helpful; I know that I can't 'hear' any transistors in a Classic 30, and I know why. If I took out the effects send transistor and then played through the amp it would sound exactly the same as with it, as the signal only goes through that buffer when the effects loop is in use. Etc.

And what might the difference be between a switching transistor conducting signal and a bit of wire conducting signal? Have you tried substituting, say, a relay for a switching FET? Lots of good sounding amps use FETs in the signal path for switching - I never before heard anyone assert that switching transistors affected tone, so there will have to be a little theory to back it up, as assertions can't really count for anything.

[JC@]

Gotta say that I'm no fan of most models of Sound City.

Also, those Fender HotRodBluesDeLuxeDeVille things do not excite me much and are flimsy. I do know how to tune them to get them to sound good to the folks who like them.

In my modest opinion not everything in guitar has to be loud...
I tried once a ss Sound City combo and it was "tuby" and sounded beautiful

On the other hand I must agree I don't like the hot rod fenders you mention. I fact I always recommend to get rid of some of the "hot" part in these amps and the customers never regret.

[drewl]

can't we all just get along?


I frequent several boards, but this is the place i go for hard facts and help, not fights or pissing matches.
let's not anger those who share their wealth of information with the rest of us okay?

[Baxthorpe]

There is a slight difference between using switching transistors and physical switches - in comparison,the transistors delay the signal slightly. When you get used to playing through tube amps, you really feel that delay if you go over to a transistor amp. It is like the delay you get on a wind organ - after a while you get used to it, and you allow for it as you play - but it exists.

[bob p]

The PV schematic (No. 81501580) I'm looking at has U1A, U1B 4558 op amps (in case you had not noticed, op amps contain LOTS of transistors), Q1 the FET, Q2 5534, which are ALL in the signal path using effects loop or not. It's JUST like PV to spoil the sound of a tube amp with (yuck) telephone parts.
Maybe Enzo needs glasses.

i think that your final comment is out of place. its definitely not representative of the type of interactions that characterize the users of this board.

one of the reasons that I've always found Ampage to be the best DIY site on the internet is because the people here are so helpful to one another, while keeping a well-mannered gentleman's perspective when interacting with one another. as a result, this board has never had any sort of need for heavy handed moderation, banning of members, etc.

while its certainly OK for people to have differences of opinion, i don't understand the desire to berate other people, or to be so openly offensive toward them. please rethink this approach for everyone's benefit.