SVT Classic

lyle_from_minneapolis · Sat Feb 24, 2007 8:31 am

I don't know if these help, Charly, because I'm an idiot. But I was bored so I poked around. Hope one of these is what you need:

http://www.freeinfosociety.com/electronics/schempage.php?cat=1

http://users.aol.com/bluemuse/schematics.html

http://www.ampeg.com/pdf/SVT-CL.PDF

charlyg · Post by **charlyg** » Sat Feb 24, 2007 8:37 am

Close but no cigar. The ampeg page does not open. I had found the second. The first is different but not right.........

Thanks for the effort though!

Oh, wait, the first did help. The yellow go to the power switch and the black go to the standby switch.

lyle_from_minneapolis · Sat Feb 24, 2007 8:55 am

...yeah, see I knew that...mm-hmmm... Sure I did...

;-D

charlyg · Post by **charlyg** » Sat Feb 24, 2007 1:17 pm

I bought a 110 volt fan from Fry's to replace the noisy one that is in the SVT, but it is noisier than my truck! I only play for 20 minutes or so , so I am thinking of unhooking it til I get a quieter one.........

koobler · Post by **koobler** » Sat Feb 24, 2007 7:57 pm

things like this make me want to pull the fresh NOS GE power tubes from my '72 Blackline SVT, but they just sound so damn good!

soundmasterg · Post by **soundmasterg** » Sat Feb 24, 2007 9:30 pm

Charley, I'd suggest to email or call Jess Oliver. He worked at Ampeg in the 60's, designed the Portaflex amp, and is still repairing amps in NY I believe. He should be able to hook you up with a great fan or point you to where you can get one. I looked but I can't find his info here....I used to have it though. Do a search for him and see if you can find him, or email Bill Moore who wrote the Ampeg book. He can help you too. If you don't have the Ampeg book yet, you should get it. Its VERY good. http://users.aol.com/bluemuse/book.html

jnbass · Post by **jnbass** » Sun Feb 25, 2007 8:47 am

Jess sells his old B-15s and other stuff from time 2 time on evilbay.

Try Mouser electronics for a 240V fan, and run at half speed. www.mouser.com

charlyg · Post by **charlyg** » Sat Mar 10, 2007 12:42 pm

I still don't have a fan, but I just swapped out the tubes. The ones that were in there were very nondescript. They said Electronic tube 6550A made in USA. Other than that no indication as to mfg?

The new ones are a matched set of 6 JJ KT88's. In 20 minutes, I will adjust the bias, and then crank 'er up. At home it is going through the 8x10!!!!

charlyg · Post by **charlyg** » Sat Mar 10, 2007 2:17 pm

Interesting!! First, you must understand, I haven't dealt with tubes since, oh, about 1978, so the memory is foggy, and the tubes were in rf circuits, not audio. Same tubes though! With the old set, I thought the gain and master pots were dirty as there was all this crackling and popping when adjusting either pot. With the new tubes, it is quieter at rest, and there is NO issue with adjusting the pots! The bias adjustment went smooth, and since all 6 were matched, it stays on green with no signal!

Settings for a rockin 4004 setup. switch down vol max, tone min.

SVT settings. treb and bass flat, hi and lo boost off, mid freq at 4 (1.6k center), and the mid at 2:00. Gain at 9:00 and master at 11:30.

Use pick behind bridge pu, and ROCK OUT!!

jnbass · Post by **jnbass** » Sat Mar 10, 2007 6:33 pm

ROCK OUT LIKE MOTORHEAD!

charlyg · Post by **charlyg** » Sat Mar 10, 2007 7:05 pm

Pretty much! 'cept I couldn't name ONE song they do....

soundmasterg · Post by **soundmasterg** » Mon Mar 12, 2007 9:32 am

Glad to hear it is up and running CHarley. I haven't fired up my SVT in a couple months but there is nothing like one in full song!

charlyg · Post by **charlyg** » Mon Mar 12, 2007 6:06 pm

Man, you said it. I 've always thought, what's the big deal, I have 450 watts SS! Who needs an old tube thing with less watts that will fail! As you may or may not know, there was a 20 year gap in my playing, so all new equipment, with a fading memory as to how good my Sunn with 2 15s sounded!

Well, let me get my foot out of my mouth so I can tell you this thing is barely idling, but I have tone out the wazoo! The gain is about 930, and the master is about 1130. The new tubes were almost as good as a Paul or Dale refin!

cerrem · Post by **cerrem** » Thu Mar 22, 2007 11:23 am

The local electronics store near me has MANY of those 120V AC fans...in fact the exact same size as in the SVT... If you need one, Email me and i will go buy it for you and ship to you.... You can Pay-Pal me if you prefer....
I have tried lots of different tubes in the old SVT head and i have to say that the JJ KT88 tubes were the best sounding and most dependable in the SVT..they had PUNCH with good clarity and good headroom...They stayed clean and punch and tight on the bottom...the high end was clear and not murky as on other new production KT88 tubes...
As for the bias... set @ .072v per side and just stick the BALANCE control somewhere centered...
When I adjust the BALANCE control I use a spectrum analyzer, it's really the only clean way of doing it... I set the fundamental at 400Hz...When the BALANCE knob is set correctly the 2nd harmonic will drop out, cancel....
It is very sensitive adjustment...just a nat's hair off center and the balance is off again...
Plus I like the sound of even order

Chris

charlyg · Post by **charlyg** » Thu Mar 22, 2007 11:56 am

I know not of a balance adj? I just adjusted the two bias pots.

I will email you and yes I can paypal when I know the amount. Paypal is actually my preferred way to do biz online!