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200 Watt SVT? How to do it?

#61
The problems I see in the OP is that to take a 300W amp and drop it down by removing a pair of output tubes is that the output transformer will no longer match to any normal load. The power transformer would still work fine. The OPT would have to be replaced with one with a suitable primary impedance.

The other route is to boost a 100W amp to 200W. Using a quad of 6550s or KT88s will give you the desired power but not with the current OPT or PT. These will both have to be replaced. Probably a transformer company like Mercury Magnetics could supply both. Obviously the components in the 100W amp will have to be modified to handle the increased voltage and current requirements. Not a walk in the park but doable. This way at least you'll not need to do too much chassis/metal work and your cosmetics would be taken care of.

Whatever route is taken it's not a project for a neophyte but an experienced tube guy.

Paul
 
#62
Rewire the plate supply rectifier as half wave, adjust filter caps to work if you get hum. Cheaper and more practical than dummy loads and new output transformers if you can't just pull two tubes.

Actually, add an additional half wave rectifier/filter just for the output tubes, and move the output transformer B+ connection to that. Then you can go back to 300W easily later.

Should be about 200W.
 
#64
These last three posts.... THIS is the kind of stuff I'm looking for in this thread.

I'm gonna call my amp tech and pick his brain, then I'm gonna keep my eyes peeled for a suitable, blown up SVT to try this with.

I think it would be easier (safer?) to have my tech mod a 300W amp to to output 200W rather than trying to beef a V4B up to 200W.

I'm gonna post a WTB ad in the classifieds, and call my tech.

Best way to get a 200W SVT is to build a 200W SVT.
 
#66
ampegfuzz said:
How bout a Mesa Stategy 400 tube power amp and a ampeg svt cl preamp, it will push 200w at 4ohms or 8ohms.
Click to expand...

I'm actually pretty psyched about finding a busted 'ol SVT with bad transformers, and having new transformers made (or finding some that will work.)

There are tons of ways to get a dirty 200 watt tube amp... I like the challenge of trying to keep it as Ampeg as possible.
 
#67
fu22ba55 said:
These last three posts.... THIS is the kind of stuff I'm looking for in this thread.

I'm gonna call my amp tech and pick his brain, then I'm gonna keep my eyes peeled for a suitable, blown up SVT to try this with.

I think it would be easier (safer?) to have my tech mod a 300W amp to to output 200W rather than trying to beef a V4B up to 200W.

I'm gonna post a WTB ad in the classifieds, and call my tech.

Best way to get a 200W SVT is to build a 200W SVT.
Click to expand...

good call, for the amount it'll cost you to mod a v4 or svt to a 200W output you may aswell start from scratch and build something totally to your spec.
 
#69
I was trying to think the most practical way without using a pedal or "possibly" ruining a decent SVT. I personally drive the crap out of my input with a clean boost. I dont work the whole amp as hard but its not the same tone as you get. I am using a ric with the bridge soloed and like pedal dist/fuzz on top of a nasty tone.
 
#71
MAMMOTHvolume said:
for the amount it'll cost you to mod a v4 or svt to a 200W output you may aswell start from scratch and build something totally to your spec.
Click to expand...

I could obviously build something to my spec. I'm kind of trying to tap the knowledge of TB'ers to see if there's a sensible, responsible, reversible mod one could perform on a real SVT to cut it's power by a third.

It's a thought experiment. It's a challenge. It's a puzzle.
 
#76
big90sbasshorns said:
Has anyone suggested using yellowjackets yet? It will change the tonality of the amp, but you'll be able to drive the powersection into glorious tube crunch at alot more reasonable volumes.

http://www.thdelectronics.com/pdf/yj.pdf
Click to expand...

theres no way el84's will survive in a svt.

also @ paul, not sure i'd want to run el34's at that kinda voltage without properly regulated screens. They can take it but i think you'll burn through them far to quickly
 
#79
stiles72 said:
+1 to a V4 /V4BH . When paired with an efficient cab, they can pump out enough volume for you onstage while not blowing the soundman "completely" away.
Click to expand...

For sure I've got plenty of love for the V4B. The sound is exactly what I want. But I've tried 'em. Just not loud enough. I would need two of them, so that's what got me thinking about a 200W SVT.

Lots of love for the V4B though, for sure.
 
#80
ampegfuzz said:
I was trying to think the most practical way without using a pedal or "possibly" ruining a decent SVT. I personally drive the crap out of my input with a clean boost. I dont work the whole amp as hard but its not the same tone as you get. I am using a ric with the bridge soloed and like pedal dist/fuzz on top of a nasty tone.
Click to expand...

I get what you're saying... I've tried this with an MXR micro amp, and a Blackstar HT Boost, but it basically does the same thing as turning up the volume knob... (it doesn't make the existing volume knob act as a 'master' volume)

The tone I'm craving is one where the amp is already turned up high enough that it's not getting any louder.
 

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