Bought a Attenuator for a 100watt

bobtec · Post by **bobtec** » Sat Aug 01, 2015 3:14 pm

But I find out my100w.SLP ri amp puts out over 115 or more watts..So did I wasted $500.00..I guess a 100watt attenuator is really for a 50 watt...By the way a thing is called a PS Systems Power Tool...It was made in 1993 and got high review marks in Guitar Player..and it can be used down to 2 ohms,with amp set to 8 ohms...any thoughts on amp damage?

Blix · Post by **Blix** » Sun Aug 02, 2015 4:53 am

So you did no research and bought some outdated POS for $500?

$500 could have bought you this: http://www.scumbackspeakers.com/attenuator.html

Known good, one of the best sounding around.

Also, you're not so far away from a Fryette Power Station, which pretty much as good as it gets...

Your amp will probably be closer to 150w fully cranked btw.

white noise · Post by **white noise** » Sun Aug 02, 2015 3:17 pm

I would sell the Attenuator and go with the PPIMV, either George's or Marks.

vh junkie · Post by **vh junkie** » Sun Aug 02, 2015 5:11 pm

I would proceed this way:
Always set the impedance of the attenuator to the same impedance as your cabinet! You can set you amp to the same impedance or lower, NEVER higher!
Assuming you have a 16 ohm cabinet...
1) Set impedance selector to 8 ohms and pull one power tube on each side... see what kind of heat the attenuator is generating when you dime the amp... might want to take the cover off the attenuator so you can feel the larger resistors, etal and trying to get sense of how hot the attenuator is running... assuming all is well...
2) Leave the impedance at 8 ohms, and put all four power tubes back in... repeat examination of heat generated by attenuator with amp dimed. You can run the amp like this if you like... a lot of folks do.
3) If the attenuator is running relatively cool after a half hour of playing, you could try all four tubes at 16 ohms, but you might be pushing it.
4) Could add a PPIMV and set it at 7- 8 and use it in combination with the attenuator... this should allow the presence control to work to some degree without overloading the attenuator.

bobtec · Post by **bobtec** » Sun Aug 02, 2015 11:53 pm

I bought it new in 1993..But I didn't have my 100watt yet, just my vintage Fenders..what did I know, I only use 2x12 cabs with classic 30 Fanes(60w.)..One is 16 and the other is a 4 ohm..The attenuator is a 8ohm reactive load..When I used the 16ohm cab I had problems...The 4 ohm seemed to last longer (tubes)The manual says I can go down to 2 ohms....It was based off the Marshall SE100...So was that and the powerbrake made for just 50watts?

Mcquayglen · Post by **Mcquayglen** » Mon Aug 03, 2015 4:33 am

Help me find a solution for this event.

rgorke · Post by **rgorke** » Tue Aug 04, 2015 12:06 pm

white noise wrote:I would sell the Attenuator and go with the PPIMV, either George's or Marks.

I hate that the PPIMV kills the presence control. I go with either variac down and using a little attenuator....a good one like the Scumback or the Alex

Carbia · Post by **Carbia** » Tue Aug 04, 2015 4:55 pm

rgorke wrote:
white noise wrote:I would sell the Attenuator and go with the PPIMV, either George's or Marks.
I hate that the PPIMV kills the presence control. I go with either variac down and using a little attenuator....a good one like the Scumback or the Alex

Rgorke, that has an easy fix. Install a pot to make the NFB variable. Then put the master at the volume you like and set the pot to match the sound without the master.

Easy

Strat78 · Post by **Strat78** » Tue Aug 04, 2015 5:44 pm

Dosn't really matter where the NFB is, it's not effective when the PPIMV is being used. Listen to Ralle's clip, that's NFB in all it's glory and you aint getting that tone with a PPIMV. Grab a Marshall Power Brake and do the quick mod and your in business.

http://www.ebay.com/itm/Marshall-Power- ... 419a89e46e

Carbia · Post by **Carbia** » Wed Aug 05, 2015 3:11 am

Nfb with the master under 5 is too low, thats why presenc doesent works. If you can increase the Nfb when you're playing with the master, the presence will work again

Strat78 · Post by **Strat78** » Wed Aug 05, 2015 8:30 am

That variable NFB pot is a pretty damn good mod in itself, Holbrook been doing that for a while now! I wish we all had the venues to play these amps without having to jump through all the volume issue hoops. The best VH tone I've ever had was with the variac way down to around 60v with no attenuation, but it was still insanely loud. The PPIMV is the most convenient, but we are not here because old tube amps are convenient.

Ralle · Post by **Ralle** » Wed Aug 05, 2015 10:08 am

" but we are not here because old tube amps are convenient."

bobtec · Post by **bobtec** » Wed Aug 05, 2015 5:10 pm

The Power tool is a good reactive load,but the way they were advertised,as be able to use with a Plexi..It even showed one on the manual..But it does not say anything about going higher and useing a 16 ohm cab...Only it can be used down to 2 ohms...Head @8ohm, Power tool @8ohm,into a 8ohm cab...I have a 16ohm cab and a 4 ohm cab, both are 2x12...Loud as hell with the 57000pf brite cap....

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