Attenuators vs. Power Scaling

[zappazapper]

hi there...

i'm sure pretty much everybody here knows the deal with power attenuators... when i was looking around tho, i found this - http://www.londonpower.com/pscaling.htm

it seems to me that boogie users are quite accustomed to mods and stuff like that, so i wanted to see if maybe somebody has tried something like this... i like the idea that power scaling actually EXTENDS tube life, as opposed to reducing it like an attenuator would...

so has anybody out there tried this kind of thing in thier boogie, or any other amp, and if so, what was your experience with it?

 

[>Photi G<]

I haven't directly experienced it, but I know some people who have installed power scaling, and have given really good reviews of it. They say that there is no tone loss, like attenuators tend to do. The mod requires quite a bit of surgery, though. It involves splicing the high voltage supply through the control, as well as the bias supply. So unless you know where in the signal path to do this, then it isn't for you. And in some cases, you may have to install an additional Drive Compensation control. I'm not exactly sure on the specs of that, though.

 

[zappazapper]

hehe ya i'm no tech, definitely not something i would attempt myself... they have a list of installers on the page, and i'm sure anybody that works on tube amps could figure it out... i just wanted to find out if this was total BS, and i figure that boogie people are probably the most discriminating of all when it comes to stuff like this, and like i said, boogie people tend to know a bit about the whole mod thing than anybody else...

so these people you know, did they use a "london power" power scaling mod? are there other companies making stuff like this?

 

[>Photi G<]

Interestingly enough, no, they didn't use a London Power system. Hall Amplification makes a similar device called the VVR3 that has been widely accepted as a great device where I come from. Check out the MyLesPaul amp forum and do a search for power scaling. lots of info there.

 

[tonejam]

I've had a LondonPower power scaling kit put into my Boogie Studio 22+ a few years ago. Initially I didn't like it, because if you apply more than about a quarter turn to the knob, it introduces distortion. It's not going to enable you to set a sound on your amp and then turn it up from zero to full power. Full power is fine, around 75% power, it starts to break up. Not good if you value a warm CLEAN sound. Not such a problem if you play dirty, I guess.

I took my amp back to my tech, to see if he hadn't installed it properly, but he had, and pointed out that the quarter turn actually pulls the power down to around 2 watts. You have to take the amp out on a gig to appreciate the mod, because its subtle. I play in a coffee shop once a week, and its great for that environment, I can get the amp's master volume up to around 3.5, rather than 1. I have a power soak, and don't use it anymore. They have the same problem, after the first couple of settings, the amp gets choked.

I had issues with the mod overheating, so the tech put a dirty great heat sink in, which makes the amp look like its transistor powered. Boogie Blasphemy! I'd have trouble selling this baby.

I hope this helps, feel free to ask questions, cheers, Bill.

 

[zappazapper]

ya thanks man... it's good to hear a first person perspecitve... when i read the FAQ on london power's site, it made sense to me what they were doing and how it MIGHT be a better approach than an attenuator, but i could also see how it could affect the tone... right on the site the guys says that if you looked at the schematics it would look like circuits from the 40s, so it sort of made me wonder why no big amp maker took that approach...

anyway it's not something i'm in desperate need of anyway... i like my amp at any level... just sort of curious... i've never been able to get my .50 cal + past about 2 really... i thought about getting an attenuator just to see if there was much difference, then i saw the power scaling stuff... seems to suffer from, if not the same, at least equally negative problems...

thanks for the info...

 

[YellowJacket]

Power Scaling is FOR power amp distortion tones. The whole purpose of it is to reduce clean headroom so you can get 'cranked' tones at a low volumes. I have tried it and I prefer to think of it as a 'power amp gain knob'. So ya, if you are running something and you want to get the power amp involved, turn the master / drive control to the level you want and dial back the power amp until you start to hear the clip. There is a power scaling kit that allows you to adjust the channels individually. Such a kit would be best for maintaining headroom in the clean channel.

 

[zappazapper]

ok i see what you're saying there... it makes sense, since both attenuators and power scaling is meant to offer power amp distortion at reasonable levels... so power scaling isn't going to do much for people that generally run clean, and like tonejam said, it will obviously introduce distortion, which is kinda what it's supposed to be doing... and ya i read about the kit where you can adjust each tone seperately...

what i'm thinking is like i run my .50 cal + on the lead channel with the gain at about 2 for a nice bright clean that i can dirty up with the volume knobs on my guitar... but, i find that the clean channel sounds better for clean, except for the lack of gain available when i want it (being the multi-fx junkie that i am, i'm really trying to get away from channel switching and all that... i'm really trying to get as much tone out of just my guitar and my amp)... i dunno, the lead channel has alot more mid content, which i like for heavier tones, but for the cleans i'd like to be able to use the clean channel, but be able to get some bite out of it when i want... so i'm thinking that power scaling would let me turn the amp way up so that i can get some power tube distortion happening to add a little bite when i dime the volume on my guitar... i'm pretty happy with the metal tone i get with just the preamp distortion and the volume turned way down, but like i said, i'd like to see about getting some more balls happening on the clean channel without running a pedal into the front or something...

 

[boola]

The Altantic Boogie and the new Marshall amps have power scaling, which really seems to work well. I don't like the sound of the Slash amp but the YJM sounds awesome.

 

[zappazapper]

before you know it, they're gonna have speaker scaling, because people will start complaining that they can't get the sound they want unless thier speaker is on the brink of molecular disintegration... a variable wattage speaker? hmmm...

 

[tonejam]

I like that description by Yellowjacket, about setting your amp where you want it, then dialling down the power scaler until you hear the power amp 'clip'. That's what I do. As he said, think of it as a power amp gain control (but in reverse, the more you turn it DOWN, the more overdrive you get). Don't think of it (as I first did) as a master volume control, its not quite like that.
Don't get the wrong idea, I like my power scaler mod. Before I got it I was tempted to buy a 5:25 Express, so I could use the 5 watt setting for small gigs. I've tried that, and actually prefer the sound of the power scaler.
cheers, Bill.

 

[zappazapper]

ya i'm kinda on the fence about the whole thing... mainly i don't like the idea of modding the chassis for the knobs, and i REALLY don't like the idea of having to install a heatsink or a fan...

but it sounds like a cool feature... i mean, i'm starting to think that all amps should have power scaling built in from the factory... i also like the description that it's like a reverse gain control... in that case the master volume is JUST a master volume... it's still the control you would use to set the level of sound coming from the amp, it's just you can use the power scaling knob to make it sound like it's a bit louder than it really is...

ya i've been checkin' out the 5:25 too... i like the .50 cal but i don't drive and it would be nice to have something smaller and lighter for those rare times when i have to bus/subway to a gig... 50 watts is really way more than i need for 90% of what i do, and i'm also usually lugging around my gibson in a hardshell case... i went to the local music store and tried one out... i was really impressed with the 5 watt mode... i know that technically 5 watts is still half the volume of 50 watts, but it was seriously loud... i wasn't crazy about the "burn" voicing, but that's not the amp i would use if i needed that sound... all the same, i thought it was still a little too big and heavy for what i'm looking for, but at least i was convinced that a 5 watt amp could handle it... i want something seriously tiny but still able to deal with a full band situation, with a bit of room to spare... even a pro junior seems a little bulky... i used to use this little silverface champ when i worked at a studio several years ago... it wasn't mine but that's pretty much what i'm thinking of... actually, it would be a non issue if i could convince people to just let me bring my pod in and go direct to the PA... i know it's not the same, but when it's just a job, playing in a bar for drunks, what the hell's the difference?

 

[Don]

before you know it, they're gonna have speaker scaling, because people will start complaining that they can't get the sound they want unless thier speaker is on the brink of molecular disintegration... a variable wattage speaker? hmmm...

Before you know it?!?! It's already available from a few manufacturers!
http://www.eminence.com/pdf/reignmaker.pdf

 

[zappazapper]

XD well there you go... i invent it, and the next day they're already making it

i have a few other great ideas... the best one is (wait for it):
KENTUCKEY FRIED TURKEY
only between thanksgiving and new years

 

[mxr2000]

I Own a "Aracom 150 pro" Attenuator and let me tell you is the best purchase since i bought my first Tube Amp in the early 80's this is what i was hopping way back then to stop my bedroom windows from rattling and scaring the **** out of my pets.:lol: