Bare Knuckle Pickups Forum
Forum Ringside => Tech => Topic started by: Ian Price on June 28, 2009, 02:54:51 PM
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I'm a complete novice when it comes to understanding amps. My question is if I had loads of amp heads all with power scaling but different wattage (lets say 5w, 10w and 50w) would the power scaling give you the ability to make all of the amps sound the same at lower volumes?
The context of my question is if I had only one amp that was used for gigging and home use would a power scaled higher wattage amp make more sense or would it limit the cranked sound I could get at bedroom level?
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Choose the amp you like the sound of best, and Power Scale it.
When executed properly, Power Scaling will maintain the tonal character of the amp, whilst allowing you to take the volume down to bedroom levels.
There's no advantage in starting off at a lower power level, unless you prefer the sound of that amp.
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Power scaling has limits Ian - you can only go so low on the voltage before the tone gets fizzy.
A Power Scaled lower wattage amp will sound a bit better at bedroom volumes than a Power Scaled larger output amp.
If you need a gigging amp, I'd got for that and use Power Scaling and a pedal to get nicer drive at lower volumes. For example, a Power Scaled JTM45 and your OCD would be a good match :)
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Can somebody explain to me how Power Scaling works electronically please? I've been reading thru the "London Power" site, and can't seem to squeeze any useful information out of it.
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A Power Scaled lower wattage amp will sound a bit better at bedroom volumes than a Power Scaled larger output amp.
I'd have to say I don't agree with that.
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Can somebody explain to me how Power Scaling works electronically please? I've been reading thru the "London Power" site, and can't seem to squeeze any useful information out of it.
It varies the HT rail voltage downwards, and in the case of fixed bias amps, employs a tracking bias regulator which means that the bias voltage decreases in proportion to the anode and screen voltage.
Cathode bias amps don't need the bias regulator part.
The effect is that the output valves produce less power, and yet maintain their transfer characteristics (i.e. tone) to the point where they are almost 'off'.
A 'drive compensation' control is employed to reduce the size of the signal from the unscaled part of the amp at more extreme settings. This is basically a master volume, which many amps would already have.
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Choose the amp you like the sound of best, and Power Scale it.
When executed properly, Power Scaling will maintain the tonal character of the amp, whilst allowing you to take the volume down to bedroom levels.
There's no advantage in starting off at a lower power level, unless you prefer the sound of that amp.
Cheers Martin - my favourite amp sounds have aways been Hendrix and Frusciante, both Marshall based but I do prefer Frusciantes cleaner/slight break up sounds. I think he uses combinations of Jubilee, Major and JTMs.
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A Power Scaled lower wattage amp will sound a bit better at bedroom volumes than a Power Scaled larger output amp.
I'd have to say I don't agree with that.
Fair enough - you know a bit more about it than me!
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interesting thread, thanks for posting it, i've always wondered about this kind of thing too, as a home player who suspects he doesn't necessarily "like" the tone of single-enders.
How about an attenuator versus power scaling?
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Fair enough - you know a bit more about it than me!
Sorry, don't mean to be brusque! :wink: The 50W marshalls, and JTM45s I've done sound great at practise levels. Deluxes and Roadstars have the same issues with requiring drive compensation, and because of the logarythmic volume thingy, don't really seem to benefit from having a 30W head start.
A Power Scaled 5W single ended amp can sound great, but it's not going to sound like a small Marshall.
How about an attenuator versus power scaling?
Power Scaling is far better than any attenuator I've ever tried.
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So is there any disadvantage to having power scaling?
It seems like a feature that would be worth having in any amp, although I guess cost might be an issue.
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Cost is the only issue.
When the PS control is fully up, the system is invisible, so if you don't want to use it you don't have to.
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Thanks Martin, that's what I was hoping you'd say. :)
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So is there any disadvantage to having power scaling?
Power scaling has limits Ian - you can only go so low on the voltage before the tone gets fizzy.
This is the only issue I've found. If you go really low on the scaling control, you do get a bit of fizz creeping in. Other than that, it's the best solution to reducing volume that I've heard.
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thanks, martin. Just out of interest, how much does it cost to add powerscaling (either to an existing amp, or to a build-from-scratch amp)? Maybe it varies depending on the amp, but a rough ballpark figure would be cool.
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My hands-on experience with power-scaling is the JTM45 that Martin W built for me with it installed.
That amp sounded exactly the same at genuine low, home volumes as it did fully cranked.
I would thoroughly recommend it. Cost is the only negative issue as far as I can see. I certainly did not perceive any of TF's "fizzies" at low volume.
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Fair enough - must just be my bat ears playing up then!
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If you're getting fizz creeping in on most amps, you haven't reduced the DC control enough, or there's some other problem. For example, in some installations, I've seen a dual-gang pot used for both Power Scaling and Drive Compensation, which is a bit crude, but shows how much the DC needs to be reduced, i.e. nearly as much as the PS.
Dave, I thought that the improved DC control I fitted to the Deluxe had erradicated any fizziness? Also using the lower gain input? The DC on your amp will stop the fizziness, and when I tried it, both with a guitar and on the scope, it was gone at all but unrealistic volume levels (those where you could barely hear the amp over the strings.)
A problem specific to the Deluxe is it's crude preamp, phase inverter and volume/tone controls which are of course, part of the essential character of the amp, but make it harder to find settings that don't sound mushy, on the unscaled amp, and fizzy on the scaled amp. As you know the volume goes OFF/STILL OFF/ALMOST EVERYTHING/TOO MUCH before it gets to 8 o'clock!
I thought that we'd shifted the small amount of fizziness to well below anyone's realistic practise level?
If it's still a problem, let me know and we'll have a look. :)
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thanks, martin. Just out of interest, how much does it cost to add powerscaling (either to an existing amp, or to a build-from-scratch amp)? Maybe it varies depending on the amp, but a rough ballpark figure would be cool.
From £100 on a simple cathode-biased amp to £250 on a largish fixed-bias amp that requires an external mounting box and a cooling fan.
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I thought that we'd shifted the small amount of fizziness to well below anyone's realistic practise level?
If it's still a problem, let me know and we'll have a look. :)
You're right mate - it is only when it's very low and it doesn't affect my enjoyment of the amp at all :)
I don't regularly use it that low and you're right, it could probably be dialed out with the compensation pot.
So basically, I know nothing. Listen to Martin and Hamfist :lol:
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From £100 on a simple cathode-biased amp to £250 on a largish fixed-bias amp that requires an external mounting box and a cooling fan.
thanks. :)
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So basically, I know nothing. Listen to Martin and Hamfist :lol:
Hardly! :lol: :lol:
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thanks, martin. Just out of interest, how much does it cost to add powerscaling (either to an existing amp, or to a build-from-scratch amp)? Maybe it varies depending on the amp, but a rough ballpark figure would be cool.
..mmm less than I thought
From £100 on a simple cathode-biased amp to £250 on a largish fixed-bias amp that requires an external mounting box and a cooling fan.
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Cheers for all the responses guys! Very useful. Now, next question is if I wanted a power scaled amp that would cover or get close to the tones I like best (Hendrix, Frusciante, Mayer, Bonamassa) what should I go for?!?!?! Not looking for the sparkliest cleans you can imagine, as I like a ittle bit of grit with the cleans. Also need to cover gain levels up to classic rock.
Me thinks I'd better get selling my amp and other gear before getting really serious about it!
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Cheers for all the responses guys! Very useful. Now, next question is if I wanted a power scaled amp that would cover or get close to the tones I like best (Hendrix, Frusciante, Mayer, Bonamassa) what should I go for?!?!?! Not looking for the sparkliest cleans you can imagine, as I like a ittle bit of grit with the cleans. Also need to cover gain levels up to classic rock.
Me thinks I'd better get selling my amp and other gear before getting really serious about it!
Hiwatt ;)
Gotta say that my bassman that Martin did covers all that clean Hendrix & Mayer sound & then pop a pedal infront to push it
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Cheers for all the responses guys! Very useful. Now, next question is if I wanted a power scaled amp that would cover or get close to the tones I like best (Hendrix, Frusciante, Mayer, Bonamassa) what should I go for?!?!?! Not looking for the sparkliest cleans you can imagine, as I like a ittle bit of grit with the cleans. Also need to cover gain levels up to classic rock.
Me thinks I'd better get selling my amp and other gear before getting really serious about it!
Hiwatt ;)
Gotta say that my bassman that Martin did covers all that clean Hendrix & Mayer sound & then pop a pedal infront to push it
Have you posted pics of the Bassman? I assume it was a combo?
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Cheers for all the responses guys! Very useful. Now, next question is if I wanted a power scaled amp that would cover or get close to the tones I like best (Hendrix, Frusciante, Mayer, Bonamassa) what should I go for?!?!?! Not looking for the sparkliest cleans you can imagine, as I like a ittle bit of grit with the cleans. Also need to cover gain levels up to classic rock.
I think a JTM45 with Power Scaling and a 2x12 with Greenbacks would be perfect :)
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Cheers for all the responses guys! Very useful. Now, next question is if I wanted a power scaled amp that would cover or get close to the tones I like best (Hendrix, Frusciante, Mayer, Bonamassa) what should I go for?!?!?! Not looking for the sparkliest cleans you can imagine, as I like a ittle bit of grit with the cleans. Also need to cover gain levels up to classic rock.
I think a JTM45 with Power Scaling and a 2x12 with Greenbacks would be perfect :)
Greenbacks really are the perfect speakers for every Marshall built in the 60's AND 70's !!!! (IMHO, of course).
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Cheers for all the responses guys! Very useful. Now, next question is if I wanted a power scaled amp that would cover or get close to the tones I like best (Hendrix, Frusciante, Mayer, Bonamassa) what should I go for?!?!?! Not looking for the sparkliest cleans you can imagine, as I like a ittle bit of grit with the cleans. Also need to cover gain levels up to classic rock.
I think a JTM45 with Power Scaling and a 2x12 with Greenbacks would be perfect :)
and the price is roughly?
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Spot on Dave. See, you do know stuff! :D
PM me for an exact price Ian, but you're looking at about £1300 ish. I might have a deal for you.
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Cheers Martin - will do. I guess my options will be dictated by what I can get for the stuff I am selling minus the money I want/need to put to one side for family stuff!
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Spot on Dave. See, you do know stuff! :D
PM me for an exact price Ian, but you're looking at about £1300 ish. I might have a deal for you.
Aw shucks, maybe I do :lol:
Ian - if the deal is what I think it is, I'd give Martin a shout. I'd be interested myself if I didn't already have something similar ;)
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My comments to add on power scaling are that it's pretty good, but nothing will ever sound the same as moving a lot of air with a loud as hell speaker and the knock on effect of added sustain from the sound waves hitting your strings
You can get some fantastic sounds with power scaling and I would recommend it to anyone.
I tend to play late on. If I didn't have it, the amp would get used about once a week
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Does power scaling sound/work better on smaller wattages than higher one - like would a 45 watt sound better at full tilt but power scaled down sound better than a 100 watt at full tilt scaled down to the same level? Or would there be no noticeable difference?
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Does power scaling sound/work better on smaller wattages than higher one - like would a 45 watt sound better at full tilt but power scaled down sound better than a 100 watt at full tilt scaled down to the same level? Or would there be no noticeable difference?
See: Earlier in this thread.
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I would agree with most of the above - in my opinion you do need a bit of volume to make it sound right but I am talking tv volume. Its not the power scaling but the fact that there isn't enough signal going to the speakers (I think). You get this with pretty much all amps.
Martin built me a JMP50 with PS and it is brilliant. For me what it does best is totally authentic cranked tones :P