Anyone here tried 'power scaling' amps or circuitry. AFAIK it's selectively 
lowering the voltages, other than the heater voltage, on the power stage 
valves but keeping the bias proportionate. Presumably a cheaper alternative 
to 'power soak' devices or similar operating between the o/p transformer and 
speaker but more than a master volume, acting between the pre and power 
amps.

icarusi
--

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On 28 Oct, 02:40, "icarusi"  wrote:
> Anyone here tried 'power scaling' amps or circuitry. AFAIK it's selectively
> lowering the voltages, other than the heater voltage, on the power stage
> valves but keeping the bias proportionate. Presumably a cheaper alternative
> to 'power soak' devices or similar operating between the o/p transformer and
> speaker but more than a master volume, acting between the pre and power
> amps.
>
> icarusi
> --
>
> remove the 00 to reply

Never tried it, but there's a lot of talk about it over on the
ampgarage.com forums.  It seems to be quite a common mod (VVR, they
call it) to the Trainwreck clones.

www.londonpower.com also has quite a bit of detail on power scaling.


Ross.
--
www.rossedwards.net

Ross Edwards  wrote in
news:5df4e1ec-c7aa-4729-982e-5f5496950fc8@b15g2000yqd.googlegroups.com: 

> On 28 Oct, 02:40, "icarusi"  wrote:
>> Anyone here tried 'power scaling' amps or circuitry. AFAIK it's
>> selectively lowering the voltages, other than the heater voltage, on
>> the power stage valves but keeping the bias proportionate. Presumably
>> a cheaper alternative to 'power soak' devices or similar operating
>> between the o/p transformer and speaker but more than a master
>> volume, acting between the pre and power amps.
>>
>> icarusi
>> --
>>
>> remove the 00 to reply
> 
> Never tried it, but there's a lot of talk about it over on the
> ampgarage.com forums.  It seems to be quite a common mod (VVR, they
> call it) to the Trainwreck clones.
> 
> www.londonpower.com also has quite a bit of detail on power scaling.
> 
> 
> Ross.
> --
> www.rossedwards.net
> 
> 

i have one of these http://www.stephensonamps.com/old/lj10head.htm which 
has power scaling built in. i have no idea how it works but it does give 
full tube crunch at very low volume levels.

:-)

"Dave"  wrote in message

> i have one of these http://www.stephensonamps.com/old/lj10head.htm which
> has power scaling built in. i have no idea how it works but it does give
> full tube crunch at very low volume levels.


I have it in my evj hot rod.

No idea how it works though.
I cant even compare it to other products doing a similar job as I have never 
used them - so my inputs a bit crap really. Sorry.



-- 
no66y©
no66y AT gmx DOT co DOT uk

"no66y©"  wrote in message 
news:JLWdnVyHYMac1XXXnZ2dnUVZ8gudnZ2d@bt.com...

> No idea how it works though.
> I cant even compare it to other products doing a similar job as I have 
> never used them - so my inputs a bit crap really. Sorry.

Should be somewhere between a 'master vol' and 'power soak/hotcake' in 
sound. Obviously it's no going to drive the speakers the same way as the amp 
going full belt, but should sound better than 'master vol' for power amp 
distortion and cause less stress than soak/hotcake action, so just the 
question of how it sounds running power valves on lower HTs vs higher HTs.

icarusi
--

remove the 00 to reply

Does this help?

http://www.londonpower.com/pscaling.htm



-- 
no66y©
no66y AT gmx DOT co DOT uk

"no66y©"  wrote in message 
news:CL2dnamtY4a74HXXnZ2dnUVZ7s-dnZ2d@bt.com...
> Does this help?
>
> http://www.londonpower.com/pscaling.htm
>
>
>
> -- 
> no66y©
> no66y AT gmx DOT co DOT uk


'perfectly imperfect' eh!  Their site appears to wrap a lot of wool around 
what they're actually doing.  Could it be that they're regulating the HT 
voltage down using, ahem ... a transistor?

Chris

"christofire"  wrote in message 
news:lcCdncZAu-d8Q3XXnZ2dnUVZ8qadnZ2d@bt.com...

> 'perfectly imperfect' eh!  Their site appears to wrap a lot of wool around 
> what they're actually doing.  Could it be that they're regulating the HT 
> voltage down using, ahem ... a transistor?

FET AFAIK

icarusi
--

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"no66y©"  wrote in message 
news:CL2dnamtY4a74HXXnZ2dnUVZ7s-dnZ2d@bt.com...
> Does this help?
>
> http://www.londonpower.com/pscaling.htm

Been there. More interested in how they sound in use, for those who have 
them, or have modded amps.

icarusi
--

remove the 00 to reply

On Oct 30, 12:13 am, "icarusi"  wrote:
> "no66y©"  wrote in message
>
> news:CL2dnamtY4a74HXXnZ2dnUVZ7s-dnZ2d@bt.com...
>
> > Does this help?
>
> >http://www.londonpower.com/pscaling.htm
>
> Been there. More interested in how they sound in use, for those who have
> them, or have modded amps.
>
> icarusi
> --
>
> remove the 00 to reply

How long do you think it would take to add this mod to an amp?
Assuming we can gather the assembled brains and intelligence of UKMG
together at Buxton, I'm perfectly willing to "donate" one of my
Nanovalves to the cause of science.  If we mod one of them,  I could
bring them both down,  then we can A-B them directly to see what the
change in sound is like.

anyone up for assisting with this?


cheers


Andrew_S

> > Been there. More interested in how they sound in use, for those who have
> > them, or have modded amps.
>
> > icarusi
> > --
>
> > remove the 00 to reply
>
> How long do you think it would take to add this mod to an amp?
> Assuming we can gather the assembled brains and intelligence of UKMG
> together at Buxton, I'm perfectly willing to "donate" one of my
> Nanovalves to the cause of science.  If we mod one of them,  I could
> bring them both down,  then we can A-B them directly to see what the
> change in sound is like.
>
> anyone up for assisting with this?
>
> cheers
>
> Andrew_S


I had something like this in mind :
http://www.mastertone-amplifiers.co.uk/Power%20Scaling%20Kits/Power%20scaling%20kit.htm


anyone interested in helping me with open-amp surgery?    <grin>

cheers

Andrew

"icarusi" wrote in message
> More interested in how they sound in use, for those who have them, or have 
> modded amps.

Mine (which has power scaling):
http://www.youtube.com/watch?v=2gPWU6aD8pk

I do find the power scaling dial a bit non linear but other than that it 
does the job.

I can bring it to Buxton for people to have a play with if needed?



-- 
no66y©
no66y AT gmx DOT co DOT uk

"icarusi"  wrote in
news:meGdne8L6t0WsnfXnZ2dnUVZ8gSdnZ2d@brightview.co.uk: 

> "no66y©"  wrote in message 
> news:CL2dnamtY4a74HXXnZ2dnUVZ7s-dnZ2d@bt.com...
>> Does this help?
>>
>> http://www.londonpower.com/pscaling.htm
> 
> Been there. More interested in how they sound in use, for those who
> have them, or have modded amps.
> 
> icarusi
> --
> 
> remove the 00 to reply
> 
> 
> 

mine sounds great at low levels and i have used it gigging a few times
in small venues. 

with any amp at low volume tho you are never really going to get the
speakers moving. i really want to try mine thru a 4 by 12 with some
decent speakers in it. 

Dave

"andrew_s"  wrote in message 
news:329c8953-0672-4af0-888b-23a1fb254199@d5g2000yqm.googlegroups.com...

>>I had something like this in mind :
http://www.mastertone-amplifiers.co.uk/Power%20Scaling%20Kits/Power%20scaling%20kit.htm<<

"The installer of this mod should be able to recognize the relevant circuit 
points without a layout or schematic for the subject amp."

icarusi
--

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"icarusi"  wrote in message 
news:meGdne8L6t0WsnfXnZ2dnUVZ8gSdnZ2d@brightview.co.uk...
> "no66y©"  wrote in message 
> news:CL2dnamtY4a74HXXnZ2dnUVZ7s-dnZ2d@bt.com...
>> Does this help?
>>
>> http://www.londonpower.com/pscaling.htm
>
> Been there. More interested in how they sound in use, for those who have 
> them, or have modded amps.

This sounds pretty convincing:-

http://www.youtube.com/watch?v=llHu3bot24c

icarusi
--

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"icarusi"  wrote in 
news:kvOdnZ29gJIWg2vXnZ2dnUVZ8uudnZ2d@brightview.co.uk:

> http://www.youtube.com/watch?v=llHu3bot24c

thats just how mine gets, the power scaling does work :-)

"Dave"  wrote in message 
news:Xns9CBEA6D6E80D7blutacspamhotmailcom@194.80.134.122...
> "icarusi"  wrote in
> news:kvOdnZ29gJIWg2vXnZ2dnUVZ8uudnZ2d@brightview.co.uk:
>
>> http://www.youtube.com/watch?v=llHu3bot24c
>
> thats just how mine gets, the power scaling does work :-)

Looks I deal for doing guitar playing demo vids, being able to talk over a 
good rock/metal guitar sound.

icarusi
--

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