Has anyone used London Power scaling

[Planobilly]

Hi,

Has anyone here installed a London Power power scaling device?

I have not spoken to the company yet or have any idea what the cost of there device is.

Just would like to know if anyone has used it and if so what you think.

Cheers,

Billy

 

[DUG]

Would be nice to have a link so an opinion may be generated without searching for what we think you are talking about.

🙂

 

[JonSnell Electronic]

I have just looked at the lower part of the document Selecting a Power Scaling Kit Looks like it is a form of compressor. Not really much information at all apart from some rubbish about high impedance bias circuits.

 

[jazbo8]

So it appears that you have not done any research before posting a question... You can PM/email/call Kevin O'Connor, I am sure he is more than happy to tell you about the device. His handle here is struth.

 

[Planobilly]

Here is the link
https://www.google.com/webhp?source...=1&espv=2&ie=UTF-8#q=london power scaling kit

I have looked over the web site. My question is simple.

Has anyone here installed the device and what was the results.

Thanks for the feedback.

Cheers,

Billy

 

[Printer2]

A buddy has put one in an 18 Watt variant. I had to troubleshoot why it was not working, he built it as a kit. Was a wiring issue, circuit worked fine. The circuit used to get the power scaling is a level up from the simple ones you can find schematics for. It is well thought out and probably one of the best ones out there.

 

[boobtube]

Not sure if this helps or not but here are the companies that are licensed to use the technology in their amps: Power Scaling Builders & Installers Quite an impressive list, so if you've heard the power scaling option on one of these, you've heard this circuit.

 

[bear]

Kevin is a participant here. I think his login is "Struth", although I may have that wrong.
Smart fellow about electronics.

Some people like his stuff.
Others do not. Talking about the Power Scaling... his site has a lot of information on it.

_-_-

 

[Planobilly]

Thanks for all the feedback guys. I have in mind to call the company tomorrow during business hours. The feedback here and other places seems to indicate the device does a better job than some of the other solutions that exist.

I am finishing the build of a JTM45 Metroamp for someone. He has ask me to come up with a solution to reduce the volume while keeping as much of the tone as possible. While this is possible to some extent nothing that I have every played through works 100%.

Thanks Printer2 and bear...this was just the kind of feedback I was looking for.

Cheers,

Billy

 

[gingertube]

Yes - See this thread.
http://www.diyaudio.com/forums/instruments-amps/251971-power-scaling.html
Cheers,
Ian

 

[Struth]

Hi Guys

Power Scaling does what we say it does and thousands of players agree. Please feel free to disagree.

Power Scaling maintains the transfer function of the output stage, so the tone stays the same.This is very easy to do but the patentees of the 1980s failed to implement correct methods to do this. The effects of transformer bandwidth limiting and speaker dynamic nonlinearity is lost, but... Those things occur at SPLs well beyond the Human Scale of perception so no one standing near the cabinet hears them accurately anyway (their ears close up due to aural compression). TUT4 explains all of this in detail, and the "Power Scaling Q&A" on our site provides player-accessible information, as do many other guides on our site and the product descriptions themselves.

Post-3 demonstrates a reading comprehension shortfall. An example of "maintaining the cusp of compression" is used to illustrate how to set controls.

There are a few people/companies doing power reduction but generally the wrong way. Those methods change the tone of the amp and players are dissatisfied as expected. At least those companies are making an effort to help players retain their hearing so a lifetime of musical enjoyment can be realised.

Have fun

 

[Planobilly]

Hi Guys

Power Scaling does what we say it does and thousands of players agree. Please feel free to disagree.

Power Scaling maintains the transfer function of the output stage, so the tone stays the same.This is very easy to do but the patentees of the 1980s failed to implement correct methods to do this. The effects of transformer bandwidth limiting and speaker dynamic nonlinearity is lost, but... Those things occur at SPLs well beyond the Human Scale of perception so no one standing near the cabinet hears them accurately anyway (their ears close up due to aural compression). TUT4 explains all of this in detail, and the "Power Scaling Q&A" on our site provides player-accessible information, as do many other guides on our site and the product descriptions themselves.

Post-3 demonstrates a reading comprehension shortfall. An example of "maintaining the cusp of compression" is used to illustrate how to set controls.

There are a few people/companies doing power reduction but generally the wrong way. Those methods change the tone of the amp and players are dissatisfied as expected. At least those companies are making an effort to help players retain their hearing so a lifetime of musical enjoyment can be realised.

Have fun

Thanks Kevin,

A client tried to build a Metroamp kit and really made a mess of things and fried the output transformer in the process. I had to take everything apart and start over. The new transformer will arrive in a day or two. As soon as I get the amp up and stable I will give you a call and order the part.

I don't normally build amps but the Metro amp was a simple design and the instructions were very easy to follow. Paint by numbers kind of thing. From what I have read and been told by people I trust the kit George put together sounds pretty good.We will see when I get it running.

As I understand, the parts you sell are less than $100 so I think that is a small amount of money to solve a classic problem. I have several clients who have very loud amps and are using attenuators which cause problems and don't sound very good. I am sure some of them would be very happy for me to find a better solution.

Looking forward to giving your product a try.

I also think I will buy your book that relates to grounding issues and re-ground a couple of amps I own to see what the results are for me.

I have little trouble repairing tube amps but all this electronics stuff is a more or less a new adventure for me and I have a lot to learn.

Being new at this it is sometimes hard to sort out what is useful information and what is simply nonsense.

I really had a hard time at the start reading through the miles of total BS written about tubes for example. Fortunately for me I found a very knowledgeable vendor who gave me some proper education and I no longer have any tube issues both in understanding how they work and where to buy them.

This has been a fun adventure.

Cheers,

Billy

 

[Struth]

Hi Guys

Billy, thanks for your kind support!

It is unfortunate that all the clone kits retain the original wiring errors - and some have even worse ones. It is SO easy to make those amps quieter and more articulate just by moving wires and changing the grounding.

For a peak at Galactic Grounding (detailed in TUT3 and shown in layout drawings as real applications), look at the "PTP vs PCFB" thread, and also another about grounding power amps in the solid-state area. TUT3 has been out since 2003 so there is no excuse for amps to poorly wired anymore. Tubes amps do not have to be noisey.

Have fun