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My Marshall with Power Scaling
#1
Hey
I got this Marshall amp way back, kinda beat up but it has master volume and sounded cool. Got it cheap so how can you go wrong with an amp like Eddy uses? After you live with it for a while and hear how quiet your buddy's amp is and other guys amps you wonder if you can get your amp quiet too? can you get that really loud sound without it having to be really loud?

I tried an attenuater but that kinda ruined the tone when you got it to be quiet. I know the whole point of the master volume amp is to be able to get the sound of a cranked amp at low volume, but it doesn't have that smoothness that turns out comes from the power amp clipping. Who knew? Huh 

I guess Kevin at london power knew cuz he came up with power scaling so rockers like me could get the tone without the cops coming by every time. This is like the best thing since electricity Wink I had done a few simple mods like adding a gain cap and snipping out some bright caps. The tone got better each time but then I heard about this little master volume mod from a friend that has the first TUT book. It worked! Just adding one resistor made the MV totally useful! So I figure this guy knows what hes doing - haha

The London Power site has all kinds of cool nformation and I read about the power scaling stuff for hours, trying to absorb it all. Kevin answered all my Qs and gave me lots of help before and after I bought the kits. Stuffing the board was a bit weird with the one-percent resistors, but i used my meter to check them and got everything built, then got it wired in. I did the testing without tubes and then put in some glass and fired it up. Holy cow ! I got awesome tones at stupid low volumes. Like I could hear my strings rattling even with the sound like a stack blowing up Big Grin This is like crazy good!

The most amazing thing is that the amp sounds better quiet than loud which is like totally opposite of what everyone says it should be Rolleyes Guess KO was right about that one too.

I think this was the hardest mod I'll ever do but it is way worth it. I got The Ultimate Tone 3 after that to see if I could make the amp noise lower. of course, it worked out exactly as I hoped with a lot of chatting with Kevin about what parts I missed along the way. He was like my cheer leader giving me encouragement and I couldn't have done it otherwise. I have a great sounding amp now and a new friend. Good thing he's a rocker too or I'd be really confused Big Grin
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#2
Thumbs Up 
Nice! What model is your Marshall?
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#3
Hi victor86hm

It's just the 50W MV amp.

Since the power scaling works so awesome and the TUT3 wiring stuff made the amp so quiet, I got the bias mod kit for 2 tubes. All the projects in the book have a bias pot pot for each tube. The 800 project is kevin's version of my 50W amp but it uses 4 power tubes even though the amp is only 50W. That confused me at first - but like I'm easily confused  Huh

Kevin's 800 uses the extra tubes for tone - he calls it "100W of tone but only 50W" and the really cool thing is you can use any tubes in it or even mix tubes  Big Grin

Even though I read that part of the book a lot of times I had to call the master and he made it really clear for me. I bought  the BMK2 and installed it and tested without tubes again - how many times did KOC tell me that! - and then tried my original tubes first. Holyw cow -it's so easy to bis a tube. Then i changed one tube like Kevin suggested and had a 6L6 working with a EL34 and it sounded much cooler !!!  Then I changed the 34 to another 6L6 and it had this smooth Fender vibe but the marshall distortion from the preamp. kevin said I could use 6V6 in this amp, so I got some of those - just some cheap ones since I still had a doubt from what evryone else says on the net - and fired it up and it worked great. 

The 6V6s in my Marshall sound really great. I tried pulling one 6V6 nd stuck a el34 back in and that combo sounded really really good Cool How is it other techs don't know this stuff? My buddies can't believe how good my amp sounds now and then I show them the tubes in the back and they freak. They tell me the tubes will blow up and its dangerous and all the kind of stuff I saw on the web before I tried this. Then I show them the book and say "this is the real sh#t man, this is like the truth no body wants you to know" I don't know anything but I got this really cool amp now that i was able to make sound good by myself all thanks to KOC  Big Grin
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Come in where it's warm!
A warm welcome to those interested in tube and hi-fi audio! Fans of Kevin O'Connor's The Ultimate Tone (TUT) book series form a part of our population. Kevin O'Connor is the creator of the popular Power Scaling methodology for amplifiers.
Please remember these three principles: respect, sharing, community.
Not familiar with The Ultimate Tone book series? See discussion topics, or click here to visit London Power/Power Press Publishing.

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