12000 amp build in the UK!

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shackman
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12000 amp build in the UK!

Post by shackman » Sun May 17, 2015 8:48 am

Well I've been lurking on here for some time reading about all the amp builds going on.

I've built a couple of JTM45's in the past, I am a qualified electronics engineer and used to work for a Amplification factor as the test engineer.

I decided to bite the bullet and build a 12000 series for myself. (I had to sell one of the JTM45's to fund it!)

You would have thought that getting the parts in the UK would be easy, you know being how Marshall built them in the first place, but no.

Michael at Modulus Amps was very helpful, so I could get the chassis and some other parts from him. But the transformers where a different story. Michael told me not to take short cuts on the tx's so it was to email American manufactures the way to go.
Chris at ****** came up trumps and I ordered all the iron from him.

I managed to find a fully populated main board and power board on ebay for decent money and it had Sozo caps on it!

So I had the chassis prepped as much I could and then had to wait of the tx's.

They arrived Friday, so I spent the day putting the amp together. I had read so many build stories on here I did most of it from second sense.

Got the amp working yesterday and could not believe how much gain you get out of a standard circuit!

I don't know if it's the Sozo caps or the resistors used but it's amazing. I used some NOS Marshall Ecc 83's in the preamp with the RED valve on V1 and JJ EL34L valves on the power section.

It sounds amazing, I had to fit a Lar/Mar PPIMV on it to control the power, without that anything above 2 was mad!

I'll get some pics up in the next few days, I want to identify the type of resistors used if I could.

shackman
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Re: 12000 amp build in the UK!

Post by shackman » Sun May 17, 2015 1:18 pm

Can anyone recognise these resistors?


Image

Tazin
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Re: 12000 amp build in the UK!

Post by Tazin » Sun May 17, 2015 6:08 pm

shackman wrote:Can anyone recognise these resistors?
As in the types?....The dark brown ones are Allen Bradley carbon composition, the tan ones are Xicon carbon film, and the blue ones are Xicon metal film. The carbon composition resistors with five color bands (the additional yellow band) are mil-spec resistors.

shackman
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Re: 12000 amp build in the UK!

Post by shackman » Mon May 18, 2015 2:47 am

Thanks Tazin,
I thought they where CC resistors but wasn't sure. I thought all this (special) resistor and capacitor types where a load of rubbish, when I was at college being taught electronics all those years ago a resistor was a resistor and a capacitor was just that, how wrong I was!

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neikeel
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Re: 12000 amp build in the UK!

Post by neikeel » Mon May 18, 2015 8:17 am

Looks good, glad it sounds good

Hope you have straightened out the lead of that 10k resistor on the PI tail, recipe for problems hovering over that mounting bolt!
Neil

shackman
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Re: 12000 amp build in the UK!

Post by shackman » Mon May 18, 2015 12:35 pm

neikeel wrote:Looks good, glad it sounds good

Hope you have straightened out the lead of that 10k resistor on the PI tail, recipe for problems hovering over that mounting bolt!
Will do!

It's about 5mm away from the bolt but I hear what you say.

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vanhalen5150
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Re: 12000 amp build in the UK!

Post by vanhalen5150 » Sat May 23, 2015 9:44 am

neikeel wrote:Looks good, glad it sounds good

Hope you have straightened out the lead of that 10k resistor on the PI tail, recipe for problems hovering over that mounting bolt!
That's the first thing my eye went to as well. :)
12000 Metro Kit

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rgorke
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Re: 12000 amp build in the UK!

Post by rgorke » Wed Jul 15, 2015 10:00 am

vanhalen5150 wrote:
neikeel wrote:Looks good, glad it sounds good

Hope you have straightened out the lead of that 10k resistor on the PI tail, recipe for problems hovering over that mounting bolt!
That's the first thing my eye went to as well. :)
Just make it a straight shot like the 220k resistors to the right.
"If you make a mistake, do it twice and smile and let people think you meant it." Jan Van Halen.

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