#34/#36/#39 scheme

Tube or solid-state, this section goes to eleven!
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alexhangman
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Post by alexhangman »

Can you tell me, is this scheme right for making preamp or not?
Maybe there is some fresh scheme? Who was trying this?
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39v2-1.jpg

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apollomusicservice
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Post by apollomusicservice »

The schematic is ok but there are a lot of things between rows when you building tube preamps.
Here is very dangerous high voltage and selection of components is very important.
Are you already made something with tubes?

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alexhangman
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Post by alexhangman »

apollomusicservice wrote:The schematic is ok but there are a lot of things between rows when you building tube preamps.
Here is very dangerous high voltage and selection of components is very important.
Are you already made something with tubes?
No, but my friend can, he made a lot of preamp for sale. He will do it, but i want to be sure that this schem is working. Because i found it from internet and i don't know is it working well or not.
We're gonna make the preamp and i will use it right through my power amp of Marshall JCM Slash jubilee 2555SL. What do you think?

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Post by apollomusicservice »

Great amp with built in two channels, clean and distorted. Your friend, who has a lot of experience,
will certainly recognize that schematic is ok. Go ahead guys and share with us yours working progress. :thumbsup

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Post by alexhangman »

apollomusicservice wrote:Great amp with built in two channels, clean and distorted. Your friend, who has a lot of experience,
will certainly recognize that schematic is ok. Go ahead guys and share with us yours working progress. :thumbsup
He said the schem is working, but i just can't decide what schem is better because there is a lot of schems, Duke amps schem and Shenier amps schem, candy fx... a lot of people do this mods with a different schems.

Btw is it ok that we will making just preamp without power amp, and i'm gonna put it to return of my JCM Slash 2555jubilee? Or it needs to make full amp 'cos power amp is modding too?
How will this affect on tone? Can i reach the Slash's tone with only preamp modding?

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phatt
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Post by phatt »

A quick look at the Amp circuit you mention tells me you are heading for a disaster. :blackeye
If I'm looking at the right schematic the Fx loop returns to another triode stage and then the tone tree then into PI and power tubes.
The result will likely be buzz, hum, crackle and a lot of squeal if you try to turn up the volume. :slap:

You can get extra crunch and gain easy with a pedals but a lot of guys shun pedals.
Don't be fooled by hype there are many ways to get the same sound and many of those will likely be cheaper and easier to attain.
Phil.

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Post by alexhangman »

phatt wrote:A quick look at the Amp circuit you mention tells me you are heading for a disaster. :blackeye
If I'm looking at the right schematic the Fx loop returns to another triode stage and then the tone tree then into PI and power tubes.
The result will likely be buzz, hum, crackle and a lot of squeal if you try to turn up the volume. :slap:

You can get extra crunch and gain easy with a pedals but a lot of guys shun pedals.
Don't be fooled by hype there are many ways to get the same sound and many of those will likely be cheaper and easier to attain.
Phil.
What circuit do you mean? Circuit of my 2555 jubilee or circuit of the schem in the first post?

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Post by alexhangman »

I have one more amp, AFD100, there is a correct loop, right to the power amp. I can use it with that preamp.

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Post by phatt »

Hi Alex,
Sorry if I was not clear,
I'm refering to this schematic,, down a bit for schematic.
http://www.ampspecs.com/marshall-jcm2555-schematics/

If that is your Amplifier then you will likely run into problems as the preamp you have will unlikely give you the same sound with more gain.
You can't just keep adding gain stages,, YES a fair bet that the tone will be different and Murphy's Law suggests in a bad way. :blackeye

Please Note;
You said you have a 2555 Marshall Amp head Slash model.
Now you want to build a separate preamp to get Slash's tone. :scratch: :scratch: :scratch:
I'm sorry but that logic does not compute

yes if the other amplifier's efx return goes direct to PI then it will work but remember layout is super critical with these circuits,, it might look simple on paper but there are a lot of traps lurking when building multi stage preamps.
Phil.

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Post by alexhangman »

Jubilee is not so trebly as #34 and other mods #36 and #39 has another tone compare to 2555.
Jubilee has a sweet tone but those mods have a little bit different.
Many people do these mods and it works -
for example

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Post by phatt »

Thanks for the link,,
I did not hear any real difference in that clip but if that suits your needs then just mod the existing amplifier and a switch system or whatever suits your needs,, I was just giving you other possibilities you may wish to consider. :thumbsup

I've just been researching some pedals one of these might be cheaper and possibly more versatile;

Phil.

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Post by sinner »

Can you take some gutshots of your JCM Slash 2555jubilee for me, please?

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Post by alexhangman »

sinner wrote:Can you take some gutshots of your JCM Slash 2555jubilee for me, please?
What do you mean?

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Post by sinner »

alexhangman wrote:
sinner wrote:Can you take some gutshots of your JCM Slash 2555jubilee for me, please?
What do you mean?

Innards, PCB's pictures

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Post by alexhangman »

sinner wrote:
alexhangman wrote:
sinner wrote:Can you take some gutshots of your JCM Slash 2555jubilee for me, please?
What do you mean?
Innards, PCB's pictures
ok but it takes time. In the near future, when i will change tubes.

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Post by okgb »

It's allot of reading on that Metro site, gets a little confusing with people trying different things
but sometimes not a strong consensus on the different ways to get that sound !

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Post by alexhangman »

I just bought full amp Marshall JMP '79 with those mods #34/#36 from Dukeamps (Nigel). :D Amp on its way.

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Post by alexhangman »

Preamp 2203/#34 on its way too. :D

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Post by alexhangman »

my JCM800 preamp

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Post by okgb »

Nice work ! What schematics did you use for this ? I was going to build one with a jubilee one channel and an AFD the other

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