36w headroom question

Marshall Amp Discussion

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peckjed
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36w headroom question

Post by peckjed »

Hey everyone! I am in the process of soursing parts for my 2nd build and was looking to build a 36w style TMB with ef86 channel. I found a layout (attached) that I will probably use as a base and then tweak as I go. My question is, are there any tweaks I can add to give it a bit more clean headroom?
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Roe
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Re: 36w headroom question

Post by Roe »

ss rectifier, higher voltages and filtering typically
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Stevem
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Post by Stevem »

The easiest thing to do would be to make it fixed bias , or the option to do such by means of a DPDH switch.
After that you can convert two of the output tubes over to 6V6s, or all 4 of them, 6v6s need more drive signal then 84s do !
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Phil_S
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Re: 36w headroom question

Post by Phil_S »

Hmm...it is heresy, as it rolls off some of that Marshall goodness, and not that it's bad, just different...you can reduce the 470K resistors in the PI to 330K or 220K, which moves towards Fender territory. YMMV. I liked my 18-watt with 220K, so people can say what the will about heresy!
pdf64
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Re: 36w headroom question

Post by pdf64 »

I hate that 'headroom' word - what is the technical definition of the headroom in the context of a guitar amp:?
The pro-audio definition just doesn't seem to fit https://en.wikipedia.org/wiki/Headroom_ ... rocessing)

What does everyone else understand by it?

It just seems a vague term, like 'how do I get more mojo out of my amp'.
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Post by Stevem »

There's no cheap way to do this!
You can go the route of a better speaker (s) or more speakers, or add a seperate filament transformer as that would free up a few Milliamps and kick up the B+ a hair.
You could sub in a bigger PT that would do the same.
The more speakers route can make a major change in clean head room!
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Not screaming like the passengers in his car!😊

Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
bluesfendermanblues
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Re: 36w headroom question

Post by bluesfendermanblues »

pdf64 wrote:I hate that 'headroom' word - what is the technical definition of the headroom in the context of a guitar amp:?
The pro-audio definition just doesn't seem to fit https://en.wikipedia.org/wiki/Headroom_ ... rocessing)

What does everyone else understand by it?

It just seems a vague term, like 'how do I get more mojo out of my amp'.
I'm ok with headroom. However, I tend to agree a little bit, since tube amps are never clean anyway.

You could argue that the headroom term, makes more sense when talking about HiFi gear, where you want enough clean headroom in order for louder passages not to compress or clip. E.g. with Mahler's 5th symphony that has a lot of dynamic space between quiet passages and the louder ones.
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