Express Choke.

Express, Liverpool, Rocket, Dirty Little Monster, etc.

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leadfootdriver
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Express Choke.

Post by leadfootdriver »

I have a Hammond 159P laying around. It specs out at 10 Henry's and 125 miliamps.

Good choice for an Express build?
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Colossal
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Re: Express Choke.

Post by Colossal »

A choke is used in the Rocket, not the Express. If you are looking to build an Express clone, a very important piece of the Trainwreck Equation (i.e. bloom, harmonics, compression) is that a 1k/25W power resistor is used in the "choke" position. Replacing that resistor with a choke will change the amplifier's response (and voltages).
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leadfootdriver
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Re: Express Choke.

Post by leadfootdriver »

I might be alright with that. I won't be using the exact same components, so it won't be an exact Clone anyways.

I don't even know if I'll like it, because I've never even played a Clone, much less the real thing.
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Colossal
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Re: Express Choke.

Post by Colossal »

leadfootdriver wrote:I might be alright with that. I won't be using the exact same components, so it won't be an exact Clone anyways.

I don't even know if I'll like it, because I've never even played a Clone, much less the real thing.
If you're cool with it, ok, but it will change the amp's tone, feel, and operating conditions (screen and preamp voltages). I recently built my first Wreck and the power supply design is a major factor in getting the amp to sound and feel the way it does. If you haven't built one yet, when you do, I might recommend that you try it first as designed, with the 1k/25W resistor. I think it might be a bummer to build a Wreck and not at least see how it was intended to be, possibly missing the boat because of one component (the choke) choice. I'm certainly not implying that to stray is heresy, experimentation is part of finding one's tone. But I've got to say that having finally built one for myself (a Liverpool) the Trainwreck design made for the best sounding amplifier I've ever heard. I was a Marshall guy through and through, but I've found my new muse.
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geetarpicker
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Re: Express Choke.

Post by geetarpicker »

Most likely with a Choke the amp won't have as much finely tuned power supply sag. This will mean the "clean to mean" volume will change more, making your cleans seems too quiet compared to the dirty which will then seem too loud in comparison. IMHO an Express/Liverpool's ability to nicely compress and keep the dirty tones very similar in volume to the clean tones is one of it's best traits. To me if the amp dioesn't clean up well (without loosing much volume) it would be missing half the point at least.
Roe
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Re: Express Choke.

Post by Roe »

just add a resistor in series with the choke. the originals use a 1k connected to two 1k screen grid resistors
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DaveMon
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Re: Express Choke.

Post by DaveMon »

Colossal wrote:A choke is used in the Rocket, not the Express. If you are looking to build an Express clone, a very important piece of the Trainwreck Equation (i.e. bloom, harmonics, compression) is that a 1k/25W power resistor is used in the "choke" position. Replacing that resistor with a choke will change the amplifier's response (and voltages).

Always wondered how this was accomplished..... glad I found this out
Roe
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Re: Express Choke.

Post by Roe »

what about using a big 250-300mA choke right after the rectifier? do you think it would improve the low end of the express without getting a stiff feeling amp?
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Express, Comet 60, Jtm45, jtm50, jmp50, 6g6b, vibroverb, champster, alessandro rottweiler
4x12" w/H75s
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