Lower Voltage JCM 800 Build
Moderators: pompeiisneaks, Colossal
Lower Voltage JCM 800 Build
Been almost 40 years since I owned one of these. I forgot how loud they are! Had most of the parts accumulating over the years and after the Marshall section was added to the forum, and reading all the impressive ideas here, managed to assemble another working amp.
In the spirit of keep it simple, and with kudos to everyone here, this all went together in a blank JTM 45 chassis. It's very nearly identical to Jana's specifications with Trainwreck/Bassman type transformers and a modified power rail (closer to Trainwreck). It is indeed a very sweet sounding amp! Much better cleans than I remember with harmonics to rival anything I have ever built. Did I mention it is loud?
D
In the spirit of keep it simple, and with kudos to everyone here, this all went together in a blank JTM 45 chassis. It's very nearly identical to Jana's specifications with Trainwreck/Bassman type transformers and a modified power rail (closer to Trainwreck). It is indeed a very sweet sounding amp! Much better cleans than I remember with harmonics to rival anything I have ever built. Did I mention it is loud?
D
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Anything in moderation...nothing to excess
Re: Lower Voltage JCM 800 Build
Dave,
That looks very clean. Great build! What does the mod switch under the input jack do?
That looks very clean. Great build! What does the mod switch under the input jack do?
Re: Lower Voltage JCM 800 Build
That's the low input switch I borrowed from Jana. Puts a 100k in series with the 470K on V2a (before CF), grid to ground. Two distinct gain options through one jack. Very versatile.
Anything in moderation...nothing to excess
Re: Lower Voltage JCM 800 Build
Correction ...100K in parallel with 470k....
Anything in moderation...nothing to excess
Re: Lower Voltage JCM 800 Build
Very nice build!
You have some nice parts there!
Mustards
Takmans
looks like the voltages are fairly close.
Is this the 2204?
Does the master volume on those work well?
And it goes to 11!
You have some nice parts there!
Mustards
Takmans
looks like the voltages are fairly close.
Is this the 2204?
Does the master volume on those work well?
And it goes to 11!
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: Lower Voltage JCM 800 Build
Very nice amp Looks killer and I bet is does sound great too.
I built something like this a few years back using TW PT and Dynaclone A-470-S OT 4k3 into a BF Champ chassis very cool amp for sure.
Mark
I built something like this a few years back using TW PT and Dynaclone A-470-S OT 4k3 into a BF Champ chassis very cool amp for sure.
Mark
Re: Lower Voltage JCM 800 Build
Thanks guys. Yes, it is based on a 2204. It's all preamp with this master and it does sound best opened up into the PI. Running it through a 100 watt MASS right now, trying to decide if I want to add a PPIMV. Do you guys think this would benefit with a second master?
Anything in moderation...nothing to excess
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Re: Lower Voltage JCM 800 Build
I've got 1 with both a normal and PPIMV . PPIMV just stays all the way up You can get some different sounds out of it though(not all good!) I'm biased though Ive never met a PPIMV I liked.
Re: Lower Voltage JCM 800 Build
That there is a nice looking build - well done.
I'm also not a fan of a PPIMV in this circuit.
Jana's hi/low switch is a nice option.
Bet this amp sounds killer.
I'm also not a fan of a PPIMV in this circuit.
Jana's hi/low switch is a nice option.
Bet this amp sounds killer.
Why Aye Man
Re: Lower Voltage JCM 800 Build
Thanks for the input. Think I will let it ride for a while and use the MASS to appease the neighbors.
D
D
Anything in moderation...nothing to excess
Re: Lower Voltage JCM 800 Build
The lead dress is very neat. I use both Pre and Post MV's with my 2203 and it works great at any level. I beleive some are pro and others are con but according to me it is the best of two worlds.davesi wrote:Thanks guys. Yes, it is based on a 2204. It's all preamp with this master and it does sound best opened up into the PI. Running it through a 100 watt MASS right now, trying to decide if I want to add a PPIMV. Do you guys think this would benefit with a second master?
If you don't like it, it's easy backing your amp to what it was, but you know that mate
2203/2204-ish/Deluxe Reverb