JCM 800 – building a quieter version

[Leo_Gnardo]

Immortals/cardboard stacks/Hellfest/Photoshop

Now, that's terrific! Luv the Lead 12, that little SS thing actually does the Marshall tone without a tube, and you don't even need to drive a speaker. DI straight to the monitor and FOH mixer, bob's yer uncle. Wonder what the audience thinks when the show's over and one stagehand carries both stacks, all in one piece, off the stage & onto the truck. What a larf! Hey, it's show biz.

Whups now I see the Lead 12's been "flown in", still a helluva gag. Good work.

[elipsey]

Does anyone know of a circuit I could use to build a Power amp that wouldn't be so powerful?.

How about high power tubes with:

• lower plate voltage
• higher primary impedance
• cathode bias

Some of the amps I thought sounded coolest when I got to try them do it this way, and yield about 25 to 35 watts. Some examples include the Valco 1200/Supro 6420, Star (Sampson) amps Gainstar 30, Deluxe Reverb power section with 6L6/5881 tubes. Obviously these are not marshall preamps, so you would have to improvise a bit.

Weber sells a couple of lower voltage PTs with sufficient current ratings that don't cost very much, e.g.: http://www.tedweber.com/media/import/w022723sch.JPG

[Willholmania]

How about high power tubes with:

• lower plate voltage
• higher primary impedance
• cathode bias

Some of the amps I thought sounded coolest when I got to try them do it this way, and yield about 25 to 35 watts. Some examples include the Valco 1200/Supro 6420, Star (Sampson) amps Gainstar 30, Deluxe Reverb power section with 6L6/5881 tubes. Obviously these are not marshall preamps, so you would have to improvise a bit.
[ATTACH=CONFIG]35088[/ATTACH]
Weber sells a couple of lower voltage PTs with sufficient current ratings that don't cost very much, e.g.: http://www.tedweber.com/media/import/w022723sch.JPG

Thanks. These are good ideas. Thanks for the circuit too.

[pdf64]

See Ian's EL34 amp http://music-electronics-forum.com/t21602-2/#post313328

[tedmich]

Now, that's terrific! Luv the Lead 12, that little SS thing actually does the Marshall tone without a tube, and you don't even need to drive a speaker. DI straight to the monitor and FOH mixer, bob's yer uncle. Wonder what the audience thinks when the show's over and one stagehand carries both stacks, all in one piece, off the stage & onto the truck. What a larf! Hey, it's show biz.

Whups now I see the Lead 12's been "flown in", still a helluva gag. Good work.

original picture here:


a couple of Engls behind a big faux Marshall stack wall

[guitarmike2107]

Building a new amp seems extreme compared to adding VVR or or using an attenuator like the Weber Mass etc

I used to gig with a 50w Marshall, now I normally use 10w - 20 watt amps with different speaker cabs depending on the gig,
There are not many places in the UK you can really turn a 50w Marshall up fully, bigger venues mic everything up anyway and provide foldback monitors.
I once did a gig for 3000 people where I had to play quieter than my normal weekly gig for 150 people...

[Willholmania]

It is a bit extreme, Mike, but I like building amps and have been discouraged from modifying the original. Plus, I have an empty JCM 800 1x12 cab and a custom made front panel for a combo with a 'Power' control added – for VVR.

[dai h.]

(since you're in UK, where I presume there are more Marshalls around) maybe find someone with the aforementioned lower B+ version they find, "isn't loud enough", and trade? (Just a thought.) The ones with the lower voltage (I would guess) are probably 30W-ish. Guess it also depends where exactly you intend to use it though also. Thirty watts (without attenuation) would still be too loud for home use (unless you live in a giant mansion or something).

[guitarmike2107]

Ha ha don't let me stop you, if you are into building amps then build one to suit your needs. Either VVR or use lower plate voltages or go with 6V6's

[printer2]

I built a 5E3 with 6AK6 output tubes. Want to build a 5F6A Bassman with them for output tubes. Here is the thread on the 5E3, So your 5E3 is still too loud huh? - Page 2 - Telecaster Guitar Forum

Want to hear it first? A buddy and his first impression of the amp. http://1drv.ms/1hDNpt3

The acoustic file is a walnut guitar I built and him trying it out also.