JCM-800/2204 Build

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ampgeek
Posts: 1009
Joined: Sun Oct 15, 2006 1:31 am

Re: JCM-800/2204 Build

Post by ampgeek »

I acquired an old, mid 80's Tascam Porta Two (in dead mint condition!), whipped out my Carvin M68 (vocal) mic and had at it this weekend.

First impression is....thank gawwwd we have recording engineers!! The "in room" tone/feel for the clipped segments was a very convincing, agressive rock sound. I can't say that the recordings are at all the same!

The sound clips all repeat the same riff at the beginning. The clipper circuit is switched in and out on a regular basis so you can get a feeling for the volume drop imposed by the various clipper arrangements (squish control set for maximum attenuation).

For the later bits, I dialed up the aforementioned "convincing" sound and noodled around with what felt right for the moment. Squish control backed off to varying degrees (less attenuation) and volumes tweaked to what felt good.

The overall room volume was nearing window pane rattling levels so the amp was definitely breathing-deeply for all clips (save the significant volume drop from some of the clipper circuits).

Surprisingly, the clean tone recorded, relatively, quite well!

Other particulars:
Guitar: 74 LP Custom with Seymour Duncan Pearly Gates PUs
Cab: Closed back Lopoline single 12"
Speaker: Well broken in Scumback M75
Mic Placement: Straight on ~1/2 way between the center voice coil and outer edge about 5" away.
Mixdown: Totally dry via Audacity (cool little program BTW!)

Not sure if I should consider this excercise a success or not. But one thing is for certain....I sure am glad that I have a day job! :lol:

Cheers,
Dave O.
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ampgeek
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Re: JCM-800/2204 Build

Post by ampgeek »

Postion 1 & 2 clips.
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ampgeek
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Re: JCM-800/2204 Build

Post by ampgeek »

Position 3 & 4 clips.
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ampgeek
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Re: JCM-800/2204 Build

Post by ampgeek »

Position 5 & 6 clips.
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Smokebreak
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Location: Texas

Re: JCM-800/2204 Build

Post by Smokebreak »

Great demo Dave! I like the Jubilee best too. I'm currently switching between 5v and 20v zeners. 2N5400 PNP transistors is what I'll try next. Apparently these are close to the spec Jose used, if I have my Internet folklore correct.
Cheers-J
ampgeek
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Joined: Sun Oct 15, 2006 1:31 am

Re: JCM-800/2204 Build

Post by ampgeek »

Thanks mate! Very glad that you found them useful.

Looks like your AFD project is a winner. Are you experimenting with clippers in that build?

Thanks again,
Dave O.
Smokebreak
Posts: 1391
Joined: Tue Dec 18, 2012 5:53 pm
Location: Texas

Re: JCM-800/2204 Build

Post by Smokebreak »

ampgeek wrote:Thanks mate! Very glad that you found them useful.

Looks like your AFD project is a winner. Are you experimenting with clippers in that build?

Thanks again,
Dave O.
I thought about it, but there is a boatload of gain with all the stages and bypass possibilities in the AFD. My Jose amp is a 6V6 thing, and I'm gonna dink around with it today
john l
Posts: 115
Joined: Tue Mar 15, 2011 2:12 am

Re: JCM-800/2204 Build

Post by john l »

Shit I'm down to my iPad and don't see a link to hear your amp Dave. I want to try that Jubilee clipper but I'm not sure if I'm reading that scheme right.... Hmm.
John
john l
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Joined: Tue Mar 15, 2011 2:12 am

Re: JCM-800/2204 Build

Post by john l »

Double post
Last edited by john l on Tue Feb 25, 2014 6:42 am, edited 1 time in total.
John
ampgeek
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Re: JCM-800/2204 Build

Post by ampgeek »

Hey John,
PM your email address and I will punch them along directly if you would like.
Cheers,
Dave O.
john l
Posts: 115
Joined: Tue Mar 15, 2011 2:12 am

Re: JCM-800/2204 Build

Post by john l »

Hey Dave I got your email. Sounds good buddy. I still haven't tried the Jube clipper but it's on my list. I've pretty much settled on just the clipper with no CF Master going to a 3 way that has trannys, nothing and a single red LED on it. Honestly I never really even thought about the symmetry of the clipping so I'm going pot set aside some time and play with that some in the next few days. Miles really created a cool circuit here didn't he? :D
John
ampgeek
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Re: JCM-800/2204 Build

Post by ampgeek »

Right on John! Glad that you were able to listen to them. Like I said though, the recordings just don't do justice to what it really sounds like out in the room.

Indeed! Miles sure knows what works in these circuits and I can't thank him (and you!) enough for sharing your experiences.

Speaking of which.....where has dear Miles been this last week? Haven't seen a thing from him which is rather un-usual. Hope that everything is OK at his end!

Dave O.
john l
Posts: 115
Joined: Tue Mar 15, 2011 2:12 am

Re: JCM-800/2204 Build

Post by john l »

Hmmm I spoke to him last week to pick his brain on bootstrapping cathode followers and he said he was keeping busy. Lots of good dudes here but it's deffinatley not the same when he's not around huh :lol:

I did one for a buddy of mine and he's selling a bunch of his old jmps now he loves it so much
John
Smokebreak
Posts: 1391
Joined: Tue Dec 18, 2012 5:53 pm
Location: Texas

Re: JCM-800/2204 Build

Post by Smokebreak »

Great looking build John! Where are you sourcing those box caps?
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