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Tonight, I was driving home and listening to Hair Nation (sirius) and I realized that there's still some cock rocker left in me...

so I'm going to build a 50watt jcm800....just for kicks!

-F

Cool which one?

_________________
Richard Johnson
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Playing an insturment doesn't make you a musician, listening does

Dunno, regular 2204 I suspect...that's the 50watt one, right?

There was the original 2203, the later 2204, and the transitional amp that eventually turned into the JCM900. That one had some clipping diodes in the preamp.

You will hear endless argument and debate over which of the 2203 and 2204 is better. I like the 2204. But I still think you should build a Wreck first :)

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--s2
www.s2amps.com
www.category5amps.com

I would never build anything 100 watts, which is what i believe the 2203 was/is...

I was thinking of the 50watt version of whatever jcm800 doesn't have the clipping diodes...but has a plexi voiced channel for a lo input and the high input adds in another triode....I think that's the 2204 right?

Here...Whatever Mark's got here:

http://www.mhuss.com/MyJCM/index.html

Yeah, a 2204...


-F

So why do't you just put it on 6V6s and rock out at low volumes? That would be the ultimate hairy recording amp!

_________________
--s2
www.s2amps.com
www.category5amps.com

That's not a bad idea....and it would probably still be loud enough to gig with....

hmm....

B&V, I thought you were taking a rest what with Baby & all!

I have a JCM800 2203, 100W gathering dust down here.. tooo loud!

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

No way man...

I stopped thinking about building stuff for about 2-3 weeks....and as soon as the dust settled...I started brewing some ideas...I'm currently in the middle of a 6v6-fixed bias amp named after a muscle car that Chevy just rereleased...

After that's done in a few weeks, I gotta do something that'll scratch my 80s hair rock itch....gobs of gain, an effects loop for some cheesy 80s chorus and delay.....you get the picture.


Also, that's the one thing that's preventing me from wanting to do this build with 6v6s...I want to have an effects loop in this thing for gobs of chorus, delay and other 80s artifacts ....and el34s will give me enough headroom to have that stuff....and I'll rely on preamp gain, like those JCM800s were supposed to do anyway...

I dunno...I'm thinking out loud here....

If you tweak it with more conservative voltages on the plates, you could probably do like the TW Express and swap in more robust 6V6's for the EL-34's as needed. Depending on how loud you need, the 6V6's might have plenty of good headroom.

For gobs of gain, I might look beyond the JCM-800 and look at the SLO homebrew stuff. There's a Soldano forum that seems well populated to guide you along if you so chose. Keep in mind that a lot of those Marshalls were modded, and Soldanno was one of the most sought after modders. If you're going to go for the Marshall gain staging, you'll probably want to go for a different MV design, anyway, as the originals thinned out the sound at lower volumes.

And I've thougth about the Chevy design before - did you have a proper scheme or did you take another route and meander?

Bear

Hmm....the SLO is something to consider as well. The reason I've been thinking JCM800 is to totally capture that 80s LA sound...blame Hair Nation....listening to DLR, Whitesnake, Dokken and most of all White Lion (Vito's my favorite 80s hair rock guitarist) on the radio again makes me feel all young and tingly. The JCM800 was the basis for all of those bands (except whitesnake, as John Sykes used a 200 watt Mesa Boogie Colusseum head)....so that's where I'm going with this.

I remember back a few months, someone posted a few clips of an amp he built. He basically slapped the preamp from a rocca HH100 onto a 6v6 power stage (like mark huss's 6v6 plexi)....and the sounds he posted were pure LA hair rock...Dokken, VH, etc...So I might go in that direction as well...

Part of me wants to build something with EL34s just to do it....Granted, I do love 6v6s...


As for the chevy design....email me offline and I'll be glad to fill you in on the particulars....

Man, some of them clips on that website are KILLER

Don't discount an SLO style build. If you want a one channel amp, then it will only take 5 triodes. Three 12ax7s. The extra triode could be used for FX loop recovery. Add a 4th 12ax7 for PI and some 6V6s, KT66s or EL34s and you're all set!

I've built a few high gain channel switchers. Three are based on and SLO style gain channel. Two are on BBQ 6xS (SLO style) chassis. These both use chokes and JTM45 style output stages. One amp has EL34s (my current main amp) and the other uses KT-66s. The third was just recently rebuilt from a single channel high gain 18 watter into a 6V6 based version using a GDS chassis and trannies.

All three feature a Fenderish clean channel (think Deluxe/Twin Normal channel) and a Gain channel. The gain channel has two modes, one is medium-high gain Marshall (JCM-800 style with a less bright voice) and SLO (same basic topology with some tweaks). To switch modes I just bypass the gain stage with the 39k cathode resistor to get the Marshall voicing. Each mode also has its own pair of gain/volume controls on the larger amps and a shared volume with separate gains on the 6V6 amp. The two gain modes share EQ. Any large manufacturer would call it a three channel amp.

It is very effective, although a little complex to build on a turret board. The nice thing about the SLO type gain channel is that you can make it go from low gain sounds to a good sounding high gain sound. The trick is balancing low end levels. There's nothing to keep you from using some toggles to go from a Plexi set of gain stages to a modern high gain setup.

Just some ideas.

_________________
Richard Johnson
-------------------
Playing an insturment doesn't make you a musician, listening does

Richard, what are you using for a channel switching relay?

-F

I'd be interested in channel switching sometime. I've thought about it.
But how can you jump channels with such a rig? Or maybe it's not a requirement.
Does this just add complexity? or what is the reason to do this?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

you know, the whole channel switching relay, as far as I can tell, is a way to clean up the input section of the amp...

I don't see a problem having a two channel amp with an A/B switch out in front of the amp....

but some folks dont like having 2 cables going into the amp instead of one...I dunno...

-F

Well I can sure se the benefit of cleaning up the guts & the front panel, but I'd want to be able to mimic A-B-Y switch and how do you handle Hi - Lo inputs ? Or do you?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

If it is a JCM800 style preamp, you could just have the high input jack and switch out the first gain stage the way Doug Hoffman does his "Hot" switch. Because the only difference between the high and low inputs of a JCM800 is that one gain stage. Hoffman sells all the parts and has a layout at his site explaining how to mount the relay.
Just an idea, mark

I just use some pretty common relays from Mouser (NTE 526-R40-11D2-5/6 Relay). Even the 5v or 12v ones rat shack sells will work. For a real easy solution, the W.e.b.e.r relay board works well too.

Having a channel switching amp is most convenient if you need to cover a lot of range. Especially moving from a really clean sound to a distorted sound. If you're in a blues/rock band a one channel amp with the guitar's volume control is probably just as convenient. Also, for many people an A/B/Y box will work.

However, I'm playing in my church praise band and we cover everything from folky stuff to Jazzy, Gospel and modern rock styles. So I need to be very clean one moment and instantly be very distorted for leads or rhythm. Some of the time I use the "Marshall" mode like a one channel amp and use the guitar volume to go from clean to dirty. The other nice thing is since each channel/mode has a different voicing, it can be like having three amps. I also use the active tube driven FX loop for TC Electronics GMajor and use a MIDI Footcontroller to change FX and switch channels.

But here's my dirty little secret. If I could play through just a one channel amp with a cable to the guitar I'd be most happy. There's nothing I like more than playing through a Marshall 1987 or Marshall 1974 cranked.

Unfortunately, I have to play for the gig so the channel switcher is the practical choice.


P.S. love the filter on a certain vendor's name!

_________________
Richard Johnson
-------------------
Playing an insturment doesn't make you a musician, listening does

SPAM!!