I very recently did a trade and received a 50-watt JCM Bass Series head in very nice condition. 1981, I believe.
Anyone use one of these? It had been used for guitar for many years but I would like to use it for guitar and bass recording.
Commentary?
JCM 800 Bass Series
2I dig em. I had a 50w JCM 800 bass series for a bit. For guitar, they are a bad ass foundation for pedals. I liked it for low volume bass recording too. Ton's of balls and a great alternative to cranking an SVT.
I didn't like it nearly as much as my 78 JMP Super Bass. The tone of the JCM 800 bass was just a bit more dull compared to the Super Bass 100 watter. I like mids in my bass tone and the 800 provided that, no problems. I just liked the top/low end better on the SB 100. I still wish I had the 800 though.
I didn't like it nearly as much as my 78 JMP Super Bass. The tone of the JCM 800 bass was just a bit more dull compared to the Super Bass 100 watter. I like mids in my bass tone and the 800 provided that, no problems. I just liked the top/low end better on the SB 100. I still wish I had the 800 though.
JCM 800 Bass Series
3I was gonna say if it's anything like its JMP predecessor, it's almost the same thing but with a couple resistor and cap values different on the cathodes, in the tone stack, coupling caps... and one version of the JMP bass amp (model 1986) doesn't use the second half of V2 to drive the tone stack from the cathode like the 1987 does, and like other versions of the 1986 do.
BUT.
It looks like it's pretty radically different. If this is the right schem, for the amp you're talking about, it looks pretty atypical of all the other JMP and JCM800 amps I've seen, and is full of extra caps like mad in the signal path cause of the "slope" control. Weird EQ topology, too. I have no idea if that's the 50W JCM800 bass amp you've got though, without knowing the exact model number.
That schem indicates individual bias controls for each output tube, so that's nice.
Never heard the amp though, and if you have it in your possession, then obviously you'll know how useful it is as soon as you use it.
BUT.
It looks like it's pretty radically different. If this is the right schem, for the amp you're talking about, it looks pretty atypical of all the other JMP and JCM800 amps I've seen, and is full of extra caps like mad in the signal path cause of the "slope" control. Weird EQ topology, too. I have no idea if that's the 50W JCM800 bass amp you've got though, without knowing the exact model number.
That schem indicates individual bias controls for each output tube, so that's nice.
Never heard the amp though, and if you have it in your possession, then obviously you'll know how useful it is as soon as you use it.
"The bastards have landed"
www.myspace.com/thechromerobes - now has a couple songs from the new album
www.myspace.com/thechromerobes - now has a couple songs from the new album
JCM 800 Bass Series
4Model 1986, and it does have the unusual tone controls.
I've heard it used for guitar at a couple of shows through a 4x12 loaded with Fanes and it sounded great.
I've heard it used for guitar at a couple of shows through a 4x12 loaded with Fanes and it sounded great.
JCM 800 Bass Series
51986 or 1996? The only 1986 schems I've seen (I have two different ones) are both for non-master-volume amps with conventional JMP tone controls.
"The bastards have landed"
www.myspace.com/thechromerobes - now has a couple songs from the new album
www.myspace.com/thechromerobes - now has a couple songs from the new album
JCM 800 Bass Series
6The little info panel on the back says "1986" as far as I can tell.
No master volume, but the weird "slope" and "sweep" stuff in the eq.
No master volume, but the weird "slope" and "sweep" stuff in the eq.
JCM 800 Bass Series
7Seems like that's probably the right schematic, then. It runs at remarkably low voltage, too (+358 on that schem). Weirdness abounds!
Let us know how it works out.
Let us know how it works out.
"The bastards have landed"
www.myspace.com/thechromerobes - now has a couple songs from the new album
www.myspace.com/thechromerobes - now has a couple songs from the new album
JCM 800 Bass Series
8It's going to be used for bass tonight in rehearsal, through my 4x12 Peavey bass cabinet.
Do you know what cabinet this would have originally been paired with?
Do you know what cabinet this would have originally been paired with?
JCM 800 Bass Series
9My guess is they had multiple options.
I own a JCM 800 bass series cab that is 2x10 and 1x15 in the same cab. I used to have 2 of these things, fun fun. I have also seen a 1x15 cab, a 4x12 cab all in the same 800 bass series.
I own a JCM 800 bass series cab that is 2x10 and 1x15 in the same cab. I used to have 2 of these things, fun fun. I have also seen a 1x15 cab, a 4x12 cab all in the same 800 bass series.
JCM 800 Bass Series
10Tried it out last night at practice with an SG "reissue" bass and a Burns Bison. Sounded really, really great. I love it. Plenty loud for a 50-watt as well.