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previous: Geoff Van Brunt The 2205 & 2210 preamps are the sam... -- 12/16/1999 7:39 PM

Re: JCM 800 #2210- site with schems

12/16/1999 11:44 PM
Stan Bailey	Re: JCM 800 #2210- site with schems Ok, this is what I can see without pulling out the pcb. V1A: Ra = 100K Rg = no resistor Rk = 1.5K Ck = .1uF V1B: Ra = 220K Rg = 6.8K from V1A grid (soldered on pins 2 and 7) Rk = 2.7K Ck = .68uF V2A: Ra = 220K Rg = no resistor ( signal taken from middle of 1M gain pot. Rk = 1.5K Ck = .1uF V2B: Looks like cathode follower. Also, there are 4 BC182 NPN transistors in there. Switching? I don't see the IC that is on the 2205 schematic. The PI is a little different in R values as well. Where is V1B on schematic? My copy is very poor, but I swear the other part of the first tube is not there. Man, I sure do love point to point. Screw this trying to figure out pcb traces. The only markings on the amp are: Front Panel - JCM 800 Lead Series Back- Model 2210 written in. Maybe a screw-up? You say this is the same as a 2205, but I would love to have the 2210 schematic so I can confirm this for myself. Thanks for your reply. Stan

12/16/1999 11:44 PM

Stan Bailey

Re: JCM 800 #2210- site with schems

Ok, this is what I can see without pulling out the pcb.

V1A:
Ra = 100K
Rg = no resistor
Rk = 1.5K
Ck = .1uF

V1B:
Ra = 220K
Rg = 6.8K from V1A grid (soldered on pins 2 and 7)
Rk = 2.7K
Ck = .68uF

V2A:
Ra = 220K
Rg = no resistor ( signal taken from middle of 1M gain pot.
Rk = 1.5K
Ck = .1uF

V2B:
Looks like cathode follower.

Also, there are 4 BC182 NPN transistors in there. Switching? I don't see the IC that is on the 2205 schematic. The PI is a little different in R values as well.
Where is V1B on schematic? My copy is very poor, but I swear the other part of the first tube is not there.
Man, I sure do love point to point. Screw this trying to figure out pcb traces. The only markings on the amp are:
Front Panel - JCM 800 Lead Series
Back- Model 2210 written in. Maybe a screw-up?
You say this is the same as a 2205, but I would love to have the 2210 schematic so I can confirm this for myself. Thanks for your reply.
Stan

Replies:

A.S The schem I have is for the 2205 an... -- 12/17/1999 6:47 AM
anon Is the high gain channel using the ... -- 12/17/1999 12:00 PM
Tonefactor You've got one of the earlier versi... -- 12/17/1999 9:34 PM