2204 - 36w

Chubsman · Post by **Chubsman** » Wed 04/26/06 12:32 pm

What are the odds of getting assistance putting a 2204 preamp into replace the normal channel of my 36w?? Do-able???

blaren · Post by **blaren** » Thu 04/27/06 2:32 am

settle-down there psycho boy. lmao
What are you trying to do? you really dont like that thing do ya.
I bought an 82? cant remember, 2204 about a year and a half ago in a store here for $400. I brought it home (before paying for it) and took some pics and listed it. Got $700+ US which was worth quite a bit back then (actually it was more than a year and a half ago). I didnt even plug it in. Not sure whether to put a sad or happy face there.
Anyway, get a pedal or look for a JCM....the combos are cheap too.
I'm just buggin ya though....just sounds weird. Like wearing a 3 piece suit and putting an orange and purple poke-a-dot tie on.

Chubsman · Post by **Chubsman** » Thu 04/27/06 6:11 am

Nah, I changed my mind... I'lll just build a 2204... leave the 36 alone.... Why... because I finaly (i think) figured out what is wrong with my amp..... the 8.2k (Grey-red-red) resistor next to the 1st filter cap (16uf 450v, orange) is indication 9.8K instead ... and is giving me a bigger voltage drop thus running everything cool... thus making my amp wimpy...

bitsandvolts · Post by **bitsandvolts** » Thu 04/27/06 9:11 am

If you can buy a JCM800 2204 for 400 bucks these days...DO IT!
They are regularly selling for twice that on ebay...if nothing for the pure investment value of it.

However, having said all of that...nothing wrong with building a full blown 2204. A number of us are in the middle of 2203/4 builds as we speak....as soon as finals are over for me, my drill is getting dusted off and I'm going to start drilling holes in the chassis and the fiberboard.

Go here for more info on what we're all building.

BobD · Post by **BobD** » Thu 04/27/06 12:04 pm

Lowering that dropping resistor from 9.8k to 8.2k will increase the voltage to your phase inverter and preamp but it won't be enough of a change to suddenly make you like an amp that you currently think is wimpy.

My 36 watter sounds like a cranked Plexi so I'm thinking that either somethings wired wrong with yours or maybe this amp just isn't for you.

Have you checked all of the voltages on all of the tube sockets ?

BobD · Post by **BobD** » Thu 04/27/06 12:04 pm

Lowering that dropping resistor from 9.8k to 8.2k will increase the voltage to your phase inverter and preamp but it won't be enough of a change to suddenly make you like an amp that you currently think is wimpy.

My 36 watter sounds like a cranked Plexi so I'm thinking that either somethings wired wrong with yours or maybe this amp just isn't for you.

Have you checked all of the voltages on all of the tube sockets ?

Chubsman · Post by **Chubsman** » Thu 04/27/06 8:56 pm

Hey Bob, here are my voltages, as you can see, they are low across the board. I have checked and checked and checked and checked, re-soldered, changed cathode, screen resistors, changed the rectifier from SS (Copper cap) to JJ tube, cap can, cap can resistor from 1.5k to 1k, nothing ever changes. The only thing I found was ... my 8.2k resistor at the 1st filer cap is reading 9.8K ... and that see, to be dropping my voltages.... Plexi was helping me, but he or I can't see what the problem is.... I feel that the missing voltages are making the amp too clean... so perhaps you can help....

Tubes
V1 â€“ - Now - Should be
PIN1 125V -- (170V)
PIN3 1.0V -- (1.2v)
PIN6- 144 -- (173v)
PIN8 1.3 -- (1.2V)

V2 â€“
PIN1 122 -- (152V)
PIN3 1.3 --(1.3V)
PIN6 232 -- (258V)
PIN7 123 -- (152V)
PIN8 124 -- (152V)

V3 â€“
PIN1 183 -- (206V)
PIN2 44 -- (43V)
PIN3 62 -- (65)
PIN6 183 -- (206)
PIN7 46 -- (45)
PIN8 62 -- (65)

V4 V5 V6 V7 V8
Pin3- 11V -- (11.6)
Pin7- 327 -- (332)
Pin9- 281 -- (322)

allynmey · Post by **allynmey** » Thu 04/27/06 11:02 pm

Chubsman wrote:Hey Bob, here are my voltages, as you can see, they are low across the board. I have checked and checked and checked and checked, re-soldered, changed cathode, screen resistors, changed the rectifier from SS (Copper cap) to JJ tube, cap can, cap can resistor from 1.5k to 1k, nothing ever changes. The only thing I found was ... my 8.2k resistor at the 1st filer cap is reading 9.8K ... and that see, to be dropping my voltages.... Plexi was helping me, but he or I can't see what the problem is.... I feel that the missing voltages are making the amp too clean... so perhaps you can help....

Tubes
V1 â€“ - Now - Should be
PIN1 125V -- (170V)
PIN3 1.0V -- (1.2v)
PIN6- 144 -- (173v)
PIN8 1.3 -- (1.2V)

V2 â€“
PIN1 122 -- (152V)
PIN3 1.3 --(1.3V)
PIN6 232 -- (258V)
PIN7 123 -- (152V)
PIN8 124 -- (152V)

V3 â€“
PIN1 183 -- (206V)
PIN2 44 -- (43V)
PIN3 62 -- (65)
PIN6 183 -- (206)
PIN7 46 -- (45)
PIN8 62 -- (65)

V4 V5 V6 V7 V8
Pin3- 11V -- (11.6)
Pin7- 327 -- (332)
Pin9- 281 -- (322)

Chubsman, What is voltage coming off your PT? and the voltage on the B+ (pin8) on the rectifier. Also Who's PT did you use?

Allynmey

Chubsman · Post by **Chubsman** » Fri 04/28/06 8:40 pm

Allynmey,

PT is Heyboer: HTS-7042

Voltage off the of the PT with no rectifier installed is :
300 AC per red wire,
5 volts off the yellows.

With rect.
Pin8 of rectifier is 330 V

Looks normal to me....

BobD · Post by **BobD** » Sat 04/29/06 8:17 pm

The only thing that jumps out at me is your screens are pretty low compared to the plates. What size screen resistors did you use ?

BobD · Post by **BobD** » Sat 04/29/06 8:19 pm

The only thing that jumps out at me is your screens are pretty low compared to the plates. What size screen resistors did you use ?

Chubsman · Post by **Chubsman** » Sat 04/29/06 11:00 pm

1k/5w screens
120R / 5w cathode

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2204 - 36w

2204 - 36w

Allynmey