Author Topic: Sunn 1000s power supply tech help  (Read 2777 times)

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Offline Sparks

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Sunn 1000s power supply tech help
« on: July 20, 2007, 03:47:42 pm »
I am working on my 1000s power supply. I had to replace the power transformer and some bad filter caps. I have a schematic for the 2000s Power supply and it does not compare to what I see here in the 1000s. 2000s uses a 15Kohm and 33Kohm 2watt resistor for the "B" & "C" voltages (400v) (300v). My 1000s uses a 6.8Kohm and 6.8kohm for the "B" & "C" voltages. I have no schematic for the 1000s and do not know if this was a stock setup. Does any one know what the "A" "B" & "C" stock voltages were for the 1000s. Sunn Septre has some of the circuitry in common with 1000s. is this where I should be looking?

Offline JoeArthur

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Re: Sunn 1000s power supply tech help
« Reply #1 on: July 20, 2007, 03:56:12 pm »
I am working on my 1000s power supply. I had to replace the power transformer and some bad filter caps. I have a schematic for the 2000s Power supply and it does not compare to what I see here in the 1000s. 2000s uses a 15Kohm and 33Kohm 2watt resistor for the "B" & "C" voltages (400v) (300v). My 1000s uses a 6.8Kohm and 6.8kohm for the "B" & "C" voltages. I have no schematic for the 1000s and do not know if this was a stock setup. Does any one know what the "A" "B" & "C" stock voltages were for the 1000s. Sunn Septre has some of the circuitry in common with 1000s. is this where I should be looking?

The 1000s is pretty much the same head as the 1200s. The 1200s has a 6.8K between the A & B source, a 6.8K between the B & C source, and a 10K between the C & D source - all 2 watt resistors.

The voltages for these sources are listed as:
A - 500V
B - 390V
C - 295V
D - 250V

Offline Sparks

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Re: Sunn 1000s power supply tech help
« Reply #2 on: July 20, 2007, 04:26:42 pm »
Thank you Joe. As for the "D" source ?? the way the last tech left the power supply setup is as such. Power transformer supply for HV. Separate transformer 55Vac for Bias supply. Separate 24Vac transformer making up the 16.5Vdc supply. There is an "A" "B" "C" setup with the 6.8Kohm resistors. The 250v "D" supply from the 10Kohm is not there. It may have been a mod and eliminated? do you know what the 250Vdc "D" supply is feeding ? If you have a copy of the 1200s guts that would probably get me out of the woods.

Offline JoeArthur

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Re: Sunn 1000s power supply tech help
« Reply #3 on: July 21, 2007, 09:25:42 am »

Sounds like somebody hacked that one...

The "D" supply is used for three stages - plate supply for the 12AX7 preamp tube (through 100K resistors connected to pins 1 & 6) and the first stage of the 12AU7 reverb driver tube (through a 100K resistor connected to pin 6).

I sent you a pdf copy of the 1200 schematic.