Hewlet Packard transformer

[Original Burnedfingers]

Does anyone have any information on a #9100-0082 transformer?

I am looking for ratings and wire code.


It has a pair of green 6.3 volts?

a pair of gray

a pair of brown

a pair of yellow 5volts?

a pair of red with a red/yellow which has to be HV

a blk, blk/yellow, blk/red, blk green

[Original Burnedfingers]

another shot

[Original Burnedfingers]

last picture


unit bolts up to a blank Dynaco stereo chassis and as you can see it is quite a bit taller than the Dynaco transformer.

Now, how to figure what the hell it is and if it would work to build another amp.

[Ty_Bower]

I've found the information in this thread to be useful when attempting to identify mystery power transformers:
http://www.diytube.com/phpBB2/viewtopic.php?t=1465

[Original Burnedfingers]

Ok my secondaries measure 21.6 ohms each or 43.2 across.

The secondary output is 830 with no load.

Would this give me about 400 volts out at about 275mA with cap input and 380mA with choke input?

[Tom Bavis]

I would estimate current ratings of about 250 mA cap / 350 mA choke from your resistance readings.

Download the free PSU designer program from duncanamps.com to estimate the output voltage with your rectifier of choice.

[HollowState]

Originally posted by burnedfingers
Does anyone have any information on a #9100-0082 transformer? I am looking for ratings and wire code.

I took a look through my old HP manuals and found the instrument your transformer was used in. It's from the type 738B AC/DC calibrator. This was essentially a well regulated DC supply with a 400~ oscillator and a power amplifier that used a pair of 6550s in PP with up to 300 volts output. It's a nice transformer. But I think the estimate of 350mA w/choke input is too much. Also, the unregulated DC out was 440V and was on the 6550 plates.

Tube compliment:
2) 6550
1) 12AU7
4) 12AX7
1) 6BA6
1) 6CL6
1) 6AU6
1) 6AV5GA
1) 5U4GB
1) 5651A

I am looking for ratings and wire code.

a pair of green...............6.3V for 2/6550, 12AU7, 12AX7, 6BA6

a pair of gray.................6.3V for 6AU6, 6CL6, 12AX7

a pair of brown...............6.3V for 6AV5GA, 2/12AX7 (regulator/elevated)

a pair of yellow 5volts?....yes

a pair of red with a red/yellow which has to be HV...yes

a blk, blk/yellow.............115V

blk/red, blk green...........115V

blk+blk/red....................230V (blk/yel & blk/grn tied together)

[Original Burnedfingers]

Thanks for the info.

Do you think I can use it for a Dynaco clone project?

I'm missing the bias winding so can I use a voltage divider off one leg of the AC then rectify it to come up with my B- and then go to my bias pots?

[Tekko]

Yes you can.

[kevinkr]

The voltage regulator is quite an interesting design as well, better than my long ago efforts using differential error amplifiers in that it should have a lot more open loop gain. I'm inclined to investigate further.. Thanks to HollowState for posting the schematic...