Recent content by jordankersten

I have the power supply figured out but my next problem is the output transformer is extremely expensive and hard to find. So I am wondering if there is a way to omit the output transformer using that circuit maybe by making the 12BH7 a cathode follower? If that is not feasible, I am...

Here is a schematic from an earlier Hammond preamp...why are they using a 250-0-250V transformer in this unit to get the 280V and 290V supply voltages? Does it have to do with the different rectifiers? http://www.captain-foldback.com/Hammond_sub/schematics/AO10.gif

One final question: would it be an issue to run that Hammond circuit with a 250V transformer and a solid state rectifier??

I had actually already found that circuit and considered building it. How would I go about adding an additional gain stage...maybe using a 12BH7:)? Also, I would want to use a linear power supply instead of a switching PS.

I have tried many solid state preamps for this purpose and I am not happy with the tone.

When calculating the VA would I include the heater current as well as the plate current...the transformers I am looking at have a separate heater winding.

Thank you for replying! I am planning on using a 250V-0V-250V power transformer with a center tapped full wave rectifier. The Leslie 147 input is not actually 8 ohms. There is a "console load resistor" selector switch for when the Leslie 147 is to be connected to an organ's internal...

I am getting ready to make a tube preamp to drive a Leslie speaker. I want to use a 12AX7 and 12BH7. I plan on using both triodes of the 12AX7 and possibly both oh the 12BH7. I have two questions: First, any design suggestions would be greatly appreciated. Any schematics would be GREAT! and...

Thanks for the reply! I have actually never played a Wurlitizer. Just my Rhodes and my B3...but playing Steinways on jazz gigs, the Rhodes feels good to me...I tend to like the heavier action.

Very Sorry, I thought that was a direct link to the schematic. To get to the schematic, click on "schematics" and it is Fig 11-8 "Pre-amp for 80 Watt suitcase and super satellite."

Hello everyone! I have an old Fender Rhodes electric piano I am rebuilding and I have a question. It uses a stereo pan circuit which pans the signal back and forth between the left and right amplifiers. It does this with a simple oscillator circuit that drives two 2N3053 transistors (now...

It's not really sparkle. It's just "dashed" or broken up when the readout is on.

One more thing: if there are two readout displays on (CH1 and time) there are two sets of dashes that scan across the trace. If you add other things to the readout (CH1 CH2, time, etc.) another set of dashes scans across the trace for everything you add to the readout.

If the 7.5 Volt adjust is at exactly 7.5V, the "dashes" produced by the readout scans across the trace. If you bring the 7.5V adjust lower, it scans faster and faster. If you bring the 7.5V up, the "dashes" scan faster and faster disappearing right around 8 volts. All other voltages check out...

Ok, the service manual says that When ROR (Readout Request or something like that) input is low, chop blanking is disabled and the ROB (Read Out Blanking) is inverted and controls the blanking. When ROR goes from low to high, the blank output remains connected to the readout blank signal for an...