Hi, it's a bit unclear what you really want to build and what the requirements are for your power supply in terms of voltages and currents.
If you already have a schematic, please post it.
In general to the posted ebay auction. This is a complete power supply from a smaller Grundig TK tape recorder. I use these transformers from time to time and consider them to be of high quality. The built-in selenium rectifier and the reservoir capacitor usually still work, but I strongly advise you not to use them, as they are simply too old (approx. 60 years!) and the capacitor can explode.
As I said, the transformer is good and flexible, it can be configured internationally on the primary side (220 or 230V does not make such a big difference, in Germany it was operated in the 220V position) and offers approx. 220-280V DC on the secondary side on the first capacitor after rectification, depending on the load. Up to 50mA are possible, depending on the type and the corresponding circuit. Please post the link to the ebay auction, then I can tell you the exact data. The heater current is approx. between 1.1A and 1.8A at 6.3V AC, depending on the type of transformer. The larger models sometimes have two heater windings, one for the V1 (EF86/EF804) and a second one for the rest.
These transformers are therefore ideal for preamps, EQs, tube mics and mono compressors as well as small guitar amps such as mini Champ or Gibson Skylark with sand rectifier.
If you want to heat with DC, my project
here is an ideal partner for such transformers.
13.90€ would be a good price for the transformer, but please bear in mind that you can sometimes get these whole donor device for free or for the same money. Then you get a few good tubes and an output transformer for free...
Attached: service manual for some TK models
View attachment 128701
Hello
rock soderstrom,
Thank for your reply with datasheet!
Ok, that is good to know, that they are so versatile.
This project is a slow project for me, since it's my frist DIY Tube preamp project besides my commercial tube preamp.
Yes, old capacitors having a short with HV AC can make them blow up like firecrackers.
I already had this happen to me on an Vintage sewing machine of my mother, but it was inside the motor compartment and the walls were blackened with capacitor ashes.
I think it was a RF Decoupling capacitor between the poles of the motor with like two to three capacity values or so, in one capacitor!, because the Light bulb was in parallel IIRC, to the motor.
It was weird, I never had the interest to repair it, because my mother threw away the blown capacitor, I guess I'll have to look up some recommended values someday and fix it. One can't have too many projects lying around.
I listened to your advice and bought the line output stage tubes, as a first step.
So I bought some
6N23P NOS tubes, off of ebay, for the output stage, I have to pick them up locally here where I live because they were cheaply available and still strong in function.
But still have to pick them up.
I will try to post pictures of both soon.
Thanks for your reply
But I still have yet to pick them up, probably tomorrow on wednesday.
In terms of gainstages,
For the mic input stage I have chinese
12AX7 and
TAD 5751 for more warmth, and hopfully someday the trasnsformers for in/out.
I am trying to build the TwinLine Tube Amplifier, as a mono Mic preamp.
One (1) Amp heater current in toal @ 6,3V should be around the maximum for both Tubes in total, with one half of each the systems/valves working, I assume.
I am still very new to how the tubes react to changes in the circuit.
Again it's a longhaul project for me, since I try to complete at least 1 SSL Preamp first.
I am not trying to build a tube distortion box, but rather a clean preamp for XLR mics.
