My Tabor Clone is finished.

[Tyimo]

Thanks Shoog!
I will try it with step down 2:1+1.
Few more questions:
- What VA rating do you sugest? 20-30Va?
- What voltages? 110Vac: 55Vac+55Vac?
- What is that OEP? "I used microphone transformers from OEP for phase splitting."

Tyimo

[Shoog]

The lowest VA should give you the highest inductance. I found it difficult to get anything less than about 50VA in 110:55+55

OEP are this manufacturer;

OEP

I got mine through Farnell.

Hope that helps

Shoog

[kenpeter]

What did you use for ccs?

[Tyimo]

Thanks Shoog!
I am trying to build a Tabor clone with EL82.
Could you give me some suggestions?

Tyimo

[Tyimo]

Sorry. I typed wrong.
I mean with EL84 tube.

[Shoog]

I used IXY900 chips in the Tabor. I had real issues finding a CCS which was stable enough to withstand the power up spikes - the IXY900 was the only one which has been reliable. I have no zeners for protection in this one, but using zeners across the CCS should help.

In the latest project which is update to the DC7 6080 amp I built, and which is based on the Tabor concept, I used a version of the LM317 with a voltage rating of 125V, this has worked flawlessly. I included 120V Zeners across them for protection.

I can only really point you to my schematic for hints. The real issue with the Tabor is its relatively complex stacked power supply. I avoided this by using a +/- power supply off the single power transformer and hanging the front end off of the negative rail. All the usual complexities of this (ie biasing up the front end using voltage dividers and caps) is avoided by using the input transformer which is biased down to the grid voltage of the drivers. In the DC7 version I even managed to arrange the voltages such that the screens of the driver pentode were at 0V (effectively about +180V) which avoided the need for a seperate screen supply.

I have included the schematics of the DC7 Mk II because they represent the ultimate refinement of what I have worked on for the last 7yrs or so. Its quite simple but there are many hidden tricks. This would be a good one to attempt to copy or as a conceptual starting point.

Shoog

[Tyimo]

Thanks for the info!

Tyimo

[kenpeter]

And if you cross couple the ADJ to halfpoint of opposite sense resistor?
Blumlein garter style....

Remembering that both anodes are capacitor coupled and share the
same voltage swing.... I don't think blocking impedance is reduced,
but you might get better matching DC.

[Tyimo]

Hi Shoog!
Is this OPE transformer a 600R:600R line input transformer?
Could you tell me how much indcutance has it?

Tyimo

[Shoog]

This is the datasheet of the one I used. I have no other details.

Shoog