SSLV1.1 builds & fairytales

[le´flu]

Hi Salas,

WOW - thanks a lot

[Salas]

Cheers. Are you going to do point to point? Got K117GR?

[le´flu]

Yes, i´ve got some 117GR but have to measure the IDSS.

Thanks

[Salas]

They will all work, but try to concentrate between 3-4mA so to ballpark well with those resistor values.

[le´flu]

Hi Salas,
today was measurement day ;-)

As to the Regs:
- 2sk117gr are between 5.5 and 4.36mA. Will pair them and solder like in the
Manual: low IDSS for 102/302, medium for 103/303 and strong IDSS inPos
105/305
- LEDs: got green ones within 1.99 V for string D102-104 and red ones with
1.9V for D105
- Whats the best hfe for BC550c ?
- Zobel: in the BiB Manual you recommend MKT. Is this still your todays Recommendation?

As to the FoldedSimp. Stupid me has 2sk369 within 6.8 and 7.3mA....
will have to buy some more to get 12mA.

Greetings Ulf

[merlin el mago]

The best BC550C with the highest hfe possible.

[Salas]

Originally Posted by le´flu

Hi Salas,
today was measurement day ;-)

As to the Regs:
- 2sk117gr are between 5.5 and 4.36mA. Will pair them and solder like in the
Manual: low IDSS for 102/302, medium for 103/303 and strong IDSS inPos
105/305
- LEDs: got green ones within 1.99 V for string D102-104 and red ones with
1.9V for D105
- Whats the best hfe for BC550c ?
- Zobel: in the BiB Manual you recommend MKT. Is this still your todays Recommendation?

As to the FoldedSimp. Stupid me has 2sk369 within 6.8 and 7.3mA....
will have to buy some more to get 12mA.

Greetings Ulf

For 550C as Merlin said.

Your other reg stuff will work, use 5K6 instead of 6K8, one led, and 5K trimmer in the see text area.

Use 18 Ohm R101/301 with 1.99Vx4 Leds for circa 200mA CCS.

MKT in Zobel is very good for the money. Then you enter audiophile caps area, and you can save that for icing on the cake after you know you like the concept as a whole, given you can hear Zobel quality influence when substituting to an industrial grade MKP for a test.

2SK369BL are 8-16mA by Toshiba manual. If yours are not GR and you don't measure with a DMM that has excessive burden voltage issues in mA mode, then those you got may be fake. Get 2SK369BL on ammo tape, they are usually original. You need a couple of circa 11mA for the phono. Measure those you got again with 1 Ohm in series to drain pin with gate and source shorted. Power the whole thing from a 9V battery and put the DMM in DCmV mode. Use Ohm's law to verify the IDSS by the drop across the 1 Ohm. Use short test cabling.

[lehmanhill]

I just put together a +/- pair of SSLV1.1 from the 2012 June group buy. The transistors and such are from the mini-kits with other components high quality and sized through the excel spreadsheet. At the moment, I am only testing the regulators using a 100 ohm resistor per the BiB pdf.

For the most part, everything is working properly with the exception that Q201 on the negative regulator runs just warm and Q101 on the positive regulator runs very hot (burn your fingers hot, even on the heat sink). I'm using heat sink paste on both sides of the silicone insulator, have a good clamp load from the heat sink screw, and am using the same heat sink on the positive as the negative regulator (both sized to the spreadsheet). If anything, the air around the Q101 heat sink is better than on the Q201 side.

Can you suggest any diagnostics to resolve the problem? Would swapping out the mosfet be the easiest step? Is this difference between plus and minus performance an indication that the plus side is oscillating? I admit that I haven't gotten a scope on it yet.

For reference, both positive and negative regulators are 29 V DC in and set at 15 V out. Load current is about 150 mA max with a little over 100 mA excess current, so that Q101 is running about 260 mA per the spreadsheet.

Thanks in advance for any suggestions.

Jac

[Salas]

If you measure the voltage drops across the CCS setting resistors for both polarities, does the positive one indicate more running current than the negative when divided by the resistor values? If yes, trim the resistor value higher to drop some CCS current. 29-15=14V and can heat up fast a CCS Mosfet if running more enough mA respective to another. Still, If both CCS are indeed running about same currents, and there is such a heat difference then it should certianly need to be checked for oscillation and insulation with scope and DMM, which is rather weird to happen in the CCS Mosfet in the positive as build reports never suggested such an issue up to now.

[RollE2k]

Salas: When running a 30VCT transformer and building a +-15VDC Supply, should i connect centertap on both negative and positive board, and then just wire together +S0 and -S0 at the i/v it will be power? (will still twist +S0 separately and the same with -S0, just that i connect them together at target).

Or will there be any trouble with a Center tapped transformer this way? Maybe have to remove some diodes or so, to not make a voltage difference between both rails?