SSLV1.1 builds & fairy tales

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le´flu

Member
Joined 2004
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
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
le´flu said:
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
Click to expand...

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

lehmanhill

Member
Joined 2008
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

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
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.
 
R

RollE2k

Member
Joined 2007
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?
 
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Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
Can't picture it off hand right now, I will have to look on what you say about designations. It is conceived as double bridge double secondaries scheme, but it can be converted to 3 wires secondary and single bridge between polarities, I remember some had used it like that.
 
R

RollE2k

Member
Joined 2007
An externally hosted image should be here but it was not working when we last tested it.


Ok, i got it wrong before.. after searching a bit - this is as i have understand it should be wired... so wouldn't that mean that removing D213/214 and D113/114 on the boards, then wiring center tap to a both caps which take positive-side-gnd, negative-side-plus.
And last, wire both +-15VAC to both regulator AC terminals. (or to one of them and wire underneath the PCB to the other one)

That should be right?
 
lehmanhill

lehmanhill

Member
Joined 2008
Problem understood and on the way to solved

Salas said:
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.
Click to expand...

Thanks Salas,

You called it correctly. There was about 0.36 V difference between the polarities across the CCS resistors. That correlates to about 50 mA out of 260 in CCS and explains the positive being hotter. After further testing, I have decided that both are hotter than ideal, so I will buy a lower voltage transformer in addition to balancing the CCS current. I was lazy and trying to use a transformer that I already had.

Thanks again.

Jac
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
You can't really tell how the dac layout and psu wiring to it adds inductance and resistance that really make the cap a problem to the reg's termination or is good there without seeing the rail on a scope for stability. If you don't have a scope add a 100uF on the sense terminals of the reg for good or bad. You can also listen with the local cap and without, trying to determine best, but its poor approach, it really takes a scope to know.
 
S

samoloko

Member
Joined 2006
Salas I have a scope
what Is the best - stay with 4.7 uF at regulator termination and to lower as possible ( 0.1 - 0.2 uF) dac decoupling caps value without series resistor and inspecting with scope or ?
what Is the correct procedure to use a scope for checking - scope switched to ac or dc and x100 ?
 
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