SSLV1.1 builds & fairy tales

[mcluxun]

Hi

I am not using such a DAC but if you look at early posts here there have been some examples and discussions about the consumptions and the values by some members.

Hey Salas
I got all the parts and the 9vac transformer's output is little high with low load.
I am getting 11vac in the input,5.8-6 on d123/124/122/121.
14v dc on c105
According to the calc I shorted r103 and put 363 on r105.
shorted d101
The problem is im getting 1.5v each on 4 green leds on D102A 102B 103 104
and no voltage on D106 105.
With this set up Im getting 9.5v dc output.
Where should I start looking to solve the problem?
Thanks.

 

[Salas]

What is the drop across R108? By the voltage drop across R105 divided by its value you will know the running current in the voltage reference. 0.6V+VfD105+VfD106+VR105=Vout. VR105=IQ103*R105. Is there any IQ103? If not, change it. The two red Leds should light firstly. Are they wrongly oriented?
After there is Vref current, maybe you got a stronger or weaker Q103 for IDSS than thought? Vary the resistive part for drop according to target.

 

[Salas]

Also look, is there Vbe voltage on Q104?

 

[mcluxun]

What is the drop across R108? By the voltage drop across R105 divided by its value you will know the running current in the voltage reference. 0.6V+VfD105+VfD106+VR105=Vout. VR105=IQ103*R105. Is there any IQ103? If not, change it. The two red Leds should light firstly. Are they wrongly oriented?
After there is Vref current, maybe you got a stronger or weaker Q103 for IDSS than thought? Vary the resistive part for drop according to target.

I got no voltage on R108 and R105.

 

[Salas]

Points towards semiconductors.
-Does Q101 have any VGS? If yes, is Q102 healthy given R108 is really 47R?
-Do D105,106 have right orientation?
-Does Q104 show Vbe?
-Is Q103 healthy?
-Does Q106 show Vgs?

 

[mcluxun]

VGS of Q101 : 10.5
Q102 seems to be healthy.
R108 is 47R
D105 D106 are good orientation wise.
No vgs on Q 106

 

[Salas]

VGS should be around 4V to be good. See if there is a problem by changing that. Vbe on Q104?
The JFETs can be measured in circuit with the power off like you measure IDSS when free if you will connect G to S with a crock and use a 9V battery D to S with a mA meter in series.

 

[mcluxun]

VGS should be around 4V to be good. See if there is a problem by changing that. Vbe on Q104?
The JFETs can be measured in circuit with the power off like you measure IDSS when free if you will connect G to S with a crock and use a 9V battery D to S with a mA meter in series.

I dont have a 9v battery around right now, let me do some test and get back to you.

 

[mcluxun]

VGS should be around 4V to be good. See if there is a problem by changing that. Vbe on Q104?
The JFETs can be measured in circuit with the power off like you measure IDSS when free if you will connect G to S with a crock and use a 9V battery D to S with a mA meter in series.

Vbe on Q104 0.01v
swapped Q101 still getting 10v between g and s

 

[Salas]

Q104 either wrong or dead. Replace.

 

[mcluxun]

Q104 either wrong or dead. Replace.

Actually D102 was in reverse polar.
Fixed.
Now Im getting 5.8v dc output it's too high because my 9vac transformer giving me 11vac.
Will replace that and fix it.
Thanks a lot.
BTW for a digital device supply what's the preferred value on C102 & C104

 

[Salas]

C102 470uF 25-35V C104 4.7-5.6uF 63V MKT. R107 remains in place.

 

[alexkosha]

capacitance multiplier filter for BHL PSU

Hi Salas,

Here is capacitance multiplier filter for BHL post BIB.
Please let me know and thank you in advance.

 

[Salas]

Just delete R4 in this case. And readjust the BIB for measuring the proper Vout for BHL at the emitter of Q4 now. There should be one Vbe loss across the multiplier to compensate, i.e. around 0.6V.

 

[alexkosha]

Just delete R4 in this case. And readjust the BIB for measuring the proper Vout for BHL at the emitter of Q4 now. There should be one Vbe loss across the multiplier to compensate, i.e. around 0.6V.

OK. I'll try and report ASAP.
Thank you.

 

[alexkosha]

Just delete R4 in this case. And readjust the BIB for measuring the proper Vout for BHL at the emitter of Q4 now. There should be one Vbe loss across the multiplier to compensate, i.e. around 0.6V.

Here it is as you advised. Did I got you right?

 

[alexkosha]

Disregard 0.6V on drawing. It is my mistake since it is a loss on Vbe.

 

[alexkosha]

-No need of sink for that resistor it will be even cooler than in the previous value.
-At how many C is the sink now?
-You mean hiss noise, like an old tape sorta? If its not the phono itself and it surely acquired it recently with the PSU experiment, only then you should worry about it.
If so, put a 100uF/50V capacitor across the sense wires at the reg's connector or across the phono's +V/GND receiving points. Wherever most effective. If there are any small value film or oil caps there across the rail, remove them. Keep a tight power wires loop both in width and length. Have them twisted. Check that stuff first and then check GND.

Old Caddock 8R2 is heating sink to 55 C in about 45 min.The temperature now is 39 C with new Caddock 12R and I measured it after 1 hour. R301 12R Caddock itself is about at room temperate now. 8R2 was about 39 C.

100uF/50V capacitor and GND did not resolve hiss (btw, it is not a loud noise and I can leave with it if nothing will solve it. But any way, it is worth to try to deduce it). As you advised, I'll go now for capacitance multiplier filter.
Thank you.

 

[pchw]

What is the reason to have a CM after the BIB?

 

[Salas]

He is experiencing some mild hiss in his phono, a BHL. By not having some experimental data from oscope or FFT we try to see if we can buffer some bad interaction with the PSU, filter some pick up, we don't know. Its a trial and error thing. If it will not change anything, then its integral.