B! finished - HELP needed...

Xandrell · 10th October 2011, 07:13 PM

Hi everyone...

I've just finished my new B1. Schematic taken from Passlabs. But there is only dead silence at the outputs.

Here is the schematic:

Here is my layout:

I can't find any mistake... So please anyone help me with this problem.

WithTarragon · 10th October 2011, 07:20 PM

The schematics are not showing up.

None the less, tell us what is working.

For instance is there a voltage after the smoothing caps? What does a voltmeter or scope show at the outputs, when a signal is on or off at the input etc....?

6L6 · 07:49 PM

Your images --

If you can take any voltage measurements anywhere, that will help.

Also, could you take some photos of it and post them here?

For reference, the Original B1 schematic -

Xandrell · 10th October 2011, 07:53 PM

Oh... I took some voltage measurements. VCC behind the smoothingcaps is 18,68V. I used 2SK170 as mentionend in the Passlabs article. No matching. I only want to see if this gem is working. But it won't make any noise.

Where are positions to measure which would be interesting?

I can take some pictures of the inside tomorrow when i'm back from work.

Xandrell · 10th October 2011, 08:12 PM

Are you now able to open the pictures?

6L6 · 08:28 PM

Yes, the photos of the preamp are visible.

Looking at your layout it seems that you have the signal going to the source of the 'top' transistor. I could be wrong, it's hard to see.

Check your transistor layout.

Here is the datasheet for the 2sk170

http://www.datasheetcatalog.org/data...shiba/1027.pdf

generg · 08:47 PM

Hi xandrell,

Is far as I can see, you used the pin layout of the IRF 610 or IRF 9610 were the gate is on the left side looking on the front of semiconductor, where the words are, but Sk170 has the gate in the middle and the drain and source outside.

So check your j-FETs and solder them new twisting the legs!

http://www.datasheetcatalog.org/data...shiba/1027.pdf

6L6 is right!

Xandrell · 11th October 2011, 03:16 AM

Yes. You both are right. Had this idea while sleeping ;-) I will try to fix that. So pin1 goes to slot2 and vice versa? 3 stays at slot 3.
Or is this also wrong?

6L6 · 11th October 2011, 04:42 AM

If the board was designed for IRF610, then yes, you need to get a bit of teflon tubing and insulate a lead or two and cross the legs.

For reference, IRF610 datasheet -- http://www.hebertech.com/datasheet/vishay/irf610.html

generg · 05:40 AM

Pin 3 to slot 3, isn't then the drain of J-Fet connected to the source place of IRF holes?

In German im zweiten Pinbelegungsbild sieht man den Transistor von unten und im ersten von der Schriftseite.

It is so easy to get confused by the pin pictures, reflect 5 times please!

At least for me!

Nevertheless you did a fine work!

10th October 2011, 07:13 PM	#1
Xandrell diyAudio Member Join Date: Sep 2009 Location: Dortmund	B! finished - HELP needed... Hi everyone... I've just finished my new B1. Schematic taken from Passlabs. But there is only dead silence at the outputs. Here is the schematic: Here is my layout: I can't find any mistake... So please anyone help me with this problem.

10th October 2011, 07:43 PM	#3
6L6 diyAudio Member Join Date: Oct 2010 Location: Denver, Colorado	Your images -- If you can take any voltage measurements anywhere, that will help. Also, could you take some photos of it and post them here? For reference, the Original B1 schematic - __________________ Pass Labs Pearl Phono -- Pass B1 Preamp -- Pass F5 amplifier -- Pass Labs Pearl 2 Last edited by 6L6; 10th October 2011 at 07:49 PM.

10th October 2011, 08:24 PM	#6
6L6 diyAudio Member Join Date: Oct 2010 Location: Denver, Colorado	Yes, the photos of the preamp are visible. Looking at your layout it seems that you have the signal going to the source of the 'top' transistor. I could be wrong, it's hard to see. Check your transistor layout. Here is the datasheet for the 2sk170 http://www.datasheetcatalog.org/data...shiba/1027.pdf __________________ Pass Labs Pearl Phono -- Pass B1 Preamp -- Pass F5 amplifier -- Pass Labs Pearl 2 Last edited by 6L6; 10th October 2011 at 08:28 PM.

10th October 2011, 08:44 PM	#7
generg diyAudio Member Join Date: Jul 2009 Location: Germany	Hi xandrell, Is far as I can see, you used the pin layout of the IRF 610 or IRF 9610 were the gate is on the left side looking on the front of semiconductor, where the words are, but Sk170 has the gate in the middle and the drain and source outside. So check your j-FETs and solder them new twisting the legs! http://www.datasheetcatalog.org/data...shiba/1027.pdf 6L6 is right! __________________ and the First Wtt is......a really First Class PSS Idea ! Last edited by generg; 10th October 2011 at 08:47 PM.

11th October 2011, 04:42 AM	#9
6L6 diyAudio Member Join Date: Oct 2010 Location: Denver, Colorado	If the board was designed for IRF610, then yes, you need to get a bit of teflon tubing and insulate a lead or two and cross the legs. For reference, IRF610 datasheet -- http://www.hebertech.com/datasheet/vishay/irf610.html __________________ Pass Labs Pearl Phono -- Pass B1 Preamp -- Pass F5 amplifier -- Pass Labs Pearl 2


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10th October 2011, 07:20 PM	#2
WithTarragon diyAudio Member Join Date: Jun 2007	The schematics are not showing up. None the less, tell us what is working. For instance is there a voltage after the smoothing caps? What does a voltmeter or scope show at the outputs, when a signal is on or off at the input etc....?

10th October 2011, 07:53 PM	#4
Xandrell diyAudio Member Join Date: Sep 2009 Location: Dortmund	Oh... I took some voltage measurements. VCC behind the smoothingcaps is 18,68V. I used 2SK170 as mentionend in the Passlabs article. No matching. I only want to see if this gem is working. But it won't make any noise. Where are positions to measure which would be interesting? I can take some pictures of the inside tomorrow when i'm back from work.

11th October 2011, 03:16 AM	#8
Xandrell diyAudio Member Join Date: Sep 2009 Location: Dortmund	Yes. You both are right. Had this idea while sleeping ;-) I will try to fix that. So pin1 goes to slot2 and vice versa? 3 stays at slot 3. Or is this also wrong?

11th October 2011, 05:36 AM	#10
generg diyAudio Member Join Date: Jul 2009 Location: Germany	Pin 3 to slot 3, isn't then the drain of J-Fet connected to the source place of IRF holes? In German im zweiten Pinbelegungsbild sieht man den Transistor von unten und im ersten von der Schriftseite. It is so easy to get confused by the pin pictures, reflect 5 times please! At least for me! Nevertheless you did a fine work! __________________ and the First Wtt is......a really First Class PSS Idea ! Last edited by generg; 11th October 2011 at 05:40 AM.

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