Complete Novice Needs Help

[CanAm Man]

I was using the original Jim's chinese boards that had to be botched to make work , so this is probably a good thing 🙂

Thank you , Rich

Just curious--what did you have to do to "the original Jim's boards) to make them work? I know a number of folks using them, right out of the box, without any problems......

 

[richluvsound]

Can am

It could have been my fault , but there was a short where the rectifer goes . I had to cut through it and put a jumper in....

Rich

 

[CanAm Man]

Thanks, Rick..... was curious, because that was the first I had heard of any of Jim's power supply boards (not that I'm advocating for Jim, et al....)

 

[richluvsound]

Schematic ?

Hi,

I have Algar's schematic..... I'm not experienced enough to figure it out .
Is there a Schematic specific to Brian's boards and BOM ?

Thanks , Rich

 

[richluvsound]

Screw It

Time to re-build the channel .....

I'm desperately needing A diff pair + 1 IRFP 9610 . I'm willing to pay well
for them . Would be great if they came from the EU too !

Thank you , Rich

 

[Itsmee]

I'm desperately needing A diff pair + 1 IRFP 9610 .

diyAudio member h_a may be able to help you.http://www.diyaudio.com/forums/swap-meet/178558-matched-fets-your-f1-f4-f5-aleph-j.html

 

[richluvsound]

thanks Itsme,



Hannes has the 240's which I have ordered from him ,but sadly he does not have 9610's

Thanks for replying mate 🙂

Rich

 

[Itsmee]

Your welcome 😉

 

[Marra]

I'm sure that I have some of these buried in my wardrobe. Should be able to let you know in the morning. Do you just need one matched pair and an odd one for the current source?

 

[richluvsound]

PM 4 U

Cheers Marra ,

I have installed 3.15 A fuses between the PSU and the amplifier board .
This won't happen again . I sure hope it does not affect the sound or am I being silly ?

Rich

 

[richluvsound]

Gents ,

Is there a way to test 9610 with a DDM without using the test rig with a power supply . I just need to see if they are fried or not ?

cheers , Rich

 

[Itsmee]

MOSFET testing

 

[richluvsound]

OK , fets are ok .... Had them working ,but no audio signal .
I have been try to glean the voltages from the Algar schematic and apply them
to Brian's boards.

Gate , Q4 to R17 = 4 VDC

R 18 to R 17 = 15 VDC

Gate 3 to R 4 = 18 VDC

Q3 Drain to R 8 = 3.6 VDC

R 5 to R 4 - Z5 = 16 vdc

My output voltage from PSU is 30.44 VDC so my readings will be relative as the Rail VDC on the Schematic is 26.00 VDC ....

Am I driving down the right Street ?

Rich

 

[richluvsound]

Good day Gents ,

could someone please confirm that I have the correct value resistors for R 8 & R13 ?


I used 500R trimmer for R 8 and 100k for R 13

R 8 set to 221 R and R 13 to 47.5 kR pre bias adjustment .

Thanks for your time , Rich

 

[Bill Fuss]

If you are using the Chipamp schematic, yes. 47K should push the bias down enough for start up so you can get it set up to your chosen bias current. Your rails are quite a bit higher than normal so don't over do it with the bias.

The 500 ohm trimmer should enable you to eliminate any offset once it's warmed up.

Best, Bill

 

[richluvsound]

Thank you Bill

 

[richluvsound]

Good morning all !

I have just rebuilt my Aleph 30 . It works great ,but I still have a small thump when I turn it off . I guess the caps need a bleed resistor on them ?

If so , what value and where do they go ?

`thanks for your time , Rich

 

[nar]

Good morning all !

I have just rebuilt my Aleph 30 . It works great ,but I still have a small thump when I turn it off . I guess the caps need a bleed resistor on them ?

If so , what value and where do they go ?

`thanks for your time , Rich

Yes, bleeder as seen in F5 power supply. 2K2 / 3W parallel each 1st capacitor (V+, V-) after rectifiers. You can also use thermistor ( CL-60 ) in series with mains, to get the thump damped.

Best,

nAr

 

[Russellc]

Say, I have noticed differences in part numbers between the original Aleph 30schematic and the part numbers as used in Brian's boards. I have searched the chip amp site, but only find BOM lists.....is there a schematic somewhere that shows brian's version? I have the original schematic, just not the version for Brian's boards. I am easy enough to confuse already...

Thanks,

Russellc

 

[Russellc]

If you are using the Chipamp schematic, yes. 47K should push the bias down enough for start up so you can get it set up to your chosen bias current. Your rails are quite a bit higher than normal so don't over do it with the bias.

The 500 ohm trimmer should enable you to eliminate any offset once it's warmed up.

Best, Bill

I'm sure Bill no doubt had it.....

Russellc