Can't tell - packing slip, which I found in my desk o' junk - was the transistor kit for the Aleph J. But there was no writing on the baggy holding the parts.
The three remaining zener diodes in the baggy and the one on the PCB were smaller than the 9.1Vs I bought from Mouser.
Long story short - I ended up replacing the zener on the PCB with a 9.1V one from Mouser and now my offset is (after a few twists of the pot is) down to zero. And I'm biasing both sides up now.
I'm just glad this mystery is solved!
Thanks, everyone!
The three remaining zener diodes in the baggy and the one on the PCB were smaller than the 9.1Vs I bought from Mouser.
Long story short - I ended up replacing the zener on the PCB with a 9.1V one from Mouser and now my offset is (after a few twists of the pot is) down to zero. And I'm biasing both sides up now.
I'm just glad this mystery is solved!
Thanks, everyone!
Biased at .375mv on each channel so I could do a quick listen.
Very impressed - closest that any of my DIY creations came to this was a single-ended "universal" tube amp that I built that had fixed bias so you could use EL34s/6550s/6L6GCs/etc. That amp cost a lot more to build, given that the output transformers alone cost about as much as everything in this amps.
Very impressed - closest that any of my DIY creations came to this was a single-ended "universal" tube amp that I built that had fixed bias so you could use EL34s/6550s/6L6GCs/etc. That amp cost a lot more to build, given that the output transformers alone cost about as much as everything in this amps.
Congrats on finding the problem. When something odd like this occurs in a build you need to go back and examine everything you’ve done. Eventually the truth is revealed. Not sure why those lower voltage zeners would have been included! Perhaps an earlier version of the kit had different resistors in the front end and needed a lower bias voltage on the current source.
Today I started work on my Aleph J.
I managed to almost completely populate both amp boards as well as the power supply board.
However I have a couple of polarity questions before final soldering on a few items.
In particular does the 5pf mica cap at C5 have a polarity and if so how can it be fitted correctly.
Same problem with the large block 1uf cap at C1.
I managed to get the wrong caps for C6 and C7 so when the right ones arrive I'll be wanting to know which way they go as well please.
Then I need advice to fit the LED's properly. I see a flat on one side drawn on the board and I see one leg is shorter on the LED. Just not sure which way that goes. No indication on the power supply board either. I may just wait till power up to see if I got them in the right way as I took a stab in the dark.
Will the amp work without them being fitted right?
I did get some of those small voltage zener diodes in the transistor kit from DIY as mentioned above but luckily I had already ordered a 9v one. Perhaps they need to be made aware that they are supplying wrong parts there.
Your help will be most appreciated from this novice.
Next step to get some panels laser cut and do some drilling and tapping on the heatsinks.
Here's a pic of one of my new boards.
Cheers.
I managed to almost completely populate both amp boards as well as the power supply board.
However I have a couple of polarity questions before final soldering on a few items.
In particular does the 5pf mica cap at C5 have a polarity and if so how can it be fitted correctly.
Same problem with the large block 1uf cap at C1.
I managed to get the wrong caps for C6 and C7 so when the right ones arrive I'll be wanting to know which way they go as well please.
Then I need advice to fit the LED's properly. I see a flat on one side drawn on the board and I see one leg is shorter on the LED. Just not sure which way that goes. No indication on the power supply board either. I may just wait till power up to see if I got them in the right way as I took a stab in the dark.
Will the amp work without them being fitted right?
I did get some of those small voltage zener diodes in the transistor kit from DIY as mentioned above but luckily I had already ordered a 9v one. Perhaps they need to be made aware that they are supplying wrong parts there.
Your help will be most appreciated from this novice.
Next step to get some panels laser cut and do some drilling and tapping on the heatsinks.
Here's a pic of one of my new boards.
Cheers.
Today I started work on my Aleph J.
I managed to almost completely populate both amp boards as well as the power supply board.
However I have a couple of polarity questions before final soldering on a few items.
In particular does the 5pf mica cap at C5 have a polarity and if so how can it be fitted correctly.
Same problem with the large block 1uf cap at C1.
I managed to get the wrong caps for C6 and C7 so when the right ones arrive I'll be wanting to know which way they go as well please.
Then I need advice to fit the LED's properly. I see a flat on one side drawn on the board and I see one leg is shorter on the LED. Just not sure which way that goes. No indication on the power supply board either. I may just wait till power up to see if I got them in the right way as I took a stab in the dark.
Will the amp work without them being fitted right?
I did get some of those small voltage zener diodes in the transistor kit from DIY as mentioned above but luckily I had already ordered a 9v one. Perhaps they need to be made aware that they are supplying wrong parts there.
Your help will be most appreciated from this novice.
Next step to get some panels laser cut and do some drilling and tapping on the heatsinks.
Here's a pic of one of my new boards.
Cheers.
Mica capacitor has no polarity, the big WIMA red capacitor also no polarity.
With the LED, the short leg is negative side, long leg positive.
Using Russian caps for C1 input capacitor in Aleph J
I don't know if this has been mentioned already, but there are several interesting Russian military-grade capacitors that could be used as a replacement for the input capacitor C1 in the Aleph J, and they are cheap compared to the high-end capacitors by Mundorf and the like.
One of them is the K71-4 / K71-4B, with a polysterene dielectricum, which is seen as the second best after teflon for audio use.
The other one is the K42Y-2, a paper-in-oil (PIO) capacitor.
Both capacitors should have a distinct sound if I have to believe audio reviews on these caps.
Does anyone have experience using these caps in audio circuits?
They are much bigger than a polypropylene cap, so on the Aleph J PCB's the short leads have to be extended and insulated with heat shrink tube and maybe fastened with a dot of hot glue.
I don't know if this has been mentioned already, but there are several interesting Russian military-grade capacitors that could be used as a replacement for the input capacitor C1 in the Aleph J, and they are cheap compared to the high-end capacitors by Mundorf and the like.
One of them is the K71-4 / K71-4B, with a polysterene dielectricum, which is seen as the second best after teflon for audio use.
The other one is the K42Y-2, a paper-in-oil (PIO) capacitor.
Both capacitors should have a distinct sound if I have to believe audio reviews on these caps.
Does anyone have experience using these caps in audio circuits?
They are much bigger than a polypropylene cap, so on the Aleph J PCB's the short leads have to be extended and insulated with heat shrink tube and maybe fastened with a dot of hot glue.
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Hi everyone
The AJ was so tempting, I jumped in a few weeks ago. Now it’s almost finished and I’ m about to fire it up, but without smoke this time ��.
I just have one question, for the 220uF I used green Nichicon caps, but I notice these are not polarized ( not sure the word is correct ), they have no + and - poles, is this gonna be a problem ?
Thanks in advance
Pierre-Antoine
The AJ was so tempting, I jumped in a few weeks ago. Now it’s almost finished and I’ m about to fire it up, but without smoke this time ��.
I just have one question, for the 220uF I used green Nichicon caps, but I notice these are not polarized ( not sure the word is correct ), they have no + and - poles, is this gonna be a problem ?
Thanks in advance
Pierre-Antoine
I am also just in the process of building one of these amps and I'm a complete novice.
However,
Freyahel,
I checked out the 220uf caps and these are caps C2 and C3.
The parts list specifies electrolytic caps and they are DEFINITELY polarized.
The negative side has the stripe down the side and the circuit board clearly shows the positive side.
Have a look at the build photos at the beginning of this thread to see.
Plus yes it will be a big problem if you get those wrong because they will apparently explode like a loud gunshot and if you are near without eye protection or earmuffs you could get injured.
Here's the pic of the Nichicon
The black stripe with the negative signs along it is the negative side.
However,
Freyahel,
I checked out the 220uf caps and these are caps C2 and C3.
The parts list specifies electrolytic caps and they are DEFINITELY polarized.
The negative side has the stripe down the side and the circuit board clearly shows the positive side.
Have a look at the build photos at the beginning of this thread to see.
Plus yes it will be a big problem if you get those wrong because they will apparently explode like a loud gunshot and if you are near without eye protection or earmuffs you could get injured.
Here's the pic of the Nichicon
The black stripe with the negative signs along it is the negative side.
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