Another great project. Myself i was never lucky enough to own or listen to the A1. I did listen to the B1 quite a bit, and have thought about modding it. Big fan of TdP.
You should do Babelfish M4000 next, Zen Mod. Babelshark? I feel if we can just come up with fugly enough name for it...
You should do Babelfish M4000 next, Zen Mod. Babelshark? I feel if we can just come up with fugly enough name for it...
memory lane .......... after my first one, I remember making another pair of pcbs ( Yore, sharpie on pertinax, etching with acid+peroxid) but never completed
I found few days ago that pair of pcbs, laying in cardbox for more than 3 decades
so, old vs. new:
and, while I was there, another piece of funny history .......
few years in direction to now ( so just under 3 decades) I did bought one smoked A1 for semi-decent price
I did repair it using "my" recipe of 2N3055+BDX18 in output, but still without knowing for sure "what Factory used there?!?!"
So, times predating www, ZM concocted cunning plan - I wrote a letter (!!!!) to Factory - asking what exact type of TO3 cans are used in their A1), cleverly citing Ser. No. of amp in my hands
Surprise - month or so after (when I already abandoned any hope in deepening my knowledge), I did receive one big fluffy mail envelope, containing no less than two pairs of driver tranistors (BD139/140) and two pairs of TO3 outputs ........ even if I decidedly wrote in my letter than just one channel is broken
and - no single letter written about what type they are
that much about me learning anything new
anyhow, I wasn't lazy, took my firstly made Clone and replaced "my" 2N3055+BDX18 with original ones (A1N & A1P), just to be totally flabbergasted with fact that not only DC Offset and Iq were not changed at all (say under 1% change) but also sound wasn't changed at all
after all, my conclusion was that I'm unbelievably clever, deducing proper type of output transistors in A1
later I did put back my combo, leaving originals in cardbox for who know what shiny future project
here's pic, as pudding
finally, I'm getting tomorrow (long time ago-ish) ordered TTA/TTC biguns
I already have bunch of pcbs ready for kits, same as plethora of other parts
Arrived today! With presoldered SMD caps on the back of the circuit boards. Well, thank you. 🙂👍
As if i needed another amplifier build…
🙂🙂🙂
But this is a really perfect, fun Christmas break project!
As if i needed another amplifier build…
🙂🙂🙂
But this is a really perfect, fun Christmas break project!
My first PCBs was also done by "painting" on the Cu-side using a special black pen and then etching using ferric chloride. After that drilling using special PCB drill bits (expensive). Then later PCBs that was photo sensitive on the Cu side was used. It made it a bit easier to make multiple PCBs by first creating a PCB photo template.
I also remember an etching machine where the PCB was placed at an angle and ferric chloride foam was created and heated by the machine to flow down the PCB to have a more even etching. I can even remember the smell of the hot ferric chloride. It was not a bad smell......but I never tasted it.
When I look at vintage Threshold amp PCB's it looks like the photo-technique may have been used. At least the PCB's looks "hand-made".
I also remember an etching machine where the PCB was placed at an angle and ferric chloride foam was created and heated by the machine to flow down the PCB to have a more even etching. I can even remember the smell of the hot ferric chloride. It was not a bad smell......but I never tasted it.
When I look at vintage Threshold amp PCB's it looks like the photo-technique may have been used. At least the PCB's looks "hand-made".
Yea 🙂
And They are both built and ready to be heatsinked! So now i am doing the metalworks, building the monoblocks. Those are going to have very fine heat dissipating capacity, since they are designed to also be able to take SB and LSB level of heat.
And They are both built and ready to be heatsinked! So now i am doing the metalworks, building the monoblocks. Those are going to have very fine heat dissipating capacity, since they are designed to also be able to take SB and LSB level of heat.
Hi ZM. Wonder how your A-1 amp would compare to the one suggested by hbtaudio? Two quite different approaches...memory lane .......... after my first one, I remember making another pair of pcbs ( Yore, sharpie on pertinax, etching with acid+peroxid) but never completed
I found few days ago that pair of pcbs, laying in cardbox for more than 3 decades
so, old vs. new:
View attachment 1386718
and, while I was there, another piece of funny history .......
few years in direction to now ( so just under 3 decades) I did bought one smoked A1 for semi-decent price
I did repair it using "my" recipe of 2N3055+BDX18 in output, but still without knowing for sure "what Factory used there?!?!"
So, times predating www, ZM concocted cunning plan - I wrote a letter (!!!!) to Factory - asking what exact type of TO3 cans are used in their A1), cleverly citing Ser. No. of amp in my hands
Surprise - month or so after (when I already abandoned any hope in deepening my knowledge), I did receive one big fluffy mail envelope, containing no less than two pairs of driver tranistors (BD139/140) and two pairs of TO3 outputs ........ even if I decidedly wrote in my letter than just one channel is broken
and - no single letter written about what type they are
that much about me learning anything new
anyhow, I wasn't lazy, took my firstly made Clone and replaced "my" 2N3055+BDX18 with original ones (A1N & A1P), just to be totally flabbergasted with fact that not only DC Offset and Iq were not changed at all (say under 1% change) but also sound wasn't changed at all
after all, my conclusion was that I'm unbelievably clever, deducing proper type of output transistors in A1
later I did put back my combo, leaving originals in cardbox for who know what shiny future project View attachment 1386720
here's pic, as pudding
View attachment 1386721
finally, I'm getting tomorrow (long time ago-ish) ordered TTA/TTC biguns
I already have bunch of pcbs ready for kits, same as plethora of other parts
View attachment 1386723
For comparison:
What du you think?
🙂 morten
in short - I don't care ....... everyone is entitled to have own fun
whenever I see schematic I think I can learn something from, I'm interested; when I can't see (either objective or subjective reasons), I'm not
I was repeatedly called in that thread, and - maybe it's just me - I didn't had impression of anyone having a concept what is a goal ........ except if gilding the lily was
We both enjoy our projects - and we should leave it at /like that. But to pick up on your sentence about learning and discovering interesting things, 3/4 + 3/4 already has a lot of surprises in store - and is already much more than just a reboot of the legendary MF-A1.
#
I also like your incarnation (but why isn't it posted in the public Solid State area?). Nice PCB.
kindly,
HBt.
Thank you, and leave it exactly as is
Pass Labs Forum is public enough for my Joie de vivre
Now, if you proceed to press your criteria on me, I'm just going to report your posts written here