First Aleph-3 build will be continued till the end

[All_DIY_STUFF]

I'm just interested in source of your Weed, Man .........

Firs of all, how can Audio people always tell wen I'm high !?!?! Secondly, I grow my own .

 

[Zen Mod]

Share my Man, share........

 

[Logon]

how can Audio people always tell wen I'm high !?!?!

Don't take personally what @Zen Mod told you, look at it as an initiation...

 

[jjasniew]

any net DC imbalance
between the current of the + supply and the - will tend to
saturate the core of the transformer and create noise. This is
seen for quite low current differences and can also show up with
low frequency output. Using two bridges eliminates the problem.

Interesting and understandable in engineering parlance ;') High or not.

 

[Zen Mod]

Papa most likely wasn't high when he wrote that

Though, with his mileage, high or not, no difference in expertise

 

[Craigl59]

Have just completed the calibration of the Thatcher/Pass Aleph 30 set and think it might be good to point out the helpful trimpots Randy added to his clone recreation. I have been using this order:
1. Adjust the current so that the 3 mosfet pairs produce 2.15 amps current. Can take a while to get this perfect and the amp should be on for an hour or so before the final adjustment is made. =P3 trimpot.
2. Adjust the AC Gain proportion so that you achieve your sonic goal -- there is a recommended 50% value that can be dialed in or you can use your own proportion. Either way, the estimable Thatcher has provided a very clear description of the method and a PDF is supplied below. =P2 trimpot.
3. Set the DC offset to "0." Easy and often takes a lot of turns to get a small movement. =P1 trimpot. Oh, and don't forget to short out the RCA plug...
Having completed this set, should point out that I had a problem with one of the monos and there was some smoke upon turn on (a mosfet pair was soldered in the wrong position). Replaced the mosfets (all 6) but found that when doing the calibration the current was not correct. SO, using a newly-acquired Hakko 301, went in and replaced all of the resistors surrounding the smoke area and voila! Problem solved. And the value of calibration and proper tools affirmed.
SO:, this is the fourth and, hopefully, final set of Alephs for my two places and this pair is going down to the valley in October with the rest of the "Turtle" set. Yes, wanted to get a photo of them all in and, therefore, you can see the front and back of the Dual PSU combination (PhonoPre, LineStage, and Monoblocks) below. It's dual PSUs all down the line (=Turtle analogy) with a discrete PSU for each left or right channel circuit board. Sounds better than good.

 

[All_DIY_STUFF]

Don't take personally what @Zen Mod told you, look at it as an initiation...

Naaa . No problem . I was actually high wen signed up and replayed to you guys. So not afended at all .

 

[All_DIY_STUFF]

So I got my transformer, and the production was very fast. I finally went with a 450VA 21-0-21V transformer with the secondary made from double strand winding (2x1.6mm). Everything was great until I measured it and found a 1.2V imbalance, so I had to take it apart and balance it out. I lost 1.5V total, but OMG, it made the amp sound great. With the new transformer, the sound has even more body, and the hum is inaudible. I can finally move to the enclosure build next week.

Can anyone tell me what value potentiometer to use?

 

[All_DIY_STUFF]

So Hy guys, finished my Aleph-3 . It's great but I did run into an issue that has taken me 2 days to figure out. When I connected a 4 ohm load it distorted very badly the distortion sounded like the amp doesn't have enough power so but it turned out to be an oscillating tranzistor q105, in that spot I have a BC550C any good replacement suggestions are greatly appreciated, for now it has a 1nf cap across base - colector. But it's ok now and sounds incredible. Here are some pics . This is my other music room at my mother's . I can only do metal fab at the shop I have set up at her place . Here are some pictures . Videos will follow once I upload to YouTube .

 

[Zen Mod]

2 positions of 1nF caps are there for exact purpose - to tame (possible) oscillations

if cap solved the issue, no need for change of BC, if part itself is OK

as is, in that position ( Aleph CCS), you can put any decent small NPN transistor in TO92 case (size) and it'll work

considering your thermal arrangement, be sure to check temperature of mosfets; if heatsink is at roughly 55C max, and transistor case no more than +10C, you did it good

 

[All_DIY_STUFF]

I finished my Aleph-3 clone, and it sounds incredible. In summary, for the power supply, I used a large 450VA transformer with 20.5-0-20.5V secondaries. The setup includes two full bridge rectifiers made with STTH1506TPI diodes, and filtering is handled by two banks of 44,000 µF per rail, made up of Kemet 22,000 µF / 35V capacitors (8 pieces). Additionally, I used 0.3 mH coils for further filtering. The boards are Moffi Audio Aleph-3 clones, which are of very good build quality. One issue I encountered was the need to place a 1nF capacitor across the base and collector of Q105 to stabilize the transistor. In my opinion it's a very simple build you just have to go all out on Power Supply and cooling . Total cost for me was :
Transformer, new buit to order : 140 euros
Capacitors, diodes, : 75 euros
Connectors, fans: 25 euros
Alumínium : can't say it's from work ( about 35 euros)
So basically: 280 - 300 euros ( with all parts )