PassLabs Aleph 4.0

[t_majerovic]

Hello

This is my very first discussion thread to DIY community. I'm building Aleph 4.0 like many others people with few modifications (added protection circuit and controlled soft-start circuit).

For beginning I have question about possibility to replace ZTX450 by BC639 (I'm unable to buy/get ZTX450 in Slovakia and BC639 looks similar).

Thank you for answer/reaction in advance.

Tomas

 

[Gyuri]

Aleph 4

Szervusz Thomas!
This is a piece with a pleasure!
Do not be sad about the transistors. Any kind of similar one suits.
I hope for it a some kind of friendship, which could serve as a sample to our folk, takes shape between us!
The trouble is never with the individuals!

Gyuri

 

[t_majerovic]

Hello Gyuri

Thanks for your post...I read few discussions about ZTX450 replacement by any BCxxx transistor. But it was always connected to smaller PassLabs Aleph versions. Well, I expect that amplifier “first turn on” occurs next month. It shows me if BC639 is right equivalent in this circuit. I'm really curious....

My Aleph 4.0 adaptation uses concept of two mono blocks in common enclosure with independent power supply for each mono block. There is only one common part – power supply soft-start control and input filter.
Currently finished parts are: enclosure, whole power supply and I'm waiting for powerstage components. Oh, and I forgot mentioned that IRFP240 are already matched to 4 groups with 6 pieces transistors (I have 50 pieces population of IRFP240). IRF9610 remains to matching very soon.

Here is look to inside of enclosure my PassLabs Aleph 4.0 adaptation:

 

[Gyuri]

Ztx450

I am top notch for roughly 100 forints for you if you believe it in that manner to obtain ZTX450 transistor.
The ZTX653 transistor is what I used here, this is real overkill here.
With a greeting:
Gyuri.
This amplifier between the most beautiful ones owes, what I saw here.

 

[Taco]

Very neat layout, a very clean build!

 

[t_majerovic]

ZTX450

Hello Gyuri

Thanks for your offer. Today morning I had some email communication to one shop in Zilina. They have few of ZTX450 in store but don’t offer over internet. However we agreed to send transistors over normal post mail service. I expect delivery next Monday.

To Gyuri and Taco:
Thank you for your appreciation…

 

[t_majerovic]

Schematics - enjoy

Hello

I share schematics for everybody who is interested.

Complete schematics of power supply:
http://www.facebook.com/photo.php?pid=30092922&l=c4d59&id=1386409150

Complete schematics of Aleph 4.0 + protection circuit – one channel/mono block:
http://www.facebook.com/photo.php?pid=30092907&l=958ba&id=1386409150

 

[t_majerovic]

Today morning ZTX450 and 220uF capacitors arrived. I'm waiting for another package with remains components.

 

[stoN_Cold]

Hi!

t_majerovic, do you have some beter Pic, on facebook

Are Unredable!

Regards zeoN_Rider

 

[jacco vermeulen]

Tomas,

ditto here, me old and blind.
(bigger pics of the girlfriends too, please)

 

[stoN_Cold]

Hi!

Tomas,

ditto here, me old and blind.
(bigger pics of the girlfriends too, please)

For Me 2!!

Regards zeoN_Rider

 

[lineup]

You can download Aleph 4 schematics from Russia.
http://schematic.narod.ru/a_index.htm

 

[stoN_Cold]

Hi!

Thanks LineUp, but this is Gen. Pass Labs Service
manual!


I ment schematic of t_majerovic!

Regards zeoN_Rider

 

[lineup]

If I wanted to build this amplifier and had 2 versions to chose from: N. Pass or T. Majerovic,
it would be a nightmare to make up my mind.
They could both work very well.

One thing extra in Majerovic's version is relay operated protection circuit.
Otherwise I do not think he has changed much form the original.
I would not do this myself.
Because Nelson test his amplifiers well before offer them to people.
He does not only listen to the sound. He makes some nice data curves, too.
In order to be sure he is not imagine and to trim for best electrical performance.

 

[stoN_Cold]

Hi LUP!

Relay operated protection circuit.

That what I, tallking about!

Regards zeoN_Rider

 

[t_majerovic]

Comment

Audio part is Aleph 4.0 without any modification except replacement IRF244 by IRFP240 and my own PCB design. Power supply (with soft start – on/off sequencer) and speaker protection circuit are my own design. I prepare schematics in better quality and attach here.
Protection circuit must be part of each kind audio power amplifier without output capacitor. I follow this rule and it save my speakers many times. I also prefer delayed switch on amplifier output.

 

[t_majerovic]

Schematics 1

Aleph 4.0
Protection circuit (tested on simulator only!)

 

[t_majerovic]

PCB Aleph 4.0

PCB wit Aleph 4.0 (except power mosfets) + protection circuit

 

[stoN_Cold]

Hi t_majerovic !

That what I, tallking about!

Nice work, what about "Values"of parts?

Regards zeoN_Rider

 

[t_majerovic]

I didn't publish values because protection circuit is tested only in TINA simulator and not on real/physical circuit. So I can't 100% promise that this schematics will work without any modification. So, anyway. If you are interested here is exported schematics from TINA simulator.

Few notes to components values/types are here:
switching transistor controlling relay is replaced by TIP117 – TO220 in physical circuit
R13 (connected to emitter of TIP42 ) presents relay internal resistance - FINDER 40.61S, 24V/900R,One pole
zener diodes Z2 & Z3 1N3022 is replaced by BZX85/C15 in physical circuit
zener diode (connected to collector to TIP42) is replaced by BZX85/C24 in physical circuit
bidirectional dual color LED diode is BL-BHG234
switch SW-SPST1 in simulation circuit is replaced by LTV826/DIP8 in physical circuit
C1 47uF in simulation circuit is replaced by two 100uF capacitors C7 & C8 in physical circuit

Expected issues:
circuit sensitivity (too big)
insufficient current over dual color LED