Will sound reasonable?... this amplifier is amps lab cousin

[destroyer X]

I made modifications.

Simulates very well, but this do not guarantee nothing related the sonic qualities.

Can tell me if will work or not...and worked very reasonable.

Easy can produce 150 RMS watts to 8 ohms.... to reach something alike 250 or 300 hundred watts can be reached if supply can hold the power needed.... 600 Watts transformer may work with 4 ohms speakers.

If you want to connect to hard loads, as 1.5 or 2.0 ohms, put 4 pairs of 250 watts transistors.

3dB loss is around 5 hertz and 105 kilohertz.

The MPS transistor can be replaced with some 100 Megahertz that can hold more than 100 volts peak to peak swing.

Square wave shape remember a Vulcano when full power is reproducing frequencies higher than 60 Kilohertz.

Low frequency shows sligth overshot

Sinusoidal turns triangle around 120 Kilohertz

Square wave turns ugly around 108 Kilohertz

I am thinking in assemble that complicated thing...do you think this will sound good?

Could you find errors?

Have something to include or supress?

Please, having something to say.... go ahead.

regards,

Carlos

[MikeB]

Hi Carlos !

Looks fine, except maybe the "unbalanced" input. The inputside of
diffamp has 11kohms, the feedbackside has 22kohms. This can
give some DC-offset.
The bd139/140 has 80volts ratings, but might see more than
100volts. Why the mpsa92 ? This transistor should not see more than 55volts.
You might consider a 1k basestopper on the lower bd139 in the vas
for safetyreasons.

Ok, sofar looks okay, i see no further problems.
What transistors are you using for outputstage ?

Mike

[Jan Dupont]

Which make of MPSA92 do you use ????????

Fairchild / Onsemi's MPSA92 are rated 300V, and can handle it!
Trust me as the MPSA's are one of my favorite amp transistors

[Jan Dupont]

I don't think I have to tell you my opinion, as you well know my view on non sym. amps

And maybe you should use 2SA970 / 2SC2240 in the input

[destroyer X]

I am just thinking about to construct.

We bougth a new furniture to the television and audio room, and some pretty wood panels and some perfurated chromium plated parts were not used to put Cds inside.

This way, having the pretty enclosure, and very big, i was thinking in construct something stronger than the average power i normally have here "Watt vírus powerholic" are attacking me.

Yes Jan i know very well you like the simetrical, double simetrical inputs used in your Linnx and others you have on your manufacturer line.

I am trying some Digital and feel that cannot betray my old tradition of AB and C.

So, i may do this one...not sure. To be more decided i put it here to have some evaluation from our forum people.

I take note your modifications my dear friend from Good luck place (guterloh is impossible to me to pronunciate.... happy not to have bonds in my tongue...because if bonds inside i had...they were broken trying to pronouciate your town name Mike)

Thank you the family picture Mike....i was happy to see your best friend, his wife and your mother...and you are really big!

Well, is good to see that spirit of cooperation, this way i love to post schematics, i think interesting different oppinions and ideas...many ideas i use to test here to see if i like the audio results.

thank you.

Carlos

[sam9]

A: My faith in the predictive power of simulation is limited but I see nothing obviously amiss. Ultimately one has to build it in order to know.

B: There are two things I would do differently if it were my project, but that does not mean there is anything "wrong" as it is. Just my own preferences. Just so you know, they are:
B1- For 150W I would use three rather than two pairs bor better
heat transfer and less distortion penaty at low loads.
B2- Instead of connecting the driver emmitters to the output via a
pair of 33-ohm resistors, I would connect these emmitters only to
each other via a singple 150-220 ohm resistor by passed by an
~1uF cap. This improves crossover distortion by forcing one side
off when the other turns on.

Would anyone notice the difference when listening? Who knows? Probably not.

[destroyer X]

To the output MikeB, i have two pair of those rectangular 250 watts Sanken Devices...not the last models, a little bit older...2SA1215 and 2SC2922.... they are always the same, as i am using them to all the amplifiers i make.... to driver i think i will borrow some Aksa drivers transistors...just for testing purposes, as it will return to Aksa again...guaranteed.

Yes!...those BD139 sometimes hold a little bit more voltage...also the BC556, those values of maximum voltage are not so precise.

A long time ago we could see some "load charge lines graphics" to see where the transistor are more linear, and decide the best current to your working voltage...but i did not perceive those graphics anymore....i will see some Ic/Ib to try do deduce the best point, and to adequated better thetransistors choices...i am just using some reference schematics, from products, published by our forum friend Matt www.schematicsforfree.com , those schematics i use to have one idea if the transistor is adequated or not..if works well, in some Yamaha, using the same voltage and current i will intend to use, i suppose i can conclude that will work fine in my amplifier too... am i rigth?

But the question is...is this kind of schematic, with all those CCS and mirrors, good sounding circuits?

I made some last year, and i dislike those more complicated circuits, maybe some matter of coincidence...the more complicated resulted in worst sound...maybe because all tollerances out working together (and bad!) so, i was running from them a long time.

Now going again to complicated designs.... not sure if will sound good...that's i would be happy to hear someone saying to me:

" I assemble one circuit with the same CCS, using the same red LED and those mirrors and same thopology and sounds this or that way"

That's i am searching, that kind of information....can be subjective feelings.... alike:

"Hummm, those mirrored normally sounds so so so despite having excelent slew rate"

regards,

Carlos

[darkfenriz]

a true beast
it is hard for me to say if it is sophisticated or over-complicated (with so many stages and huge open loop gain)
TRY IT
what's the purpose of 6,8k at colector of bc546 at current souce?

this amp looks more like (old-stylish??) commertial amp then a diy project I feel.....

regards

[destroyer X]

Do not remember, but may be to supply energy to the led.

Darkferinz, this is a recent stilish comercial kit amplifier as you could perceive.

I already had one vote...try it!

thanks

Carlos

[MikeB]

Originally posted by ACD
Which make of MPSA92 do you use ????????

Fairchild / Onsemi's MPSA92 are rated 300V, and can handle it!
Trust me as the MPSA's are one of my favorite amp transistors

My point was, that a mpsa92 is a bit overkill here, it's a highvoltagebjt,
not a real smallsignal one. So a bc556 would do a better job.
And i would always use original onsemi-parts, i once had non-onsemi
mje15030/31, they gave nice firecrackers...

Originally posted by ACD
I don't think I have to tell you my opinion, as you well know my view on non sym. amps

And maybe you should use 2SA970 / 2SC2240 in the input

Maybe i bug you, but the bc546b/556b are quite good transistors,
and their +/-65volts are enough here...
I see no real reason to use the sc2240, which has about ten times
the price. (At least here in germany, the bc546 costs 4cents, the
sc2240 > 40cents)
In sims, the bc546 often outperforms the sc2240.
Maybe a mpsa18 would be perfect here, as diffamp is cascoded,
their low max-vce is no problem. (or mps6521 ?)

Mike