Amplifier based on 2N3055

[analog_sa]

Would it be any improvement in sound quality and do you have to re-adjust the bias?

You don't have to readjust anything but with those horror elcos at output i doubt if you'll hear any difference.

 

[Zombie]

Hello!
What elcos would you suggest as replacement?
Cheers,
Tom

 

[thoriated]

That reminds me of the early '80's when I decided to build a 'lousy' stereo transistor zero bias 741 opamp input ceramic capacitor diode switched class H amplifier with a quasi-complementary configuration output with 2n3055s using mostly parts I had laying around. I don't even recall now if I used any heat sinks at all - I figured I could slide since the supply rails would only support about 25W/channel.

Well, it didn't sound quite as bad as I thought it would, although it wasn't anything special. But it was a fun two day near zero cost project.

 

[djk]

"Phase Linear ( i.e. Bob Carver ) used a whole bunch of 2N3055's in the 400 series IIRC ( about 6 or 8 per channel ) to deliver 200 Watts...."

I don't think so. A 2N3055 is a 60V part, a Phase 400 runs on 170V p-p.

Try MJ410

 

[filippo22]

Hi
there is also this interesting italian project

http://www.rudistor.com/sound-lab/ars20eng.htm

ciao
Filippo
www.audiofanatic.it

 

[Easyamp]

You could use them in this circuit just swap the tip36's with the 2n3055's and swap r14, r,18 (both oops), r16, r19,19 to keep them on the emitters and you'd have fairly standard Sziklai pair amp.

Probably get you 100 watts or so.

You may want to add a pot of about 30k at r5 to gain some offset control, and a 220n cap between q9,q10 bases. The mjf15031 are a bit dated but it's what I had, any similar device could be used.

 

[Easyamp]

this might help http://www.easyamp.com/img/revised-quasi.gif

 

[sreten]

this might help http://www.easyamp.com/img/revised-quasi.gif

sorry but that is not the way to build a quasi complementary
output stage at all, biasing is all wrong and distortion will be awful.

Suggest you investigate using a "Baxendall diode"
and get your biasing of the output stage sorted.

🙂 sreten.

 

[Easyamp]

Well there are a couple of ways to go quasi the Baxandall Diode is one as well as the triple quad like the quad 303 and while this is an oversimplification of the quad triple it works very well.

I don’t have a distortion analyzer so I can only watch the scope and I see what your talking about but at the level the sine wave zeros at 210 and 330 degrees (increasing as I lower the input) is inaudible and I'm thinking this is acceptable for a couple older transistors. Anyway it seems like fun to do things a little bit different and it sounds good.

I would like to get a distortion analyzer does anybody have a suggestion.

Thanks

 

[Easyamp]

I forgot to mention that r9,r10 are actually a 2k pot

 

[sreten]

Well it doesn't look anything like the Quad 303 triple according
to my D.Selfs PA design handbook, the quad triple doesn't need
a Baxendall diode.

Parasitic oscillations are a real pain with triples, and triples should
be avoided unless you have a high bandwidth oscilloscope IMO.

🙂 sreten.

 

[Easyamp]

Thanks for the advice I haven't run into that ye. When I mention the quad 303 I was just saying that they had used the triple quad output stage and you are right mine looks nothing like the quad 303.

 

[Easyamp]

I noticed some others who went the 3 4 route put a diode in the pre-driver stage. Would this help get rid of the crossover distortion in this design? Like maybe between r13 and q12 base or should it go between the FB and r13? I am not fully versed on the triple quad so I'm not sure how to improve this other than shooting in the dark.

Thanks

 

[tiefbassuebertr]

to the same topic I start this thread:
http://www.diyaudio.com/forums/soli...-models-quasi-complementary-power-output.html

 

[nigelwright7557]

Maplin used to do a kit for a 2n3055/mj2955 225WRMS amplifier.
I used one on a mobile disco for years and it was never short of power.

 

[Madaudio]

hello everybody,I found the attached cct somewhere in internet. looks like an Elektor baby. anybody have PCB layout for this?

 

[blu_glo]

judging by the stains on the schematic, I think I would avoid it - as it appears the last one who attempted it may have come to a somewhat nasty conclusion.....😱

 

[Bigun]

It looks more like they were enjoying some nice BBQ ribs to me 😀

 

[blu_glo]

OK then; but as long as its not THEIR ribs splattered about the place....

 

[kaka]

Must be FeSO4 blob.