2x2sc2879 amp questions

[Lerch256]

Hello I have attempted to build a 2 transistor amplifier seems to be working ok dead key 20 swing 100 bird 300 pep on bird but my question is I put the trimmers/tuners in and I tuned it best I know how I have 1/8 watt reflect on meter but it is at 200pf on input and 170pf on output does that seem correct?

Look at pics give me some advice or whatever your thoughts only issue is when I key it up and modulate I can kinda hear myself in the transistors

[Deleted User 14541]

That's close if it's a dave made style amplifier. Usually 180pf on the input and 150pf on the output if memory serves me. The output transformers talking may be due to the output tuning being off or possibly a dirty radio.

[Crusher]

Don't see any pics. Also, what mix transformer and lengths since no pics

-- January 29 2017 --

Don't see any pics. Also, what mix transformer and lengths since no pics

[Lerch256]

I have a 1/2x1/2 input transformer with 3 wraps of 16ga teflon and a 1 1/2x5/8 output transformer with 16ga teflon also wrapped twice

If I can figure out how to upload a pic I'll post one thanks

-- Tuesday, 31 January 2017, 23:15 PM --

Pic 1

[Crusher]

So the output transformer is a comp style transformer. But the 1/2" x 1/2" input transformer, is that a 43, 61 or 67 mix?

-- January 31 2017 --

It looks like 61 mix which is good. It may take 200pf, but that is not a common value. 180&220pf are. If it needs 200pf, just parallel 2 x 100pf and call it good

[Lerch256]

Pic 2

20170127_052851_opt.jpg

-- Tuesday, 31 January 2017, 23:37 PM --

Yes it is a type 61

I had a 3 wrap on the output but I changed it to a 2 wrap just messing around which would be correct or better in your opinion

Wish I would've went with the 1.25x5/8 output but I didn't know chalk it up to learning experience

[Crusher]

Usually on that setup it is 3in, 2 out

[Lerch256]

Thanks Crusher

When I got home last night I changed the output back to a 3 wrap it brought the bird watts up to 140 and the pep to 400 on the bird after playing with the tune still got 1/8 watt or so reflect but I have not checked the pf on the input or output yet will when I get home working night shift well my evenings ate from 2:30am to 7 or so lol

Does that sound right on the rms and pep on a 2 pill??
Or does that seem to be a little much?

-- Wednesday, 01 February 2017, 17:23 PM --

That's with a Galaxy 99 and into a 100 watt dummy load

-- Wednesday, 01 February 2017, 17:47 PM --

1000 watt dummy load

-- Friday, 03 February 2017, 16:43 PM --

Took it back to two wraps thank crusher