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Old 11th Sep 2006, 4:28 pm   #1
Hunts smoothing bomb
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Default Homebrew push-pull stereo power amp

Hi all,
Just been reading the thread on Steve bell's amp and also Percival007's.
They look very good chaps. Well done

Well I started designing last year and It is seriously a budget amp. All the transformers are recycled from other gear,the output tranny's are from an old stereo amp so they are matched. The mains Tx came from an old Heathkit stereo amp that was beyond economical repair. The rest is all brand new components including the ali chassis which was mail order from Bluebell Audio. The whole thing together with paint did not cost me much more than 100 quid and was mighty interesting to buld and is equally satisfying to look at in the corner of the lounge!

Cheers
Lee
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Old 11th Sep 2006, 9:43 pm   #2
Nickthedentist
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Default Re: Homebrew push-pull stereo power amp

Looks good, Lee. Like the wooden "cheeks"
Quote:
Originally Posted by Hunts smoothing bomb View Post
The... thing... was mighty interesting to buld and is equally satisfying to look at in the corner of the lounge!
But just as imporantly, how does it SOUND?

Nick.
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Old 11th Sep 2006, 10:26 pm   #3
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Default Re: Homebrew push-pull stereo power amp

The... thing... does actually sound pretty good I think, It has very warm bass and very crisp treble, sounds extremely good when playing vynil I think. Very surprising how loud it goes before the thing distortes, I took the ideas for the phase splitter stages from "valve Amplifiers" by Morgan Jones. The push pull output stage with the 6V6's is pretty much identical to the amp that it came from originally, according to the oscilloscope it doesn't perform linear though, I still have an awfull lot to learn about valve amplifiers and constructing these circuits and may well think it is quite cr@p in the future!!
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Old 12th Sep 2006, 5:23 pm   #4
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Default Re: Homebrew push-pull stereo power amp

Well you said it all..if you like the way the thing sounds, then why worry about the technicalities. I always think that listening to something that you have created always sounds better than on commercial gear anyway.

Biggles.
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Old 12th Sep 2006, 5:56 pm   #5
percival007
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Default Re: Homebrew push-pull stereo power amp

That looks great. I too like the wooden side cheeks. It makes it look really classy. Don't worry too much about the "paper spec's", as Biggles says, if you think it sounds good, then it sounds good. I used to rely on the spec's of equipment too much but the longer i do this kind of work i realise allthough they have a certain use, it is more about personal preferences. What one person thinks sounds/looks good, is completely different to another persons opinion, and that's great!!!!!!!
Get off your soap box Percy!!! The amp looks really professsional.
Cheers, Perc
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Old 13th Sep 2006, 12:50 pm   #6
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Default Re: Homebrew push-pull stereo power amp

Quote:
Originally Posted by Hunts smoothing bomb View Post
, I took the ideas for the phase splitter stages from "valve Amplifiers" by Morgan Jones.
Nice work!
What are the phase splitters then?

Last edited by Kat Manton; 13th Sep 2006 at 2:57 pm. Reason: Fixed quote
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Old 15th Sep 2006, 1:25 pm   #7
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Default Re: Homebrew push-pull stereo power amp

Hi Merlin,

I was using ECC88's from an old Solartron scope I had but have moved to ECC83's (I don't know if there is a correct or incorrect valve to use in this position) I just think in my mind that the ECC83's sounded better on the bottom end. Improved it again since the photo too by getting four brand new matched 6v6's in there which are unusual as they have clear glass and gettering on the top compared to the NOS versions with smoked grey glass which you can't see through, Anode construction is different too, they are very much like the EL34 with a box anode which has rectangular holes in the sides so you can see the electrodes and glowing cathode.........MMmmmm yummy!!

Cheers Lee
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