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Bonsai 3rd June 2012 10:58 AM

Ovation e-Amp is Completed
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My 180W per channel e-Amp is finished. There's a .pdf file you can download to read about by design effort on the first page of my website.


Bonsai 3rd June 2012 02:20 PM

2 Attachment(s)
Heres some more pictures. This amp weighs 30Kg's (my earlier Ovation 250 came in at 38Kg's) but this one is actually mechanically a lot stronger/more solid.

The second picture shows the e-Amp on the left, and right foreground the Ovation 250.

I did some more sound tests this weekend and the sonics are very good. I need to spend some time comparing the different feedback modes over the coming weeks. Its currently set up for TMC and wide band feedback.

I am pretty pleased with the noise as well - absolutely silent (inputs unplugged) and ear right up against the speaker bass, mid and treble units.
No hiss and zero hum.

Antoinel 3rd June 2012 02:38 PM

You've done a fabulous job on your [absolutely Class A] website. e-Amp is quite impressive and no doubt an excellent performer all around.

Bonsai 3rd June 2012 02:47 PM

Thanks Antoinel!

Nico Ras 3rd June 2012 04:35 PM

Hi Andrew,
excellent and very detailed paper on your e-amp. I noticed that page 18 was blank, was this intentional? The quality of the build is world class. Very well done, anyone who owns it will be very proud of you, the designer!!

Bonsai 3rd June 2012 10:30 PM

Thanks Nico.

Page 18 in the word document is not blank, but when I publish it, it sticks a blank page in there for some reason. I will need to look at it sometime.

Ian Finch 4th June 2012 02:47 AM

WoW! What a paper accompanying the pics.- That will ring a lot of bells on this forum at least.
I'm a little puzzled about the choice of mounting the Vbe sensor transistor. You describe it variously as "loosely coupled" early in the paper and "tight" later when detailing it but the assembly shows a fair gap between the sensor and collector lead. I guess you would need to take such an approach with a commercial product but for your own use, perhaps an E-line package device would allow direct contact by say, inserting through a hole from the top side of the PCB?

That's no criticism of what looks to be an absolutely awsome and well researched project. Congratulations and wouldn;t have a spare lying about would you? :D

Bonsai 4th June 2012 04:53 AM

Sorry, no spares lying about Ian!

I need to check out what you found and clarify it when I update the doc. I am afraid I looked at that doc so many times I no longer see the wood for the trees. I expect there'll be quite a few typo's I ll need to correct. Thanks for the comments and pointing that out.


dadod 4th June 2012 12:00 PM

Instead to load the VAS in case of wide band feedback you can use loacal VAS NFB, as Self suggested in his book. I think in this case you can even go down with distortion.

Walkalone 4th June 2012 12:14 PM

The PCB look very professional and very nice! Congratulations to Bonsai.

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