ETI 477 article

[kevinchiranga]

please send me the article of the Eti477 project

[sandyK]

Kevin
I think you may be referring to the ETI5000 by David Tilbrook.
I no longer have the article, but having built this project, and the later AEM6000 by David Tilbrook, I can assure you that using the original design without modifications, the performance was nowhere nearly as good as the AEM6000, or it's little brother, the AEM6005.These are much better performers. The original ETI5000 could sound quite harsh, particularly until fully warmed up.
The EETI 477 was published in ETI (Australian edition) in February 1981, if that is of any help.
SandyK

[kevinchiranga]

i am looking for a good mosfet amp to build.

[kevinchiranga]

SandyK can you scan the articles of AEM6005 or AEM6000 for me.

[sandyK]

Kevin
I will scan AEM 6005 tomorrow.,and send you an email when scanned
SandyK

[sandyK]

Kevin
Do you realise that these projects use the dual jfet ECG 461 in the input stage? It was made by New Tone Electronics (NTE) and it is almost certainly no longer available . It may be very hard to come up with a suitable substitute too.
SandyK

[Greg Erskine]

Have you seen this site?

Suzyj has some interesting information about her version of the ETI477/AEM6000
http://www.littlefishbicycles.com/poweramp/index.html

There is also a thread concerning this amp. Search for suzyj.

regards

[sandyK]

Kevin
I had a quick look at the website that Greg provided a link to, and I think you will be far better off with that newer version than a scanned copy of the original, where parts will be a problem.
SandyK

[suzyj]

The ETI477 (used in the ETI5000 poweramp) used a bipolar input stage (BC550s), not JFETs. The later AEM6000 and AEM6005 amps used the ECG461 matched JFET.

I've got a scan of the ETI477, here .

The design has been discussed previously, see the ETI5000 thread.

I decided to do an amp based on the later AEM6000. I changed the input JFETs, as well as a few other transistors, and optimised the design for low THD using spice (as documented on my website). My amp has been running for a while, and I'm extremely happy with it.

[sandyK]

I built both the ETI5000 and the AEM6000. I did not recommend the ETI5000 as I found it mediocre . It also had a design flaw which I was able to discuss personally with David Tilbrook. This (from memory) involved the 2nd stage pair being very unbalanced as far as heat dissipation was concerned, which in turn tended to unbalance the front end a little. I inserted an 18V zener diode in one side to equalise. David Tilbrook agreed, and this area was mentioned in the article about the 6000. I no longer have this circuit , so I can't be more specific. I also used separate transformers for each channel with improved results. This did not agree with Tilbrook's reasoning at the time. However he did this differently in the 6000. I also heard another ETI5000 at a Jaycar store, and again was less than impressed with the original unmodified amplifier.
SandyK