ETI 5000 MOSFET Power amp

[ocaukrell]

I havent heard a 5000, BUT I have built, and am still using an AEM6000.
I opted for lower voltage transformers, giving approx 150wrms.

In a system comprising of ;
Musical fidelity x-ray cd,
Nakamichi st-7,
Nakamichi ca-7,
Home built JBL's (15" 16 ohm, horn mid with lens, slot loaded tweeter)

Comparason between the AEM 6000 and a QUAD 522 Pro, (modified - Bypass input transformers).

AEM has more detail, much better control of the speakers through out the spectrum, slightly deeper bass.
Cannot find anything negative about it at all.

** NOTE **
tilbrook later brought out a 6005 version.
These modules were designed to replace the modules in the 5000 case, an upgrade as it were.
Although they had slighly worse (on paper) performance than the original 6000, it was still (apparently) a massive step foward for those with the 5000.

Personly, for a cheap bang for buck amp, I'd be looking for a quad 405 and doing a few minor mods.
should be able to find one in aus for $200-$400.

The 6000 as a kit was around the $800 mark, when I built mine it cost me about $1,300, due to building it bit by bit and using better parts.
Oh, I still have all the original articles too. including the 'statis monitors' (speaker protectors) and the add on dc servo boards.

[clem_o]

Originally posted by Samuel Jayaraj
If you have the skills and competence, you could make the Stochino amp. It can be rated among the very best. I have made a few of these.

Looking at Suzy's current area of research, I'd say she's much more than competent!!

Cheers!

[hifryer]

ETI 500 power amp


I built and still own one of these amps.

They sound unbelievably aweful!!! I thought it was OK when I knew no better.

My conclusion is that Tillbrook had no idea. Just another guy copying application notes and relying solely on traditional THD measurements!!

Mine took out very expensive tweeters when I first tried it out. It was an x MHz transmitter - turned out it was highly unstable and Tillbrook was no help at the time. Eventually solved with caps across the output devices. Blame was on inductive R's supplied by *aycar!!

Steer well clear of and dont waste money on S/H.

My take is that most such electronics mag designs even since are better but still dont sound great as they are designed by "engineers" who never listen to anything, ridicule tubes and are guided by numbers which bear almost no correlation to actual good sound.

Rely on guys like Hugh Dean (AKSA) , Nelson Pass, Bruce Rozenblitz and Jim Hagerman. They care, are smart enough to know what they don't know and have built and refined over many years.

cheers,

[macka]

The 5000 by todays standards is horrible.

The stuff mentioned above would be a wise choice.

[quasi]

Whoa...I built one too (in my mid 20's). I was disappointed too. With what I know now, looking back at the design, PCB and case layout the amp was only ever going to be mediocre.


Cheer

[The Saint]

mediocre or not a lot of these eti 5000 amps were built.
Having said that they were one of those amps that suffered from the so called MOSFET mist, the central imaging,,, well there was none... was very poor, the AEM 6000 was much better and very stable, but again suffered from MOSFET mist.
One needs to remember back then MOSFETs had just been released and no body knew how to drive them Properly. 20 odd years down the track we have the benefit of hind sight and the Experience and knowledge of those that have gone before us.

I have a lot of respect for David Tillbrook as he was one of the founding designers of some good amplifiers for their time.
and he for me was an inspiration to getting into amplifier design.
Dispite their problems, The question must be asked where were you in Jan, Feb 1981. I didn't see any ones name here in ETI or EA or AEM and I have read everyone of them...


Flame Suit On....

[quasi]

Originally posted by The Saint
mediocre or not a lot of these eti 5000 amps were built.
Having said that they were one of those amps that suffered from the so called MOSFET mist, the central imaging,,, ................. I didn't see any ones name here in ETI or EA or AEM and I have read everyone of them...


Flame Suit On....

Good post, put into perspective as you have done many Aussies have respect for DT, indeed he can be credited for DIY Audio being very strong here. As a younger person I remember waiting for his next contribution and indeed the next ETI / EA / AEM publication.

Your point about breaking new ground with these new "MOSFETS" is also well defined and I guess everything has a beginning. My only real point is that I made only simple changes to the recommended layout and the performance improved significantly. So it may have been a compromise made to suit a kit-set approach or some other market criteria.

But as you say, DT will always be known for his contributions and the innovations he provided.

Cheers

[macka]

I would point out the SKA at least to my earrs is one of the better simple mostfet amps and no doubt there are others.

There is no hint of that mostfet mist at all in this instance nor that hard metalic or glare sound of the BJTs.

I think the more modern output devices have a lot to do with it and also the designers ability to hardness and optimise their performance characteristics.

Macka

[The Saint]

No Worries Quasi...







Well done on you recent N-channel designs be the way, very professional... PCB layouts... keep it up.

[hifryer]

Yes, I should be thankful that DT made something available to build. I got a real kick out of it until someone let me hear the real Hi-Fi of the time but of course this was very expensive and well beyond my abilities to copy at that time.

There wasn't a lot of original design in the ETI5000 - he really just packaged the published Hitachi application notes and his bit where he decided that the two transformers were better in parallel than used as a supply per channel was most likely a poor call.

I also built his overly complex pre-amp and this was detailed but harsh. cascaded 5534 op-amps. Again knowing what we know today it is easy to do better re power supplies, bypassing and cap quality etc.

My point is that the Silicon Chip type designers refuse to acknowledge a lot of this and consider it lunatic tweak fashion stuff as things measure well without it!!

I agree we have much better devices to play with today and at least part of our advance is down to this.

As a result, a very simple traditional design can sound very fine if impecably implemented.

DIY has come a long way and most enthusiasts now expect close to the state of the art!! Audio Express and forums like this are generally a long way ahead of Elektor or S.C.

cheers