Susan parker Zeus amplifier

[moray james]

curious to know if anyone here has built up one of Susan's amplifiers or if there has been discussion on the forum? For those who have not heard of the Zeus amplifier you can take a look at Susan's site. There is a long thread at diy about 1500 plus posts including input from John Curl of Parasound fame and others. This is a very interesting design and I am much interested in that it is capable of preserving so much phase information. As far as diy it does not get much more accessible for the first time builder. I have included a link to Susan's site here http://www.audiophonics.com/. Best regards Moray James.

 

[susan-parker]

Building the Zeus

The main thing with my design (see attached schematic example) is the quality of the transformers. I do get comments quite often asking about alternatives however with such a minimalist approach it is all down to the iron.

It is possible to do some initial testing using certain mains toroids with dual 115 mains primary windings, which have to be used in push-pull since they can't be gapped for DC. This gives a bit of practical bench experience and hopefully confidence to invest in the more expensive quad-filar wound transformers. The best bandwidth I have managed from these is about 22kHz which is wide enough to get some idea about quality and some may find it good enough if one is listening from ripped CD or computer downloads. I can't make any guarantees about this though as it very much depends on the parts available.

Also I would note that it is possible to hand wind the big EI120 line driver and output transformers assuming one has a source of materials. This can help with the otherwise high cost of international shipping. When I say hand wind, I mean literally holding the bobbin in ones hand and wrapping the four wires on turn by turn. I have done this, although I would be first to admit it takes time and patience. A next step up is to use a lathe with a handle in the spindle to rotate the bobbin, again hand holding the wires for tension and layering. Still a bit fiddly, but much easier on ones wrists. (I still use this method for my EI120 transformers as my heavy duty coil winding machine has a traverse maximum of 1.5mm per turn.)

For the smaller input transformers if one is doing both stages as SE then it is possible to hand wind (perhaps using a variable speed electric drill) as one isn't worried about having to match two sets of secondary turns. Otherwise some form of winding machine with a turns counter is really needed.

Always happy to get emails and I do my best to answer any questions, although with the pressures of work and life I am not always able to reply immediately. Note that I don't often check the lists for PMs so unless there has been an email notification I may not see it for a while (several years on one occasion... oops!).

My website is a little out of date, hope to find time to dust it off during the Easter break.

 

[moray james]

Thank you very much for the post along with all the information Susan. I am not going to be up to attempting winding my own iron. So I will have to purchase my iron ready built. will send yo a PM with some specific questions. Best regards Moray James.

 

[nj pheonix]

none of the xfmr links seems to work. Do you if they have relocated or are doing some kind of server upgrade?

 

[susan-parker]

Sowter Transformer Links

Sowter have changed their website...

If you go to http://www.sowter.co.uk/acatalog/search.html and search for [ zeus ] then the three transformer links are:

8160 Zeus Power Amplifier by Susan Parker Input Transformer (CLASSIC AMPS)

9840 Zeus Power Amplifier by Susan Parker Output Transformer (CLASSIC AMPS)

9940 Zeus VMOS Line Driver by Susan Parker Output Transformer (CLASSIC AMPS)

Best wishes,
Susan.

 

[susan-parker]

SE Zeus

Have been doing a quick set of tests on the SE version of the EI120 size output transformer. Whilst nominally full range it is something I am working on for the HF part of a Bi-Amp output stage.

For bench testing I use an old CPU cooler with a fan.

Bias is 1.5 amps at 30 volts DC supply.

 

[audiozaz]

Very interesting stuff. :thmbsp: I'm drawn to minimalist designs such as this. I might have to give this one some thought for future DIY projects...

az

 

[goldleaf]

Thanks for posting Susan.

Curious about why you chose this design over a tube design. What motivated you?

 

[susan-parker]

Conception

Thanks for posting Susan.

Curious about why you chose this design over a tube design. What motivated you?

I started working on this design as I wasn't happy with conventional solid state amplifier sound that I was hearing from my marble sphere speakers.

As it happened at the time I was living in a house with 5 variously aged children who all played field hockey (up to and including county championship level) and were given to impromptu practise sessions around the home, so valve/tube amplifiers would have been "life expired" within a very short time.

Taking direction from my work in designing the sphere speakers where I was into the whole concept of drive units as transformers and so I decided to continue this backwards throughout the amplification chain with transformers as the primary building blocks.

That was in the winter of 1992/3 when I first started with my Tabula Rasa blank slate. I decided on using mosfet followers pretty much from the get go. It did take some time and rather a lot of experimentation to work out the details of the transformers.

So in answer to you question, I didn't chose the design, I worked it out from first principles.

Best,
Susan.