Considering playmaster pro series 3... Opinons?

[wintermute]

Has anyone built/listened to the playmaster Pro series 3 amp (Electronics Australia 1994).

I'm guessing that it can't be all bad if they are still selling 10 years on, but thought I'd see what people think.

Link to blurb http://www1.jaycar.com.au/productVie...=&SUBCATID=557

there is a Link to actual instructions including ciruit diagram on the above page, note big file approx 4.5MB.

Regards,

Tony.

[owdeo]

Yes, I built one about 9 years ago.

It was/is the worst sounding amplifier ever designed/built in my opinion. Basically just a souped up Hitachi configuration out of their data sheet for MOSFETS. It totally killed my enjoyment of music. It sounds like a bad PA amp - grainy and harsh.

The funny thing is it was meant to improve on the old eti5000 amp of 1981, and yet the "Pro Three" is a far inferior design both objectively and subjectively.

The fact that Jaycar have been selling it for years doesn't prove anything - Tricky Dicky are still selling the ETI480 module (probably the second worst sounding amp ever designed)!

I would recommend looking up the Leach amp - you will find a link to it by searching these pages. It is a really musical and nice amp and as a bonus is just about blow-up proof. And it is designed by someone who knows what they are doing rather than a bunch of clowns at EA ;-).

[Greg Erskine]

I haven't built a playmaster Pro series 3 amp but have built 3 or 4 other amps. I would recommend an AKSA, might end up costing a bit more but well worth it IMHO.
http://www.aksaonline.com/index.html

[wintermute]

Thanks Guys Much appreciated!!!!

I'll check out the Leach and AKSA amps.

Regards,

Tony.

[mrfeedback]

With a few mods the ETI-480 makes an acceptably good entry level amplifier.
Faster output transistors, correct the power and earth arrangements and change a few passive components and these are reasonably good, easily available and cheap.

Eric.

[wintermute]

Hi Eric,

I guess that's the difference between someone with an understanding of how the circuit works (and what can be tweaked) and someone like me who has only a basic understanding, but good enough soldering skills to build something someone else has designed!

I can make it but it will have whatever limitations were in the original design. You on the other hand can look at it and say hmmmm, I think it would be better if I changed this, and end up with something much better...... Maybe one day I'll be at that stage, but for the moment I'm concentrating more on learning about designing speakers.

I'm Looking at another amp, as I'm thinking of using my existing one for a sub amp and building a new one for the main speakers

Regards,

Tony.

[mrfeedback]

Cheers.

To improve your ETI-480 do not use the existing power and output points (pins/pads) for power and speaker output.

Use fuses external to the module and bring B+ and B- to the board where the emitter resistors are connected.
Take the output from the track connecting the output transistor colletors (the existing setup causes causes imd because the NFB line is carrying speaker currents).
The speaker return line should go straight to the centre of the power supply and nowhere near the pcb.
Use a larger (10x) value low esr cap for the NFB shunt capacitor, and bypass this with a smaller value.
Use better/faster transistors for the outputs - I used Jap flatpacks - MJ15003/004 would be bullet proofing.

That's off the top of my head right now - 15 years since I did this - if you want I can take a closer look tonight.
These simple mods will improve the performance markedly.

Eric.

[wintermute]

Hi Eric,

My existing amp is actually a somewhat modified Playmaster Series 200 (mods all in the preamp section). Yeah I know It's probably even worse than the pro series III........ I've had some suggestions for improvement of it (power amp section) in another thread, which I'm yet to implement.

I'm looking to go for something fairly high end to replace it, not sure that a modified ETI-480 would be as much of an improvement over the 200 as what I'm after (of course I could be completely wrong there!).....

Regards,

Tony.

[Greg Erskine]

The ETI 480 has been effectively superseded by the SC 480. It's on special this month at Dick Smith's for just under AU$40 per channel. I haven't heard one so I can't comment on the sonics but I woun't expect miracles as both the ETI480 and SC480 cheap output transistors. The enhancements mentioned will obviously improve the situation. I am building one of these at the moment and I suppose you can sum by saying "you get what you pay for."

I can't offer much on the Leach Amp other than the design looks very good and his web site is a great source for learning how these amps work.

I've just brought my second AKSA so I may be a little biased towards them. There are considered by many to be high end at a budget price, but I must admit I have not compared them myself to high end equipment. You might want to look here for more information and maybe find someone in your area to get an audition.

http://www.audiocircle.com/circles/viewforum.php?f=19

[Brett]

Originally posted by owdeo
Yes, I built one about 9 years ago.

It was/is the worst sounding amplifier ever designed/built in my opinion. Basically just a souped up Hitachi configuration out of their data sheet for MOSFETS. It totally killed my enjoyment of music. It sounds like a bad PA amp - grainy and harsh.

It could be a serious rival to the early Crown and Phase Linear squalid states as the worst sounding amplifiers of all time.

The funny thing is it was meant to improve on the old eti5000 amp of 1981, and yet the "Pro Three" is a far inferior design both objectively and subjectively.

The Tilbrook amps were pretty good.