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Peter Daniel 4th June 2002 06:04 PM

If we are talking about rect. bridges, I tried to parallel two bridges (25A) to achieve more power, however, abandoned that because I was under the impression that single one sounded better. Any experience with that?

Praudio 4th June 2002 06:41 PM

HPotter,the good sounding solution is 2 bridges;
one for + and one for - , to do that you need 2 secd. winding and
if I well remember the Plitron Lono has 4. I do this way for many

BeanZ 4th June 2002 07:04 PM

The eye is on the hole and not the doughnut. The design should start with a well designed and executed amplifier circuit and the power supply should be designed to the circuit. However, knowing ahead of time that monster power is desired, it is common to spec out the monster power supply. As a power engineer I would highly discourage the use of IXYS parts due to horribly, disasterous experiences with many of their different components. Has any of the more experienced designers ever thought about switching power in thier amps. It can reduce the size and weight dramatically, and the efficiency is hight increased as well.


Aud_Mot 4th June 2002 07:34 PM


Switching power supplies (and their variations) have been tried in commercial power amps for years. Everybody thinks they can do it, then abandon the design. In the consumer market, they tend to blow up, creating a service nightmare.

The closest successful example I can think of is the Carver amps. As I recall they are not a true switching PS, but do aim for efficiency and advantages. For what ever reason, they are not popular among audiophiles (audio purists)

Switching power supplies are cheap to build, but not cheap to repair. Being modular is a case of good and bad. Most computer techs will just buy a new PS, not repair one. This is do-able when there many companies that make PC style power supplies.

In the context of this forum, linear supplies are easier to understand, design, build, test, and repair. They have the reputaion of "sounding" better.

Also this is the forum for sound, not practicality. That explains all the people building high power single ended solid state amps that are 12- 25% efficient.

Peter Daniel 4th June 2002 07:45 PM


Originally posted by Praudio
HPotter,the good sounding solution is 2 bridges;
one for + and one for - , to do that you need 2 secd. winding and
if I well remember the Plitron Lono has 4. I do this way for many

And I always do it as well. However, as I mentioned before I had some bridges failures (when using inrush thermistors) so I wanted make them a bit stronger.;)

mlloyd1 4th June 2002 07:48 PM

I think it was Radio Electronics (RIP) some years ago that featured a power MOSFET based amp that used a switching power supply. I know the guy that did the power supply design. The amp designer's name escapes me at the moment, but he sells kits of the projects. Look in the thread on distortion analysis and you'll see his name with pointers to his web site.
OK, OK I just remembered - reinhard metz

BeanZ 4th June 2002 08:08 PM


Originally posted by Aud_Mot

...In the context of this forum, linear supplies are easier to understand, design, build, test, and repair. They have the reputaion of "sounding" better.
Also this is the forum for sound, not practicality. That explains all the people building high power single ended solid state amps that are 12- 25% efficient.

All of the above points are accurate. In fact, my high power dual mono amplifier uses a huge 1500VA linear unregulated power supply, so I do implement them as well. I am just fishing for people who want to try something new. Good answer Aud_Mot!


BeanZ 4th June 2002 08:20 PM


Since we are slightly off topic of the thread lets address the original neophyte. It is recommended to choose an amplifier design which you want to implement. There are lots of projects which you can execute yourself and range in all classes of amplification. Not knowing your background a good book to look at is :High Power Audio Amplifier Construction Manual, by Randy Slone and the Audio Power Amplifier Design Handbook, by Douglas Self. These are good references however not absolutely necessary. The next expensive investment after the power supply and the enclosure is going to be the heatsinks. The size of the heatsinks are dependent on the class of amplifier you build. Class-A amplifiers require huge heatsinks, AB require large heatisinks, Class-T requires tiny heatisinks. I assume that quality throughout the entire range is desired so I have eliminated class-D. Class-T is very difficult and quite different to implement. Heatsinks can be found at surplus shops for cheap. Buying them new are extremely expensive. Once class is decided the next investment will be the output transistors. No matter what class you choose or what kind of transistor output )MOSFET or Bipolar, this is the next expensive investment. Complementary pairs are quite often chosen for best quality. Bipolar pairs are MJ15003 /4 pair or the MJE21193/4 pair. Though with most of the available projects online it will tell you the best parts for the application. What are your requirements?


Pete Fleming 5th June 2002 12:31 AM

Mr Feedback, thanks for that article by Jim Hagerman, very interesting reading indeed. Makes a change from my typical “that looks about right” approach.

Aud_mot, actually Linn use switching supplies on their Klimax amps, regarded as very good amps indeed. Yes switching supplies can be difficult to design and repair, but they have many advantages over a conventional linear supply.

I felt tiroth’s suggestion to build a smaller amp as a first project was a very worthwhile suggestion.



Scorpion 5th June 2002 04:14 PM

Hi all,

thank to all for you very kind answers. As it is only my second post on this site, I don't know (yet) how to respond personnaly to each and everyone of you therefore my reply will cover many of your comments.


I am not sufficiently skilled or have a great knowledge in DIY stuff. That is why I am on this site to ask pros like you guies.

Money was spent this way: 600$ US (1000$ CAN) for the Plitron LONO transformers (2 at 1KVa ), another 600$ US (1000$ CAN) for the boards, wiring and components and 300$ US for the all-around 5/16 '' thick chassis, machining and anodizing.

I am not looking for exotic stuff but just trying to have tips to maximise my efforts with the components I have. Of course, I will be tweaking and tunning the amp for a year or two (and might change some components along the way). Anyway, it's all about system synergy and more than everything the final product will have to be pleasant to my ears.


Of course, good parts does not always mean good sound (altough it might help). To me it's all about synergy. Synergy between the components in the amp and between the amp and the rest of my system and more importantly between the final sound and my level of pleasure !!! :)

I bought lot of stuff from a surplus store. For exemple, Mallory CGS capacitors cost me a total of 70$ CAN (45$ US) for 4 70V 40 000uf and 8 75V 20 000uF !!!


I was talking canadian dollars, sorry for the mistake !! :) . Here are some important details that all of you should know :

This circuits I will use are built here in Montreal by a friend that has over 30 years of experience in the audio field. He personnaly knows the owners (see inventors) of companies like Sim Audio, Classé, Totem (years ago) and especially Tenor Audio (recently)and has sometimes helped or commented on their project (some of the Tenor Audio stuff are now on the market). This guy has been building amps for more than a decade. I listenned to some of them, they are incredibly musical and...they sound true.

The circuits I will use are his. I don't have a great knowledge of DIY and that's why he'll help/supevised me. Here are some details about the boards:

Bipolar boards with 4 outputs per channel mounted directly on board, working in class AB, running at +- 64V, Teflon OFC 4 onces (like in big Levinson) board with a dielectric of +- 2, trace fully balanced, impedance fully balanced, heatsink and output transistors mounted directly on board so it is fully operationnal even without a chassis, each electrolytic can is bypassed by a prolypolen cap (Solen for now) directly on board. These boards will be my starting point but any comments on how to improve them are truly welcomed. I might try to scan them and provide a picture.

As far as LEDs are concern, I am wondering why companies that build big and expensive amps (like Gryphon, Burmesteer for exemple) seperate the LEDs from the audio path if they're are no differences in the sound or why display can sometimes be turned off. It might just be a marketing strategy. I'm inclined to think that LEDs might make a difference in sound, even slightly but again (as someone once told me) some golden ears can hear flies fart....;-)


It seems like there is no consensus on wether IXYS bridges are the way to go (at least it seems to be the opinion of BeanZ). Comments on the sound of Digikey diodes and/or IXYS bridges would be appreciated.

After reading your posts I have no doubt that 2 bridges per channel are the way to go. That's exactly what I am going to do. I'll just have to select the proper one.

I will use 4.5% silver AND 3% solder (? brand ? it will be provided by my friend). Both are better sounding than anything eslse I have tried this far. Now wich will go where is another story. I'll have to experiment. In my experience Cardas solder gives weight and ambiance but at the detriment of pace and rythm. It muffled a little too much the sound for my taste. The 3% solder I am using has IMHO the qualities of the Cardas but offer a more natural and transparent presentation of the stage . The 4.5% solder (while lacking in body and warmth) is clean, fast, transparent, vivid and has superbe detail retrivals and do the pace and rythm thing extremely well. It sounds better to me than any 4% I've tried.

In my experience putting the solder in that order give the best results: 4.5-3-3-4.5 (in my speaker`s crossover).

Again, thank to all for your kind answers

Best regards to all,

Marc-André Rodrigue

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