New dual-mono power amp

[peranders]

Originally posted by Scorpion

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.
Marc-André Rodrigue

When you use two bridges and two windings (for plus and minus supply) you won't load the transformer so much. If you use only one bridge you half wave rectify the current in each winding and this creates more losses in the transformer but you get half in rectifier losses. You win also a volt or two. I gather the losses thing is not important in your case....

Correction: My statement is true (or more true) if the load is unsymmetrical, not likely in an amp....) It's very true if you connect the windings in parallel. You can then get losses due to not equal voltage...

My recommendation is that it's no harm to use two bridges if you can afford it and/or have the room them.

My bridge type recommendation is a slow ordinary type with 4 caps. Use 10-100nF film or ceramic, good HF performance. 100 nF polyester 63V or 100V is quite alright.

You can also use a faster bridge but beware of the emission and decouple it carefully.

[HarryHaller]

"My bridge type recommendation is a slow ordinary type with 4 caps. Use 10-100nF film or ceramic, good HF performance. 100 nF polyester 63V or 100V is quite alright.

You can also use a faster bridge but beware of the emission and decouple it carefully"

Use RC snubbers instead of just caps.

High speed soft recovery diodes generate MUCH LESS RFI noise. That is the point of using them.

Two bridges are worth using to keep the charging current out of the finite impedances of the power supply ground wiring.

The load on a power amplifier is asymmetric during large bass transients and music signals are also asymmetric.

I suggest all interested do a search since this has been discussed in some detail in the forum.

H.H.

[mrfeedback]

IMO lead and silver sonically do not go well together.
96%tin/4%silver is quite ok.
60% lead/38%tin/2%copper is quite decent, and tins/solders very well.


Regards, Eric.

[Persig]

I know this is an old thread, but I was surprised that nobody mentioned the Chord Electronics amps (UK, nothing to do with with Chord interconnects). All of their amps have used SMPS for at least a decade, possibly two. These are very highly regarded-and expensive-units.

Check out this site: www.chordelectronics.co.uk

They look gorgeous too!

[phase_accurate]

Hi Persig

The Chords are indeed an exception. They don't have an SMPS for cost reasons but because they are convinced that their power supply is better than a conventional supply.
But there is much effort put into the development and construction of their SMPS compared to a PC grade powersupply, i.e. it is definitely NOT cheaper than a conventional power supply.

I once heard a real beefy Chord amp connected to a newer Tannoy Speaker (I think the name was "Dimension 12"). And I can confirm the combination sounded clean and pleasing. And when cranked up it sounded still that clean and unstrained but quite brutal !

Chord amplifiers are the ones that are recommended for use with the larger Dynaudio Acoustics Studio Monitors.

Even though I once developped an SMPS, I would strongly recommend generously designed conventional powersupplies for DIY.

Regards

Charles

[Persig]

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

Agreed, it's the route of choice for pretty much all of us. PSU for my A75 is to be PI filter, traditional but sound (sic!).

A question for Scorpion:

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 !!!

. Where is this surplus store please? A website would be most helpful, but an address will help.

Thanks

[HarryHaller]

The IXYS high speed soft recovery diodes are excellent. I have also used RC snubber on hign speed diodes and seen reduction of high frequency noise. The only reason I can think of to use regular slow diode bridges is to save money. I have changed to high speed soft recovery diodes on dozens of audio circuits with great results.

http://www.gensemi.com/appnotespdf/quik108.pdf

http://www.ixys.com/

http://131.109.59.51/images/pdf/Calculatin_%
20Optimum_Snubbers.pdf

http://www.gensemi.com/appnotespdf/quik108.pdf

[Luke123]

Scorpion

You said :" 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)."

What is the name of this guy?

Luke123

[Scorpion]

Hi all,

I know it was years ago but should you guies be interested in how my dual-mono power amp looks, here are a few pictures. It weights 140 lbs !!!

This is the MKII version as I modified a few things along the way.

Should you have any questions, please don't hesitate.

Regards

Marc-André alias ''Scorpion''

[Scorpion]

another pic