He claim 1000V/uS slew rate...
The amp described in this thread is at 90V/uS at most,
still a respectable number, but nowhere close to claimed figure.
If this amp is good, it has more to do with Hitachi s lateral fets
than with a so called design philosophy as the schematic himself
is a poor variation of broad designs at the time...
Alex,
You are a true artist with the pcb design. How you accomplish this so fast is beyond me. Nice.
After reading the Goldmund article it might be a good idea to limit most builds to 60 volts. All of this leads me to believe any small changes in the layout could result in high frequency oscillation issues. Much of Goldmund's design engineering was not done by accident. Potting the small signal transistors and coupling the stages together cost money. Something commercial companies do not do unless they must. Just a word of caution.
This is much more akin to a Porsche than a Chevrolet. No large hammers in the tool box.
Tad
You are a true artist with the pcb design. How you accomplish this so fast is beyond me. Nice.
After reading the Goldmund article it might be a good idea to limit most builds to 60 volts. All of this leads me to believe any small changes in the layout could result in high frequency oscillation issues. Much of Goldmund's design engineering was not done by accident. Potting the small signal transistors and coupling the stages together cost money. Something commercial companies do not do unless they must. Just a word of caution.
This is much more akin to a Porsche than a Chevrolet. No large hammers in the tool box.
Tad
I am also very impressed by Alex pcb design skill, Alex do you use NASA computers or what?
I have no experience with Goldmund, but I have some experience with Swiss made hifi equipment brands such as Nagra, Studer, Revox. They are pricey but their designs are state of art, one can Google to search for tweaks on these brands there are not much. I own 2 Studer CD players (more than 30 years old) still operating perfectly, the sound is very nice.
If the project here is a true Goldmund amp design I will try to build it, I am not able to tell if the proposed design is good or not.
I have no experience with Goldmund, but I have some experience with Swiss made hifi equipment brands such as Nagra, Studer, Revox. They are pricey but their designs are state of art, one can Google to search for tweaks on these brands there are not much. I own 2 Studer CD players (more than 30 years old) still operating perfectly, the sound is very nice.
If the project here is a true Goldmund amp design I will try to build it, I am not able to tell if the proposed design is good or not.
how about they deliberately decoupled the power limiter, on purpos, because it sounded better that way
anyway
is a power limiter needed at all
this is not PA
obviously Goldmund didnt like the power limiter
but didnt redesign it
we could do that
why not just stick to sensible power
instead of "selling" power
or what would come natural to this amp
what I see in the picture is a classB biased amp
limited by its size
small heatsinks etc
typical restrictions for any commercial amp
but doesnt have to be that way
please, take the time needed
The goldmund amp circuit
I just did a little web search of Goldmund. I had never heard of them before. Anyway they are not CHEAP. There is a set of monoblocks for 189,000 dollars and change which, according to them, are sold out in the current production run. Go figure.
This circuit schematic may have been something they wished to keep secret. I sure want a set of boards. Could never afford the commercial offering. They get fabulous reviews if you take stock in that sort of thing. No square wave overshoot, almost zero distortion, and over 2 megahertz frequency response. And as fanatical anal DIYers we are suppose to improve on this. Did I say something about how much they cost. I wish I had Jocko's money. He lives on the beach.
Tad
I just did a little web search of Goldmund. I had never heard of them before. Anyway they are not CHEAP. There is a set of monoblocks for 189,000 dollars and change which, according to them, are sold out in the current production run. Go figure.
This circuit schematic may have been something they wished to keep secret. I sure want a set of boards. Could never afford the commercial offering. They get fabulous reviews if you take stock in that sort of thing. No square wave overshoot, almost zero distortion, and over 2 megahertz frequency response. And as fanatical anal DIYers we are suppose to improve on this. Did I say something about how much they cost. I wish I had Jocko's money. He lives on the beach.
Tad
According to this article there was (is?) considerable care taken in the grounding and mechanical isolation of the power supply, torfo's, signal PWB's etc., and without this included into the construction of the amplifier it did not perform to it's best capabilities. Thus even the best PWB's and components will not matter much unless a suitable chassis etc. is included as part of the construction.
I do know that mechanical stability is an important consideration around lasers and some hi-freq. RF, but had not considered it in the area of audio amps (TT's and CDP's sure). Any thoughts about this aspect of construction?
Distorsion is very high in respect to current standards,
even compared to a cheap gainclones...
http://www.diyaudio.com/forums/soli...mplifier-i-have-ever-heard-8.html#post2320168
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They can be had for less - however used. Nice review of the 9.2 here too.
Goldmund Mimesis 9+ For Sale | AudiogoN
Let me state at first that I am no guru. However, I have assembled a few projects with OP amp ic's and quite a few LM3886 "gainclone" type amplifiers and not installing a low value film cap as close to or on the legs of the IC there was always some interference. I find it hard to believe that this discrete OP amp type module has no film caps anywhere for stability. It must be in the design.
Alex, What type of resistor dimensions did you use in the layout. Will full size Vishay/Dales fit this item. Not that it matters that much.
The specs I read for the Telos 5000 were .0005% distortion for a 1250 watt into 8ohm amp. That works for me.
Tad
Alex, What type of resistor dimensions did you use in the layout. Will full size Vishay/Dales fit this item. Not that it matters that much.
The specs I read for the Telos 5000 were .0005% distortion for a 1250 watt into 8ohm amp. That works for me.
Tad
14500$ = yes - for new unit. Used price is listed as 2800$ US - and so is much more "affordable" (relative term - for some is toooooo much (i.e. me)) and for others that's "spare change".
Still - even at 2800$ US - we can do better than that - and I think make a better unit at the same time. I don't think I will join the builders group just now thou - SWMBO would give birth to a cow - and then get up and kick my a(mp).
Agree, will even add that for half this sum, that is,Still - even at 2800$ US - we can do better than that - and I think make a better unit at the same time.
10% of the original price, you could easily make something
that would put this one to great shame...