Want
Very interested in building this, but it would be my first SS/Class A, so I could use a little help. I apologize in advance for my questions.
I suppose a suitable power supply for the M2 would be the same that goes with the F5 as shown in the
illustrated building guide? What rating should the transformer have?
Are there any proven vendors for 2SJ74/2SK170 pairs? I already wrote to alweit and Spencer hoping for an answer.
Do the IRFP240 and IRFP9240 need matching? If so, how do I do this?
In his PCB Jean-Paul catered for TO247 cased resistors to also be attached to the heat sink. Is that a necessity? Any problem with "regular" 3W resistors not heat sinked?
I may be interested in a GB of the PCB, but for sure I'd be interested in a GB of the transformers.
Best, ElFishi
Very interested in building this, but it would be my first SS/Class A, so I could use a little help. I apologize in advance for my questions.
I suppose a suitable power supply for the M2 would be the same that goes with the F5 as shown in the
illustrated building guide? What rating should the transformer have?
Are there any proven vendors for 2SJ74/2SK170 pairs? I already wrote to alweit and Spencer hoping for an answer.
Do the IRFP240 and IRFP9240 need matching? If so, how do I do this?
In his PCB Jean-Paul catered for TO247 cased resistors to also be attached to the heat sink. Is that a necessity? Any problem with "regular" 3W resistors not heat sinked?
I may be interested in a GB of the PCB, but for sure I'd be interested in a GB of the transformers.
Best, ElFishi
Thx for the swift response, more Q:
1) that's 2x18VAC, right?
2) Spencer responded and still sells
3) So I take it that "regular" won't turn into a problem heat-wise
4) Do MOSFETs need matching?
5) How high is the bias current in this circuit?
6) When choosing heat sinks: what K/W rating should I be looking for (per MOSFET)?
7) There seem to be several opinions on C2. Nelson and Zen Mod imply electrolytic while Jean-Paul writes MKP. What would be the arguments for either?
1) Yes
2) great
3) no
4) no
5) F5 was 1.3 A so at least that amount 1.3A but more is probably better. Someone mentioned M2 uses 1.5A but not sure if that is correct or not. Either way you can't go wrong with adding a little more provided you have the necessay heatsinking. Probably best keeping them under 40W per device. 35W per device is a good figure.
6) To keep it very simple a 4U case will do the job but I prefer the 5U case purely for more room and keeping my options open for future builds. If you just want heatsinks then something like Conrad heatsinks mf35 151.5 (one per channel )
7) Polypropyle is usually best as a general rule but Elna Silmic seems to be the exception to the rule. They are very nice.
Not worth losing sleep over. Choose either.
2) great
3) no
4) no
5) F5 was 1.3 A so at least that amount 1.3A but more is probably better. Someone mentioned M2 uses 1.5A but not sure if that is correct or not. Either way you can't go wrong with adding a little more provided you have the necessay heatsinking. Probably best keeping them under 40W per device. 35W per device is a good figure.
6) To keep it very simple a 4U case will do the job but I prefer the 5U case purely for more room and keeping my options open for future builds. If you just want heatsinks then something like Conrad heatsinks mf35 151.5 (one per channel )
7) Polypropyle is usually best as a general rule but Elna Silmic seems to be the exception to the rule. They are very nice.
Not worth losing sleep over. Choose either.
thankyouthankyouthankyou.
The question on the bias was to understand what I need to dissipate. The way the biasing is designed I find very intriguing. I just don't know how I could back out the actual bias current the circuit will have. So thanks for the number.
Maybe that's another feature good to have on the PCB: options for different configurations of the coupling cap.
Jean-Paul, I hope you have recovered!
The question on the bias was to understand what I need to dissipate. The way the biasing is designed I find very intriguing. I just don't know how I could back out the actual bias current the circuit will have. So thanks for the number.
Are you an astrophysicist?
Maybe that's another feature good to have on the PCB: options for different configurations of the coupling cap.
Jean-Paul, I hope you have recovered!
This seems to turn into a Zombie project
: JFETs that aren't live anymore and the caps seem undead as well. Are there any MKC caps being produced anymore?... I´m alive! Bad that PDF is limited to 1MB, I´ve a nice 3D PDF!
The vector font isn´t sexy and I will try today the Hershey-Text ULP. I´m expecting good results.
I´m waiting for remarks until monday. DRC/ERC and I will be ready for GB thread.
@ELFishi
JFET are still available in the diyAudio store.
Sorry I don´t want to waste time for all possible coupling capacitor configurations: it was really hard to place the shielding without big layout modification. Electrolytics paralleled with MKP, MKS: the coupling MKP is 20mm width, 42 length and the pitch is 37.5mm. I will add some additionnal pads.
I will start soon a CLC power supply for this amplifier (L = Hammond).
Jean-Paul
The vector font isn´t sexy and I will try today the Hershey-Text ULP. I´m expecting good results.
I´m waiting for remarks until monday. DRC/ERC and I will be ready for GB thread.
@ELFishi
JFET are still available in the diyAudio store.
Sorry I don´t want to waste time for all possible coupling capacitor configurations: it was really hard to place the shielding without big layout modification. Electrolytics paralleled with MKP, MKS: the coupling MKP is 20mm width, 42 length and the pitch is 37.5mm. I will add some additionnal pads.
I will start soon a CLC power supply for this amplifier (L = Hammond).
Jean-Paul
Attachments
from me…
if you don't like me here…
https://www.don-audio.com/Neu-Edcor-transformer-Europa-Vertrieb-1
but they don't have them available….
o.K. I got some PMs….
so I declare, my two Edcors are sold and my two experimental boards I had, the ones shown in the picture with the cat, thinking about the function of the diodes, went to Sweden.
So don't ask any more… nothing left….
transformers
AFAICS on their web site Don Audio have Edcor PC type transformers, but not the right specs (impedances and ratio) and they have the right specs in WSM and XSM types. At least the dimensions differ in these types.
If you look up the PC600/15K with edcorusa.com it says
AFAICS on their web site Don Audio have Edcor PC type transformers, but not the right specs (impedances and ratio) and they have the right specs in WSM and XSM types. At least the dimensions differ in these types.
If you look up the PC600/15K with edcorusa.com it says
I have bought from Edcor a few times of late and the longest from order to ship has been 3 weeks but I do understand it can take longer. The last order I made was built and shipped in 2 weeks. It is the price one has to pay for good quality and low cost. I have ordered the transformers for the M2.
My understanding is the company caters mostly to the commercial large companies but do offer smaller orders for hobbyist and we are fortunate they do. As an example, when Firstwatt or Pass labs makes a large order they take precedence over hobbyist and their orders will come first.
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6 weeks waiting and paying a fairly high postal fee to Germany is nothing against the pleasure you have hearing this amp.
Don't hesitate and order today....or make a mini mini group buy.
And do not forget the price is so cheap it is almost like giving them to you. It is hard to find a good meal at the price of two. The biggest cost is going to be shipping to Europe.