[n_maher]

Jay,

The Cerafine line has been discontinued as far as I know. Try searching for Elna Silmic II's or Nichicon Muse Caps. I know that Handmade Audio carries some of each line, perhaps not exactly what you're looking for but close.

Also, I posted a thread about this a while ago (which you can search for) and the general opinion from amb was that I was worrying about things which had little effect on the overall sound of the amp.

HTH,

Nate

 

[amb]

JayPeterman, check out Michael Percy Audio or Handmade for boutiquey-stuff. I don't believe that such caps would make a difference in C4 and C5, but if you insist...

steel, the R9 resistors normally do not get hot. The 2W rating is chosen because the output stage is capable of very high current output (such as when driving speakers or very low-Z headphones) and we don't want the resistors to fail even under extreme conditions. While there is no harm in mounting the resistors the manner that you did, it is not necessary.

 

[Syzygies]

I've gotten the impression from various tech notes that it's a good idea to solder resistors flush with the PCB, to minimize signal path and stray inductances and so forth. On the other hand, we see 'dead bug' construction all the time for CMOY and similar amps, and the limitations of those circuits swamp whatever's wrong with the wiring of the jumble of parts.

Amb has weighed in (for example) that the increased signal path can work against any benefits to switched attenuators, so for the M³ how one solders resistors may matter.

So I don't know if R9 is a "good idea" as pictured, but this is the question the picture raises in my mind.

 

[amb]

Syzygies, it's true that additional lead length increases inductance but that only matters in high impedance areas of the circuit. At the output of the amp where R9 is, this is not the case.

 

[Syzygies]

Quote:

Originally Posted by amb ...only matters in high impedance areas of the circuit. At the output of the amp where R9 is, this is not the case.

Hard to tell with the depth of field blur in the photo, but it looks like all the resistors are mounted in the same style?

As a beginner myself, I know the temptation to emulate the style in the most beautiful photos, and that's one beautiful photo, which is why I raised the question.

 

[stadams]

Quote:

Originally Posted by Jaypetermen Does anyone know of additional suppliers for the 100uf/35V ELNA Cerafines or of an alternative bouquet cap for C4 and C5?

Thrice has a few leftover SILMIC II's from the group buy a couple of months ago. Give him a buzz.

Later,

 

[Jazper]

Heya all, just planning an M3 build and organising parts from various suppliers (well planning orders) and have a few questions.

First of all, is there any downside to running the amp at 25-26v (for headphone use only)?

Second, I plan to use ELNA silmic II 100uF(c4, c5) and 330uF(c7) caps, however I'm looking at the 35v versions to keep costs under control, am I safe using these if I'm going to be running said 25-26v?

Thirdly, is there any benefit here using vishay dale low tolerance resistors here or will any generic low tolerance brand be fine?

Forthly, (only if you can tell me) what's the peak current draw when the caps are charging at startup when c7 are 330uF caps?

and finally, is there any downside to using an ad8610 for the ground channel while I use opa 637s for the left and right (as this is what I have handy at the moment)?


Anyhow, great amp, appreciate the work you all put into it

Now to see if I can build it

 

[amb]

Quote:

Originally Posted by Jazper First of all, is there any downside to running the amp at 25-26v (for headphone use only)?

No, the only exception is if the headphones you are planning to use are extremely inefficient and require a huge amount of output voltage swing to get loud, and you like your music at earsplitting levels. Since it's been reported that even the (in)famous AKG K1000 worked well with a stock M³, I think this won't be an issue for other headphones.

Quote:

Second, I plan to use ELNA silmic II 100uF(c4, c5) and 330uF(c7) caps, however I'm looking at the 35v versions to keep costs under control, am I safe using these if I'm going to be running said 25-26v?

Yeah, that is ok.

Quote:

Thirdly, is there any benefit here using vishay dale low tolerance resistors here or will any generic low tolerance brand be fine?

Any good quality metal film 1/8W or 1/4W resistors are fine, except for R9 which should be 2W. Vishay-Dale RN55 series are very good and not too expensive, but cheaper generic resistors will be fine too.

Quote:

Forthly, (only if you can tell me) what's the peak current draw when the caps are charging at startup when c7 are 330uF caps?

The actual peak current draw is difficult to estimate because it is limited by the ESR of the capacitors, as well as the impedances of the pcb traces to the capacitors, D1, wiring and connectors, and the PSU internal current limiting.

Quote:

and finally, is there any downside to using an ad8610 for the ground channel while I use opa 637s for the left and right (as this is what I have handy at the moment)?

The transfer curves of the two types of opamps are different and you lose a bit of the "symmetry" (as seen from the headphone transducers) thus affecting linearity.

 

[DigiPete]

I was wondering is it is possible to implement a treble cut circuit in the M³ to help with some of those really harsh 80s CD (which I love so much).

DigiPete

 

[skyskraper]

it would probably be better to get a proper eq unit like a parametric eq

 

[DigiPete]

Quote:

Originally Posted by skyskraper it would probably be better to get a proper eq unit like a parametric eq

That is one serious piece of hardware, with a serious price

I guess I could continue to listen to those CDs through speakers and use my receiver's treble control.

 

[skyskraper]

haahaha yeah i love avalon stuff, only used it once in a studio before.

there are other parametrics in the sub 500 range that will do a really good job too.

hell you don't even need a parametric, a graphic eq would do the trick and theyre plentifully cheap these days

 

[Jaypetermen]

Is "-dB" a suitable substitute for "Volume" for labeling the volume knob on the front panel of the M3?

 

[skyskraper]

you can label it whatever you want, you still know the function of the knob. the common use of the word decibel is for a relative measure of sound pressure level

label it whatever you want

on the front panel you have more freedom then most other parts of the amp

 

[Ob3ron]

Quote:

s "-dB" a suitable substitute for "Volume" for labeling the volume knob on the front panel of the M3?

As was said above, call it whatever you like! And I do happen to like it!