[Mad Max]

I'm using 820μF FM's as well.  I haven't swapped the other caps yet, but I'm trying out these FM's first since I'm not familiar with them.  I think the treble will get fatiguing with SR325is if I put in more FM's.
Trying to source some Rubycon YXH and ZLJ to try as well.

 

[BlaBlaBla]

So far my complaints about Matrix M-Stage are heating (without reason - because of totally closed enclosure without venting holes), and arrangement of capacitors across the board (which does not allow you to put higher grade capacitors)...
 
M-Stage goes hot (for output power). So I tried to find out why. And main reason was that ventilation/cooling of internal components is absent. After I had drilled the ventilation holes, chassis temperature was halved. I think that purpose of A class amp is not heating, but constant current flow. So there is possibility to have true A class amp, with proper ventilation (without cooking something on the chassis)...
 
Right now, Elna Cerafines (470uF) are in M-Stage in power rail, and Nichicon Muse in opamp rail (22uF is enough,because opamp circuit does not need energy reserves like headphone output, but it is more ESR demanding). I got Silmics II, but they are too big, so I will put them in another amplifier... I  can see the improvement clearly. Elna is far better than industrial Panasonic. Better positioning, great bass, refined treble (not hissing), excellent mids... But as I said before, I know that Elna wouldn't last long because 85C characteristic. Topology of M-Stage is very cost-wise (small/restricted). It is limited to 105C minimalistic and industrial capacitors. Especially in power stage. It is illogical to put capacitors between two biggest heat sources in amp (input regulators and output transistors). (That is the reason why I have drilled the holes on top and on both sides of the M-Stage...)
 
 
 
 
 

 

[Mad Max]

Are you keeping in the amp in a spot with little air circulation?  What headphones are you using with it?
 
I've noticed how much it heats up depends on what 'phones you use, but mine runs only a little warm - I keep it in an open spot and my ceiling fan is on to keep air moving past it or else it does get kind of hot.  Same goes for my source.

 

[BlaBlaBla]

From my experience M Stage goes hot, if I use low efficent headphones like AKG. They need more amplification and more current from power stage. And also more current through main LM regulators.
Output transistors BC139 and BC140 are directly connected after regulators. They (with regulators) make an amplifier very hot. If you have sensitive 85C electrolytes between LM regulators and BD transistors, and want to run current demanding headphones, it will be good to keep the temperature between 50 and 80 C (when you have made a measurement on the top of electrolytes).
When I had switched AKG-s with Sennheiser-s, temperature fell down.
For example, I must drive AKG with volume pot turned to 3/4 of entire range, and Sennheiser only between 1/3 and 1/2. For the same volume.

 

[Mad Max]

It only takes a little air flow to drastically lower the case temperature.  Mine only gets mildly warm at most and I use a bunch of low-impedance 'phones.  My lowest impedance earphones, RE252, RE-ZERO, and Turbine Pro Copper, make the amp run a bit warmer, but never hot.  AKGs are something else, though.

 

[Golden Monkey]

Well, I couldn't tell you jack about the Matrix, but I used to own an MKV, and it did a good job with lower impedence phones like the 701's and the Denon D2000's.  If you want a good amp and don't want to go all op-amp crazy with the rolling and whatnot, and you just want a good unit to plug and play, the MKV is a decent bet.  Only reason I sold mine is because I own HD650's and my Woo just destroyed the MKV in terms of performance...

 

[Mad Max]

No need to go op-amp crazy.  Stick 2x HA3-2525-5 on a 2x1 adapter in the M-Stage and you're done! 

 

[BlaBlaBla]

Mad Max, AKG-s can warm things up. A lot.

Despite the low efficiency, sterility and too much highs versus low, they have something what keeps me to stick with them. Burson will be beter bet. Bursons need at least +/-12 volts.

Stock Matrix M Stage supplies opamps with +/-14,2 volts.
 
Golden Monkey, did you have any problems with overheating on MKV? Loss in power after few hours? Because I saw in MKV that main voltage regulators don't have heatsink... And that bothers me a lot. Too much heat can kill a lots of things. And yes, tube amps behave much better with high impedance headphones.
 

 

[Golden Monkey]

The MKV did get pretty warm, but I don't think it was overly hot.  There's really no ventilation, per se, but the body of the amp does a good job of heat dispersal.  I didn't notice any long-term loss of power or dynamics, but there would be times where it would just "run out of gas" trying to drive HD650s during especially dynamic/bombastic passages.  It would recover quickly though, but it was annoying when it did that.  I don't mean it would completely die or anything, it was just like the musical equivalent of drinking a partially flat soda compared to a fresh one, lol.
 
EDIT: I think the design of the tube amp is very important as well, where high impedance cans are concerned. OTL drives them with much more authority that a transformer coupled design, IMO.

 

[shiaulou]

I own a LD MkV and it gets warm but not hot (I also own a Schiit Asgard so that's my definition of hot). I sometimes run my MkV for 8-10 hours (sometimes with a HD650 or DT880 600 ohm) and I haven't experienced overheating or loss of power.

 

[Golden Monkey]

Quote:

I own a LD MkV and it gets warm but not hot (I also own a Schiit Asgard so that's my definition of hot). I sometimes run my MkV for 8-10 hours (sometimes with a HD650 or DT880 600 ohm) and I haven't experienced overheating or loss of power.

You also haven't experienced the full potential of those great phones if you use the MKV to power them.  I tried both for a while with the MKV, then borrowed my friend's Woo 3, and it was all over for the LD.  The HD650's for example sounded good in comparison to other (lesser) phones, but...well, put it this way, all that talk of HD650's sounding dark and veiled made a lot more sense once you actually drive them properly.  Higher impedance cans really need the tube juice to become magical.  I haven't tried the Asgard yet...how does it compare to the MKV, in your opinion?

 

[shiaulou]

Yeah I have no doubt that HD650's can perform better but to be fair, you're comparing apples and oranges. SS vs OTL tube and the price difference... a $300 dollar amp vs a $500-600 amp. I would hope the Woo amps would deliver more so than the LD.
 
I think the Asgard tends to be very slighty warmer, smoother. LD MKV tends to be more analytical and detailed. Not really sure which I prefer more with HD650's but at least with the DT880's, I think the Asgard is a bit better but honestly the Beyer's perform better with a tube amp.

 

[BlaBlaBla]

I am curious too!

 
Asgard is made on single ended topology, that is reason why it goes so hot. But single ended topology has its own strengths. People are saying that single ended topology has more musicality and more "air" (or better sound stage)...
MKV looks to me, like it is made on push-pull topology. (Similar to M Stage, but with two separated channels.) Strengths usually are: more output power for less input power - better efficiency. Could I say the word "efficiency", when we are talking about class A amps ?

 
Golden Monkey, you have a tube amplifier, so which headphones would you recommend me, other than HD650? What is difference between HD650 and DT880? I made a thread about headphones under 250 USD. I am interested in high-impedance headphones...

 

[Golden Monkey]

Yes, it is apples to oranges, but once I ate that juicy orange I swore off the apple forever, lol.
 
3xBlah, I'll check out your thread and post there, but I don't have much experience in that price range.  I've been away from the hobby for a bit, so I'm not sure what's out there and what's new.
Comparing the HD650 to the DT880, I LIKED the 880s, but they were very neutral almost to the point of bland.  They were amazing with vocals and acoustic music, no sibilance, nice rolloff on the top end, solid at the bottom, but not as detailed in bass response...very nuanced and smooth, great imaging...a much more forward presentation compared to the laid back 650s, almost like the performers are right in front of you.  The 650s are very lush and warm in comparison, with a more wide open soundstage and sense of airiness.  If I had to choose another headphone other than the 650s, I'd definitely give the 880s a much longer look.  I infinitely prefer them over the dry and sterile AKG K701s, but I like the Denon D5000 a little bit more maybe, just for the music I listen to (rock, techno, etc.).  The 880s for sure if I listented to more blues, jazz, vocals, or acoustic stuff.

 

[BlaBlaBla]

Thanks for advice!

 
It seems that DT880 are real deal for me. I like acoustic music and vocals.