LuDEF

[tombo56]

If it is 3U x 400mm deep, then yes. Need room for proper dual-mono PSU.
I have my M2x in a 2.5U x 400mm chassis. Just gets warm to the touch. Same power dissipation as the LuDEF.

Heatsinks must be very different than those on Dsisipante (or you are a resident of Alasca). 🙂
Otherwise, impossible low temperatures.

I have 4U/400 and heatsinks are at 40 deg. now. In summer, I expect close to 50 deg.

 

[Zen Mod]

LuDEF is made with 1A5-6-7-8 in mind

original M2 is hovering around 1A2 to 1A3

though, everything is matter of choice

I already posted this one somewhere, when speaking about Best Papamp ever - M2 (though - Careful with that Axe, Eugene!........ I didn't drew it absolutely idiotproof - starting is with trimpot set all the way up):

 

[TungstenAudio]

My rebuilt M2x now runs on +/– 25V rails and it’s original 1.3A bias. The chassis was originally modified to conduct more heat down into the baseplate.

I live in Seattle, close enough to Alaska that all my amps can be winter amps. 😉

 

[Dan K]

Chaps, Another couple of questions..

Regards the 10uF Silmic in the signal path, what's the smallest value it can be reduced to and still function properly? Ie will a 2.2uF film cap or PIO etc work perfectly well? I know on the M2 this cap only has 5V DC across it, but I'm interested if a smaller capacitance value will chop off the bass etc.

For the other on-board caps what's the max voltage across each of them? Is it less than 10V for the 3300 uF item, as on the M2?

I'm thinking of going for SMT multi layer or tants, possibly mtd to the back of the boards far away from any source of radiated noise. Assume that I'll need to be careful about temperature stability

Thanks again

 

[Jcris]

“ORGANICITY” ,
Add that to the ongoing creative
Zencabulary.
You crack me up
Have a great day

 

[Zen Mod]

C101/102 - 16V min
C103/104 - 6V3 min
C105/106 -10V min
C107/108 - 6V3 min
C109 - 10V min

regaring value of Silmic+bypass : Rin of OS itself is in range of 20fewK (20-22K)

by simple calc, C=1/(2*Pi*F*R), you can calc that, using no more than 5Hz as corner F, so being sure that phase is correct at 20Hz

so, C=1/(2*Pi*5*22K) = 1.44uF

so, 2.2uF will do as first bigger value

though - no way that it'll sound better than Silmic + MKC combo, whatever you put there

 

[Dan K]

Thanks ZM 🙂. Looks like SMT caps are a real possibility.

3x1000uF 10V in place of C105/106 on the back of each board. Do you think 2000uF might be enough?

https://uk.rs-online.com/web/p/tantalum-capacitors/7173947
On the M2 I found these large caps were aerials for noise getting back into the boards, radiated from the traffo.

 

[Zen Mod]

good to go

 

[Dan K]

good to go

I'll go for 2x the above caps on the back of each board then 🙂

Unless anyone feels that 2000uF really isn't enough

 

[Zen Mod]

it is enough

 

[Dan K]

it is enough

Thanks again, is the esr very important for that position? The large Pana FC cap looks to be 15m Ohms and the tants are 55. Obviously I'd need 3 of them to get down to 18 or so. If not needed then that's great.

 

[Zen Mod]

no fret

it is good enough

 

[Dan K]

Next silly question..

On the First Watt M2 the autoformers have very well made Mu-Metal shields covering them. Assuming that I go with the Cinemags for my LuDEF, where do I get the covers?

Thanks again

 

[Zen Mod]

go to attic, find your old PC monitor (cathode ray), dismantle it and you'll find enough shielding inside for dozen of M2 channels

besides that ..... there was thread about minimized M2 board, and guys did found ready made cover

can't recall how thread is titled, maybe something with SMD ......

with my builds, I didn't found shielding of input xformers necessary, but - I'm always using 400deep cases, and my big Donuts are always magnetically shielded

 

[TungstenAudio]

Judging by reports from the DIY community, the Cinemag and Jensen transformers are not as susceptible to EMI as the Edcors.
Enough space between them and the power trafos is always your friend.

 

[tombo56]

No need for any transformer tinfoil hat. 🙂

This is LuDEF output noise with PS having only several uV ripple and noise, so 9 uV at 50 Hz is not coming through power supply but is noise induced by power transformer stray field. Nothing to even mention.

 

[Dan K]

T

go to attic, find your old PC monitor (cathode ray), dismantle it and you'll find enough shielding inside for dozen of M2 channels

besides that ..... there was thread about minimized M2 board, and guys did found ready made cover

can't recall how thread is titled, maybe something with SMD ......

with my builds, I didn't found shielding of input xformers necessary, but - I'm always using 400deep cases, and my big Donuts are always magnetically shielded

Thanks, I'll look for that thread. GOSS banded traffo(s) will be the way to go!

Judging by reports from the DIY community, the Cinemag and Jensen transformers are not as susceptible to EMI as the Edcors.
Enough space between them and the power trafos is always your friend.

Is there an obvious winner performance wise? Which one is best to go for in Europe?

No need for any transformer tinfoil hat. 🙂

This is LuDEF output noise with PS having only several uV ripple and noise, so 9 uV at 50 Hz is not coming through power supply but is noise induced by power transformer stray field. Nothing to even mention.

Which autoformer?

I reckon that noise is getting in via the 'big' lytic caps.. SMT on the the back of the board is what I'll be doing

 

[Dan K]

But if I'm using a CapMx then I'll have ~500uV anyway

 

[tombo56]

My LuDEF has Cinemags. This noise measurement was to illustrate that input transformer is not very sensitive to EMI.
Noise or ripple at amplifier supply rails is not directly transferred to the amp output. It is attenuated by amplifier PSRR. Nothing to worry even with 50 mV supply ripple.

 

[Dan K]

Thanks for that 🙂