[carlo]

forgot to add: i love kester 63/37 44 rosin core solder. stuff flows like a dream.

 

[Jupiter]

Quote:

Originally posted by geom_tol I've also wondered about the mosfets in the power supply. Maybe it's a common high voltage ps technique we don't know about?

My preamp has a mosfet regulated power supply. Maybe it's something like that?

Kevin Gilmore also used mosfets in the power supply for his newest amp.

 

[Voodoochile]

NICE Carlo...

... I like the amp, too. How long have you been working on this, really??

 

[carlo]

Voodoochile,
thanks man

i bought the amp in late july/early august, started getting the traces worked out and relearned some long forgotten electronics stuff immediately afterward. around then was when i started asking industry people (and searching aa's archives) for advice on what they had success in and formulating a list of what components to try. was breaking in caps on my preamp by mid/late august, right around the time when the stock board came to life. lost most of september to the maestrobator, when i was spending all my free time either listening to the amp or tweaking it (seriously, i left a [boring] party to go home and solder, i couldn't get enough of this stuff). still fiddling with the amp now, project isn't done yet: need to try more headphones and sources.

seems so long ago...
carlo.

 

[Zanth]

Hey carlo! This was a fantastic thread and an excellent post to read. My mystery melos should be at my office right now and I am dying to give it a go. I will have a listen for a few weeks and then send you my hp-1's so you can have fun making your melos the best of the bunch.

 

[carlo]

Zanth,

you should post the pics of that thing, i'm sure people would love to see it

thanks again for the offer with the headphones, i'm excited to finally hear what joe grado headphones sound like. heh heh heh.

carlo.

 

[aeberbach]

zanth, did you buy that cheap Melos on Audiogon?

 

[Zanth]

Nope, nothing cheap about this melos...

I will say more when I get it. Suffice to say this baby is one of a kind.

 

[erix]

.. but here's a pic of the guts of one I got from a guy on AA.

(Guy: Sorry if I can't remember your name to give you full credit!)

This one was sent to Melos Audio Restorations (in my home town) for the full $$ treatment. I left it large so you can see lots of detail.

A few things to note:

- Single big-ass filter cap above the transformer
- Off-board rectifier made with heat-sinked FREDs for the HV section
- All signal caps replaced with Auricaps (Ouch! My Wallet!)
- Looks like IRC caps at the extreme top edge of the board?

See anything else, carlo?

ok,
erix

 

[Voodoochile]

I've got to get me some of this Melos lovin'.

May I ask how much dinero you might have to part with to get one, typically? It's cool if you'd rather not say, I understand completely.

 

[aeberbach]

Anywhere from $450 to ...anything, as erix has just shown. Erix, I think you need to replace all those caps with Audionote teflon/copper.

 

[erix]

Quote:

Erix, I think you need to replace all those caps with Audionote teflon/copper.

Heh, that's not mine!

I just got the photo from the owner as part of my board-building adventure.

I might not be able to afford that photo!

ok,
erix

 

[aeberbach]

I have just finished removing every component from my board and cleaning it. I lost about three pads in the process but they were not connected to anything so no big deal. It took around eight hours.

 

[carlo]

erix,

glad you posted that pic man - looks like you've got everything. that huge filter cap off the tranny looks interesting... this thing has so many filter caps (at such high capacitance) that its obvious the guys at melos/mar don't like to skimp in that department

outside of that i wonder what the values of the signal path auricaps are - they're a hell of a lot bigger than mine (i used 1uf, 200 or 250v caps for all my experiments per the parts sheet). looks like the board ps electrolytics and resistors are stock, but can't tell for sure from the pics.

the two top auricaps (by the large black high voltage cap and to the left of the top heatsink) are the blocking caps i omitted - not needed if there's no dc issues at the source and to my ears the amp sounded more open. the huge caps on the bottom are once again the preamp output caps, the tiny board by the front of the face is for remote (for those without schematics).

i'm slightly surprised none of the board's electrolytics have been changed (although those are different bypass caps than i had - from the pic they look like the same caps used for the signal path on my stock board - the ones behind the tubes in the closeups), i found gains by going over to blackgates (especially the nx series). i'm sure mar had their reasons though. thats a pretty amp

aeberbach,

man, totally want to experiment with paper in oil as well but that stuff is $$$... when i get around to the preamp section i may give it a shot. gotten a chance to experiment with them yet?

voodoo,

depends man. both amps pictured in this thread are melos gold reference/maestro boards (not sha-1s) so its a bit more expensive. factor in parts and stuff and obviously it gets pricey... damn audiophelia.

best,
carlo.

EDIT - anyone (markl?) know what signal caps mar uses on the normal upgrade?

 

[carlo]

add-on notes:

for those with melos gold references/maestro assembled amps following along: the board input goes from the remote board, so its possible that those two dc blocking caps on the main board i keep talking about are needed (i don't have the schematic for the remote board, just the stuffing diagram).

the boxes on the top right are for the mute relay (looks like this thing is supposed to be quiet for a while after switching something) - omitted on my board because i didn't need it but i keep the volume all the way down when i turn the maestrobator on*

auricaps: i'm listening to the magnolia soundtrack right now and i think i realized another thing about the caps, they let me hear sounds as if they're well beyond the boundaries of my headphones (hd580). i'm listening to aimee mann's voice overdubs on "deathly" (track 4) and they each have a distinct sense of space. first time i've had the experience with headphones in my setup - normally there is no layering or depth, as if everything was confined to a very shallow space. and that gorgeous delay... i love them on this amp. i know they're semi expensive, but they're way cheaper than hovlands and to my ears sounds better (for what its worth).


*= see, its funny. i was going to take a pic for "amp turned on" with the kama sutra on it but there were complications...