Melos Modding Extravaganza

[dsavitsk]

I have been thinking about parting with my Melos SHA-1 for a while. It was [url=http://www.stereophile.com/headphones/617/]Corey Greenberg

Edited July 14, 2009 by dsavitsk

[tkam]

That's some very nice work there!

[robm321]

My Melos has been down for a bit, and I've been considering whether to DIY upgrade or just get it fixed or both.

This is much appreciated! Lot's of good work, pictures, details A+++++

Thanks for sharing.

[Dusty Chalk]

Flashbacks.

No, seriously, nice detail there, will have to print out and read later.

[NoValidTitle]

Awesome work there! Ari will appreciate this too.

[luvdunhill]

yup, I'm a big fan of the regulator with pass device type arrangement for high voltage duty as well, seems to cure lots of little problems, as you've shown above.

[aerius]

Wow, there sure is a lot of extra room in the chassis for all the new parts you put in on the mod.

Great work!

[dsavitsk]

Thanks. It's a tough call as to how much work to do on one of these. Certainly, one could use all V-Caps and Blackgate NXes, build some super duper fancy regulator, rework the solid state power supply, etc. But, the circuit has inherent limitations, and I tried to stay within them and not let this get out of hand. Though, those 2u caps may get replaced with something a little better.

[Smeggy]

the insides are a lot smaller than I imagined. Is that a European board design?

[luvdunhill]

Doug:

In your PSUD2 sim, did you use a stepped load to check for ringing?

[dsavitsk]

the insides are a lot smaller than I imagined. Is that a European board design?

I don't think it adheres to any standards. They basically drew it with a sharpie and used jumpers and bits of wire to connect things -- you should see under the board.

In your PSUD2 sim, did you use a stepped load to check for ringing?

Yeah -- I think it is a 2mA jump.

[n_maher]

Ditto what others have said Doug, great work there.

[guzziguy]

Yes, nice job. I bet you can even fix SP amps.

[HeadphoneAddict]

Somewhat unfortunately, the Melos does use 6922

[dsavitsk]

Not one to leave well enough alone, I thought I'd tinker a little more. The obvious next thing to do was to swap out the last PS cap. I had used a Blackgate Std, but these aren't my favorite caps, and I figured a film cap would be better. To that end, I removed the Blackgate and added a big Motor Run film cap. These are just big polypropylene caps dipped in oil of some sort.

This improved clarity a little, but unfortunately it also lost some bass. The usual solution to not enough bass is bigger caps. So, I got a bigger cap.

[Dusty Chalk]

:drool:

s'awesome.

[FallenAngel]

Very cool build Doug! Now if only we could compare notes

[penger]

Is that the one you brought to the meet?

[luvdunhill]

Very cool build Doug! Now if only we could compare notes

did you just swap parts, or did you also ensure the part changes didn't cause instability? Looks from Doug's analysis that this requires more care than the typical "modder" is willing to take...

[FallenAngel]

Yep, that's the one I brought to the meet.

No stability testing, just by ear.

[dsavitsk]

Just swapping parts is probably OK. I ran into issues when I tried to put a choke in the PS and it started oscillating. I could have just left it out, but I think the benefits of a choke are sufficient that I was interested in getting to the bottom of what was oscillating. This led to the PS rebuild and regulator replacement.

My sense is that this does more good than just swapping caps -- better to get a circuit right in the first place than to add the band-aid of audiophile boutique parts. It is less expensive in terms of parts, though it is probably more expensive in terms of time. And, I happened to have the little PCBs around.

[voodoochile]

The inside of the Melos sure is funky looking (stock).

Doug, you're one of those people who is just plain cool. Nice work, and much more fun than just selling it off.

[georgypo]

Hello Dsavitsk,

Surfing the net and found out a beauty work you done on your melos sha1. Nice work!!

Since my melos sha1 is not working and required for the repair work and totally love the way you mod. Could you please send me the details of components you added at the front?

Actually my previous maintenance guy messed up my sha1 and that makes me come up to search a schematic of it and finally got you guys on hand whose know what is it. Last but not least, May I know any of you guys got schematic of this? I'm in Hong Kong and everyone refuse to do a repair for me if I can't find a schematic.

Cheers,

George Po

[Aura]

Hello Dsavitsk,

Surfing the net and found out a beauty work you done on your melos sha1. Nice work!!

Since my melos sha1 is not working and required for the repair work and totally love the way you mod. Could you please send me the details of components you added at the front?

Actually my previous maintenance guy messed up my sha1 and that makes me come up to search a schematic of it and finally got you guys on hand whose know what is it. Last but not least, May I know any of you guys got schematic of this? I'm in Hong Kong and everyone refuse to do a repair for me if I can't find a schematic.

Cheers,

George Po

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