Melcore PCBs

I bought some melcore pcbs off someone on this board but I can't remember who it is.

Anyway, I remember that I got set more than I ordered because he had some ones with eratta laying around.

I want to make sure that I dig up the info on the eratta and make sure to use the non eratta boards first.

d./

I'll alert the media.

Twas it you?

d./

Fabio

Hmm.. I got my sontecs from fabio but I don't think I got the melcore from him...

Anyway, has anybody built any melcores? If so what parts did you use?

I am specifically interested in what caps you used.

alo
build some 1731 melcor,and used cog caps.
other fellows use normal ceramic ones.
best regards
pedro

Anyway, has anybody built any melcores? If so what parts did you use?

Click to expand...

I have some 1731-PCBs coming up from Fallout / Jay.
- anybody built these ? Do these have errors ?

Thanks,

Peter

Are you thinking about these?

Error:


Corrected:


..look at the upper left corner..

Jakob E.

Are you thinking about these?

Click to expand...

Thank you Jakob, that's a nice overview.
I'll check those PCBs for that error when they've arrived.

Thanks,

Peter

Thats's the ones.

Anybody have a decent parts list for these?

Also, has anybody built the sontec with ICs.
I am thinking of just forgoing the discrete opamps.

d./

Clint, the ones you're getting DONT have the error...

-Jay

TheDug.. I'll try to post a parts list sometime today!

Clint, the ones you're getting DONT have the error...

-Jay

Click to expand...

Hi,

Thanks Jay, good to know. Wouldn't be too big a problem since it seems simple to correct - but good to know there's no error in it altogether. :thumb:

Bye & have a good weekend all,

Peter

The 3 things are am unsure about are

1) which caps need to be poly and which can just be ceramic. I doubt there is enough room to make them all poly.
2) what to search on to find the little pins that fit into the main board and the opamp board
3) What I should get for the transisters **see below**



------------- transiters ------------------

Fabio sent me the links below, except they don't quite match up wit yours.

1) He doesn't list Q2, but it looks like you have it a BD550? Your's is a little hard to read
2) He has Q7 as 139 but you have it as 135
3) He has Q8 as 140 but you have it as 136

http://www.thediypill.phx.com.br/api312/m1731_v1.jpg

http://www.thediypill.phx.com.br/forumfiles/M1731_partlist.pdf



d./

Oh 1 more quick question.

Can the melcores run off +/- 24V?

alo
my 1731 have cog all around.
used bd139 and bd140.
as for +-24v i do not know.
best regards
pedro

Excuse my ignorance but what exactly is COG?

What about Q2?

alo
cog/precision multileyer capacitor.very small.
q2 it is bc550c.do not use bc550a or bc550b.
best regards
pedro

From looking at mouser COG appears to be a ceramic?

Are all the 550s the C version?

From Fallout's pictures it looks like he has 1 polysterene in there.
Are there any caps in the circuit that could benefit from being higher quality?

FYI.. The BC550C is 'preferred' but you can certainly use a BC550B.. Just make sure the hfe is above 400.. You dont have to use a poly cap on the input, a ceramic will work..

-Jay

Cool, so if I am considering using poly, is the input cap the only one that would really make a difference?

Jay, I'd still like to see your parts list if it is available.

Also, do you know if the melcor can do +/- 24V?