525 build thread

[tommypiper]

Kazper. Why are you going to all the bother trying to make an API face plate when you don't have an API lunch rack for it? Why not put it in a regular rack case. More roomy and options...

 

[Siegfried Meier]

I'm thinking of doing just this - make a single rack space, Front Panel Express file, get EDAC connectors, or whatever, and just rack the 2 units. Only thing is the P/S. Anyone know what I need? Or maybe just buy the JLM powerstation, and that will most likely work for what I need.

Thanks,
Sig

 

[Siegfried Meier]

Will these even fit into a single space chassis, with the size of the transformers??

Thanks,
Sig

 

[edanderson]

[quote author="Siegfried Meier"]Will these even fit into a single space chassis, with the size of the transformers??

Thanks,
Sig[/quote]

sure. remember that there are single rack space racks for 500 modules:

http://www.apiaudio.de/500-h.pdf
(seems to have disappeared from the API usa site)

http://www.avedisaudio.com/R52.html

ed

 

[kazper]

I'm planning on buying a lunch box for them.. and the edison mic pre's I want to do..

I'm wishing that I bought the full kit now.... after seeing the small part's needed.

Don't know where yet to look for the 0.1" spaced switches

Honestly This is a back burner project for me.

 

[gar381]

Peter

I'm I safe to asume that CD5 and CD6 are both 33p and
the 2 unmarked caps next to A4 are 100n ??

These parts are not on the BOM. :?

Thanks

GARY

 

[peter purpose]

Yeah, sorry again Gary. Your assumptions are correct.

 

[mata_haze]

Hi everybody.
I am trying to understand if I could use a 100uA amperometer on the 525 instead of the 200uA.
I thought I might just add a resistor in series to make the 100 uA work like a 200uA.
is this assumption correct? if so could someone suggest me a value for the resistor?

 

[capnspoony]

In the BOM I'm a bit confused by the capacitor section where it says

C1 250UF/ 6 V (470UF/16V)

does that mean we can use either or?

--Richie

 

[shabtek]

ohms law

to halve the current, double the resistance

this works for a more sensitive movement: but for one with more mA for FSD the driving bit might poop out

 

[capnspoony]

So I ordered most of my parts from Digikey and Mouser tonight. I had some questions regarding the rest.

Where could I find.

1) VCR2N transistor and socket

2) all the caps that are in the pf range minus the 150pf ... mouser and digikey seem to not go that small.

3) and I don't understand what "LM391X meter driver IC if using the LED meter or 200uA FSD meter" means.

thanks

--Richie

 

[dissonantstring]

hi richie,
i haven't had time to really take a good look at this project yet, but here's my understanding of the following:

1) VCR2N transistor and socket
this is the vertical opamp i believe. One of the smaller boards square-ish boards with the 5 transistors on it. you do not necessarily need sockets for this board but it might be a good idea if you want to remove it later.
you could just add some buss wire and solder to the pads on the DOA board and then solder to the pads on the mother board for connection. look on the third page of the BOM it shows what parts go into this DOA marked "upright opamp".

2) all the caps that are in the pf range minus the 150pf ... mouser and digikey seem to not go that small.
haven't had a chance to check on these yet. :? edit: i just checked the BOM and the only pF value caps are 47pF and 150pF which are readily available in ceramic versions from both mouser and digikey.

3) and I don't understand what "LM391X meter driver IC if using the LED meter or 200uA FSD meter" means.
you'll need an LM391x series IC to do the meter driver duties. there is a meter driver board that Peter supplies with the set of PCBs (the one with the row of LED markings on the overlay). the LM391x IC goes on this board.
hope this helps.
-grant

 

[capnspoony]

Thank you soo much Grant

I wasn't aware we could use ceramic in this situation- Past projects have said when to use them so I wasn't sure.

there is an optional 10pf cap to put in also there is a 5pf cap that goes on the opamp board

I understand the rest, Great! :thumb:

--Richie

 

[Tubemooley]

yo - check it......
i've been e-mailing with David at Cinemag. i measured the 525 circuit board and sent him a crude but effective drawing showing dimensions allowed for the transformers. he had to go do a little measuring but he is positively recommending his CMOQ-3 for our 525 compressor kits. he does not have any drawings or datasheets for this model on his website yet. but he made up a one page .pdf of the mechanical dimensions and sent it to me. it shows overall dimensions of the CMOQ-3 to be 41.5mm x 33.27mm. the center-to-center distance between the mounting holes is not shown. i measured the space on the board to be 43mm x 37mm so it definitely looks like this trannie will fit on the board. it is unclear whether the board will have to be trimmed or modified (for the bobbin or the mounting screws) but i'd be fairly certain that this can be done with a minimum of effort and not much risk in terms of damaging the board.

i've already asked David if he minds if i post that drawing on this here forum. i doubt he will but it's best to check first. if he says OK, then i will post the drawing. but the july 4th holiday is coming up and i'm taking a few days off so getting this done for you guys may take up to a week.

i'm sure that Ed's edcor trannies will work fine and they are probably very cost effective. however, i will probably get the Cinemag's for my 525's. i did not check on pricing for these bad boys yet. the CMOQ-3 comes in two versions: the -3H and the -3L. i believe that the -3H is the high nickel version and the -3L is the "regular" nickel version but we'll find out from David. go to www.cinemag.dot.biz

thought you guys would want to know. DW.

 

[peter purpose]

Grant... tsk tsk.

The vcr2n and it's little house.....

It is not mandatory to use the socket, but makes testing and swapping a breeze.

 

[peter purpose]

VCR2N available at...
http://www.goldmine-elec.com/

Punch in VCR2N to the search. 2 for a buck, 100 for 40.

 

[peter purpose]

[quote author="capnspoony"]In the BOM I'm a bit confused by the capacitor section where it says

C1 250UF/ 6 V (470UF/16V)

does that mean we can use either or?

--Richie[/quote]

The stuff in brackets is what I had to hand and used.
Some were used for improvement.

 

[peter purpose]

Bom updated again...

http://www.twin-x.com/groupdiy/albums/userpics/525bomupdt3.pdf

Added CD5 & CD6

 

[peter purpose]

And again....

http://www.twin-x.com/groupdiy/albums/userpics/525bomupdt3~0.pdf

added unmarked caps.

 

[peter purpose]

[quote author="Tubemooley"]thought you guys would want to know. DW.[/quote]

Good stuff DW.. :thumb: