API 553 PCB
- Thread starter Strawtles
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gar381
Well-known member
gar381
Well-known member
gar381
Well-known member
Checks Jeff CAPI site....
http://www.classicapi.com/catalog/images/reference_docs/API-553-schematic.pdf
Best copy I have seen.
Any questions on unreadable part values I can help you.
Best
GARY
BTW... Build yourself a CAPI 553f. It;s better than the orginal
http://www.classicapi.com/catalog/images/reference_docs/API-553-schematic.pdf
Best copy I have seen.
Any questions on unreadable part values I can help you.
Best
GARY
BTW... Build yourself a CAPI 553f. It;s better than the orginal
Strawtles
Well-known member
- Joined
- Mar 20, 2009
- Messages
- 191
Thank you Gary
This schematic is better than mine, but still there are some value I am not too sure:
R9= 1.3k?
C5= 500uF 6v?
C6= 47uF 10v?
C9?= 5uF 6v? (the one after R1)
Do you know if it is possible to change the mid frequency control to 3Khz?
P.S.
I have considered the possibility to build the 553F but I'd prefer to try the original and simpler one
This schematic is better than mine, but still there are some value I am not too sure:
R9= 1.3k?
C5= 500uF 6v?
C6= 47uF 10v?
C9?= 5uF 6v? (the one after R1)
Do you know if it is possible to change the mid frequency control to 3Khz?
P.S.
I have considered the possibility to build the 553F but I'd prefer to try the original and simpler one
gar381
Well-known member
Strawtles said:
Strawtles
Well-known member
- Joined
- Mar 20, 2009
- Messages
- 191
Thanks a lot Gary!
Do you think I can use a 10k:10k (Lundahl LL1540) transformer for balanced input?
What do you think about the Lundahl LL1539 as output transformer (I have a couple of these transformers at home)?
Finally, can you suggest to me some good inductors?
Do you think I can use a 10k:10k (Lundahl LL1540) transformer for balanced input?
What do you think about the Lundahl LL1539 as output transformer (I have a couple of these transformers at home)?
Finally, can you suggest to me some good inductors?
jensenmann
Well-known member
Lundahl cores have higher nickel content than the API output tranny. This will give you less distortion at lower levels. You can see it in these graphs: Nickel has a more linear range than iron.
Gary is it possible that in the PCB design there are some missing parts?
Comparing the PCB with the unstuffed PCB photo it seems that the PCB is missing of the R13, C3 and R3 joining place and the C5, R11 connections to the transformer input
Anyway, I am interested to realize a couple of these circuits too
Comparing the PCB with the unstuffed PCB photo it seems that the PCB is missing of the R13, C3 and R3 joining place and the C5, R11 connections to the transformer input
Anyway, I am interested to realize a couple of these circuits too
gar381
Well-known member
Fablab said:
Hi Fablab
These attachments are of real Datatronix PCBs that I scaned myself about 6 years ago.
I stuffed them and used peterc's 5003 Inductors. They sound GREAT.
In the next few daysI'll pull one out of the rack and see if I can answer your "missing" questions. I stuffed
these guys years ago and can't remember if there were any problems/mods that I had to do to
make them work.
Best
GARY
