mick
Well-known member
4-5 mhz
ours sound like the 2*5*2*0?
- Thread starter Mbira
- Start date
Help Support GroupDIY Audio Forum:
4-5 mhz
Samuel Groner
Well-known member
MHz :wink: (m = mili, M = mega)
Samuel
Samuel
dissonantstring
Well-known member
hi everone,
wondering if you gents could help me sort this?
i'm stuffing fabio's PP2520 (R.268) DOA board and i've come across some components that i have not been able to find info on in my searches.
so here are my questions:
1) is R17 = 2.7K?
2) is R18 = 25K?
3) is Q10 = BC550C?
4) what do you do with the circles marked "L"? are these two pads marked "L" supposed to be linked?
any help with this would be greatly appreciated.
cheers,
grant
edit: got word from fabio that you do indeed need to link the two pads marked as "L" on the PP2520 boards. you also need to be aware that the screened component markings for Q3 legs E and B should be switched.
meaning the emitter leg of Q3 should go to the pad marked "B" and the base leg of Q3 should go to the pad marked "E". to clarify this is for the PP2520 R.268 DOA boards.
BIG THANKS TO FABIO FOR CLEARING THIS UP. :thumb:
wondering if you gents could help me sort this?
i'm stuffing fabio's PP2520 (R.268) DOA board and i've come across some components that i have not been able to find info on in my searches.
so here are my questions:
1) is R17 = 2.7K?
2) is R18 = 25K?
3) is Q10 = BC550C?
4) what do you do with the circles marked "L"? are these two pads marked "L" supposed to be linked?
any help with this would be greatly appreciated.
cheers,
grant
edit: got word from fabio that you do indeed need to link the two pads marked as "L" on the PP2520 boards. you also need to be aware that the screened component markings for Q3 legs E and B should be switched.
meaning the emitter leg of Q3 should go to the pad marked "B" and the base leg of Q3 should go to the pad marked "E". to clarify this is for the PP2520 R.268 DOA boards.
BIG THANKS TO FABIO FOR CLEARING THIS UP. :thumb:
dissonantstring
Well-known member
thanks for clearing that up for me drpat! :thumb:
much appreciated.
i'll check the schematic to see what those "L" pads are linking together and see if it's necessary.
thanks again!
-grant
much appreciated.
i'll check the schematic to see what those "L" pads are linking together and see if it's necessary.
thanks again!
-grant
No problemo. I wish Peter could chime in with a definitive BOM for these boards. I have a whole stack of them, and I'd like to try the values that were meant to be in this board. They seem to be way more stable than the BC boards...
nielsk
Well-known member
Mick, please clarify: the 2520 BC R1 schematic shows C5 between the base of Q8 and the base of Q3
are you suggesting moving the Q3 base connection to the base of Q2 (audio - input)?
NielsK
are you suggesting moving the Q3 base connection to the base of Q2 (audio - input)?
NielsK
mick
Well-known member
Hi NielsK
I have updated Fabio's schematic for the 2520 BC with the values I used and the moved capacitor leg, but I have tried and tried to post it to were I keep my photo's on the web and it never displays so I can't put a link up on this forum, can you PM me with your email and I'll send it direct, maybe you can post it here as I can't ?
Mick
I have updated Fabio's schematic for the 2520 BC with the values I used and the moved capacitor leg, but I have tried and tried to post it to were I keep my photo's on the web and it never displays so I can't put a link up on this forum, can you PM me with your email and I'll send it direct, maybe you can post it here as I can't ?
Mick
nielsk
Well-known member
I have tried the c5 to -in mod, r3 & 4 at 20k & 82 K, and the output transistors Q7&8 are still running very hot (65C) with heat sinks on them. Everything else is fine, I thought it sounded a bit better w/ r3/4 @ 20K.......any ideas on how to get Q7/8 to run cool?
bobschwenkler
Well-known member
Is that new schematic available yet?
bobschwenkler
Well-known member
Also, I am looking at the BC and PP schematics that I got from Fabio's site. They appear to be exactly the same except for a couple different transistors. Is that the only difference or is there a PCB layout difference?
Hi,
so which version to build? BC with 139/140 or BC with 3053/4036 or PP (same as BC but different lay out).Could any one confirm that actually any of this is working? Read the whole API 312 Help thread and
this thread as well but I'm not sure shall i go PP or BC version....
thank you
so which version to build? BC with 139/140 or BC with 3053/4036 or PP (same as BC but different lay out).Could any one confirm that actually any of this is working? Read the whole API 312 Help thread and
this thread as well but I'm not sure shall i go PP or BC version....
thank you
Thank you Roger
No one else to give their opinion on building the 2520?
What would be the procedure to check opamp(2520) once is built,
without the rest of the circuit? 75ohm on the output? Anything on the input of the opamp? Just want to check does it pass audio...
Thank you
No one else to give their opinion on building the 2520?
What would be the procedure to check opamp(2520) once is built,
without the rest of the circuit? 75ohm on the output? Anything on the input of the opamp? Just want to check does it pass audio...
Thank you
Walrus
Well-known member
I've been looking at using the E-Line ZTX453 and ZTX553 as output transistors for the 2520. They have a higher voltage and collector current rating than the 2N3053 and 2N4036, and the advantage of a much smaller package.
Anybody know of a good reason not to use them??
Anybody know of a good reason not to use them??
Walrus
Well-known member
Do I take it that no one knows, or that no one can be bothered?? :grin:
nielsk
Well-known member
I have built the "BC" board with 2n4036/3053 and the BD139/140, trying C5 in every suggested position. The 3053 version overheats, the 139 runs cool. With the input not terminated, there is a HF oscillation no matter what, but it is least with C5 to -in. When input is terminated it goes away.
therecordingart
Well-known member
Is there an up to date BOM for the PP2520 that takes into account the changes to keep from oscillation?
I've tried both, and can't get the BC version to behave no matter which configuration I try. I've done 10 or so, with no luck.
The pp version has worked like a champ on about five or six that I've built. The extra transistor is for the current source, and it's pretty easy to implement into the pp board.
The pp version has worked like a champ on about five or six that I've built. The extra transistor is for the current source, and it's pretty easy to implement into the pp board.
drpat, that doesn't sound good..
I'm going to build the BC board soon so i'm wondering what recipe is working? Have read through the threads several times but i don't really get it..
nielsk, what changes did you make to succeed with the BC board? Or could anyone post an updated BOM for it?
I'm going to build the BC board soon so i'm wondering what recipe is working? Have read through the threads several times but i don't really get it..
nielsk, what changes did you make to succeed with the BC board? Or could anyone post an updated BOM for it?
