PRR-176 REV 4 Build Thread ***Manual up!***1/16/14 - (chk 1st post)

[abechap024]

Has anyone found a supply of 45 volt bipolar electrolytics with a 2,5 mm lead spacing?

/taz

You mean the 47uF 25v? I've never heard of 45volt caps..

 

[ilfungo]

Thanks Abe for all answers....
sorry only  for confirmation
with Output transformer I ca remove:
R38-39-40-41-42-43-44-45-46-47-48-49-50
C15-16-17-18 and 5532
Correct?


Thanks

 

[tazwolf]

Has anyone found a supply of 45 volt bipolar electrolytics with a 2,5 mm lead spacing?

/taz

You mean the 47uF 25v? I've never heard of 45volt caps..

Hi
Yes, I meant 47uf 25v, I was looking at Nichicon muse but they have 5mm lead spacing, so I was just wondering what people have used in their builds..

 

[e.oelberg]

abe !

sorry to ask again: the bd140 and 139 where does the silver side go, or where does the emitter go.

I#m sure there is a standard for the silkscreen I just don't know it.

nicholas

 

[berkleystudios]

my 139 and 140's dont fit in through the holes. which ones have yall ordered?

 

[bastrika]

Hi , i plan tu use LL1540 trafos, i've noticed ground/shield are not routed to anywhere.
Are they routed in previous revisions to take out hum problems ?

 

[abechap024]

Thanks Abe for all answers....
sorry only  for confirmation
with Output transformer I ca remove:
R38-39-40-41-42-43-44-45-46-47-48-49-50
C15-16-17-18 and 5532
Correct?


Thanks

 

[ilfungo]

Thnks ABE!!!

 

[abechap024]

abe !

sorry to ask again: the bd140 and 139 where does the silver side go, or where does the emitter go.

I#m sure there is a standard for the silkscreen I just don't know it.

nicholas

The back (silver side) goes towards the side with double lines

my 139 and 140's dont fit in through the holes. which ones have yall ordered?

Mine were a little tight too. But they should fit.

Hi , i plan tu use LL1540 trafos, i've noticed ground/shield are not routed to anywhere.
Are they routed in previous revisions to take out hum problems ?

The best way is to solder a wire from that pin directly to chassis.

 

[prh]

Abe, could we get a schematic for the API op-amp?

On the DOA boards, what is the orientation of the diodes?

Cheers, Paul

 

[abechap024]

Abe, could we get a schematic for the API op-amp?

On the DOA boards, what is the orientation of the diodes?

Cheers, Paul

The schematic is identical to this one:

http://www.acsoundstudio.com/manuals/BUILD_MANUAL_A_OPTIMIZED.pdf

BOM also.

***Note that all the diodes are split apart in this one, so you don't need to worry about putting 2 in series***

The diode footprint is such, that the small rectangle is the side that you want the black stripe of the diode facing towards.

 

[prh]

The schematic is identical to this one:

http://www.acsoundstudio.com/manuals/BUILD_MANUAL_A_OPTIMIZED.pdf

Excellent.  Thanks for that!

 

[e.oelberg]

here is a front panel... in case you like to modify it for your own needs.

my box is going to have a switch for sc bypass and hard (relay based) bypass

send me pm if you lke to get the fpd file

 

[prh]

Abe (or anyone),

On the DOA boards, which transistors correspond to Q1 and Q2 (BC550, which need to be matched)?

Cheers, Paul

 

[abechap024]

Abe (or anyone),

On the DOA boards, which transistors correspond to Q1 and Q2 (BC550, which need to be matched)?

Cheers, Paul

Yep, you got it. The 2 input transistors

 

[mrdarwin]

Abe,

about SPTT: on schematic "pos1=de esser, pos2=200hz hpf, pos3=no hpf" and on wiring guide " on/off/on"... so to bypass hpfilter, sptt has to be on center or on pos3?
I'm designing my frontpanel, so which is correct? schematic or wiring guide?

about DOAs: considering I've got now five doas, which pair do I have ommit for a premium result: u5/u22 or u11/u28 or u12/u30?

thanks

 

[Esoterimix]

I'd venture to guess that the SP3T switch needs to be on/on/on... I was looking for some yesterday for this project. I'm a bit confused on the input pad as far as what needs to be jumpered to what if I don't want an input pad? If anyone has a second, I would really appreciate a hand.... I'm assuming a couple of jumper shunts will do the trick, hopefully?

 

[tazwolf]

how much current will 6 x Abes discrete opamps need (plus a few integrated)? I ve done searches and found that various 2520 DOA's have  the current is specified at idle approx 20ma but how much do they need for when they are revving at  full power, to be able to dimension the power transformer correctly?

/Taz

 

[kakumei47]

If anyone finds it useful, here's a Mouser cart for the parts for the 6 DOAs using Abe's PCBs:
http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=b36f41ddbf

I am not including:
2 matched BC550s per DOA
Millmax pins
You can get those from Classic API. I'm using the 2503 output transformers so just getting those from Classic API.

Let me know if I missed something!

 

[kakumei47]

Also, does anyone have a good idea for what headers to use (for both PCB end and wiring end)? Can someone show me an example? I'm really good at buying the wrong ones with these...