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

[Esoterimix]

I read in the Rev 2 thread that people had used regular VU meters with some degree of success... However, if I remember correctly someone was having trouble with the scaling of the meter and it would only show half of the compression... I'm curious, would it be easier to use a stereo VU driver (a la JLM Audio) or just hook it up straight to the board? Anyone that has enough experience to weigh in would be greatly appreciated...

I'm starting to solder in all the components, just now ordered a matched pair of tubes and found some sockets... Surprisingly, Edcor got my order to me in probably less than a week. Which is crazy, considering their website says they are closed for the holidays, ha... Ya don't hear me complaining... Every component I populate gets me a little bit more excited... yummmm...

 

[ding]

Can you share your BOM so we can compare? Also are you using the supplied DOAs and did you find a BOM for those?

 

[Esoterimix]

I did not use the DOA's because as I started to look around the forum trying to make educated guesses as to what design they were I couldn't tell if they were more 2520 or 1730 ish and really without component values I didn't need a headache like that. So, I bought a bunch of mill-max dip 8 sockets to use in the mean time. I figure that way I can finish the DOA's at my leisure.

Got the tubes and tube sockets last night on E-Bay - supposedly the tubes are NOS and were tested to be "95% or higher," which means I either got a great deal on two matched 6bc8 tubes or this guys is scamming the numerous people looking for 6BC8 tubes hahaha.... We'll see which it is.

Edcor was on the ball and got me Input, Interstage and Output TX's in less than 2 weeks and they arrived before Christmas (despite what it said on their website that they would be closed until after New Year)... So, I have to give them props for sure.

Now, when I ordered everything, I got parts for a GSSL, some DIY D-Sub 25 pin to 8 balanced 1/4"s, a pm1000 rack job/parts and random little components to several other projects... Yes, I think I've cleared all of the excess, but you'll need to DOUBLE check. And, until I finish populating my board I can't say with ANY certainty what's right or wrong... Though this should be a good start for anyone that needs it.

I think.... I hope.... Everything is in order, there might be extras of a few things in the cart but whatever... Let me know if you notice anything that's off, I know it's not perfect but considering the alternative... I only did this as a service to the forum since so many people have been kind enough to do the same for me. Thanks guys. I'm sure the questions will start pouring in soon. I'll post pictures later today and update whether the cart was on or off, haha... Once I get a chance to use up everything I ordered I'll have a much better idea as to its accuracy. It was very tedious picking everything out off the board, literally took a couple hours a day for a few days to figure out my exact order.

- I did notice there are some ON-OFF-ON SPDT switches that are out of stock, just search for a comparable brand and it'll be just fine....

Here's my mouser cart:

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=4c7ed039b5


Bon Apetite gentlemen... Let the tasty mu'ing begin

 

[ding]

When I get a second I will take a picture of the board into photoshop and make a list and compare the two. As far as the VU I would either build or buy a VU meter driver. There is an article floating around JML's site that shows how to build it if you want to go that rout. I like to have a little bit of presission and it looks like strapping a VU to it will roughly work but not too precisely. As far as the DOA's I guess I will just have to wait for Abe or any kind soul that knows the topography because there are absolutly no component values in the silk. Thanks for your help.

-Alain

edit: http://www.jlmaudio.com/AT51%20DIY%20VU.pdf

Main PCB resistors VERIFIED  ...

 

[berkleystudios]

what is the issue using VU meters? what meters are we supposed to be using for this build?

 

[ding]

1mA meters.

 

[berkleystudios]

might be a dumb question but what is wrong with these? http://www.hairballaudio.com/shop/product_info.php?cPath=25&products_id=61

hairball has several 1mA meters

 

[ding]

If I'm not mistaken those will work perfectly. It might not be the look some people are going for though.

 

[Esoterimix]

Yeah, I just really love the way VU meters tend to dance a little. plus, I have several of them lying around from vintage boards that were on their way to the dump when I snatched them up. I also have several JLM VU driver boards and JLM VU meters. So, I'm definitely going VU over 1mA meters. I do have a stereo buffer board that I could easily populate... Just wanted to make sure it was necessary because I wanted to use the buffer for something else but it's whatever. Anyways, thanks for the input. 

As for the shopping cart... small update:

I'm pretty sure there are a couple unnecessary caps in that cart that I mixed up (with the GSSL parts list) and I can't remember if I got the 100nf film caps to populate the PSU... However, so long as I didn't remove too much from the cart, it looks like I got everything else (*in my personal order). the 100uf 16v cap I used was a little hefty but it fits.... the 1000uf 50v you might want to check dimensions (i.e. Height) - I managed to order a couple different brands and all of them were the right height except 2 but it was easy to lay them down... Now, I need to find a dirt cheap chassis

 

[Esoterimix]

Quick question, when someone gets around to it... I am waiting on my Power TX from Antek... and, well... I'm starting to wonder if I got a large enough VA rating... The TX I ordered will put out 25VA with works out to about .7 or .8 Amps... That should be enough right? I couldn't find that info anywhere, including the old threads, I'm sure it was likely looking me right in the face but.... Thanks.

 

[acarballeira]

Quick question, when someone gets around to it... I am waiting on my Power TX from Antek... and, well... I'm starting to wonder if I got a large enough VA rating... The TX I ordered will put out 25VA with works out to about .7 or .8 Amps... That should be enough right? I couldn't find that info anywhere, including the old threads, I'm sure it was likely looking me right in the face but.... Thanks.

Hi - thanks for posting your Mouser cart; saved me a ton of time I found reference to the power TX in post a while back (2011?) and consensus seemed to be that for 120V mains something like this would be more than adequate:
http://www.mouser.com/Search/ProductDetail.aspx?R=VPT36-1390virtualkey55310000virtualkey553-VPT36-1390

Cheers,
Andy

EDIT - this post could be misleading on my part. The above referenced xformer only provides for the projects low voltage requirements (+/- 18V). I had an extra xformer for the tube plates and heaters. For my unit I plan to build an external power supply containing these two toroids and the power supply board.

 

[berkleystudios]

Quick question, when someone gets around to it... I am waiting on my Power TX from Antek... and, well... I'm starting to wonder if I got a large enough VA rating... The TX I ordered will put out 25VA with works out to about .7 or .8 Amps... That should be enough right? I couldn't find that info anywhere, including the old threads, I'm sure it was likely looking me right in the face but.... Thanks.

should be fine.

 

[Esoterimix]

The torroid I ordered from Antek only ended up costing $11 plus shipping... They are cheaper than any other website I've seen thus far. They did accidentally send me the wrong one and now I have to wait for a return shipping label but none the less they are very reasonably priced.... at least for those of us sourcing parts from N. America.

 

[ding]

which one did you get?

 

[taliska]

Boards arrived in the post today...

Thanks Abe!

Kaz

 

[Corusco]

which one did you get?

I imagine that he bought the AN-0220, as they don't make an 18v 25VA model.

http://www.antekinc.com/details.php?p=22

 

[prh]

Abe, is a schematic, BOM and wiring diagram forthcoming soon?  It's great to have the boards, but I would really prefer to have the current and correct documentation before I commence a build.  The DOA boards were a nice addition to the package, but again, they are not usable without component values. 

 

[Esoterimix]

The cart I put together is missing some resistors, 2 (+ 2 if using output TX) - 39ohm, 4 - 330 ohm, 6 - 3k3 ohm, 4 - 2k ohm, 4 - 13k ohm, 1 or 2 - 100 ohm (?Depending on D24 error?), I also forgot the 1k5 ohm resistors and that looks like about it.... Everything else should be there??? I think??

Also, looks like there is an error on the PSU on the bottom left hand corner (when writing is right side up)... It shows "D24" as being "100 ohms." This is obviously a misprint and I would be willing to bet it is supposed to be a 1n4007 diode since there is a single 100 ohm resistor and single 1n4007 diode after each Vreg... Can anyone verify, before I solder something in there?

Only capacitors I can't seem to find in the order is 2 of the 100 uf elco caps near the output of each channel.... I do believe that is all I for now...

 

[ding]

Hi!
Received my boards on thursday 9th... The packaging had split too and one opamp pcb lost!!!
Did someone noticed that the opamp footprints don't match with original 2520footprints? Do we have to use only Abe's opamp?

I had a look at this just now.

The footprints on Abe's opamp boards and on the main board match each other.  However, these footprints do NOT match the 2520/990 footprint.  It is almost like Abe's opamp footprint is upside down.

It would be really helpful if Abe would confirm is this is intentional or an error.  I am a little disconcerted by the lack of a v4 schematic and official BOM and wiring diagram.  The opamp boards don't have values on the silk-screen, so without a schematic these are useless.

This was on the old thread but I think this belongs on this thread for the Rev 4 build. Can anyone building this confirm? I haven't started my build yet due to waiting for official DOA BOM so I can't confirm. Can regular 2520 DOAs be used?

 

[kakumei47]

Yeah, the opamp pinout seems upside down. 2520 footprint amps do not match rightside up. The pins on the right side of the opamps on the pcb use the top four of five pins instead of the bottom four of five. Matching the pinout of the 5534, it seems they are indeed upside down (putting the 2520-style opamp on the bottom of the board indeed seems to match the inputs and outputs as far as I can tell. May not be a big deal in putting these in a 2-space rack, but probably to get it in a one space you'd have to do some work drilling another hole and cutting traces/rewiring where the 2520 pins go. It would be some work but looks like it wouldn't be too bad. Or just build Abes if they match.

Hi!
Received my boards on thursday 9th... The packaging had split too and one opamp pcb lost!!!
Did someone noticed that the opamp footprints don't match with original 2520footprints? Do we have to use only Abe's opamp?

I had a look at this just now.

The footprints on Abe's opamp boards and on the main board match each other.  However, these footprints do NOT match the 2520/990 footprint.  It is almost like Abe's opamp footprint is upside down.

It would be really helpful if Abe would confirm is this is intentional or an error.  I am a little disconcerted by the lack of a v4 schematic and official BOM and wiring diagram.  The opamp boards don't have values on the silk-screen, so without a schematic these are useless.

This was on the old thread but I think this belongs on this thread for the Rev 4 build. Can anyone building this confirm? I haven't started my build yet due to waiting for official DOA BOM so I can't confirm. Can regular 2520 DOAs be used?