[pabbi1]

I've gotten as far as tubes... just a couple of projects to finish up first.

 

[n3rdling]

Got my parts from mouser in the mail today and almost finished populating the board while watching basketball.  This is a lot of fun!  I have a couple questions and things I noticed:
 
 
On the BOM you forgot to put the 10 Ohm 2W resistors for R22/R23
On the BOM for the caps at C1/C2 the "value" and "description" are different.  Should I use 1uF/63V or 1uF/100V?
I know the LEDs have a negative and positive lead, but the board doesn't indicate polarity.  Does orientation matter on this amp?
In your picture of the populated PCB it looks like you have some kind of jumper installed at JP1.  I didn't see a JP1 on the BOM...what is that part and is it necessary?
 
The wirewound resistor I'm using at R5 is the recommended part in the BOM ( 71-CW005220R0JE73 ).  I ordered two of these (one backup) from Mouser and the package is labeled correctly but I'm wondering if they put the wrong resistors in the package.  The following text is printed on the resistor:
 
DALE
CW-5
220 Ohm 5%
6.5W
M1016
MEXICO
 
The part that confuses me is the "6.5W".  Is this normal?  I am looking at the data sheet for those resistors ( http://www.vishay.com/docs/30215/cw.pdf ) and I can see a CW-5 under "historical model" and then the corresponding data shows a Characteristic U of 5.0 and a Characteristic V of 6.5...I'm guessing that explains the confusion and there's nothing to worry about?  This is my first build so I'm being extra cautious so nothing blows up on me.
 
Once I find out the answers to these concerns I'll put in a second Mouser order and hopefully the amp will be done next week!  I'll probably do some of the chassis work tomorrow.

 

[HiGHFLYiN9]

Mine's populated but I'm waiting on some particular ceramic tube sockets from Hong Kong. It looks like Pete used some plastic / phenolic sockets that are relatively straight without side protrusions for mounting to a chassis in order to make use of the relatively small 1/4" standoffs. Once those sockets come in I can finish the drilling of the chassis and get it off to the powdercoater along with the Edcor Bells.
 
N3rdling, The 10ohm resistors were missing on the BOM as you noticed, I mentioned it on DIYAudio but forgot to post it here. You don't have anything to worry about with the resistor. The BOM calls for a 5W and you have a higher spec'd 6.5W, no worries. The orientation of the LEDs is shown on the schematic.

 

[pmillett]

 
Quote:

On the BOM you forgot to put the 10 Ohm 2W resistors for R22/R23
On the BOM for the caps at C1/C2 the "value" and "description" are different.  Should I use 1uF/63V or 1uF/100V?
I know the LEDs have a negative and positive lead, but the board doesn't indicate polarity.  Does orientation matter on this amp?
In your picture of the populated PCB it looks like you have some kind of jumper installed at JP1.  I didn't see a JP1 on the BOM...what is that part and is it necessary?
 
The wirewound resistor I'm using at R5 is the recommended part in the BOM ( 71-CW005220R0JE73 ).  I ordered two of these (one backup) from Mouser and the package is labeled correctly but I'm wondering if they put the wrong resistors in the package.  The following text is printed on the resistor:
 
DALE
CW-5
220 Ohm 5%
6.5W
M1016
MEXICO
 
The part that confuses me is the "6.5W".  Is this normal?  I am looking at the data sheet for those resistors ( http://www.vishay.com/docs/30215/cw.pdf ) and I can see a CW-5 under "historical model" and then the corresponding data shows a Characteristic U of 5.0 and a Characteristic V of 6.5...I'm guessing that explains the confusion and there's nothing to worry about?  This is my first build so I'm being extra cautious so nothing blows up on me.
 
Once I find out the answers to these concerns I'll put in a second Mouser order and hopefully the amp will be done next week!  I'll probably do some of the chassis work tomorrow.

 
Yes, I left off the 10 ohm resistors on the BOM.  Sorry, need to fix that.  Though they are not strictly required, they help to lower the noise caused by coupling from the power transformer to the output transformers, and also make the amp perform more consistently into differing headphone impedances.
 
The caps should preferably by 100V.  63V is OK but has very little margin. 
 
The LEDs do need to be oriented correctly.  The end closest to the tube sockets is the anode... so anode/cathode of the upper LED and anode/cathode of the lower LED.
 
JP1 is there so you can short out the ground loop breaker if you want.  You should not need anything there.  If you experience hum problems you can try shorting it.
 
The 5W (6.5W) resistor is fine.  Dale up-rated the power on many of their wirewound resistors.  Just a spec change, same part.
 
Quote:

Mine's populated but I'm waiting on some particular ceramic tube sockets from Hong Kong. It looks like Pete used some plastic / phenolic sockets that are relatively straight without side protrusions for mounting to a chassis in order to make use of the relatively small 1/4" standoffs. Once those sockets come in I can finish the drilling of the chassis and get it off to the powdercoater along with the Edcor Bells.
 
N3rdling, The 10ohm resistors were missing on the BOM as you noticed, I mentioned it on DIYAudio but forgot to post it here. You don't have anything to worry about with the resistor. The BOM calls for a 5W and you have a higher spec'd 6.5W, no worries. The orientation of the LEDs is shown on the schematic.

Good observation on the sockets.  I used some sockets that do not have that "lip" that most of the ceramic sockets have.  So you will need to match the hole in your chassis to the socket.  FYI, the sockets I used are really good, tight (phosphor bronze!), and cheap.  They come from Allied... https://www.alliedelec.com/search/productdetail.aspx?SKU=5870024
 
Pete
 
 

 

[n3rdling]

Thanks for the help guys.  Everything soldered into place.  Now I just need to get those 10 Ohm resistors and the tube sockets/diodes are in the mail right now.  Just double checking but I won't need to drill different holes than what is shown on the guide if I'm using these sockets right? http://www.partsconnexion.com/product9597.html  Also, what knobs did you guys settle on?

 

[pmillett]

 
Quote:

Thanks for the help guys.  Everything soldered into place.  Now I just need to get those 10 Ohm resistors and the tube sockets/diodes are in the mail right now.  Just double checking but I won't need to drill different holes than what is shown on the guide if I'm using these sockets right? http://www.partsconnexion.com/product9597.html  Also, what knobs did you guys settle on?

If you use 1/4" standoffs, you will have to make the tube socket holes bigger than I did, because the flange on the ceramic socket will not fit into the hole.
 
Pete
 
 

 

[wotts]

I saw this and thought it would be a fun project. I finished populating the board a few days ago, and just ordered the FPE kit. I swapped the color to dust magnet (black anodize) and changed the in-lay color. When the case comes, I'll post some pictures. Thanks for a cool project Pete!
 
-Tim

 

[wotts]

The case came so here are the pictures. I also included some of the pictures of my board, complete with the sockets on the wrong side. I fixed that and there is a picture of that as well. And there are a few internal shots of the I/O wiring. I'm now waiting on the transformers. Enjoy!
 

 

[wotts]

 
 

 

[the_equalizer]

Looks VERY nice, so far!!

 

[c12mech]

Looks good.
 
I'm looking forward to hearing some listening impressions for one of these.  I'm on the fence as to whether or not to build this one.  The price is definitely right in my range.

 

[HiGHFLYiN9]

Doh, I bet it was tough to get those tube sockets flipped around, 8 pins to desolder. I probably would have cut my losses, snipped the pins and desoldered them individually. 
 
I'm pretty much finished drilling out the hammond chassis on mine, just have to run it over to the powdercoater. I ended up using the allied sockets that Pete used. 

 

[wotts]

I used about 3ft of .1" solder braid and numerous shot of the desolder pump.

  There were a few Sam Adams that helped along the way. I'm not sure if I mentioned it already, but I missed the part about the case needing the socket holes to be bigger when using the sockets on the BOM, so I had to ream them out. Ended up using a large step bit and them brought it to work and used a deburring tool on it. 

 
Quote:

Doh, I bet it was tough to get those tube sockets flipped around, 8 pins to desolder. I probably would have cut my losses, snipped the pins and desoldered them individually. 
 
I'm pretty much finished drilling out the hammond chassis on mine, just have to run it over to the powdercoater. I ended up using the allied sockets that Pete used. 

 

 

[n3rdling]

I actually finished mine about two weeks ago and it's been running perfectly ever since.   I'll post more about it when I'm able to take some pics.

 

[wotts]

How long did it take to get the transformers? I think I was quoted a 4-6 week lead time.