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

[taliska]

Hi.  For European builders I think there are three options for powering:

A) Using two different power transformers for 220v.
- 230v prim to 18v+18v sec
- 230v prim to 120v sec
Both primarys are connected on IEC plug and both secundarys are connected directly to PSU board... that's all.

B) Using Gyraff mode (back to back).  The first tx should be 230V prim to 18+18V sec (transformer number 1) and the second should be 120V prim to 18V sec (transformer number 2), but used in reverse mode, which means that you should connect the 18V of tx number 2 as a prim to one of the two 18V of tx number 1.

C) Using Abe's suggestion.  Dual primary trick, changing R10, R11, R12 to 3K9 @ 5watt resistors and change the 100V zener to a 5W one (just to be safe, might be unnecessary).

I used option A) and it's working in a 2U case.

Regards

Cool, thanks for the info! ;-)

You forgot:

D) Don Audio toroid.

Apologies, if I seem to be flogging a dead horse, but I guess what I'm really trying to get to the bottom of is the space constraints for the various solutions for EU builders. Reading between the lines, it seems like the following is true:

If using A) or B) or D) then 2U or larger case is required.
If using C) then 1U case is possible (though I'm not going to choose this for reasons already mentioned - safety).

I haven't bought a case yet, so it's not a big deal for me...though I'm fast running out of rack space which is why I was trying to hit 1U...

I think I'm going to go away and have a think about it, but at this point in time I'm leaning towards D) as the price doesn't seem particularly different to the cost of two toroids and at least the fields will be entirely coincident which can only be a good thing! ;-)

Cheers,

Kaz

 

[tazwolf]

I had bought the don audio trafo and the collective cases 1u rack so i have both but cannot use them together, i will go for abes suggestion and buy anorher trafo, so if any wants to buy a don audio trafo let me know, im in Sweden.

/taz

 

[Jeremy.Starseed]

I should get in line for a set of tube-boards too, yes?

With all the OP boards that came with...I was like Yay, confetti!

Almost lost sight of the upside-down tube thing.

 

[boneindian]

Finally wiring mine up.  Hopefully power it all up tomorrow.  Anyone have any thoughts on the "optional" power in on the left channel?  Pros...cons?  Purpose? After that all I've got are the XLRs and Output transformers...very exciting!

 

[berkleystudios]

got my boards replacement boards in. Still waiting on/ deciding on a case as im trying to get one with the "threshold" on the front

 

[abechap024]

Manual!

www.acsoundstudio.com/manuals/PRR_REV4_BUILD_MANUAL2.pdf

 

[muffy1975]

Well done Abe,

nice job. Really cleared everything up here.

Michael ;D

 

[ilfungo]

Hi!!!
I'm building the second  176
I know the hum problem with Edcor as Interstage transformer, but I've 2 PCW 10k:10K left.
The have the same problems also as input transformer?
Thanks!!!

 

[ding]

I have a 2U case and I am going to be using edcor on interstage. I am not too worried about it. Let's see but I think I can place the toroid so as not to get hum.  ;D

 

[tazwolf]

Is anybody else having problems printing the manual? The printer prints 2 pages and then resets the print job.

/Taz

 

[muffy1975]

NO,


no problems with the printer. manual is quite data heavy.

Michael

 

[anjing]

Does Abe send the correct tube adaptors to all or do you need ask for them?

 

[boneindian]

Hi boneindian!
If I remember correctly
Meter + and G goes to the meter
G and Led goes to the led meter (negative tension/ must be reversed)

Ilfungo, can you explain what you mean by negative tension/must be reversed?  Does LED outlet go to the negative terminal of the lamp and G to the positive?  Sorry if that's a dumb extrapolation, I'm just not sure what you meant by that...

 

[ilfungo]

Hi boneindian!
If you see from the schematic , or put a multimeter accross pads for meter led, there is a negative tension.
You must send the M+ to - of the led and G to +.
I hope I'm explain
sorry for my english...
Ciao

 

[boneindian]

Thanks ilfungo, I thought that's what you meant and I did it that way and it worked! 
My +16V rail (I was planning on setting it at 18V but after reading the build manual I dialed it down), blew as soon as I hooked it to the board.  Ordered some more 317s since that's where it blew and it seems others have dealt with it by upgrading to a higher V rated 317...One thing I can't figure out is why my heater starts at 12.6V, tubes are glowing, meters creep up to zero.....and then after 45 seconds or so (sometimes less), the voltage drops down(quickly at first and then bottoming out around 1.5V for a minute before dropping to 0), the tubes stop glowing and the meters die down all the way to the left. Every time I turn it on. The only thing I don't have hooked up is the output to the transformer.  Anyone have a hunch what might problem might be?

 

[ding]

Which transformer are you using?

 

[muffy1975]

Thanks ilfungo, I thought that's what you meant and I did it that way and it worked! 
My +16V rail (I was planning on setting it at 18V but after reading the build manual I dialed it down), blew as soon as I hooked it to the board.  Ordered some more 317s since that's where it blew and it seems others have dealt with it by upgrading to a higher V rated 317...One thing I can't figure out is why my heater starts at 12.6V, tubes are glowing, meters creep up to zero.....and then after 45 seconds or so (sometimes less), the voltage drops down(quickly at first and then bottoming out around 1.5V for a minute before dropping to 0), the tubes stop glowing and the meters die down all the way to the left. Every time I turn it on. The only thing I don't have hooked up is the output to the transformer.  Anyone have a hunch what might problem might be?

sounds to me as though your regs are shutting down. Up grade your regs and add massive heatsinks to them.

Michael

 

[boneindian]

Hey ding, I'm using this one

http://www.mouser.com/Search/ProductDetail.aspx?R=VPT36-1390virtualkey55310000virtualkey553-VPT36-1390   


And thanks muffy I'll try that, I have some heatsinks I just hadn't strapped them on yet.

 

[boneindian]

Well the heat sinks solved the 12.6V rail dying...Put one on another 317 i had around but it went as soon as I hooked it to the main board as well. That there power supply gets reeeaaal warm.  Definitely get beefy heat sinks for all your regs. Gonna have to wait for the higher voltage rated 317s from Digikey.

Under load my 100V rail has dropped from 110 to 74V.  I'm up to 3k3 3W resistors to get it down to 110V before it's hooked to the board ( I originally wanted to get all the voltages in line before doing that) but what conditions should the 100V rail be measured under?  Should I just go back to 1K and see if it's closer to 100V when hooked to the main board? I think it was about 136V before I started upping the resistor values...which means I dropped it 26V. Which is exactly what it is below 100V when actually feeding the main board...

I don't think this has been discussed, I have been following this thread post by post for 5 months though so I MAY HAVE MISSED SOMETHING.

 

[muffy1975]

Yep,

you've guessed  it. Replace all those resistors on the 100v line. Maybe even go to lower values if needs be.

MIchael