[silent:arts]

D-AOC PCBs - the building and help Thread
« Reply #20 on: February 29, 2008, 02:24:42 PM »
THE PSUs

as mentioned before the PCB contains 3 PSUs:


all components colored red are part of the
High Voltage PSU
CAUTION: Mains or High Voltages are lethal, you have to work very carefully here.
it is a good idea to always have a separate Voltmeter constantly connected to the High Voltage when working, this can be easily done at R128 or R218.

since this is an adaption of the Gyraf G9 High Voltage PSU, please read the Basic safety rules Jakob wrote on the Gyraf G9 site.

R2 & R3 are setting the B+ voltage, I used some sockets on my prototype to empirically find the "right" values:

with 470R + 47R resistors (silkscreened values) I get 238V after Rx28, close enough.
if you want to come closer to the 243V from analags schematic you can use a single 510R and a jumper, this gives me 241V (again, after Rx28).

don't forget to mount the TL783 insulated to the heat-sink, otherwise you will have a short from the regulator's output to ground !!!

!!! be aware that this PSU needs a load to work properly, with no tubes inserted you will have more than 350V !!!
!!! with no tubes inserted the High Voltage caps need a very long time to discharge, read the safety rules again !!!
if you are unsure and afraid of the tubes, test with only one channel fitted first.

and yes, you need a power transformer with a 220V - 250V secondary @ 0.1A even living in a 230V country.
DON'T KILL YOURSELF

all components colored yellow are part of the
Heater PSU
the power transformer needs to have a 9V - 12V secondary @ 2.5A, and the LM350T gets hot.
you need a good heat-sink here !!! the SK129 38.1 I used in mine (and which is silkscreened on the PCB) is not enough in my opinion.

may be a SK129 50,8 or SK129 63,5 will work, but I don't have one of either to test.
with a larger heat-sink and the regulator mounted off board to the chassis the regulator stays quite cool:

like the TL783, the LM350T must be mounted insulated to the heat-sink, otherwise you will have a short from the regulator's output to ground !!!

before inserting the tubes adjust the heater voltage to 6,3V using RV1.
there are two test points next to C8.
after inserting the tubes check again and readjust.

all components colored blue are part of the
universal PSU
use this PSU for relay bypass, meter lamps, VU buffers, what you want.
if you don't plan to use any of the above you can just let this components out.
the output voltage is chosen by the 78XX you use.
take 7805 if you want 5V, 7812 for 12V, 7824 for 24V.
of course you need a matching secondary on your power transformer, and C11, C12 and C13 should be in the right voltage range.
if you want a real true hardwire bypass take very low values for C11 and C12.
at the moment my PSU3 holds the power for 4 seconds after switching off the unit, using 2200uF and 100uF (24V).
will have to change this since I want the compressor to be immediately in bypass after switching it off.

it is not necessary to insulate the 78XX from the heat-sink, but more elegant.
the PSU3 has its own ground path, you can use it floating, or use a little jumper (provided on the PCB) to connect the PSU3 ground to the main PCB ground.

hope this is helpful,
more to come
« Last Edit: February 09, 2009, 04:06:49 AM by [silent:arts] »


Purusha

D-AOC PCBs - the building and help Thread
« Reply #21 on: March 01, 2008, 07:38:48 AM »
Very excited about this project. Thanks!!!  :thumb:  :thumb:  :thumb:

Volker, like many others I would also love to hear about the best possible meter option in this one, of course when you find the time.
Regards as always, Purusha

[silent:arts]

D-AOC PCBs - the building and help Thread
« Reply #22 on: March 01, 2008, 08:12:41 AM »
metering is just the metering circuit from the LA2A.
same options, same problems, what ever you like to call it.

Purusha

D-AOC PCBs - the building and help Thread
« Reply #23 on: March 01, 2008, 08:21:37 AM »
OK, I have no problem with LA-2A metering. Thanks for letting me know.
Regards as always, Purusha

laiben

D-AOC PCBs - the building and help Thread
« Reply #24 on: March 02, 2008, 08:53:32 PM »
What will happen with the sound if I use a 600ohm:600ohm transformer for the 1:1 tranny?
How many transformer did I burn?

OneRoomStudios

D-AOC PCBs - the building and help Thread
« Reply #25 on: March 02, 2008, 11:00:24 PM »
Volker, where did you get that nifty 3-way fast-on ground lug and what is is called?

[silent:arts]

D-AOC PCBs - the building and help Thread
« Reply #26 on: March 03, 2008, 03:23:53 AM »
don't know what they are called in english, I used one of each:




laiben, I used a 600R:600R Haufe for some tests and measured good results.
haven't compared it sound wise yet

bernbrue

D-AOC PCBs - the building and help Thread
« Reply #27 on: March 03, 2008, 04:30:15 AM »
Hi,
I just wanted to mention that http://www.musikding.de has almost all parts for this project in stock. Besides Vactrols and solen fast caps a suitable power transformer (primary 2x115V, sec1 250V 0,1A, sec2 9V 2,5A, sec3 24V 0,5A for EU and US members) is available as well.
regards
Bernd

Jim50hertz

D-AOC PCBs - the building and help Thread
« Reply #28 on: March 03, 2008, 04:48:13 AM »
Quote from: "bernbrue"
Besides Vactrols and solen fast caps a suitable power transformer (primary 2x115V, sec1 250V 0,1A, sec2 9V 2,5A, sec3 24V 0,5A for EU and US members) is available as well.

Bernd


Where?  I can't see it listed on their site

Thanks for the tip though. :thumb:

Cheers

Jim
"Nasty, talking to a slightly deaf journalist, had claimed only that the Rutles were bigger than Rod."

pyjaman

D-AOC PCBs - the building and help Thread
« Reply #29 on: March 03, 2008, 10:38:16 AM »
Hi everybody,
Since I get more and more interested by this project, I've been studying the schem and pcb's PDFs (thanks a lot for these files!) And a question (may be a stupid one) comes to my mind ... for the GR metering, are BOTH the zener and the neon bulb necessary? I'm not familiar with the use of those little neons and don't know where to source them (France)...
 I may be a little out-of-subject talking PSU, but if someone could help...
thanks,
Laurent.


pyjaman

D-AOC PCBs - the building and help Thread
« Reply #30 on: March 03, 2008, 10:45:27 AM »
Talking parts supply, Banzaieffects in Germany also sells vactrols and various   film and electro HV caps (Solen fast, wima and more expensive hi grade caps) They have tubes too, various brands for cheap...

bernbrue

D-AOC PCBs - the building and help Thread
« Reply #31 on: March 03, 2008, 10:55:32 AM »
Laurent,
you can use either the 1N5371 or the NE2 neonlamp. There is a footprint for both on the pcb. For reasons of temperature stability I would take the 1N5371, though NE2 is working fine in my prototype. The advantage of the neon light is that you see that the board is under power. The risk of touching something and getting an electrical shock is somehow lowered. Greetings to France, I´m on holiday there next week.
regards
Bernd

pyjaman

D-AOC PCBs - the building and help Thread
« Reply #32 on: March 03, 2008, 11:00:32 AM »
thank you for such a fast answer, I suspected something like that looking at the pcb traces...
Have nice holidays...

musikding transformer?
« Reply #33 on: March 03, 2008, 03:56:43 PM »
Hi bernbrue,

you mention earlier about the mains transformer at Musikding, but i cant see the one you mention, could you be so kind as to point it out?

Thanks for your help

Best
Pete

[silent:arts]

D-AOC PCBs - the building and help Thread
« Reply #34 on: March 03, 2008, 04:36:55 PM »
according Musikding:
since I had a phonecall from my transformer winding company - they are not amused to wind the same "custom transformer" every few days - which I can very much understand. they asked me if we could do it another way.
for myself, you guys are getting me crazy with the PCB orders, no way to handle a group buy with PSU transformers at the same time.
I thought about a solution, and one of my ideas was to get someone else to handle this, like a shop who sells to DIYers anyway.

bernbrue was kind enough to handle this.

we have discussed this "behind the scenes" for a time, since this should be a "no go commercial project", and Musikding will of course earn some money with kits, transformers, or anything else. I don't know if the main transformer is from the same source I do.

if Musikding offers all the parts I'm fine with it, since you DON'T have to buy there. for some people it would be easier and cheaper to have all from one source.

but may be Musikding don't have (the parts) on there website yet.

we will see.

bernbrue

D-AOC PCBs - the building and help Thread
« Reply #35 on: March 03, 2008, 04:54:08 PM »
in addition to Volkers statement, which I totally agree with: The needed parts will be on their site soon. In the meanwhile, just send the partlist to Musikding and they will make you an offer with all available parts. Everything else is none of our business, since we don´t do any business here. You can buy there, but you don´t need to.
regards
Bernd

OneRoomStudios

D-AOC PCBs - the building and help Thread
« Reply #36 on: March 03, 2008, 09:33:26 PM »
What is the reason for having such a high secondary for the filament? Would a standard 6.3 VAC secondary work with this circuit? Could the larger voltage differential be the cause for the LM350T getting so hot?

If a standard 6.3 VAC secondary would work, it would make it a lot easier to find transformers. For example, a Hammond P-T269AX (125-0-125 @ 0.1A, 6.3 @ 2A) could be used along with a cheap, smaller transformer for the universal section.

[silent:arts]

D-AOC PCBs - the building and help Thread
« Reply #37 on: March 04, 2008, 03:37:47 AM »
Quote from: "OneRoomStudios"
What is the reason for having such a high secondary for the filament? Would a standard 6.3 VAC secondary work with this circuit?

the LM350 voltage regulator needs a minimum of 3V difference between the input and output terminal to work.
yes, 9V is a bit on the high (but safe) side, thus the heat.

have not tested this for hum or noise, but of course you can leave out the whole heater PSU and use AC heating.

Jim50hertz

D-AOC PCBs - the building and help Thread
« Reply #38 on: March 04, 2008, 06:40:23 AM »
Hi Volker

In order to insulate the regs from the heatsink, what would one use?  

Thanks

Jim
"Nasty, talking to a slightly deaf journalist, had claimed only that the Rutles were bigger than Rod."

[silent:arts]

D-AOC PCBs - the building and help Thread
« Reply #39 on: March 04, 2008, 07:05:10 AM »
Jim, use something like
Farnell Nr 520214 (needs Thermal compound)
use an ohm meter to check for insulation after mounting.


 

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