Svart
Well-known member
:shock:
wow. you are one crazy guy.
i like it! :green:
wow. you are one crazy guy.
i like it! :green:
API 312 Thread!
- Thread starter fallout
- Start date
Help Support GroupDIY Audio Forum:
smallbutfine
Well-known member
:razz:
Coolest looking trafos so far :thumb:
I was very interested reading your corresponding dissection and resurrection of the Api2622 from Seth...
I am intensively looking for the parts sources in central europe (such lams seem hard to get...) as vat, taxes, shipping and customs affairs from overseas sometimes are horrible (and unpredictable).
And ofcourse i wanted to diy a transformer since the NRG hardcore thread :grin: !
A short OT quest for you:
do you think the following core/bobbin could be of use for any groupdiy project as IP or OP diy xfmr?
May you please have a short look at this specs:
2 E-Lams ("attached"/ geknüpft)
Bobbin with 8 solder pins
techn. specs: AL 500, Permeability 5000 H2 , core size 20 x20 x 6 mm
distributer claims audio range usage for them and they are DEAD cheap.
Thank you very much, CJ for doing all that funny transformer stuff! :thumb:
Kind regards
Martin
Coolest looking trafos so far :thumb:
I was very interested reading your corresponding dissection and resurrection of the Api2622 from Seth...
I am intensively looking for the parts sources in central europe (such lams seem hard to get...) as vat, taxes, shipping and customs affairs from overseas sometimes are horrible (and unpredictable).
And ofcourse i wanted to diy a transformer since the NRG hardcore thread :grin: !
A short OT quest for you:
do you think the following core/bobbin could be of use for any groupdiy project as IP or OP diy xfmr?
May you please have a short look at this specs:
2 E-Lams ("attached"/ geknüpft)
Bobbin with 8 solder pins
techn. specs: AL 500, Permeability 5000 H2 , core size 20 x20 x 6 mm
distributer claims audio range usage for them and they are DEAD cheap.
Thank you very much, CJ for doing all that funny transformer stuff! :thumb:
Kind regards
Martin
kdawg
Well-known member
Well I found my toroid cooking problem - on the PSU312 board, there are traces that are fairly close to the drill holes. I had some metal standoffs that were grounding a trace to the chassis, so heads up to anyone else who has that problem.
Now it works great - and sounds beautiful! I will take some pics later on. It looks just like Fabio's 1U with the power supply inside.
I'm still unsure about the output tranny wiring though, but is passing audio OK. From the pic above, I have brown and red as the input, n/c on the orange and yellow. Output is the green and grey, with blue and violet connected together. Should that be 150 ohms : 300 ohms? Do I need to parallel the inputs? Thanks
-kdawg
Now it works great - and sounds beautiful! I will take some pics later on. It looks just like Fabio's 1U with the power supply inside.
I'm still unsure about the output tranny wiring though, but is passing audio OK. From the pic above, I have brown and red as the input, n/c on the orange and yellow. Output is the green and grey, with blue and violet connected together. Should that be 150 ohms : 300 ohms? Do I need to parallel the inputs? Thanks
-kdawg
Svart
Well-known member
Hey Fabio, what did you use for R3, R4/5 on the 2520bc? i ended up trying 20k for each and it doesn't work at all. probing after the input BJTs with a signal seems to amplify..
Svart
Well-known member
bump.. :?
pmroz
Well-known member
.
Hi Svart,
20K for R3 and 20K for R4+R5 (1 resistor) works on mine.
Well, 7 out of 8 work...
paul
Hi Svart,
20K for R3 and 20K for R4+R5 (1 resistor) works on mine.
Well, 7 out of 8 work...
paul
Svart
Well-known member
I used 3k for both.
AnalogPackrat
Well-known member
I'm finally starting on my Fabio pcb 312s and have made my first error. I ordered the grayhill gain switches from Digikey, so they are the non-shorting type (-AJN instead of -AJS suffix). So at in-between positions the opamp will be disconnected from C3 (the cap to ground from the gain pot/switch) and POP. Not pretty.
Rather than try to find a US vendor that sells the shorting versions of these things (and spending another $15 ea) I was wondering if this workaround would be reasonable. Couldn't I strap a 500k-1M resistor across the gain switch (Ga-Gb) so that in-between positions go to very low gain with less popping? At any particular position this resistor would be in parallel with the much smaller gain setting resistor and have almost no effect. Does that sound reasonable or is it not even worth worrying about?
A P
Rather than try to find a US vendor that sells the shorting versions of these things (and spending another $15 ea) I was wondering if this workaround would be reasonable. Couldn't I strap a 500k-1M resistor across the gain switch (Ga-Gb) so that in-between positions go to very low gain with less popping? At any particular position this resistor would be in parallel with the much smaller gain setting resistor and have almost no effect. Does that sound reasonable or is it not even worth worrying about?
A P
smallbutfine
Well-known member
It would lower the pop but should not be optimal however... Fighting with a similar problem with lorlins at my greens. I will definately order shorted types to get rid of that...
gar381
Well-known member
Hi all
I found these as a cheap replacement for the DPDT_C&K_E201MD1AV2BE
from Greg's list.
Try these:
mountain switch #20126DPDT24
Mouser part# 108-0024
10 or more of them for USD $3.06 each WOW!!!
These will also work in the phase position in Peterc's Green pre as well.
GARY
I found these as a cheap replacement for the DPDT_C&K_E201MD1AV2BE
from Greg's list.
Try these:
mountain switch #20126DPDT24
Mouser part# 108-0024
10 or more of them for USD $3.06 each WOW!!!
These will also work in the phase position in Peterc's Green pre as well.
GARY
Svart
Well-known member
louder, there is a connection from V- to the middle of the board?? I didn't know that.. I shall look right now..
alo svart
i have a 2520bc rev1 in front of me right now.
there are 4 holes in one side.
top to bottom
ut/v-/g/v+
v- has two holes.one for the pin,and another to jump to another hole close to r13.i made this connection with a piece of wire.
best regards
pedro
i have a 2520bc rev1 in front of me right now.
there are 4 holes in one side.
top to bottom
ut/v-/g/v+v- has two holes.one for the pin,and another to jump to another hole close to r13.i made this connection with a piece of wire.
best regards
pedro
Svart
Well-known member
found it louder, that FIXED my problem... :thumb:
but now i feel like an idiot.. I've been looking at that little hole wondering why it had the v- next to it.. while thinking my problem must exist in something else I did.
now it makes all kinds of sense!
but now i feel like an idiot.. I've been looking at that little hole wondering why it had the v- next to it.. while thinking my problem must exist in something else I did.
now it makes all kinds of sense!
pmroz
Well-known member
.
i did that too.
simpatico!
it works now?
Fabio posted earlier which holes should still be empty when it's all done.
From top:
1. Just below 'G' and Gnd pin
2. Just left of 'R1'
3. Below 'O', right of R12
4. Just below 'C1', stamping out - designation for pin below
paul
i did that too.
simpatico!
it works now?
Fabio posted earlier which holes should still be empty when it's all done.
From top:
1. Just below 'G' and Gnd pin
2. Just left of 'R1'
3. Below 'O', right of R12
4. Just below 'C1', stamping out - designation for pin below
paul
Svart
Well-known member
hey Fabio, they sound great, but I'm sort of liking the Gainbloak here too.. but the gainbloak tends to overheat the Vregs and cause the -rail to break into oscillation.. :?
I'll figure that one out soon.
:thumb:
I used those switches too for mine
I'll figure that one out soon.
:thumb:
I used those switches too for mine
Tungstengruvsten
Well-known member
is it possible to use the servo out option as well as the tranny out? I'm using the Profile output transformer and a JH990.... I read back through this thread and didnt' really find a clear answer...
Tungstengruvsten
Well-known member
ok...maybe another option: Is it possible to make the servo/tranny out switchable? possibly switch the entire stage after the opamp and before the XLR?
