API 312 Thread!

[Arrigotti]

Okay, so here I go ansswering my own question again:

I removed R10, and just jumpered it. I have a big 5W 450Ohm resistor in there. That fixed the problem of the voltage dropping.

I'm not sure of the science behind that...Maybe the resistor was eating up too much current?

The other problem I was having is that the 48V regulator was heating up quite a bit, so after scouring the thread again, I saw that people were recommending to take the voltage from the junction of R1/C1 (BTW, R1 is a jumper, not a Resistor.

That seemed to solve the hot 48V regulator issue. I am testing it now with all the relays engaged to see if it holds.

I think maybe we should start a new API Thread called "The Official API Thread and Bauman PSU thread....What we know now". I really did search through that whole thing last night, and had to search again to find this information. The problem is, you may be in one part of the thread and find something erroneous, or not yet resolved, but in another part of the thread you will find the answer.

Thanks for all you posts though, it was very helpful.

 

[flintan]

I use 24V relay with baumans' psu, the draw less current. I also take voltage from the R1 jumper. Works great with 4 ch api and one psu.

For more efficient search ability, look for scrapbook extension for firefox. Really great tool, you can find everything that has been said about a specific component or value in seconds. Someone even made a scrapbook-guide.


Another thing. When i turn off my api it makes a lot of noise while it's powering down. Anyone else who experienced this? How do your api's behave at turnoff?


edit: Also Arrigotti, you need to change the value of some resistors around the 48V reg. to get 48V.

 

[Arrigotti]

For more efficient search ability, look for scrapbook extension for firefox. Really great tool, you can find everything that has been said about a specific component or value in seconds. Someone even made a scrapbook-guide.

Yes, thanks, I will try this.

Another thing. When i turn off my api it makes a lot of noise while it's powering down. Anyone else who experienced this? How do your api's behave at turnoff?

Haven't finished mine yet. I added an LED VU Meter, so I had to work out all the details with getting that going. I'll post once I get it up and running completely.

edit: Also Arrigotti, you need to change the value of some resistors around the 48V reg. to get 48V.

I read a few threads about this issue, and it seems like the general consensus is that +44.8 volts is fine. If I have any issues, I know which resistors to change.

Thanks for the input.

 

[flight]

Hi everybody

Is there a way to add The PAD fonction to the Line input ?? or Hiz input ??

It seems to only work with mic input ..

 

[Arrigotti]

Hi everybody

Is there a way to add The PAD fonction to the Line input ?? or Hiz input ??

It seems to only work with mic input ..

According to the schematic, you are correct, the Pad (just 2 resistors in line with the signal) is only switched into the Mic input's path.

It looks like you'd have to do a hack on the board to make it work with the Line Level Input, and use a completely different relay for the Hi-Z in since that signal bypasses the input transformer.

I think if you are need to pad the Hi-Z input, you aren't really running a Hi-Z signal.

 

[rbaker]

So I'm finally trying to finish up my 312s with the bauman psu.

I bought the parts and put it together about a year ago, so it's just been sitting.

I have the 5v relays. Should I just change them out or is it possible to use the 5v successfully? I have the regulators mounted to the chasis (im using an external chassis for power)

Also I haven't connected any of the leds, do they need to be used? my rails are all fine right now but when I unplug the unit it takes quite some time for the voltage to drop, (keep in mind it's not plugged into the 312 cards)

 

[bigswole]

on my 312 I am using a 25k log switch. It works but backwards, is there anyway to get it to work the correct way, or do I need to just build the gain switch?

 

[Arrigotti]

Also I haven't connected any of the leds, do they need to be used? my rails are all fine right now but when I unplug the unit it takes quite some time for the voltage to drop, (keep in mind it's not plugged into the 312 cards)

You don't need to use the LED's, although they do help drain the caps when you shut the unit down. Why not just stuff the ones on the PSU board? (don't forget the LED Resistors). It add the benefits of both giving you a visial that that section of the PSU is functioning, and it's cool to look at. You wouldn't even have to mount them to the chassis.....just drop them into the slots on the PSU Board.

Your 5V regulators will work, but will get really hot. I know other people have had sucess with strapping them to the chassis. I ended up using a second transformer for an LED VU meter, and I ran the 5V REG from the 12V taps of the second transformer. That thing now runs as cool as a cucumber.

 

[mick]

[quote author="flintan"]

About Q8, there's no heat problem on mine with a giutar connected.[/quote]

Sorry Flintan I've been on holiday,
can I just check that your referring to Q8 on one of Fabio's BC opamp boards, I've got to get this project finished of now, maybe I've got something on the 312 board wrong. Did the 48v switch work for you ?

Mick

 

[flintan]

[quote author="mick"][quote author="flintan"]

About Q8, there's no heat problem on mine with a giutar connected.[/quote]

Sorry Flintan I've been on holiday,
can I just check that your referring to Q8 on one of Fabio's BC opamp boards, I've got to get this project finished of now, maybe I've got something on the 312 board wrong. Did the 48v switch work for you ?

Mick[/quote]

Sorry, my mistake. At the moment i use melcor op's but i'm planning to build 2520BC boards.

I have a heat problem on Q8 on one of my (identical) melcor op's. Not only with hi_z connected but all the time. Can't find what's wrong. :?

Anyone had experience of the turnoff noise? I have left out the PSU LED's for phantom and 24 V. Could that have influence?

 

[flight]

I ended up using a second transformer for an LED VU meter, and I ran the 5V REG from the 12V taps of the second transformer. .

Can you give me a link to an easy led meter that work with that projet ? ( i mean that work with the output transformer )

 

[rbaker]

[quote author="Arrigotti"]

Also I haven't connected any of the leds, do they need to be used? my rails are all fine right now but when I unplug the unit it takes quite some time for the voltage to drop, (keep in mind it's not plugged into the 312 cards)

You don't need to use the LED's, although they do help drain the caps when you shut the unit down. Why not just stuff the ones on the PSU board? (don't forget the LED Resistors). It add the benefits of both giving you a visial that that section of the PSU is functioning, and it's cool to look at. You wouldn't even have to mount them to the chassis.....just drop them into the slots on the PSU Board.

Your 5V regulators will work, but will get really hot. I know other people have had sucess with strapping them to the chassis. I ended up using a second transformer for an LED VU meter, and I ran the 5V REG from the 12V taps of the second transformer. That thing now runs as cool as a cucumber.[/quote]

I installed all of the leds---the ones on the psu work fine except for the 5v one...it burns lighter and made the 5v rail drop to 2.5 I just took that one out (the led) and it's fine again.

The other problem is that my leds on the 312 pcbs have never worked. I thought that maybe I got them backwards not paying attention but I had them correct. I'm ok if they don't work, I'm just worried that maybe it just represents a larger problem.

I have yet to turn on the preamps with the 25.20s installed...I assume those won't affect the leds.

Anyway is there anything else I need to test? I worried about frying my 2520's. I tested the voltages for the opamps and they are all correct.

 

[Arrigotti]

Posted: Thu Aug 09, 2007 2:00 am Post subject:

--------------------------------------------------------------------------------

Arrigotti wrote:
Quote:
Also I haven't connected any of the leds, do they need to be used? my rails are all fine right now but when I unplug the unit it takes quite some time for the voltage to drop, (keep in mind it's not plugged into the 312 cards)


You don't need to use the LED's, although they do help drain the caps when you shut the unit down. Why not just stuff the ones on the PSU board? (don't forget the LED Resistors). It add the benefits of both giving you a visial that that section of the PSU is functioning, and it's cool to look at. You wouldn't even have to mount them to the chassis.....just drop them into the slots on the PSU Board.

Your 5V regulators will work, but will get really hot. I know other people have had sucess with strapping them to the chassis. I ended up using a second transformer for an LED VU meter, and I ran the 5V REG from the 12V taps of the second transformer. That thing now runs as cool as a cucumber.


I installed all of the leds---the ones on the psu work fine except for the 5v one...it burns lighter and made the 5v rail drop to 2.5 I just took that one out (the led) and it's fine again.

The other problem is that my leds on the 312 pcbs have never worked. I thought that maybe I got them backwards not paying attention but I had them correct. I'm ok if they don't work, I'm just worried that maybe it just represents a larger problem.

Did you install the LED resistor to go with the LED's both on the PSU and the main board.

Also, where did you connect the 5V regulator to? It should be connected to the junction of R1 and C1. If you installed R10 or jumpered it, your voltage will drop when you switch in the relays as well as any LED's.

Baumn really need to redo the schematic for this, and flat out get rid of the whole R10 thing. I made the same mistake.

have yet to turn on the preamps with the 25.20s installed...I assume those won't affect the leds.

Anyway is there anything else I need to test? I worried about frying my 2520's. I tested the voltages for the opamps and they are all correct.

As long as your voltages are correct and everything is stuffed correctly, you should be fine. Double check the polarity on the diodes and electrolytic caps.[/quote]

 

[Arrigotti]

Can you give me a link to an easy led meter that work with that projet ? ( i mean that work with the output transformer )

http://store.qkits.com/moreinfo.cfm/K4304

This is the one that I used. You just have to supply it with 10-15VDC. I wouldn't recommend using the +15V rail from the Bi-Polar section of the PSU. It could cause some issues. You can power it from the relay switching voltage if you used 12V regulators.

It took a bit to figure out logistically how to implement this VU. First it was how to make it look good on the front panel. Then is was finding a good way to mount it in the chasis. The final pain in the arse was figuring out how to supply it with power.

The easiest part was just hooking up the VU to output transformer, and setting the sensitivity. I used a Sowter OT which has the taps for a VU Meter.

If I ever get around to opening an account on photo bucket, I'll actually post pics of my LED VU implementation. It think it came out really nice.

 

[rbaker]

thanks for the reply!

Yes I definitely installed the resistors for the leds.

As for the other questions, I installed r10 as it said and installed the 5v regulator where in it's place on the pcb.

I'll do some searching to try to figure out what I need to do

 

[Arrigotti]

As for the other questions, I installed r10 as it said and installed the 5v regulator where in it's place on the pcb.

I'll do some searching to try to figure out what I need to do

If you search through that huge thread, you will find out that it was pretty much settled that you should connect the 5V rail side of R10 to the junction of R1 and C1, which is a jumper right next to the big cap. Your 5V rail will not work correctly if you don't do this. The relay's will not engage, and you will only be able to light up about 1 or 2 LED's before the voltage drops too low for it to work.

You should not have R10 install, nor should you have a jumper in that place. For some reason, it just doesn't work when in this PSU.

 

[rbaker]

So rather than deal with the 312 psu, I just replaced it with the jlm psu. That's all done and my rails are good and it's not overheating. I also switched to 12v relays.

Now that I've fired it up, I'm having one problem---it passes audio but there's no low end and it's distorting a little.

I went through the thread(s) and found two possible references:

1) possible transformers wired incorrectly.

2) lack of 0v reference


btw, this happens on both of my units.

I'm using the jensen jt110k input and cinemag cmoq-2s output. The jensen pins just line up and I'm 99% it's correct. For the cinemag I just followed the color code which I believe is still current.

For the 0v reference, can someone tell me if my grounding scheme is correct?

I'm using an external chassis for my psu. The preamp case has a chassis star ground. pin 1's on the input go to that, which also ties into the preamp card grounds. That ground goes through the 5pin xlr cable to the power supply chassis, which ties into the psu and the iec.

Any help is very appreciated!

 

[Phazinhead]

Hi everybody


Does somebody know the mod to do so as to discharge more rapidly the 48V phantom current ? Flitan already asked it, some post before, but anybody seems to answer..

thank for your help ! :grin:

 

[crisotop]

Does somebody know the mod to do so as to discharge more rapidly the 48V phantom current ?

I thought I'd bookmarked the thread were Fabio and Greg were chatting about using the Phantom Power LED with an 5k1 Resistor to discharge the 48V Rail, but couldn't find it now.


I'm looking for a supplier in Europe that sells Grayhill Switches that would suit Fabios cards - RS (#2508966576) only sells a two Deck Version. Would any of the Fabio-card owners reckon I could use this Version and simply cut off, or bend the non-needed pins away?

thanks
christoph

 

[Sender]

[quote author="Phazinhead"]Hi everybody


Does somebody know the mod to do so as to discharge more rapidly the 48V phantom current ? Flitan already asked it, some post before, but anybody seems to answer..

thank for your help ! :grin:[/quote]

An 5.1k, or even a 4.7k resistor in series with an LED to ground will drain the rail faster, and provide a handy little "Phantom On" function.