API 312 Thread!

[clintrubber]

from Rob:

Its probably an embarrassing mistake. Has anyone got any ideas ?

If I can`t sort this out I`m going to dump the relays & just use 3 pole switches.

Saw your relay-thread, indeed, am wondering myself as well.

About your strange things happenning, hmm, would be hard to tell from a distance. Are you using Fabio's board ? Must admit the use of the 48V for the relays should in principle be possible, but at the same time feels not good at all. Can the P48-supply deliver enough current for those relays ?
I assume they're fed from before any phantom-power switching, right ?

Regards,

Peter

 

[Rob Flinn]

Are you using Fabio's board ?

yes

Can the P48-supply deliver enough current for those relays ?

Fed with 24v the relays have a resistance of 2880 ohms which is less than 10mA each. So a max of 40mA for the lot. I`m adding a resistor thats around the same value as the relay but supplying it with 48 V

I assume they're fed from before any phantom-power switching, right ?

Of course. It comes direct from the PSU. Essentially its the same as Tekays 1290 board, it just runs from 48V instead of 24V. I`ve had no problems with Tekays board & with individual dropper resistors it seems better than the original 5v solution.

 

[pmroz]

.
Rob, I'm using 12v relays (11ma draw) and 78S12 for Reg Sw. 78S12 wired to C1/R1 junction, no R10. 4 pres at once no problem, even left on overnight with relays engaged. PS is in a small enclosed case, still no overheat problems. I'm also using 30ma leds. I bet it would work with LM7812 as well.
Didn't you give me this idea pages back? except suggesting 78S05?
There's a 78S24 available from ST micro (L78S24CV, 2a max current). You could use some such for REG SW, use circuit as-is except omit R10. With lower current draw of your 24v relays, i bet any 1amp 24v reg would work.

Maybe something like this would be easier than pulling all the relays and wiring switches?

 

[Ptownkid]

Has anyone used 5% resistors on this project? How did it come out? Is it quiet?

 

[Rob Flinn]

pmroz

I`d thought about what you`re suggesting, because someone gave me a bag of 7824 regulators. What I`m trying to avoid is having to fit another transformer, because the 2 channels & PSU are a bit tight in the box.

I`ve been playing around with it today, measuring the current to energise a single relay & its all easily within spec of the TL783.

 

[pmroz]

.
Rob, ... you (and about everybody else here) know much more than I do. But once in a while i get delusional and think i can help for a change...
...and since the separate REG plan on Fabio's boards was working for me, figured should mention.
BTW this toroid is 22+22/50va for 4 channels.

 

[deveng]

Clintrubber wrote:

As long as the loads are corrected by the squared TX-ratios it'll be OK, OK ? The 1MHz peak won't be too visible after the out-TX, but I figure it'd be fine to load the TX as usual after the TX and put the scope-probe before the output-TX, agreed ?

Agreed.

Fully agreed. But your sims together with the scope-oscillations give faith in the sim-results.

I've built a number of devices based completley on simulations (no breadboard) and all have worked with minimal changes. It's a great way to start.

The big question remains of course (and as previously formulated): if the ringing is already in the original 1731, is it part of its sound ?

Yes, my point exactly!

As I've read other posts including PRR's catch of D2 being a "dual diode" I suspect we may have other demons as well! My simulations of all the 2*5*5*0 schematics have been good overall. These seem behave. But the 1731 seems to be problematic.

I have to apologize for not posting my simulations as promised. I'm on a very tight deadline project at work that is demading all my attention at the moment. I will ge them posted eventually. It seem others have simulated this and have seen similiar results (as indicated by the posts).

It's appears that A*P*I realized the problems with the Melcor and moved on with 2*5*5*0 designs.

It will be fun to see if the Melcor can be duplicated and more importantly, improved to become a more usealbe gain block.

Regards,
Jeff

 

[clintrubber]

from Jeff:

As I've read other posts including PRR's catch of D2 being a "dual diode" I suspect we may have other demons as well! My simulations of all the 2*5*5*0 schematics have been good overall. These seem behave. But the 1731 seems to be problematic.

Hmm, it looked like we were almost there... which :twisted: :twisted: :twisted: :twisted: do you still see ?

I have to apologize for not posting my simulations as promised. I'm on a very tight deadline project at work that is demading all my attention at the moment. I will ge them posted eventually. It seem others have simulated this and have seen similiar results (as indicated by the posts).

Please don't apologize, we all know how things can go. And quite some nice info has already emerged the last week, nice to see this collective quest for the correct 1731 ! :thumb:

It's appears that A*P*I realized the problems with the Melcor and moved on with 2*5*5*0 designs.

PW from Tonelux is around here so a potential ton of info wrt this issue, but as I understand it it's polite not to approach him about 'previous' times. I might be mistaken here though.

It will be fun to see if the Melcor can be duplicated and more importantly, improved to become a more usealbe gain block.

I'm getting mixed feelings :wink:
So some misc.:
* the 1731 seems to have sonically pleasant properties (I assume so, don't know yet since haven't played anything through it, but assume originals sound good - otherwise people wouldn't have started all these activities, I figure. (I haven't been following the 1731-threads at the old place.)
* indeed, we're not sure that even with the recent corrections it's the same and sounding the same -but well, if it sounds good and still has an advantage over simply putting in a 5534 then it's OK enough
* if the cloned 1731 is improved (at least from a technical side) then why not jump to something else, like the 2*...-opamp you already mentioned ?


Regards,

Peter

 

[Rob Flinn]

pmroz

Thanks for your input. I still haven`t sorted this.

I sometimes can`t see the wood for the tree`s & I`m sure when I find what the problem is I`m going to feel stupid. Any ideas are welcome.

 

[pmroz]

.
Rob, like i said.... but... if you think it's a stupid mistake, you're in my wheelhouse.
I noticed many different models of relay w/ different latching config, but... TQ2-24V list as 2880R for coil R, is that your model? So you're probably sorted there.

If so, best i can come up with is maybe relay protection diodes are reversed, sucking voltage from power rail...???
(took me a half hour to figure which way to put those).

 

[Ptownkid]

[quote author="Ptownkid"]Has anyone used 5% resistors on this project? How did it come out? Is it quiet?[/quote]


???

 

[pmroz]

.
Ptownkid,
That 5% is just tolerance, which means variation from the given value.
So if you get some 5%, and you want a specific value, you have test each. They'll all be slightly different. But 1% may have less variation from the given value per resistor.
Example: batch of (10) 470R 1% = (2) 459R, (1)460R, (3)463R, etc.
5% might have a greater range of variation. But you can still test and choose the closest ones.
But i think if you searched for all 'exact' values, you might go crazy. A small variation from spec is usually ok.
Sorry if you knew this, haven't tried 5% on boards.
Paul

 

[Ptownkid]

I do know what it means, and it's ok, I don't mind the explaination.

I should have been more clear and asked if anyone had used them without testing them....

 

[Brizco]

ive searched alot but couldnt find the solutions for my questions...

so i have to ask:

- what are the values for R1 / R2 on the PSU ?
- Why is a pin of the RL_HZ relais connected to nowhere? (fabios board)
- when i looked at the pics of finished units, why arent the fully stuffed?

thank you very much!

 

[Bauman]

- what are the values for R1 / R2 on the PSU ?

22R / 5W, totally optional. Just use a jumper if you want.

- Why is a pin of the RL_HZ relais connected to nowhere? (fabios board)

Talking about the non-plated holes or the connections that goes to A, B and C points?

- when i looked at the pics of finished units, why arent the fully stuffed?

Because this boards can be assembled in several different ways. eg: if you have it stuffed for API configuration, the parts in for servo circuit are empty... or if you don't want the line in option, you can leave some relays and resistors out also... looking at the schematic can clarify a lot this connections.

:sam:
Fabio

 

[Brizco]

thank you for the answers.

"Talking about the non-plated holes or the connections that goes to A, B and C points?
"

pin 1 is going to c, point a comes from the resisitor and b is connected to pin 7...

my question is: why goes pin 8 of the Hi-Z Relais to nowhere?

further question on the psu: it really doesnt matter if i use a 22ohm/5w
or a jumper?? no difference?

can i use 2w 470ohm for R10 ?


aham and... what means api configuration?...

i have to read more before i start a project!!

thanks
bye
:sam:

 

[Bauman]

Hey,

my question is: why goes pin 8 of the Hi-Z Relais to nowhere?

in fact, pins 5 and 6 from relays goes nowhere, cos they do nothing, they are NC (not connected). You can check this in all of them.

further question on the psu: it really doesnt matter if i use a 22ohm/5w
or a jumper?? no difference?

can't tell. just did it as option. I think the regulators alone do a good job along with the filter caps.

can i use 2w 470ohm for R10 ?

you better off leaving it out. just connect the 7805 input at R1/C1 junction.
It will do.


Just got back from studio, tracking drums. MAN! This things shine on drums. The best drum sound I had in my studio for a long time.


Some details:

kick: RE20 -> servo channel with Forssell 992
snare: SM57 -> 312 with 2520
hihat: Royer -> 312 with Melcor (running @ 24V)
ton1: SM57 -> 312 with 2520
ton2: SM57 -> 312 with 2520
floor ton: BETA58 -> 312 with 2520
overhead: AT4050 -> servo channel with Forssell 992
room: CAD -> servo channel with JLM99V

No soundclips yet, but soon. Still have to upload the guitar soundclips first...

cheers!
Fabio

 

[asm]

2 questions (1 very stupid)...


1. (very stupid)

whats the "servo channel"


2. question about relays. since i need so many for my 8 ch, getting the ones on Gregs BOM would equal like 50$, which im not going to pay that much for, i found some cheaper nice ones on ebay...

but what are the exact specs?

besides DPDT pcb mount, what about A ratings, ect ect? any of that important that i need to look out for?

thx!
taylor

 

[Bauman]

1. (very stupid)
whats the "servo channel"

Actually it's not a stupid question, this is what I call servo channel:

http://www.forsselltech.com/schematics/JE16%20Mike%20Preamp.PDF

But mine have different input transformers:

kick is on channel with JT-16-B input transfomer.
over is on channel with CMMI-10B (more iron gain on the cymbals
room is on channel with JT13k7... and JLM99V opamp.

For relays, you just need something that fits on the footprint (it's like a DIP10 IC packaging). You can choose the supply voltage you like cos the relay supply is separated on my boards. Look for any good quality low signal relays...

:guinness:
Fabio

 

[Jonkan]

Fabio: i notice that you use alot of 2520 opamps. Which do u prefer, the melcor opamps, or the 2520?

Im thinking of stuffing some 2520s to try. Right now im using the melcor on my 2 channels.
/Jonas