GroupDIY

Project Specific Discussions => Dynamic Processors => Topic started by: peter purpose on December 10, 2011, 01:41:09 AM

Title: New API 525 build thread.
Post by: peter purpose on December 10, 2011, 01:41:09 AM
This will be the official new design 525 build resource.
I'll add stuff throughout the day.

(http://lazpro.com/525Cschsm.jpg)
Biggun http://lazpro.com/525Cschbg.jpg

This version can have a Lundahl LL1540 transformer on the front, or a differential input opamp. If using the opamp (A4)......

(http://lazpro.com/525a4.jpg)

A4 bom http://lazpro.com/525A4BOM.txt

The 2520 overlay and bom.....

(http://lazpro.com/laz2520sm.jpg)
Biggerer http://lazpro.com/laz2520.jpg

Rs 16 & 17 need] to be 1/2W, the rest 1/4W.
As some BC184C batches seem to be a bit dodgy, use 550C instead.

The switch and meter board.......

(http://lazpro.com/swmtr.jpg)

The switch resistors need to be miniature types. R9-17 should not protrude through the pcb.
Don't solder in the switch until you offer it into the metalwork, as it sits off the pcb by roughly a mm.

SWMTR bom. http://lazpro.com/SWMTRBOM.txt

The main board...

(http://lazpro.com/525main.jpg)

Main board bom http://lazpro.com/525MAINBOM.txt
Title: Re: New API 525 build thread.
Post by: peter purpose on December 10, 2011, 11:14:10 PM
Boms added.
Title: Re: New API 525 build thread.
Post by: peter purpose on December 11, 2011, 01:27:08 AM
Updated boms. Changed C15/16 to 1000uf/25v and added pins and sockets.
Title: Re: New API 525 build thread.
Post by: jsteiger on December 11, 2011, 01:46:17 AM
Peter, I am wondering why A2 is the dog's danglers?  ;D
Title: Re: New API 525 build thread.
Post by: peter purpose on December 11, 2011, 02:45:41 AM
Peter, I am wondering why A2 is the dog's danglers?  ;D

Because I couldn't fit 'you lot are a bunch of bastards' in the box.
Title: Re: New API 525 build thread.
Post by: zayance on January 14, 2012, 11:42:58 AM
Anybody found the 1K and 1M pots Log pots needed for this build? They need to be small so not much options from what i see...
Thanks a lot.
Title: Re: New API 525 build thread.
Post by: jsteiger on January 14, 2012, 12:13:57 PM
Anybody found the 1K and 1M pots Log pots needed for this build? They need to be small so not much options from what i see...
Thanks a lot.
Sorry for being a pimp but I have 1k logs. http://classicapi.com/catalog/index.php?cPath=50_131 (http://classicapi.com/catalog/index.php?cPath=50_131)

FWIW, I have 250pc of 2623-1 due in the 1st week of February. Once those arrive, I will be opening them up for individual purchase again.

Pardon me, Jeff
Title: Re: New API 525 build thread.
Post by: zayance on January 14, 2012, 02:57:25 PM
Anybody found the 1K and 1M pots Log pots needed for this build? They need to be small so not much options from what i see...
Thanks a lot.
Sorry for being a pimp but I have 1k logs. http://classicapi.com/catalog/index.php?cPath=50_131 (http://classicapi.com/catalog/index.php?cPath=50_131)

FWIW, I have 250pc of 2623-1 due in the 1st week of February. Once those arrive, I will be opening them up for individual purchase again.

Pardon me, Jeff

Allright, then the 1K's will be added to my shopping card at your place, they should fit, thanks Jeff
Now let's hunt for the 1M again....


EDIT: I guess these would do as well, forgot about the small alpha's, but won't fit the small Api knobs tough...
http://www.banzaimusic.com/Alpha-12mm/
Title: Re: New API 525 build thread.
Post by: mulletchuck on January 14, 2012, 07:31:10 PM
Howdy peter.  nothin' against your 2520 design, but i'm assuming that the Gar2520 will work as well?   I'm familiar with building that version of the 2520, and am hoping your pcb uses the same footprint, and thus opens up the doors for the gar1731 and the other DOAs that are pin compatible with the 2520..
Title: Re: New API 525 build thread.
Post by: zayance on January 14, 2012, 08:16:46 PM
Howdy peter.  nothin' against your 2520 design, but i'm assuming that the Gar2520 will work as well?   I'm familiar with building that version of the 2520, and am hoping your pcb uses the same footprint, and thus opens up the doors for the gar1731 and the other DOAs that are pin compatible with the 2520..

2520 footprints are all the same, only diff could be the pin socket size, but if you get them from Jeff then you're good to go....
Title: Re: New API 525 build thread.
Post by: zayance on January 15, 2012, 07:26:53 AM
Allright i think i found another solution, i tought these won't fit but....
So for the 1M pot will be using the CT ones found at Digikey as well as Mouser as well as banzai iirc.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=109386570&uq=634622023213144546

The 1M would fit but you need to trim it's little PCB sides and gently bend the pins  (as seen on Pic)., trimmming with pins facing down
and little holes covered to not get all the nasty dusts on the track...

It won't be possible to use CT all the way as you can see it's pretty tight, but also because the Input one won't pass
at all because the body is too big (about 15.5mm), Jeff's Bourns are 12.5mm ( 5.7mm taken from center) so that would fit better

So the setup that would work would be 1K's from Jeff and 1M from CT....both beeing log and both with 1/8"Shaft for the Api knob lovers haha....
On the pics i didn't used the CT washer, but using it will hide the Pot Thread and so make the knob sit flat on panel...

(http://img805.imageshack.us/img805/6215/20120115125924.jpg)
(http://img819.imageshack.us/img819/2046/201201151252501.jpg)
(http://img28.imageshack.us/img28/8282/20120115125143.jpg)
(http://img69.imageshack.us/img69/8210/20120115125335.jpg)
Title: Re: New API 525 build thread.
Post by: peter purpose on January 15, 2012, 07:55:34 AM
Or you could use a trimmer type for the 1M.... torque isn't the same, but it'll fit nicely.

(http://lazpro.com/potz.jpg)
Title: Re: New API 525 build thread.
Post by: zayance on January 16, 2012, 08:02:29 AM
For those who would be interested:

http://www.goldmine-elec-products.com/prodinfo.asp?number=A10751
Title: Re: New API 525 build thread.
Post by: 901 on January 21, 2012, 03:19:11 PM
Which LED Bar Driver did you guys choose? LM3916? And how to pick RM1 and RM2?

Title: Re: New API 525 build thread.
Post by: zayance on January 21, 2012, 07:31:57 PM
Which LED Bar Driver did you guys choose? LM3916? And how to pick RM1 and RM2?

Answer is in the Datasheet

http://www.ti.com/lit/ds/symlink/lm3916.pdf
Title: Re: New API 525 build thread.
Post by: 901 on January 22, 2012, 07:49:34 AM
Sorry, for my stupidity, but I have seen the datasheet. But I am missing the part of the schematic that has the LM and I can only guess what Vref should be.

Would you guys care to explain to me? Pleeeeeease....  :-[
Title: Re: New API 525 build thread.
Post by: peter purpose on January 23, 2012, 08:04:04 AM
Would you guys care to explain to me? Pleeeeeease....  :-[

If I could, I would. I'm dyslexic when it comes to datasheets and formulas.
Schematic is the standard two resistor version from the LM390X datasheet.
Title: Re: New API 525 build thread.
Post by: zayance on February 04, 2012, 03:55:39 PM
Actually the VCR2N's are also available from Electrochronic, along with some other goodies, a little more expensive than Goldmine elec, but he will ship worlwide, just for info:

https://sites.google.com/site/diypartsstore/catalog/misc-components
Title: Re: New API 525 build thread.
Post by: 901 on February 20, 2012, 04:44:16 PM
I´m 90% done with my build. Still waiting for parts to come in (Grayhills and transformers). I have once again some questions:

The RGB LED I got has 4 pins, which I think is very logical for a 3 color common cathode LED. But there are only 3 holes in the PCB. Should I solder the cathode to ground somehow?

At which point in the circuit is this LED inserted? Or in other words, I´d like to know the maximum voltage that is applied to the LED + RLED so that I can calculate RLED.

I guess there are not that big variations on LED voltages (mine is 1.9V / 3.2V / 3.2V). Maybe any of you who have already completed their builds can tell what they chose?

And whle I´m nearing completion I wonder how to set the 4 trim pots. From the schematic I gather they are Gain for the input stage, for the Limit Mode, Release Time Over-ride (?) and Meter Calibration. But how to dial them in properly?

Title: Re: New API 525 build thread.
Post by: peter purpose on February 21, 2012, 07:37:42 AM
I´m 90% done with my build. Still waiting for parts to come in (Grayhills and transformers). I have once again some questions:

1. The RGB LED I got has 4 pins, which I think is very logical for a 3 color common cathode LED. But there are only 3 holes in the PCB. Should I solder the cathode to ground somehow?

2. At which point in the circuit is this LED inserted? Or in other words, I´d like to know the maximum voltage that is applied to the LED + RLED so that I can calculate RLED.

I guess there are not that big variations on LED voltages (mine is 1.9V / 3.2V / 3.2V). Maybe any of you who have already completed their builds can tell what they chose?

3. And whle I´m nearing completion I wonder how to set the 4 trim pots. From the schematic I gather they are Gain for the input stage, for the Limit Mode, Release Time Over-ride (?) and Meter Calibration. But how to dial them in properly?

1. Can't be common cathode if they are seperate. Get a 3 leg.
2. Max V will be plus 16V.
3. http://www.twin-x.com/groupdiy/albums/userpics/525_Page_10.jpg
http://www.twin-x.com/groupdiy/albums/userpics/525_Page_11.jpg
Title: Re: New API 525 build thread.
Post by: 901 on February 21, 2012, 05:05:34 PM
Peter,
thanks a lot for the info!

Are you sure you are talking about a three-coloured LED (RGB)? If so, how does it work? anti-parallel two of the three? Can you point me to a part number?
Title: Re: New API 525 build thread.
Post by: peter purpose on February 22, 2012, 08:07:56 AM
Two colours become a third when both sides are fed.
Just get any 3mm jobbie.
Title: Re: New API 525 build thread.
Post by: 901 on February 22, 2012, 06:37:59 PM
Peter, you are too funny!  ;D

Well, I already drilled the bigger hole. And now that I took a closer look to this part of the PCB I eventually got that this LED is nothing more than displaying the state of the IN switch.

From the prescription of a RGB LED I assumed you would be doing something really cool with this LED. E.g. a coloured level meter for the input. Nevermind.

Title: Re: New API 525 build thread.
Post by: 901 on March 08, 2012, 05:02:08 PM
Now that I got the missing parts I finished my build.  :D
But I have big difficulties to dial it in using the test procedure you posted.


I stopped the test there. The unit is kind of working, but not completely as it should. I tried some music through it and it sounds really bad.  :'(

There is a very obvious distortion on the lower frequencies. Sounding like a broken speaker.

What am I missing? Do I interpret the test procedure correctly? Where does the distortion come from?

Title: Re: New API 525 build thread.
Post by: peter purpose on March 08, 2012, 05:18:46 PM
I'm going to need a week to decypher that lot.
Title: Re: New API 525 build thread.
Post by: 901 on March 08, 2012, 06:23:37 PM
In short: the unit I tested fails some of the tests given and sounds horrible. And both units I have built expose this problem (values varying slightly).

I already spent the whole week with trying to figure out what´s wrong and can´t find anything.  :-[

So I´d like to know whether I just misinterpret the test procedure and screw it up by dialling in the wrong things (R75 and maybe R52) or there is another systematic mistake (used wrong components, assumed wrong pinouts, etc.). I don´t think I failed in the built itself, since both units are the same.

I hoped that other people reading this thread have gone through it and can comment on the test procedure and my interpretation. I cannot believe I´m the only one who attempted it???  :-\

BTW here is a picture of the sisters:
(http://Lazpro 525 pair)
Title: Re: New API 525 build thread.
Post by: peter purpose on March 09, 2012, 08:28:39 AM
Let me build one of these new pcbs over the weekend and I'll see if there is something wrong.
Title: Re: New API 525 build thread.
Post by: peter purpose on March 15, 2012, 07:19:13 AM
Sorry 901, but I haven't had a chance to put one together yet.
I'll get to it as soon as I can.

peter
Title: Re: New API 525 build thread.
Post by: 901 on March 26, 2012, 07:09:28 AM
Any news?
Title: Re: New API 525 build thread.
Post by: peter purpose on March 26, 2012, 11:11:47 AM
Any news?
As yet no... haven't had the chance.
Have any that have built one experienced the same symptoms, or is it just 901?
Title: Re: New API 525 build thread.
Post by: 901 on April 07, 2012, 06:03:40 PM
Looks like I´m all alone here...  :'(
Title: Re: New API 525 build thread.
Post by: zayance on April 08, 2012, 04:09:14 AM
No you're not, i'll finish it this week.
Title: Re: New API 525 build thread.
Post by: 901 on April 08, 2012, 05:31:05 PM
Great! Happy Easter!
Title: Re: New API 525 build thread.
Post by: peter purpose on April 11, 2012, 09:39:38 AM
And I'm out of prison, so I'll get busy.
Title: Re: New API 525 build thread.
Post by: peter purpose on April 14, 2012, 02:35:42 PM
Almost there.... cough.
Title: Re: New API 525 build thread.
Post by: peter purpose on April 15, 2012, 01:12:50 PM
Slightly more almost there.
Title: Re: New API 525 build thread.
Post by: peter purpose on April 16, 2012, 09:09:37 AM
Finally got one built..... sorry for the delay chaps.
Waveforms are looking spot on.
Give me another few hours for listenning tests.
Title: Re: New API 525 build thread.
Post by: peter purpose on April 17, 2012, 01:52:00 PM
OK..... listening shows all working hunky dory and as it should, so you can rule out any pcb mistake.
901... take another look at your work.
Title: Re: New API 525 build thread.
Post by: 901 on April 26, 2012, 11:35:40 AM
Peter, thanks for the effort and the info.

I guess you also went through the API test procedure? How does the input behave at 4 (F)? Could you reach 0 dBm? Does it go down and up again when turning up the input?
Title: Re: New API 525 build thread.
Post by: peter purpose on April 26, 2012, 12:15:27 PM
I guess you also went through the API test procedure?
Yes, but as I don't have a distortion meter, I leave out that part and just leave the R52 trimmer in the middle.
How does the input behave at 4 (F)?
As it should.
Could you reach 0 dBm?
I could.
Does it go down and up again when turning up the input?
It does.
Title: Re: New API 525 build thread.
Post by: whomper on May 11, 2012, 11:05:21 AM
Hi,

Started my build and am in the process of collecting needed parts.

A quick question on part replacement; Can I replace the BC550C with BC547C or BC560C with BC556C? Can I use the BCxxxB instead of the BCxxxC?
Title: Re: New API 525 build thread.
Post by: peter purpose on May 12, 2012, 12:09:35 AM
No, no and no. Use the parts listed.
Title: Re: New API 525 build thread.
Post by: noisywill on July 05, 2012, 10:31:19 AM
Folks,

Got hold of most of the bits....just need the time now!

Quick couple of questions.....

Are 1/8w CF resistors ok for the switch board?  Difficult to find MF ones the correct physical size... I'm guessing yes, but just wanted to check before I fired in the component order.

Also, anyone have a source for 1M PRV6s?

Ta,

Will
Title: Re: New API 525 build thread.
Post by: peter purpose on July 05, 2012, 11:45:11 AM
1M prv6 are as rare as rocking horse poo.... use a trimmer.
The 1/8W resistors will be fine.
Title: Re: New API 525 build thread.
Post by: noisywill on July 05, 2012, 11:56:38 AM
Ta Peter,

Thought that was the case about prv6s.

Cheers for the info/answering of idiot questions!

Will
Title: Re: New API 525 build thread.
Post by: whomper on July 06, 2012, 02:46:05 PM
Hi,

Have a couple:
1. As I have two boards, the link thing eludes me. Have read somewhere that one should use a 120 ohm resistor, so one unit with it and the other with just a link? Also, does one need to switch both modules to stereo for this?
2. Have used the classicapi trafos. Any specifics on wiring?
Title: Re: New API 525 build thread.
Post by: peter purpose on July 07, 2012, 06:14:26 AM
Link info....
(http://lazpro.com/525link.jpg)
Total of 120R and both switched.

API 2623 info. Clearly marked on pcb.
(http://lazpro.com/api2623.jpg)
Title: Re: New API 525 build thread.
Post by: peter purpose on July 07, 2012, 06:15:46 AM
Set up info....

(http://lazpro.com/525set1.jpg)

(http://lazpro.com/525set2.jpg)
Title: Re: New API 525 build thread.
Post by: whomper on July 30, 2012, 12:12:22 AM
Hi,

In the last mile of building my two units. Am stuck with finding the 1m trimmer.
Any mouser or somewhere else alternative that one can recommend?
Title: Re: New API 525 build thread.
Post by: peter purpose on July 30, 2012, 02:12:47 AM
Any Bourns 3310 type should do you.
Title: Re: New API 525 build thread.
Post by: whomper on August 01, 2012, 10:55:48 AM
Just a quick note on build progress. While not completely done (need to source the bourns trimmers, have used alpha pots for now), have undergone calibration of the two units and they sound superb!

Great project and sound quality of the final product. Well done.

Looking forward for the EQN...

(This 500 format is addicting  :))
Title: Re: New API 525 build thread.
Post by: noisywill on August 01, 2012, 11:01:55 AM
These might do...

http://www.ebay.co.uk/itm/Panel-Mount-Sealed-Potentiometer-0-5W-Screwdriver-Adjust-Pot-Various-Values-/120805820485?pt=UK_BOI_Electrical_Components_Supplies_ET&var=&hash=item1c20968845


Cheap enough if they don't.

Will
Title: Re: New API 525 build thread.
Post by: 901 on October 20, 2012, 06:34:15 PM
I finally found the mistake I made with mine. I was tricked by the wiring of the transformers. The transformer in the sidechain has labels on the board saying "- + -_+". I assumed that one of the secondary coils should go to the first "+ -" pair and the other one to the second. While this is true for the output transformer, the sidechain transformer has its middle ground point on the side. The extra "_" actually means ground.

(http://db.tt/xCwCusxF)

Maybe others have overlooked this, too. The unit actually kind of works, but not really good.

And I had the opportunity to test mine side by side with a production API 525. It behaved quite differently. I figured this is because of the extra ATK pot. And indeed, now that I shorted the pot altogether, it´s really close to the API.

Title: Re: New API 525 build thread.
Post by: haima on October 24, 2012, 01:41:17 AM
Thanks for the report on your build 901. I need to get onto making mine one day soon!

now that I shorted the pot altogether, it´s really close to the API.

I wonder how it would work if you change the attack pot to a variable resistor, placed in series with the sidechain CV, before C3 - that way at fully counterclockwise you would effectively have the stock API circuit where the sidechain CV hits C3/R5 directly.

According to Peter's schem, C3 is wired to the wiper of the attack pot in a way that there's always an extra 1M of resistance in series with the sidechain signal compared to the stock API design - no matter how you set the attack pot.

Perhaps the series resistance option has been tried and doesn't work?
Title: Re: New API 525 build thread.
Post by: 901 on October 25, 2012, 05:47:05 PM
I wonder how it would work if you change the attack pot to a variable resistor, placed in series with the sidechain CV, before C3 -

Do you mean like this?

(http://db.tt/CXRHghSw)
Title: Re: New API 525 build thread.
Post by: haima on October 25, 2012, 09:28:59 PM
Yes, that's what I was thinking...
Title: Re: New API 525 build thread.
Post by: EmRR on October 25, 2012, 10:01:29 PM
the attack still looks whack.  See here in the old thread:

http://www.groupdiy.com/index.php?topic=22699.msg474572#msg474572
Title: Re: New API 525 build thread.
Post by: haima on October 25, 2012, 10:40:29 PM
Thanks EMRR - there's lots of good info in the previous version thread!

But, isn't dmp's schematic (below), the same as what 901 has drawn above?

(http://www.groupdiy.com/index.php?action=dlattach;topic=22699.0;attach=3338;image)

Title: Re: New API 525 build thread.
Post by: haima on October 25, 2012, 11:22:31 PM
Hmmm, I must be missing something...  ??? quite likely! ;D

To me it looks like both images describe the same circuit:

- sidechain CV enters the scene and connects to one side of a 1M variable resistor
- the other end of the 1M variable resistor connects to the junction of C3 and R5.
- C3 (0.1uF) terminates to circuit common/ground.
- R5 (30k) takes the CV on home to the gain reduction FET gate.

Where am I going wrong here? Thanks for the help!
Title: Re: New API 525 build thread.
Post by: 901 on October 27, 2012, 01:49:01 PM
No, the R's are in different order, and affect the time constant differently.

If the arrow in dmp's picture is the gate of the FET then it´s only drawn right to left instead of left to right.
Title: Re: New API 525 build thread.
Post by: EmRR on October 27, 2012, 02:01:32 PM
yep you're right, the same.  Back to my original comment; I was looking at Peter's schematic, which ain't right. 
Title: Re: New API 525 build thread.
Post by: jplebre on December 16, 2012, 04:54:22 PM
Does anyone know if Ed made a run of transformers for this new version of the 525? He said he had done enough transformers for the ones that bought the v1 of the Peter board.

Where can I get trafos in the UK? I know Jeff @ classic API sells them but was trying to avoid postal charges and the likes :)

J
Title: Re: New API 525 build thread.
Post by: zayance on December 16, 2012, 04:58:14 PM
Does anyone know if Ed made a run of transformers for this new version of the 525? He said he had done enough transformers for the ones that bought the v1 of the Peter board.

Where can I get trafos in the UK? I know Jeff @ classic API sells them but was trying to avoid postal charges and the likes :)

J

If you check the mainboard BOM, on first page, it says you can use 2X SOWTER 9935, don't know if that will be cheaper than Jeff at the end?


T.
Title: Re: New API 525 build thread.
Post by: jplebre on December 16, 2012, 05:23:23 PM
Yeah, last case scenario I was considering that.
But when I spoke with Peter he said "use Ed's have no idea what he has"

.... You know, the ever helpful Peter :)
Title: Re: New API 525 build thread.
Post by: jplebre on December 22, 2012, 04:52:18 PM
Question about the input trafo. The original has no input trafo, am I correct?
For the people that did go for the input trafo, is there really a benefit? I mean the unit is coloured enough (at least the original ones) is it worth to fork out those £40 on a Lundhall?

Pardon my noobiness if the original has in fact a trafo input. (never actually opened one, but the pictures I've seen only had the o/p and sidechain trafo)
Title: Re: New API 525 build thread.
Post by: 901 on December 22, 2012, 05:05:41 PM
The original has two transformers, but one is the output transformer and the other is used to generate the voltage that goes to the FET. No input transformer.

I built mine with the line receiver as proposed by Peter. Works fine for me.
Title: Re: New API 525 build thread.
Post by: jplebre on December 22, 2012, 05:18:18 PM
The original has two transformers, but one is the output transformer and the other is used to generate the voltage that goes to the FET. No input transformer.

I built mine with the line receiver as proposed by Peter. Works fine for me.

Thank you 901. As expected, I guess.
Title: Re: New API 525 build thread.
Post by: jplebre on January 04, 2013, 02:17:58 AM
Does anyone know if Ed made a run of transformers for this new version of the 525? He said he had done enough transformers for the ones that bought the v1 of the Peter board.

Where can I get trafos in the UK? I know Jeff @ classic API sells them but was trying to avoid postal charges and the likes :)

J

in the end, getting Ed's transformers from Jeff in the US was still cheaper for than the sowters (UK folks). ;)
Grayhill 71BDF30-02-1-AJS in stock at RS 2508966576
Title: Re: New API 525 build thread.
Post by: jplebre on January 13, 2013, 11:55:36 AM
any HFE requirements? I have tons of under 400-450hFE BC184 :P
I guess I could also use the BC550. I saw on another post they should be matched, not a problem there (Q1 and Q2)

Title: Re: New API 525 build thread.
Post by: peter purpose on January 13, 2013, 12:34:22 PM
Just match the input pair.
Title: Re: New API 525 build thread.
Post by: jplebre on January 15, 2013, 04:43:03 PM
are 1/8w ok for the miniature resistors? I've used ohms law for worse case scenario (+16v to ground) and it did give 0.250w
But I don't think in both cases it's "signal" to ground so that shouldn't matter.

I wanted to avoid carbon and the only ones I found were either 1/8w or carbon.

What are you guys getting?

Cheeeeeers
Title: Re: New API 525 build thread.
Post by: jplebre on February 03, 2013, 01:36:07 PM
Hey guys

What exactly is CG and RG?
Since it has a weird naming convention decided to look up but couldn't find on original schemo.

Is this a remnant from the old build?

Is this optional, or necessary for either the A4 or Lundahl?

I'm going A4 so I skiped XR1 and XR2. but I'm confused with CG/RG
Title: Re: New API 525 build thread.
Post by: peter purpose on February 03, 2013, 03:49:37 PM
Cap ground & resistor ground. They join power and audio grounds through 10R & 10pF... Don't ask.
Title: Re: New API 525 build thread.
Post by: jplebre on February 07, 2013, 03:40:08 PM
will 2k make a difference for R75 (2.2k?) having a hard time finding the right ones for the right footprint.

is it just setting impedance for the rail supply?
Title: Re: New API 525 build thread.
Post by: jplebre on February 12, 2013, 03:02:22 PM
Big Pete :)

in the first page of the thread you posted a pic with PRV6 lin as i/o? was this only for the picture or>

Title: Re: New API 525 build thread.
Post by: jplebre on February 18, 2013, 05:53:25 PM
2Q

is it normal that the sidechain opamp (a3) big trannies run slightly hotter than the rest? (eg. almost too hot to the touch?)
and:

Anyone else see the meters going full on when engaging true bypass?


EDIT: did the same mistake as 901 with the sidechain trafo I'll try and fix it later but that should be the end of it.. nothing to see here move along
Title: Re: New API 525 build thread.
Post by: 901 on February 19, 2013, 03:47:05 AM
Yes, bypass lights the whole meter.
Title: Re: New API 525 build thread.
Post by: jplebre on February 19, 2013, 05:10:13 AM
in normal conditions also does it? or just because i have the trafo mounted wrong?
Title: Re: New API 525 build thread.
Post by: 901 on February 19, 2013, 07:46:59 AM
No, the wrong trafo connection does not affect that behaviour.
Title: Re: New API 525 build thread.
Post by: jplebre on February 19, 2013, 03:38:00 PM
Quote
Yes, bypass lights the whole meter.

Odd! I thought that the switch was simply a 4pdt. 2 poles for the + and - copy of the signal or the trafo out, and then the extra pole used for the bi-colour LED.

Signal should still go through the whole circuit. O/p trafo still sees the 600ohm load is still there, nothing else changes in the circuit so why does this happen?

I feel like some probing and trace cutting coming on just need to understand what else is being affected :P

(not having a go in anyway, just want to learn more :)
Title: Re: New API 525 build thread.
Post by: jplebre on February 26, 2013, 07:27:15 AM
might have been me but:

- In/Out pots: they are labelled as CW being ground. it looks like as if turning CW on the schematic would smash the i/p against the threshold and would increase make up gain. The way it's suggested on the picture Peter posted (the one I downloaded anyway) it says ground pads (top 2 vias) are ground and are CW, whilst the bottom 2 are CCW.

this will make the pot perform the other way around (maximum make up gain is ccw, turning left.

Call me old fashioned, but I preferred to reverse this for both pots :)

Oh, and you really NEED that log 1k. I had put linear ones just to get things going and the useful range is from about 9-11o'clock. Then the threshold goes BUUUUUM!!!!

- Attack pot: I may try a 500k pot here. On the scope it seems as if towards the end of the travel the release starts getting severely affected (some weird release curves). That might make the pot more usefull as well? (glad I've installed a molex connector for the attack pot will make swapping a breeze ;)
Title: Re: New API 525 build thread.
Post by: qmp audio on February 26, 2013, 11:27:22 AM
I'm a little confused as to what the second value represents in the BOM.   e.g.: C1 250UF/6V (470UF/16V).
Title: Re: New API 525 build thread.
Post by: jplebre on February 26, 2013, 02:14:00 PM
first value is original, the (value) is the one that Peter had at hand and put on his prototype :)
Title: Re: New API 525 build thread.
Post by: qmp audio on March 15, 2013, 05:53:21 PM
thanks jplbre.   Can anyone point me in the right direction for Q1 & Q2 stands?   There is a note that they must be on stands... but unsure to what that means.  Thanks
Title: Re: New API 525 build thread.
Post by: jplebre on March 15, 2013, 05:58:11 PM
something like this will do http://www.mouser.com/ds/2/273/123N-58560.pdf
Title: Re: New API 525 build thread.
Post by: qmp audio on March 22, 2013, 01:25:10 AM
Thank again jplebre.

http://www.mouser.com/ds/2/244/SSL-LX3059IGW%20R-92825.pdf (http://www.mouser.com/ds/2/244/SSL-LX3059IGW%20R-92825.pdf)

I've chosen the above main pcb LED (pdf).  If i understand correctly, the LED forward voltage is 2.6V max and 20mA, and the supply is 16V, so the proper RLED would be 680Ω.

or if im doing this correctly:

~680Ω = ( 16V - 2.6V ) / 20mA.

Just hoping to verify this and make sure i have the #s right... learning.
Title: Re: New API 525 build thread.
Post by: jplebre on March 22, 2013, 02:27:31 AM
I got a much brighter LED, I limited it to 10mA and it still blinds everyone in the room w a 1.8k resistor.
You might be fine though https://www.rapidonline.com/pdf/56-0346.pdf 30mcd vs 5000mcd

if you go for 680ohms go for a 1/2w (dissipating ca. 260mW to 280mW)
Title: Re: New API 525 build thread.
Post by: Toure14 on April 09, 2013, 07:15:22 PM
Peter,

Anymore kits left?
Title: Re: New API 525 build thread.
Post by: jplebre on April 10, 2013, 02:43:02 AM
give him a shout here: http://www.lazpro.com/

He's a good fellow replies to email quicker than through here
Title: Re: New API 525 build thread.
Post by: Toure14 on April 10, 2013, 02:56:37 AM
Thanks
Title: Re: New API 525 build thread.
Post by: jplebre on April 18, 2013, 06:14:09 PM
Hi guys

one thing. I was having problems with the attack control.
I found  removing the pot and shorting would be pretty similar to the original, but I couldn't get the same results.

So, I was thinking, and I found out that what I think we should be seeing would be this.
(http://www.caffeinatedaudio.co.uk/Media/Default/forum_photobucket/525 fix.jpg)

Doing that extra connection would allow the connection to be exactly as the original in fully CCW position (eg. C3 seeing both CV and R5 without going through the 1M pot) and then at any point of the pot C3 will only see half of the potentiometer, which should regulate the rate of charge.

Basically, shorting clockwise lug/cable and wiper. Takes 2 seconds to do either on pot or PCB and in my case the attack now behaves really well.

Let me know if this help anyone, or if you foresee problems with this. Ran a whole bunch of material and so far so good.

Anyone thinks that the LED's are too slow? (eg. almost no GR shown at very fast, some then shows a lot, then less... seems like it can't pick up enough for the first half of the wiper as it's too fast, and then starts tracking correctly).

Cheers
J
Title: Re: New API 525 build thread.
Post by: qmp audio on April 27, 2013, 09:10:45 PM
Will bc550cta and bc560cta work?  They look similar except the 150mhz fT
Title: Re: New API 525 build thread.
Post by: jplebre on April 28, 2013, 09:09:03 AM
what are you trying to replace?
Title: Re: New API 525 build thread.
Post by: qmp audio on April 28, 2013, 01:57:03 PM
what are you trying to replace?

op amp transistors.

In the meantime, before i finish the opamps,  I filled my 2 units w/ known gar2520s that i have.  Unfortunately both of my units do not function correctly.  They both act identical, so whatever i did, i did the same to both of them.

The unit passes audio when in off mode ( but about 9db down... maybe not calibrated )
When i turn on.   There is barely any signal being passed.  I can hear it but its very quiet.  Like the signal is going to ground perhaps.   Im second guessing my transformer wiring.  Can anyone verify if this is correct or wrong?   particularly the sidechain.

2623 http://www.classicapi.com/catalog/images/gallery/2623/2623-1-specs.pdf (http://www.classicapi.com/catalog/images/gallery/2623/2623-1-specs.pdf)

(http://qmpaudio.com/diy/525-outputxfmr.jpg)

(http://qmpaudio.com/diy/525-sidechain.jpg)
Title: Re: New API 525 build thread.
Post by: jplebre on April 28, 2013, 04:59:04 PM
I used 550C for Q3, Q6, Q8 and 560C for Q4, Q5, Q7

as for the transformers they are wired differently. O/p is in series, but sidechain is not.

Also, mind the pinout. you currently have in-phase (dot side on the transformer schem available at classic api) on the minus, and vice versa.
I can't remember the PCB printout for the sidechain but it seems odd to me you might want to check that out. The o/p one seemed fine only out of phase
Title: Re: New API 525 build thread.
Post by: qmp audio on May 31, 2013, 08:49:16 PM
Finally got the parts to finish the laz2520s,  and finished my pair!   i did the attack mod as suggested by jplebre on one module to compare to the unmodded versions.   Yes i feel the modded version has a much better response to it... so added the mod to the 2nd unit.

However... as mentioned above,  the meter seems to be scaled by the attack pot.... attack full CCW,  the meter stays on 0.  The meter goes to full scale as the attack pot is turned clockwise.  When full clockwise the meter spans the full bar when driven.

The meter on the on-modded unit barely moved at all in any attack position ( but i could clearly hear lots of compression ).

Interesting,  something to look into further. 

Love these though,  they sound great.
Title: Re: New API 525 build thread.
Post by: 901 on June 01, 2013, 03:17:00 AM

The meter on the on-modded unit barely moved at all in any attack position ( but i could clearly hear lots of compression ).

You need to adjust R55 for meter calibration. Did you execute the API initialization procedure?
Title: Re: New API 525 build thread.
Post by: qmp audio on June 01, 2013, 04:34:08 AM

The meter on the on-modded unit barely moved at all in any attack position ( but i could clearly hear lots of compression ).

You need to adjust R55 for meter calibration. Did you execute the API initialization procedure?


Yes, calibrated.   
Title: Re: New API 525 build thread.
Post by: jplebre on June 01, 2013, 06:57:28 AM

The meter on the on-modded unit barely moved at all in any attack position ( but i could clearly hear lots of compression ).

Interesting,  something to look into further. 

Love these though,  they sound great.

Thank you for reporting back. Always good to have confirmation :)
I felt the attack was not responding as it should and more importantly not getting fast enough. The De-esser function was almost useless in some scenarios.


The meter, I didn't see anything on the spreadsheet regarding time response for common application. But meter functionality is restored once the attack time is set slightly slower.

Is R55 simply adjusting the current the meter sees?
Title: Re: New API 525 build thread.
Post by: peter purpose on June 25, 2013, 10:48:19 AM


Is R55 simply adjusting the current the meter sees?

Absolutely no idea.
Title: Re: New API 525 build thread.
Post by: jplebre on June 25, 2013, 11:03:59 AM
PETER!!! welcome back! :)
Title: Re: New API 525 build thread.
Post by: peter purpose on June 26, 2013, 08:32:34 AM
Grassy arse.
Title: Re: New API 525 build thread.
Post by: jplebre on June 26, 2013, 12:21:03 PM
I was hoping it would mean a new product :P
Or, that you still had some stock you may want to get rid off :P
Title: Re: New API 525 build thread.
Post by: peter purpose on June 27, 2013, 11:56:06 AM
Stock I have.... new goodies- nada.
Title: Re: New API 525 build thread.
Post by: agentile1990 on July 16, 2013, 12:48:45 AM
I think I'm interested in going down the rabbit hole with this one. I've built 2 units from assembly manuals(Thanks ClassicApi/Sound Skulptor) as well as wrestled one of those JLM powerstations into a custom power supply. This would be the first build (at least as far as I know) that is on my own.

Are all the parts still available for this build and does anybody have an idea of what they cost per channel?
Title: Re: New API 525 build thread.
Post by: jplebre on July 16, 2013, 04:05:09 AM
was quite significant. The hardware+PCB kits are not really cheap (not because they are overpriced, just because there's a lot to it) but the expensive bits go on the 2 transformers per channel and the grayhill doubledeck switch.

£135 for the kit, $25 ish per transformer, £25 per switch (on RS), I went for the CAPI switches which amount to about $50 with the colour inserts (for 2), $18 for the log pots which are hard to find (again, Jeff @CAPI).
I can't say about the BOM cause I always order x3 or x4 the quantity I need. I have an invoice of £200 but it had parts for other builds in there so don't rely on this.

The thing you really need to worry is the VCR2N. Frank at electrochronic had a stash of them but not many

Title: Re: New API 525 build thread.
Post by: jplebre on July 16, 2013, 06:08:16 AM
Quick one - anyone experiencing flickering LED's with the unit on bypass (bar mode)?
I had this all along but I thought it was my previous supply which was struggling to keep up the power for all the modules.

I've just built a super duper power supply and the problem is still there. I'd say the meters go off 1 LED at a time at about 2min interval and then stabilise with 4 LEd's off, the last one flickering.

I'm thinking cap, but might be wrong? bad chip?
Title: Re: New API 525 build thread.
Post by: Scrappersa on August 12, 2013, 05:46:37 PM
I have a revision of this that looks a bit different on the switch and meter board. There aren't any pads for resistors. I may have missed the information in this thread, but am I missing a board or is this correct?

Title: Re: New API 525 build thread.
Post by: jplebre on August 12, 2013, 06:15:02 PM
hi mate
there's another thread for that revision. Api 525 build thread.
this is for the new one only
Title: Re: New API 525 build thread.
Post by: whomper on October 12, 2013, 01:25:07 PM
Hi,

Built two units, working great.
One small issue that I can not resolve; consider a task to compress a BD, four on the floor. First BD hit does not get compressed, the rest do. Strange...

This can happen when there is sufficient pause between two sounds going into the unit. Its like the unit needs to wake up via the first signal only to do its work on consecutive signals.

Any ideas?

Thanks,
Whomper
Title: Re: New API 525 build thread.
Post by: jplebre on October 12, 2013, 07:54:28 PM
I've seen it happen the other way around on other compressors, due to problems on the release/time constant circuitry.
the compression would change dramatically after the first hit.

That way around, the only thing I can think of is that you have intermittent issues (eg. cold joints, bad wiring, socket issues) or a wrong sized cap.
You say the problem does also occur if there's a pause long enough, so...

sorry not much more info to think about anything more specific.

Have you done the suggested shunt on the attack?
Title: Re: New API 525 build thread.
Post by: whomper on October 13, 2013, 03:58:46 AM
That way around, the only thing I can think of is that you have intermittent issues (eg. cold joints, bad wiring, socket issues) or a wrong sized cap.
You say the problem does also occur if there's a pause long enough, so...

sorry not much more info to think about anything more specific.

Have you done the suggested shunt on the attack?

I have do the attack mod. Might it assist? The fact that it is always happening upon first attack and after some pause in signal, it does seem to be related to the attack function, not triggering the comes simon circuit.
I usually use the two units on drums and percussion, so I dial in the attack three quarters to get a somewhat longer attack and leave it there.

Another idea that comes to mind is the VCR2N as I have sourced it off eBay. Might that be a defective one causing this issue?
Title: Re: New API 525 build thread.
Post by: whomper on October 13, 2013, 04:15:15 AM
Quick one - anyone experiencing flickering LED's with the unit on bypass (bar mode)?
I had this all along but I thought it was my previous supply which was struggling to keep up the power for all the modules.

I've just built a super duper power supply and the problem is still there. I'd say the meters go off 1 LED at a time at about 2min interval and then stabilise with 4 LEd's off, the last one flickering.

I'm thinking cap, but might be wrong? bad chip?

Just saw this note while going back to this thread. The two units I have exhibit thee same behavior as per the above.
Title: Re: New API 525 build thread.
Post by: 901 on October 13, 2013, 03:46:25 PM
Maybe you could measure the voltage at the gate of the FET to better understand what is happening. I don't believe it's a bad or out of spec component if it happens on Two devices in the same way.
Title: Re: New API 525 build thread.
Post by: Rob Flinn on October 25, 2013, 12:31:51 PM
What values are people using for RM1 & RM2 ?    I only seem to be able to light 1 led in comp mode but all of them in bypass, I'm thinking the issue may be these resistor values.
Title: Re: New API 525 build thread.
Post by: 901 on October 25, 2013, 03:02:45 PM
I picked 4k7 for RM1 and 1k for RM2. Works fine.
Title: Re: New API 525 build thread.
Post by: qmp audio on October 25, 2013, 03:03:55 PM
What values are people using for RM1 & RM2 ?    I only seem to be able to light 1 led in comp mode but all of them in bypass, I'm thinking the issue may be these resistor values.

See the datasheet for your meter driver.
This is the one I used [LM3916],  has the R values in the datasheet: http://www.mouser.com/ds/2/282/snvs762a-74208.pdf (http://www.mouser.com/ds/2/282/snvs762a-74208.pdf)

r1 1.2k
r2 7.6k
Title: Re: New API 525 build thread.
Post by: qmp audio on October 25, 2013, 03:13:44 PM
What values are people using for RM1 & RM2 ?    I only seem to be able to light 1 led in comp mode but all of them in bypass, I'm thinking the issue may be these resistor values.

In addition to my above post... my meter does behave a little strange.   When my attack pot is CCW, I get about 1 LED responding.   When attack pot is full CW,  i get full meter range.   Not sure exactly what is going on.  I can hear that the amount of compression correct,  just the meter is responding different based on attack.
Title: Re: New API 525 build thread.
Post by: Rob Flinn on October 25, 2013, 03:54:31 PM
Thanks for that info.  That is what I used.  I didn't include the attack pot because of what you guys were saying & shorted the 3 attack pot pads together.   The problem is that I can only get 1 led to light on full compression.  Other than that the module seems to work fine.   

I have a mk1 version of this compressor which only has an RM1 resistor & has no issues with the meter.    I think the meter circuit may be different on the first version & seems to work properly.   Trouble is I don't have a circuit diagram for the meter which makes it difficult to work out the difference.

I suspect it may be more like this circuit since RM1 is a 1k on the rev1
http://www.next.gr/light-laser-led/led-circuits/10-LED-VU-meter-LM3915-l7590.html
Title: Re: New API 525 build thread.
Post by: Rob Flinn on October 26, 2013, 05:50:44 AM
Gunpoint, initially I was using the same values for RM1 & RM2 as yourself.  I just tried the values 901 suggested & the meter works properly with them.  I suggest you give them a try.

901, could I ask you how you arrived at those values ?  I was looking at the data sheet but was finding it rather confusing.
Title: Re: New API 525 build thread.
Post by: 901 on October 26, 2013, 05:14:21 PM

I'm glad that you got it to work!

I remember I tinkered around with the formula in the datasheet. 1k and 4k7 where resistors that I head lying around and roughly matched my results.

I also paid some attention to adjust R55 so that all LEDs are lit at the point of most compression. I built two devices and matched both to run as equal as possible. But this was purely experimental.

I wouldn't count on the meters to really show some precise dB values. I guess Peter just exchanged the meter from the schematic (which is an analog moving coil device) with the LM391x with the standard application schematic from the data sheet.
Title: Re: New API 525 build thread.
Post by: jplebre on October 27, 2013, 07:00:06 PM
Will give this a go soon too. I need to change the pots law as the current ones are IMPOSSIBLE to do with and will take the opportunity I have them put apart and replace them then.
I'll report back too!

Title: Re: New API 525 build thread.
Post by: Eliani on November 15, 2013, 02:44:01 PM
I've just started this build for two units of my own, as promised to Peter I would write down a nice build report, and that started with sourcing the parts. I wanted to make this a little bit easier on everybody, without losing the DIY in the project.

I've ordered all the parts myself, and sure I'll encounter some difficulties...
Maybe some of you need some help sourcing parts, might find it over at:

THE FACTS (http://www.eli-audio.com/2013/10/building-laz-electronics-api-525.html)

While awaiting an order from Jeff at ClassicAPI, more stuff from mouser, Grayhills from Digikey and VCR2N's from the Electro Chronic Parts store, I started building the API 252 compressor. I want to do this step by step, and take note of everything I do, why I do it that way, and why I should do it different next time! It would be nice If you guys would follow my progress, correct my mistakes, and together we could put together a very thorough build guide for Peters 525...

THE BUILD (http://www.eli-audio.com/2013/11/lazpro-api-525-build-progress.html)
Title: Re: New API 525 build thread.
Post by: mica on January 15, 2014, 11:45:19 AM
Looks like one of my REL pushbuttons died on my 525. It jumps right out on every push and basicly wont stay in. Anyone have a link to where i can get a replacement one?

/M
Title: Re: New API 525 build thread.
Post by: haima on January 15, 2014, 05:28:08 PM
I'm not sure of the part number, but someone will have it...

you could always glue the button on the switch with a little dab of epoxy?
Title: Re: New API 525 build thread.
Post by: mica on January 16, 2014, 07:05:04 AM
Thanks, but im really looking for a replacement, so if anynone knows where to get them please let me know..

Thx

/M
Title: Re: New API 525 build thread.
Post by: jplebre on February 10, 2014, 12:33:19 PM
Hi guys!

Just to say that I installed RM1 and RM2 as proposed by 901.
The unit works perfectly now! Meter tracks well at any speed, and the mod I suggested seems to make the unit work as I would expect it.

Very happy camper right now!
Title: Re: New API 525 build thread.
Post by: noisywill on February 11, 2014, 01:30:53 PM
Folks,

Struggling to work out where the pin(s) should go in the Grayhill.  Anybody got any pointers?

Ta,

Will
Title: Re: New API 525 build thread.
Post by: jplebre on February 12, 2014, 06:04:56 AM
I used this as a reference. Let us know if it helps:
(https://dl.dropboxusercontent.com/u/3370162/GroupDIY/grayhill2.jpg)
Title: Re: New API 525 build thread.
Post by: peter purpose on July 27, 2014, 10:07:02 AM
I've got a few 525 kits left. Pcbs (including 2520s) and 500 series metalwork only. £80 a pop.
Title: Re: New API 525 build thread.
Post by: taliska on August 10, 2014, 07:31:36 AM
Hello,

I'm putting together a mouser cart for a pair of 525s and have some questions regarding the electrolytics caps...

They are: (ordered by value)

C5`   5UF/25V (10UF/25V)
C12    5UF/25V (10UF/25V)
C15    10UF/25V (1000UF/25V)
C16    10UF/25V (1000UF/25V)
C19    10UF/25V
C7    33UF/16V (470UF/16V)
C17    33UF/16V
C18    33UF/16V
C1    250UF/6V (470UF/16V)
C9    320UF/2.5V (470UF/16V)

I understand what they represent, original vs (what peter used), but which ones are people using? I've tended to go with the original unless the original is hard to find, but the C15 & 16 values seem way out...10uF vs 1000uF, and the spacing on the board makes me think that I should go with peter's choice on these caps...any thoughts?

<edit>
To answer my own question a little bit. I'm going with 1000uF, because a quick look at the pcb shows that they're in the power path. So larger capacity should be better than smaller right?
</edit>

Oh, and C7 too...33uF vs 470uF...

Cheers,

Kaz
Title: Re: New API 525 build thread.
Post by: taliska on August 10, 2014, 07:29:13 PM
As it's not always easy to find electrolytic capacitors with the right combination of values/lead spacing/diameter/rating etc, I've had to be a little bit approximate with some of my selections. I've used the original values as the target values and where I've had trouble finding exact matches, I've gone for the next largest matching value that is still less than peter's values...someone shout at me if this is a bad idea...anyway, I've gone with the following:

Name        Original         Peter's           Mine              Mouser Type

C5`         5UF/25V      (10UF/25V)       6.8uF/100v    Low Impedance.
C12         5UF/25V      (10UF/25V)       6.8uF/100v    Low Impedance.
C15         10UF/25V    (1000UF/25V)   1000uF/25v    Low Impedance.
C16         10UF/25V    (1000UF/25V)   1000uF/25v    Low Impedance.
C19         10UF/25V                           10uF/100v      Audio Grade.
C7           33UF/16V    (470UF/16V)     33uF/100v      Low ESR.
C17         33UF/16V                            33uF/100v      Audio Grade.
C18         33UF/16V                            33uF/100v      Audio Grade.
C1           250UF/6V    (470UF/16V)     270uF/25v      Low ESR.
C9           320UF/2.5V (470UF/16V)     330uF/25v      General Purpose.

I'm going to order later in the week, so...

BTW, when I was choosing film caps, a few of the WIMAs came up as RF/microwave ones...I they ok for audio use? I assumed they'd just be over spec'd but wouldn't do anything bad or unwanted...correct or not?

Cheers,

Kaz

P.S. The high voltage ratings were mainly by chance / chosen if they were effectively "free" (same price as a lower rated one). I tend to go with higher load life caps if I can as I don't want to spend my days recapping. I've tried to use audio grade caps in the audio path, but that was just me looking at the pcb and following the traces to guess...not very scientific I know, but the labels make it fairly easy to do at least.

P.P.S. Also meant to mention that if people are having trouble sourcing for 1M pots & grayhills, they're both available at Allied Electronics. Specifically, there's a Honeywell 1M pot that is VERY similar to the vishay PRV6s. In fact, I suspect that's some sort of standard military spec code, as the honeywell pots have a similar code too...RV6NAYSD105A and are almost exactly the same size.
Title: Re: New API 525 build thread.
Post by: taliska on August 12, 2014, 08:29:27 AM
Looks like I'm pretty much talking to myself at this point, but FWIW, if anyone out there needs the RV6 style 1K log pots and is going to need a lot of them, then the following ebay link might be worth your time (especially if you're US based):

(it's a link to a lot of 25 pieces military surplus for (a buy it now price of) 85USD...obviously don't click it if you're not in the market for 25 pieces yourself, as the extra traffic to the page will only serve to increase the price...)

http://www.ebay.co.uk/itm/PEC-RV6NAYSA102C-1K-Potentiometers-Militery-Grade-Lot-of-25-New-/141370279309?pt=LH_DefaultDomain_0&hash=item20ea53458d#shpCntId

They're apparently these: http://www.precisionelectronics.com/0-40a-060a.html, but it seems to me that that company must have had a name change, because they look a lot more like these: http://www.etisystems.com/RV6.asp (notice the spec and site similarities...)

Anyway, I'm not the one selling them, just an observer, but figured someone else or peter might be interested...especially if another run of 525s ever happens. I didn't buy them myself, because even though RS screwed up my order meaning having to wait until october for the back order to come in, I managed to source some prv6s locally by going with different packaging options. The funny thing is that even with import taxes and expensive shipping, that lot of 25 would have made financial sense if only I was building four 525s instead of two, so there's definitely a bargain to be had there for someone...

Obviously can't comment on their condition, so exercise caution...

Cheers,

Kaz
Title: Re: New API 525 build thread.
Post by: jplebre on August 19, 2014, 07:08:48 AM
Taliska for the 1k pots I got them from Jeff steiger at classic api. they were cheaper than the PRV6 and I needed the API style aluminum knobs anyway :)
Title: Re: New API 525 build thread.
Post by: taliska on August 21, 2014, 05:12:13 AM
Taliska for the 1k pots I got them from Jeff steiger at classic api. they were cheaper than the PRV6 and I needed the API style aluminum knobs anyway :)

Yeah, I probably would have done that had I engaged my brain before ordering my stuff! ;) (after all, I got the xformers from Jeff).

While I've got you here...how are your 525s working out? I've read about the differing wiring for the attack pot and the resistor selection for the meter...was everything else straight forward?

Cheers,

Kaz
Title: Re: New API 525 build thread.
Post by: jplebre on August 23, 2014, 07:47:56 AM
working out fine! I had to do the mod I suggested on the attack a few pages back or it wouldn't work as intended.
Wiring the attack like that not only fixed the attack pot sweep, the weird release that happened at some attack speeds and the meter (would stop working at faster speeds).

I know some people did the same mod and agreed on all of the above.

I'm almost sure I went with 1.8k and 7.5k for the meter bridge LED's

its an amazing comp. using it on every project on a bunch of sources
Title: Re: New API 525 build thread.
Post by: taliska on August 24, 2014, 05:36:53 AM
its an amazing comp. using it on every project on a bunch of sources

That's good to hear! In that case, I'd better hurry up and get these things built so that I can enjoy the goodness too...  :D
Title: Re: New API 525 build thread.
Post by: jplebre on August 26, 2014, 11:22:46 AM
It's definetly not a clean comp. Lots of colour so it fits some genres/sounds.
Did an hard-rock EP not too long ago where the toms had this goodness all over them. Did a soft jazz/fusion thingy where they staid on the overheads. They are also great on acoustic guitars if you want the colour on them. I need to hurry up and get these 2 going (so I have 4ch)
Title: Re: New API 525 build thread.
Post by: dmp on August 26, 2014, 01:22:33 PM

I just read through this thread - I built up the first rev of these.
We've been trying these a lot lately. At first found them a little hard to use because I was trying to use them with a light touch, but lately been slamming them with parallel compression using a SnB. A good friend of mine commented that the added attack knob makes them much more usable and is a big improvement on the originals.
Title: Re: New API 525 build thread.
Post by: taliska on August 26, 2014, 02:56:59 PM

I just read through this thread - I built up the first rev of these.
We've been trying these a lot lately. At first found them a little hard to use because I was trying to use them with a light touch, but lately been slamming them with parallel compression using a SnB. A good friend of mine commented that the added attack knob makes them much more usable and is a big improvement on the originals.

That's interesting to hear! I've got two SnB pcbs on their way to me at this very moment for just that purpose. I plan on combining those pcbs with some ruffrecord's db25 pcbs to create a 2U box with 8 channels of blending for parallel compression for these and some other comps I haven't finished yet. Should end up with parallel comp on 2 x 525, 2 x F76, 2 x 176, 2 x pye.

Of course, I'd be much closer to finishing these if I hadn't accidentally got 1/8 watt 3k9 resistors instead of 1/4 watt ones for the mainboard...(I had a temporary moment of extreme denseness when putting my mouser cart together...)

Kaz
Title: Re: New API 525 build thread.
Post by: dmp on August 26, 2014, 03:17:14 PM
Cool - for a cheap quick build you should get a pair of the level loc pcbs. 
I just finished them and they are really nice in parallel and do things a little more extreme than my others - when that's what you want. And they come with a blend.
I did a shoot out on drums with all my diy compressors (33609, la3a, 525, 1176d, pico, SSL mixbuzz, level loc) and they were all different and all really cool.
I'd like to do it again and get some samples to post.
Title: Re: New API 525 build thread.
Post by: jplebre on August 27, 2014, 03:39:26 PM
Yes, the "Original" API speed is good either for slamming or for catching naughty undesirable fast transients (eg. de-essing or some weird pops or to catch that very fast snare attack so you don't clip whatever comes next in the chain).

With mod attack it becomes a hell of a nice shaping tool (even though the release speeds are - sometimes - a bit of a let down) with lots of colour and attitude.

Never used it as parallel compression (crushing) but I'm sure the colour would be amazing.
Title: Re: New API 525 build thread.
Post by: dmp on August 27, 2014, 03:52:42 PM
Quote
even though the release speeds are - sometimes - a bit of a let down
Another interesting (possible) mod would be to go from the 2 switches (four release options: 1Meg, 5.7Meg, 20Meg, 24.7Meg) to a pot, like this one:
http://www.mouser.com/ProductDetail/Honeywell/485025M8843/?qs=FQNPYlYYPkaMq4TukLNTUw%3d%3d

Title: Re: New API 525 build thread.
Post by: weiss on October 02, 2014, 01:21:52 PM
so everything i need in addition to the kit is the lundahl trafo and the parts of the bom, right?
btw what does swmtr mean ? (i am new to 500 modules) ;)
Title: Re: New API 525 build thread.
Post by: qmp audio on October 02, 2014, 01:45:52 PM
so everything i need in addition to the kit is the lundahl trafo and the parts of the bom, right?
btw what does swmtr mean ? (i am new to 500 modules) ;)
swmtr refers to the PCB that contains the grayhill switch and meter circuit.

yes ,  you will need to aquire most of the components listed in the bom.   The lundahl is not needed if you choose to build the input opamp pcb.
Title: Re: New API 525 build thread.
Post by: taliska on May 03, 2015, 09:56:18 AM
Hey guys,

Been a while since I posted, as I've haven't really had much time for DIY for the last year, but thought I should at least report on another successfully built pair after finally getting around to finishing these after leaving them half completed on a shelf for six months. Anyway, I know Pete's only doing special runs now, so unlikely to be much activity, but just in case anyone does come across this again, it's really straightforward but just a few things that might help:

- The input and output pots require their cw / ccw swapping when being wired up. It was mentioned by one person and one person only earlier in this thread, so I didn't do it when I wired my first unit. Once I tried using it, it was indeed counter-intuitive, so I swapped them on my second one and had to go back and redo my first which was a bit of a pain (actually broke a pot, but luckily had a spare), so you can save yourself some work by doing it right the first time. I've never used the original units, so don't know whether that's a quirk of the original units or not.

- The "term" jumper in front of the top transformer chooses between putting a 600R load across the output or not. This info is available in the old 525 build thread, but no-one's explicitly mentioned it here I think.

- Bridge the pads by the meter IC for bar mode. Leave it unbridged for dot.

- The attack mod makes everything good there.

- I used the resistor values mentioned by someone earlier in this thread and the meter works great, FYI.

Anyway, there you go. Haven't used them a lot yet, but doing some rock vocals through one worked instantly, so I'm pretty impressed with them. Also, Pete's metalwork is the best fitting around here FWIW...

Oh, and now a pic:

Kaz
Title: Re: New API 525 build thread.
Post by: tzman on April 02, 2017, 08:00:21 AM
Trying to finish up two of these, but all the links are dead...

Does someone still have the documents for this build (BOMs, overlays, schematics)? Would be much appreciated!!
Title: Re: New API 525 build thread.
Post by: qmp audio on April 02, 2017, 05:03:05 PM
Trying to finish up two of these, but all the links are dead...

Does someone still have the documents for this build (BOMs, overlays, schematics)? Would be much appreciated!!

PM'ed
Title: Re: New API 525 build thread.
Post by: tzman on April 03, 2017, 06:06:44 AM
Solved, thanks to qmp!
Title: Re: New API 525 build thread.
Post by: Ilya on April 03, 2017, 02:05:48 PM
Has anybody tried an InterFET VCR2N from Mouser? Are they any good?

http://www.mouser.com/ProductDetail/InterFET/VCR2N/?qs=sGAEpiMZZMv4z0HnGdrLjo0W1AxRZQdlOmKMZtW5%2fq6nKICE28TN7g%3d%3d
Title: Re: New API 525 build thread.
Post by: qmp audio on April 03, 2017, 02:56:41 PM
Has anybody tried an InterFET VCR2N from Mouser? Are they any good?

http://www.mouser.com/ProductDetail/InterFET/VCR2N/?qs=sGAEpiMZZMv4z0HnGdrLjo0W1AxRZQdlOmKMZtW5%2fq6nKICE28TN7g%3d%3d

those look very similar, if not the same, to the ones i used.   I may even have a few left... I would have to dig them up.
Title: Re: New API 525 build thread.
Post by: Ilya on April 03, 2017, 02:59:11 PM
I'm quite suspicious because their datasheet is very short. No graphs or other detailed information, just basic specs. Inquired on their site, will see what they tell me...
Title: Re: New API 525 build thread.
Post by: qmp audio on April 06, 2017, 12:36:23 AM
- The input and output pots require their cw / ccw swapping when being wired up. It was mentioned by one person and one person only earlier in this thread, so I didn't do it when I wired my first unit. Once I tried using it, it was indeed counter-intuitive, so I swapped them on my second one and had to go back and redo my first which was a bit of a pain (actually broke a pot, but luckily had a spare), so you can save yourself some work by doing it right the first time. I've never used the original units, so don't know whether that's a quirk of the original units or not.

I do have an original 525.  The "IN" pot is really a threshold control,  not input gain like an 1176.    IN is actually side chain IN,  so raising it lowers the output signal by adding compression.   It does seem backwards when first using a 525,  but that is how they behave.
Title: Re: New API 525 build thread.
Post by: PATAPETER on August 05, 2018, 07:00:43 PM
hi guys, anyone knows where to get the schematics for this 2520 in this post _ thanks