Building the WHAT compressor

[rpd]

:idea:
I see. Thanks.

 

[rpd]

So i am learning here, but this is my first parts order. (Please bear with me) :?
I am slowly placing an order and doing research at the same time.

What are the acceptable voltages for the caps on this project, 50v and up?
with the exception on the BOM where it says something like 10u16. Is that calling for a 10u cap at 16V? (or does this mean something different)

Are there any caps that you would recomend using something other than ceramics to improve signal quality?

Ryan

 

[smallbutfine]

You are right about the BOM desription (voltages...).
The cap question isn't that easy to answer.
Maybe someone on this board should write a book about audio caps (so all others can critisize him about every single statement in there... :grin: )

There's alot of options to change caps to change sound...BUT there's not much audiopath components here anyways, so i think it would be useful to concentrate on good sounding electrolytics (especially in the psu, maybe most important and most overlooked place) like maybe Panasonic FC or Sanyo OsCon or Elna Starget or or or or....
Ceramics used should be C0G/NP0 types (the black pointed...)...
However, on this board alot of people DON'T care about price or brand of caps and experiment much with cheap caps trying out all kind of film caps to their personal liking, and such...
There are alot opinions about ceramics and films... some swear on ceramics for the mids and polyprop film in the heights (as polyprop is reputed to be *neutral* sounding...not always what you may want...) for example in eq ckts...
In my opinion often the circuit itself is the most important part of the sound, not the single component choice...
If you want to have more background information, there's alot info on the internet about audio caps, especially over at the audiophools :grin: , but even really worthy essentials... :green:
Sorry, no simple answer here...only one: DIY... film caps are not that expensive (especially if you are a cheapy like mine who buys bulkware at ebay or slaughters medium old hifi :twisted: )...

 

[rpd]

Thanks!!
I know how the cap question is a tough one to answer. Searching the metas it is hard to find any definitive answers. But what you said point me in the right direction. It is a slow learning process here but i'm enjoying it.

Ryan :thumb:

 

[Kir_For_Pleasure]

Hello !

Im new to diy i have only built the gssl befor and are now waiting for my pcb to be arrived so i can start with the Fabio What Compressor with melcor opamps. So i must ask if someone may have a Partlist sorted by components Resistors,Leds....if...that should help me big time :wink: also instructions,guides are welcome.

Have someone built the compressor yet ?

 

[12afael]

Sheesh, what next. Burnley drops in fronm Chile?

Hey, I´m from Chile!!

I will try to build a What compressor. I will do it more simple, normal op amps and drv124 and ina134 for balanced in, out.

someone have a stereo PCB design?

is posible to get samples of optocouplers? is not easy to get some here en Chile .

is posible to implement a kind of threshold control on the bias pot ?

 

[pmroz]

.
Hi all,

Fabio mentioned a few weeks back that the schem and BOM listed previously on this thread (the link says rev2, but the schematic says rev1) does not include some of the changes he made for these boards. Stay posted and he'll update.

Also, the PS/filter section is on the board, so no need for separate power supply. If you do two comps in one box, you can fill the PS filter section of one board, then jumper it to the 2nd board. So you can leave off one PS section worth of parts for one box with 2 Whats. You'll still need a 2x15v/30va toroid off-board.

BTW, Kir-For-Pleasure, BOM = Bill of Materials, that's the parts list you were asking about. The link is earlier in the thread. Not sure if this (rev1) BOM includes parts for the opamps (or any special features Fabio added), but I don't think so. There's another link to a parts list for the 1731 on Fabio's site (DIY Pill).

Added to Martin's cap info: make sure whatever caps you use will actually fit on the boards. Some film caps are much bigger than others, like 21mm across instead of 7mm. And sometimes the higher voltage (like 10u35 instead of 10u16) electrolytic caps are too big... other times they're fine. So it's good to measure the space allowed on the board, then look in the catalog or data sheet for the cap's 'package size' to make sure it's usable. Also, "Low ESR" types can be good for electrolytics.

Hope it helps, Paul

 

[Kir_For_Pleasure]

Thanks for the information pmroz!!! :grin:

 

[Bauman]

Sorry guys, I´m late with that info, just got off hospital where my wife did a procedure... hang in there and as soon as my life get back to normal I wll post those files.

cheers
Fabio

 

[pmroz]

.
as soon as my life get back to normal
...so she's going to be okay? Hope so.
Take care (and her too).
Paul

 

[Ptownkid]

Yeah Fabio, I hope all is well :grin:

 

[alexc]

Regards to your wife and hope she is better soon. :sad:

 

[Bauman]

Thanks guys! Yea she´s doing ok.
I´m playing nurse right now... :wink:

Fabio

 

[Bauman]

Ok, back and ready to put out some docs. So you need:

- the V2 bom
- some footprint pics to show how to stuff it original and modded

- what else?

Let me know!

cheers,
Fabio

 

[AnalogPackrat]

Fabio,

A short summary of each mod and how to implement it would be cool. For instance, to add attack and release controls, which of the original fixed components need to be left out (or jumpered)? Thanks for all the work! Hope your wife is recovering quickly, too.

:guinness:
Analog Packrat

 

[mfdu]

agreed - some photo's showing the unmodded / modded boards, and/or even a short explanation of the mods would be great.

eg - 1731 op amps compared to the IC's, and (as pack rat said) the release/attack.

maybe if you have a VU meter mod to show GR that'd be nice to see . . .

the options you provide on the boards rock, it's just that i am still skill-building!

chris.

 

[rpd]

The boards made it to me safely this time!
Can't wait for more info!

Thanks
:sam:

 

[Mark Burnley]

[quote author="CJ"]Sheesh, what next. Burnley drops in fronm Chile?
:thumb:[/quote]

:grin:

Nope,

I'm safely stashed away in my Liverpool DIY lair!

Fabio,

I hope you and your wife are okay

:thumb:

Mark

 

[mfdu]

what semiconductors are to go in U2 U3 U4 and U5???

edit : sorry - found the answer -
"U1, U6, and U7 are single op-amps which are in the audio path and can be discrete or IC (5534). The others are in the sidechain and are all duals (hence the A and B suffixes on the schemo). I plan to use TL072 or TL082 for these since I have a bunch. "


chris.

 

[mfdu]

however, another question raises its head.

what value for the pcb pots - threashold, ratio, gain

and what value for the release and attack?
(if they are as simple as that)

building a detailed BOM featuring some product codes for both RS and jaycar - will need someone to host it once i have gleaned the answers i'm after.

anyone know about getting hold of the vactrol?

finally - what is the P1 and P2 10KA?????

BOM on its way.

chris.