abechap024

Re: Payment: 160VU PCB Prototype
« Reply #20 on: August 03, 2010, 06:40:14 PM »
Thanks Stuart,
Confirming Payment.
AC Sound - some DIY circuitboards


Re: Payment: LAST DAY!160VU PCB Prototype
« Reply #21 on: August 04, 2010, 02:24:59 AM »
Im in for one. :)
Payment for 1 PCB sent


abechap024

Re: Payment: LAST DAY!160VU PCB Prototype
« Reply #22 on: August 04, 2010, 02:47:53 AM »
Espen Payment Confirmed.
Thanks!

AC
AC Sound - some DIY circuitboards

Albrebreton

Re: Payment: LAST DAY!160VU PCB Prototype
« Reply #23 on: August 04, 2010, 04:31:31 AM »
Great projet, it will be fun. Payment for 1 PCB sent

Thanks, Alberto

haima

Re: Payment: LAST DAY!160VU PCB Prototype
« Reply #24 on: August 04, 2010, 11:22:54 AM »
payment sent! thanks abe

abechap024

Re: Payment: LAST DAY!160VU PCB Prototype
« Reply #25 on: August 04, 2010, 12:25:45 PM »
Confirming payment for Haima and Manuel.
Thank you!
AC Sound - some DIY circuitboards

abechap024

Re: ORDER Shipped from factory! 160VU PCB Prototype
« Reply #26 on: August 20, 2010, 05:05:42 PM »
Check first post for update.

Thanks!
AC
AC Sound - some DIY circuitboards

tommypiper

Re: ORDER Shipped from factory! 160VU PCB Prototype
« Reply #27 on: August 21, 2010, 12:05:48 AM »
Hi, I'm interested.  Thanks for the project.   :D  But your links are not working.   :'(  Would like to see the schem and such...  and the layout of your board too.
Imagine a wet, slightly chilled from its gas release and decompression, with water droplets condensing, sucking surface tension, slowly sliding down the side, capped by a healthy virgin froth on top..

abechap024

Re: ORDER Shipped from factory! 160VU PCB Prototype
« Reply #28 on: August 21, 2010, 12:45:23 AM »
Hey,
Thanks tommypiper I've put up so many different versions of the schematic its hard to keep up with them all sometimes :-) I did order a few extra PCBs for anyone that might want to jump on board when they arrive. I'm just hoping there are no MIZTAKES!!!

oh and links on first post should now work
AC
AC Sound - some DIY circuitboards

tommypiper

Re: ORDER Shipped from factory! 160VU PCB Prototype
« Reply #29 on: August 21, 2010, 06:37:28 PM »
Thanks, where is the DBX 200 footprint?
Imagine a wet, slightly chilled from its gas release and decompression, with water droplets condensing, sucking surface tension, slowly sliding down the side, capped by a healthy virgin froth on top..


abechap024

Re: ORDER Shipped from factory! 160VU PCB Prototype
« Reply #30 on: August 23, 2010, 11:06:52 AM »
They are there, look for the small rectangles. but they are filled with optional parts if one doesnt already have a dbx 200 vca/rms they can build one on board
cheers
AC
AC Sound - some DIY circuitboards

SSLtech

Re: ORDER Shipped from factory! 160VU PCB Prototype
« Reply #31 on: August 23, 2010, 11:36:40 AM »
I'd just take a moment to point out that -while the spirit of DIY is a highly commendable thing, it's worth making sure that everybody understands that the DISCRETE VCA option is a VERY difficult thing to get right.

dbx had to individually measure and hand-select transistors across a variety of temperatures, and then thermally-couple the devices together as closely as possible, which ultimately proved to be the single greatest limit to VCA performance, particularly in terms of (particularly unpleasant) distortion.

I'd expect anyone who tried to hand-roll their own VCAs to end up with an inferior result, in terms of performance. THD and temperature drift would likely be compromised.

While I'm not saying that this isn't a great idea, to allow people to try and build their own VCAs, the advantages of monolithic devices are just out of this world... and I'd have used something like a MAT-04 in a VCA, instead of four individual devices.

I'd prefer people to understand up front that -if decent performance is a priority- it's almost certainly better NOT to attempt a discrete build of the VCA section.

However, if you're cool with that, and the idea of building the whole thing from scratch is more important than decent distortion performance, by all means have at it.

By the way, the distortion is NOT 'cool' distortion; it's the type of distortion which gave VCAs such a bad name all those years ago. -It's why dbx had to spend so much time and money building specialized test-and-match setup, which the vast majority of DIY-ers simply wouldn't ever be able to recreate.

Just a caveat which I think should be clearly added; and not anything which should detract from a noble effort.

Keith
"A waist is a terrible thing to mind"
Quote from: PRR
Ah, but that was 1999; we don't party like that any more.

haima

Re: ORDER Shipped from factory! 160VU PCB Prototype
« Reply #32 on: August 23, 2010, 11:55:14 AM »
you are right keith - but perhaps we can use the THAT 300 series matched arrays to circumvent some of those issues... obviously not with this pcb revision - unless we use some kind of adapter/floating wires...

abechap024

Re: Recieved. Sending out tommorow! 160VU PCB Prototype
« Reply #33 on: August 23, 2010, 03:20:42 PM »
Hey all. Got them today! Pleasantly surprised with the quality of the PCB. Shipping them all out tomorrow. I have 3 extra if anyone wants to pay 35$ a piece for one or two or three. Thanks again for everyone who participated! This place rocks :)


AC


...it's worth making sure that everybody understands that the DISCRETE VCA option is a VERY difficult thing to get right.


Keith

Thanks Keith,
that is something I've been wondering about...and all those "select" resistors in the VCA. I for one wouldn't even know were to start on how and why to select the right resistors. Though if someone could spread some light on that I am eager to learn(does it have to do with the bias for the transistors??). The Discrete VCA is definitely not for everyone. Luckily with the help of many people on the forum we have added a THAT 2180 vca option. But I would like to start gathering any information on how and why to select the components inside the VCA. Should be a good learning experience if nothing else
Thanks all
AC
« Last Edit: August 23, 2010, 03:41:51 PM by abechap024 »
AC Sound - some DIY circuitboards

abechap024

Re: Recieved. Sending out tommorow! 160VU PCB Prototype
« Reply #34 on: August 24, 2010, 05:07:02 PM »
ALL PCBS sent out today. Thanks to all those here who participated, now time for the fun stuff!
AC
AC Sound - some DIY circuitboards

haima

Re: ALL PCBS Sent out Today! 160VU PCB Prototype
« Reply #35 on: August 24, 2010, 11:34:10 PM »
thanks for all your work AC - hopefully we don't have TOO much "fun"....  :P

it'll be interesting to see how the hard it is to get that discrete VCA right  ;D

good thing we have a few options

beatnik

Re: ALL PCBS Sent out Today! 160VU PCB Prototype
« Reply #36 on: December 30, 2010, 03:50:52 PM »
will be a second batch available?

abechap024

Re: ALL PCBS Sent out Today! 160VU PCB Prototype
« Reply #37 on: January 02, 2011, 09:12:18 PM »
Yes. Sooner than later. Very soon hopefully.
Abe
AC Sound - some DIY circuitboards

haima

Re: ALL PCBS Sent out Today! 160VU PCB Prototype
« Reply #38 on: January 02, 2011, 09:53:03 PM »
Has anyone built a 100% functional unit?

damnyankee

Re: ALL PCBS Sent out Today! 160VU PCB Prototype
« Reply #39 on: January 09, 2011, 12:36:42 PM »
I'm wrapping up soldering the last few components on the board.

I have a few questions:

On the BOM, R11, R13, R15, R67, R106 are "trim" resistors and C10 is supposed to be a trim/timing cap...but there's no values listed.  Thus, these components have not been installed on the board.  Can anyone help as to what values these components are supposed be?

Thanks in advance!

DY


 

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