2254C build/support thread

I can't speak for the meters as I used the 'correct' 1DC mA meter with a scale from 0-20, I know many are using VU meters, so that may impact things somewhat.

Cheers

Matt

Thanks Pete!

Yip, I tend to be compulsive... I also colour coded them all, each number on a molex header is associated with a colour, makes for easier troubleshooting down the line, if needed. Yes it takes longer, but worth the efforts, at least I THINK it is  ;D

Matt

sinestaraudio said:

Hey Matt,

super neat wiring, very tidy!

Pete

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hey Matt, i see your twisted wires are off_centered about 1:100000000th of a mm ;D

WHAT!!! I failed  :'( Hah Hah!

kambo said:

hey Matt, i see your twisted wires are off_centered about 1:100000000th of a mm ;D

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Matta, this is the best build quality I saw on pictures here. Hurray!
Really cool.

you should be able to get correct reading by adjusting
VU adjustment trimmer...

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Well, the issue is I set them to be the same at a given setting then at other compression levels they get off from each other.

far right is 20db or whatever point on VU you want... feel free to do your own scale...
once you mark your 20db, then you markup your 8db and so on....

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Yeah I was thinking that might be a good move.

Hope it doesn't seem like I'm being a spazz, just trying to tighten things up a little.

I know this issue. If you use Farnell's ST7, add 220 and 680 Om
to get 1ma full scale (was described some tens posts ago), at least those values I got
when calibrating the unit about a year ago, than calibrate meter's 20db for max scale of st7,
than, draw small points at 2, 4, 8, 12, 16 db.
Than, remove the scale from VU, put on scanner, photozhop it as you want, and print.
This way you have exactly calibrated scale with your own design.
One little thing. Check for different 33609 versions, they have bit different scales
(8db right or left from center).
When calibrating 20 db, be sure unit is calibrated before for 3.000v/8.00db
to get good stereo link. After first 3v/8db calibration let unit work 5-10 min and check again.

I know this issue. If you use Farnell's ST7, add 220 and 680 Om
to get 1ma full scale (was described some tens posts ago),

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Yes, this is how I have it set up.

When calibrating 20 db, be sure unit is calibrated before for 3.000v/8.00db
to get good stereo link. After first 3v/8db calibration let unit work 5-10 min and check again.

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yup!

Thanks for developing this project igor, a year and a half ago when I built my first tremelo pedal I never thought I'd be building something like this. 

Hi guys

could someone please post the size/dimension of the main 2254 PCB.

thanks for any help in advance.

mickey

Mickey,

168mm(d) x 164mm(w) i make it..

Best
Pete

a year and a half ago when I built my first tremelo pedal I never thought I'd be building something like this.

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That's cool! Really, hats off!
/I still...never built any tremolo pedal!!!

if you supply square control V to 2254c, it becomes a dynamic tremolo box  ;D

he he he

this place rules.

thanks for the info sinestar.

if you supply square control V to 2254c, it becomes a dynamic tremolo box

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AAAAAAAAAAAAAAAAAAAAAAA!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Now I can understand. Cool, guys, going to make some tremolo's in a free time!!!!
;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D

Oh man I really wanna do this project! Read the whole thread and still can't wrap my head around the calibration...

start soldering... rest is easy
may be you are confused with couple of peoples calibration posts..  actually they all the same... just a different slang...

read the Igor's calibration first. then read other posts to understand the whole procedure.
i was like WTF before soldering...
but when you have the finished pcb in front of you, things start to make sense.....
this project is easier then gssl comp, as there is no mambo_jambo about what chip, what resistor, etc...
( no offense to gssl btw. i love my gssl with lundahl inputs, cinemag output Hs/Ls filtering )

wow great  ;D
I've used a few different 2254/33609 type comps over the years and I definitely love the coloration it adds. I mean I know its not always exactly the same, but from all these pictures you can tell it sounds wonderful. Something like this would be a blast! Thanks for the input Kambo!
Now onto sourcing parts woot  ;D

hoping someone can help me out...ive just finished a stereo 2254c build. calibrated both channels and all seems good except the right channel seems to be phase reversed. im using carnhill transformers and i built both channels up side by side and have checked over all components over and over and still cant find the cause. i've also tried using the threshold and ratio boards from the left channel to try and eliminate sections of the build but the signal still comes out phase reversed. any help would be great.

also just out of interest, when switch to bypass my audio cuts out completely. is this normal?

RE phase - could it be as simple as reversing pin 2+3 on either input or output XLR?

RE bypass - i haven't built a 2254C yet, but that doesn't sound normal... look for mistakes around the bypass relays?