Orange Kongpressor Gut Shots

Antigua · Post by **Antigua** » 05 Aug 2020, 07:10

I don't have an circuit analysis to offer at this juncture, but I've not seen any gut shots of the Kongpressor on the Internet, so I thought I'd supply some. It looks like it might have originally been named "Squash Comp" in the design phase.

The clustered strips of resistors is unusual looking, to my eye, I haven't seen anything quite like it in the few dozen pedals I've opened up.

camljenkins94 · Post by **camljenkins94** » 07 Aug 2020, 22:22

I'd say it looks very much like Adrian Emsley's work. The choice of op amps, the rows of resistors, et cetera.

bow_and_error · Post by **bow_and_error** » 25 Feb 2023, 01:41

According to the Orange Bass Butler manual: "The compressor on The Bass Butler is based on the compressor found in the Orange Kongressor and designed to emulate studio compressors."

There is a thread with completed schematics of the Bass Butler here on FSB. I've uploaded that section of the schematic, but go download u/tuck's files to see it in context.

It looks like the Kongpressor uses an LT1054 charge pump to get to +18V, whereas the Bass Butler runs off an 18V DC adapter, so keep that in mind.

bajaman · Post by **bajaman** » 06 Mar 2023, 22:22

thanks Antigua
I traced the board layout from the pictures - there may be errors - not sure of the squash and decay pot values but 50kA seemed to be appropriate - essentially the same as the bass butler detection circuit with minor component value changes - interesting buffer stage

Will post the board layout and Sprint layout files soon , in the meantime here is the preliminary schematic
cheers
bajaman

bmxguitarsbmx · Post by **bmxguitarsbmx** » 06 Mar 2023, 23:29

Great work Bajaman!
I'm going to guess thatR8 should connect to the T1 emitter, not the base of T2.
I can see how Attack (RV2) would control the charging of C15, but I suspect that Decay(RV3) should control the discharge time of C15-Maybe it is wired across C15?

I know that constant current source loaded emitter followers are the stuff that cork sniffers appreciate, but this circuit could be made more simple by directly connecting R8 to the output of IC1a and eliminating a bunch of stuff, including no longer needing C5 and C6 as the voltage at IC1a pin1 will be the same as the bias voltage at IC2b pin5.

bajaman · Post by **bajaman** » 07 Mar 2023, 00:22

Thanks bmxguitarsbmx
I must admit i found the buffer strange - you are correct

Here is the revised schematic
cheers
bajaman

bajaman · Post by **bajaman** » 07 Mar 2023, 05:02

bmxguitarsbmx · Post by **bmxguitarsbmx** » 07 Mar 2023, 16:47

Bajaman! You were more correct the first time!

T1 is the Emitter follower. T2 is the constant current source that loads the T1 to improve linearity and get gain closer to unity.

R6 brings current form Ground through D2 and D3 to bias T2 and set the current.

R8 just connects to the emitter of T1.

Decay control looks good. That setup makes sense! Thanks for doing the hard work and not minding if I make wild guesses from my couch

bajaman · Post by **bajaman** » 07 Mar 2023, 19:33

woops
That is how i meant to draw it - this should be correct now (hopefully)
cheers
bajaman

george giblet · Post by **george giblet** » 08 Mar 2023, 03:03

Missed one.

woops
That is how i meant to draw it - this should be correct now (hopefully)

R8 just connects to the emitter of T1.

Makes a lot more sense for the output to come off T1's emitter. (T2 and its base-emitter components form a current source load for T1.)

Gebrey · Post by **Gebrey** » 09 Mar 2023, 23:15

Hallo everyone
I was waiting this scheme so much

I started to make super compact layouts to fit in a 1590B. I usually do but this time I doubt. We'll see..

Here my compact layout. Green dot input, purple output. Grey line is -9V. Follow the path with the original schematic and check for errors. No led circuit, made apart.

Charge pump LT1054, VTL 5C3

bajaman · Post by **bajaman** » 22 Mar 2023, 07:41

UPDATE: the rev2 schematic has a serious mistake - R8 should be connected to Q1 emiter NOT Q2 emiter
here is the corrected rev3 schematic
cheers
bajaman

bajaman · Post by **bajaman** » 24 Mar 2023, 23:38

I have built this pedal and it is verified - works well too.
I have a few spare boards available if anyone would like to build it - fits inside a standard 1590BB enclosure too

email me: baja002steve@gmail .com if you would like a board
I used an XLsemi 6007 buck boost converter to supply +15v and -15v rails (you could use +9v and -9v by changing one resistor value - I went for the higher headroom

)
You can build your own converter or simply purchase the fully built converter board from Aliexpress (https://www.aliexpress.com/item/1005002 ... 18025JYmSI)
I will post some build pictures later today but in the meantime here are some pictures of the pcb design
cheers
bajaman

bajaman · Post by **bajaman** » 25 Mar 2023, 01:20

Here are some build pictures for you all - I had to mount the vactrol on the other side of the board because of those tiny potentiometers - I used MC33178 chinese dual opamps, multi layer ceramic capacitors, metal film resistors etc and it sounds great - very low (no) noise and smooth sounding device
cheers
bajaman

plush · Post by **plush** » 25 Mar 2023, 07:20

bajaman wrote: ↑24 Mar 2023, 23:38 I used an XLsemi 6007 buck boost converter to supply +15v and -15v rails (you could use +9v and -9v by changing one resistor value - I went for the higher headroom )
You can build your own converter or simply purchase the fully built converter board from Aliexpress (https://www.aliexpress.com/item/1005002 ... 18025JYmSI)

I'd opt for using two separate converters for positive (boost/sepik) and negative (buck-boost/cuk) rails, it's better in terms of stability (in current applications both rails are dependent, but controller gets it's feedback only from one, which may lead to a skew).

bajaman · Post by **bajaman** » 25 Mar 2023, 09:21

never had any problems with the xlsemi 6007 buck boost convertor - current draw is in this application is 6mA on one rail and 4mA on the other rail - stable as, even with full compression

cheers bajaman

bajaman · Post by **bajaman** » 26 Mar 2023, 07:02

Not built this yet - not even ordered any boards yet, BUT, I think it would be a lot easier to build with normal sized WH148 potentiometers and the components all mounted on the opposite side to them

Those ridiculously small pots I used in my build are expensive and often difficult to source logarithmic types, whereas the WH148 pots are super easy to find in linear, logarithmic and antilog varieties
If sufficient interest is shown, i could order a small batch of boards. In the meantime here are some pictures to peruse - all capacitors are multilayer ceramic types (or polyester box type if you prefer) except for the two 220uf 25v filter capacitors

cheers
bajaman

Tassieviking · Post by **Tassieviking** » 26 Mar 2023, 09:33

Bajaman, what grade of MLCC's do you recommend for most jobs, and do you know of a good place to get them from ?

bajaman · Post by **bajaman** » 26 Mar 2023, 19:42

Tassieviking
Just the cheap ones from Aliexpress - they work fine - it's only rock n roll

cheers
bajaman

Tassieviking · Post by **Tassieviking** » 27 Mar 2023, 02:58

Thanks Bajaman, I guess I will start using the ones I got from Tayda in more pedals, I got the full range from 5pF to 10uF from them.