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Delegate (Warden) Upgrades

Chuck D. Bones

Well-known member
This post describes the mods in the Col. Klink.
The EQD Warden is a good optical compressor. Basic design is mostly sound, with one major defect, one minor defect and a few opportunities for improvement. Parts of this design were lifted from the Ross compressor.
Major Defect
The signal path is routed through Q1, where is gets distorted by the non-linear loading from D2 & Q3. This is easily corrected by disconnecting C14 from Q1-E and connecting it to IC1 pin 1. You can do this on top of the board simply by lifting the + lead of C14 out of the pad and running a jumper to the end of R5 closest to IC1. I did it by cutting and jumpering on the bottom of the board. If you're not experienced in trace cutting, then do the mod on the top of the board.

Col Klink - cut & jumper.png

Minor Defect
The bottom end of the TONE control is useless. I don't know about you, but I have no use for a treble cut in a compressor. A little treble boost brings the sparkle back that gets lost in compression. The stock tone control is flat at about 8:00 or 8:30 and below that cut treble. At 7:00 it's a very strong treble cut. Installing a 20K resistor in series with pin 1 of the TONE pot fixes that. Now 7:00 is flat and it's all treble boost above that. You can cut the TONE pot's lead short and install the 20K resistor between pin 1 and the board, or use a solder lug pot like I did.

Col Klink Tone & Distortion mods.png

Opportunities for Improvement
1. Q1 biasing. Q1 is biased close to saturation, which reduces its dynamic range. If we correct the major defect above, this mod is less important. However I wanted to maximize the performance of the envelope detector and remove any loading effect from the output of IC1.1. Replace C5 with a 3.3K resistor (stand it up). Replace R6 with a 10K resistor. Do not solder the bottom end (the end furthest from Q1) to the pad, solder it to the next pad over at the end of R7 (also 10K).

Col Klink - Q1 bias mod.png

2. Better component values.
2a. Change R3 to 2.2M, change R1 to 2.2M or larger; I used 4.7M. R3 = 10M makes no sense when R1 = 1M. Change C2 to 100nF, 1uF is at least 10x larger than it needs to be, even with R3 reduced to 2.2M.
2b. Change R4 to 10K for 6dB more sustain.
2c. Change the LEVEL pot from B50K to A50K. Gets unity closer to noon.

Parts Substitutions
This is all very optional. I did it because I had the parts.
Q1-Q3 can be any high-gain NPN transistor. I used 2N5210. They can all be 2N5088, 2N5089, MPSA18, etc. Don't waste your best transistors here.
I used some fast rectifiers for D4 & D5 to improve the charge pump efficiency. 1N5817 is also a good choice.
I used TC7662 for IC2, it is slightly more efficient that the usual suspects.

A note about the LED & LDR.
I used a frosted white LED. It's very bright even at low current. It turned out to be overkill. The LDR I used is in a TO-18 can, obtained from Electronic Goldmine. They were dirt cheap on sale, like 40 cents each. One ot two stinkers in the bunch, but the rest went from under 2K (illuminated) to over 2Meg (dark). Cadmium Sulfide LDRs have a quick response to light, their resistance drops in a few milliseconds. Their response to dark is much slower, over 100ms to get from 2K to 500K. The more light that hit them, the longer it takes for the resistance to go up. That's why a bright LED isn't always a good thing. I find it best to set the ATTACK at 8:00 or 9:00 so the peak LED current is less and the release is quicker.
 

Chuck D. Bones

Well-known member
It's a funny thing about cutting traces: when you're doing a repair and you don't want the trace to lift, it does. But when you're doing a mod and you want to cut a trace, it's robust as Hell! Takes a fair amount of pressure with the Exacto knife to get it to cut. These boards are well made and it really shows. I always make 2 cuts 1 or 2 mm apart and scrape out the bit between the cuts. Otherwise, one little sliver of copper will rejoin the two sides.
 

PedalPCB

Administrator
Staff member
Just to clarify for those at home just tuning in, these are not PCB defects. These are design "issues" that are also present in the original pedal, the PCB is true to the original circuit.

Now with that out of the way, maybe we should work up a Chuck's Boneyard Edition Delegate PCB so folks who want to try these mods don't have to start cutting things. :ROFLMAO:
 
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Chuck D. Bones

Well-known member
Just to clarify, these are not PCB defects. These are design "issues" that are also present in the original pedal, the PCB is true to the original circuit.

Now with that out of the way, maybe we should work up a Chuck's Boneyard Edition Delegate PCB so folks who want to try these mods don't have to start cutting things. :ROFLMAO:
Jawohl, Herr Kommandant!

Absolutely correct on both counts.

Col. Klink & Col. Hogan.jpg
 

Gordo

Active member
Chuck, honestly my man, you never cease to amaze me. I need another comp like a lack of social distancing but I might score this thing just to try the mods. Good note Bugg that this is "modding" and not correcting problems. I got all old school a few days ago and etched and built up Bajaman's LA2A limiter and is certainly worth a look-see. The Constrictor is my fave comp to date and the Closed Circuit is a regular on my rig and the LA2A (no it's not that good) take on Bajaman is a very cool. I'm definitely in the opto camp when it comes to dynamics and just a couple of knobs gives me less option anxiety but always up for new gear. Thanks for your posts.
 

jubal81

Active member
Excellent work, Chuck! I hadn't looked at this before, but it's a definite WTF were they thinking?

Looks like they have Q1 set up like it should be a JFET, which I believe you could pop in there without changing anything else. Good old 5457 would do the trick.

I'd also change the charge pump from a doubler to bipolar - fewer parts and GND makes an excellent VREF.

Another change I'd make is using a non-inverting stage on the output with a passive volume control. This would make the input and output phase match. Could also ditch that tone control and put a treble boost on the now non-inverting output stage.
 

Chuck D. Bones

Well-known member
All good ideas. Q1 is fine as a bipolar, it's just a phase splitter in this circuit. EQD definitely missed the boat on how they implemented the charge pump, should have been an inverter like you said.
 

Chuck D. Bones

Well-known member
I need another comp like a lack of social distancing...
I was of the same mind. I have a Boss CS-3 which I (knowing) bought broken for $25. Replaced the blown chip and put in the Monte Allum mods. It's a great compressor: smooth, transparent, quick and sustain for days. Then I heard the demos for the Warden and had to have the Delegate.
 

Barry

Well-known member
I was of the same mind. I have a Boss CS-3 which I (knowing) bought broken for $25. Replaced the blown chip and put in the Monte Allum mods. It's a great compressor: smooth, transparent, quick and sustain for days. Then I heard the demos for the Warden and had to have the Delegate.
I had a buddy that bought the Allum mods for a BD2, H20 I think it was, he got half way done and gave up on it, sent it to me and I finished it up and fixed his goof ups, sounded pretty good
 

cooder

Active member
Excellent and very interesting stuff, great guys! Would be great to see the updated schematic to follow and understand the description through for the not so quick switched on peeps here like me...
 

K Pedals

Well-known member
This post describes the mods in the Col. Klink.
The EQD Warden is a good optical compressor. Basic design is mostly sound, with one major defect, one minor defect and a few opportunities for improvement. Parts of this design were lifted from the Ross compressor.
Major Defect
The signal path is routed through Q1, where is gets distorted by the non-linear loading from D2 & Q3. This is easily corrected by disconnecting C14 from Q1-E and connecting it to IC1 pin 1. You can do this on top of the board simply by lifting the + lead of C14 out of the pad and running a jumper to the end of R5 closest to IC1. I did it by cutting and jumpering on the bottom of the board. If you're not experienced in trace cutting, then do the mod on the top of the board.

View attachment 4365

Minor Defect
The bottom end of the TONE control is useless. I don't know about you, but I have no use for a treble cut in a compressor. A little treble boost brings the sparkle back that gets lost in compression. The stock tone control is flat at about 8:00 or 8:30 and below that cut treble. At 7:00 it's a very strong treble cut. Installing a 20K resistor in series with pin 1 of the TONE pot fixes that. Now 7:00 is flat and it's all treble boost above that. You can cut the TONE pot's lead short and install the 20K resistor between pin 1 and the board, or use a solder lug pot like I did.

View attachment 4366

Opportunities for Improvement
1. Q1 biasing. Q1 is biased close to saturation, which reduces its dynamic range. If we correct the major defect above, this mod is less important. However I wanted to maximize the performance of the envelope detector and remove any loading effect from the output of IC1.1. Replace C5 with a 3.3K resistor (stand it up). Replace R6 with a 10K resistor. Do not solder the bottom end (the end furthest from Q1) to the pad, solder it to the next pad over at the end of R7 (also 10K).

View attachment 4367

2. Better component values.
2a. Change R3 to 2.2M, change R1 to 2.2M or larger; I used 4.7M. R3 = 10M makes no sense when R1 = 1M. Change C2 to 100nF, 1uF is at least 10x larger than it needs to be, even with R3 reduced to 2.2M.
2b. Change R4 to 10K for 6dB more sustain.
2c. Change the LEVEL pot from B50K to A50K. Gets unity closer to noon.

Parts Substitutions
This is all very optional. I did it because I had the parts.
Q1-Q3 can be any high-gain NPN transistor. I used 2N5210. They can all be 2N5088, 2N5089, MPSA18, etc. Don't waste your best transistors here.
I used some fast rectifiers for D4 & D5 to improve the charge pump efficiency. 1N5817 is also a good choice.
I used TC7662 for IC2, it is slightly more efficient that the usual suspects.

A note about the LED & LDR.
I used a frosted white LED. It's very bright even at low current. It turned out to be overkill. The LDR I used is in a TO-18 can, obtained from Electronic Goldmine. They were dirt cheap on sale, like 40 cents each. One ot two stinkers in the bunch, but the rest went from under 2K (illuminated) to over 2Meg (dark). Cadmium Sulfide LDRs have a quick response to light, their resistance drops in a few milliseconds. Their response to dark is much slower, over 100ms to get from 2K to 500K. The more light that hit them, the longer it takes for the resistance to go up. That's why a bright LED isn't always a good thing. I find it best to set the ATTACK at 8:00 or 9:00 so the peak LED current is less and the release is quicker.
Amazing work!¡!
 

music6000

Well-known member
Clever Build Chuck!
Maybe the Warden should have been labelled a Depressor.
I have had a Cmatmods Deluxe Compressor on my Board for close to 10 years & it will still be there for many more to come!
 
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