Ashly CL50E - restoration / upgrade - any idea?

[ln76d]

I've already recapped most of electrolytics in my CL50E. Only 1.5uF, but they're pretty hard to find.

It's great compressor based one 2150A VCA.
Unfortunately 2150A is from unknown producer marked only 2150A 912k SINGAPORE.
Could be any audible difference when change it to DBX or THAT VCA?

I'm thinking to replace tl072CP for soma OPA, but i'm not sure which one will best  for this circuit. Also there are few 4588CP, any idea what "better" i can put in a place of them? Unfortunatelly i have no schematic or service manual.
If someone has, please send me.

Also changing mains transformer for toroidal. Original is on 120V and i need 230V.

Any interesting propositions for mods/upgrade will be very helpful.

(**** you anal.ogguru - dig deeper you pointless creep)

 

[usekgb]

THAT Corp has a design note on replacing the 2150A VCA with a 2180 or 2181.  s for the TL072, you could try OPA2604.  Others people will have different op amps that they like.  I'm attaching the THAT design note to take a look at.

Cheers,
Zach

 

[ln76d]

Thank You Zach!

I was thinking about OPA2604, but i dont know how they would behave in this circuit.
Probably if i not try i will never find the answer
Do You think It can be audible difference with THAT VCA?
Do You think that THAT 2150A from China or Hong Kong can be fake?
I found some on ebay and they're not so expensive.
Anyone tried them?
Same with BB OPA2604 from Honkong or China , anyone have information about fakes?

 

[usekgb]

Replace the THAT 2150A with a 2180A.  This will reduce the distortion in the VCA circuit significantly.  As for the op-amps, get them from a reputable supplier like Mouser or Digikey.

Cheers,
Zach

 

[ln76d]

Ok, i'll try 2180A. Mouser or Digikey unfortunately will be unprofitable for me, because i live on a different part of globe. Shipping costs are too high. I'll buy from my local seller, costs twice but i hope i'll buy genuine.

 

[ln76d]

I've found on the net some info, that UA7915C and UA7815C (both on my psu) are not the best option, that they sounds bad...
What do You think guys?
It's there any simple option to replace them with something better, if they really "sounds bad"?

Second thing are 1,5uF electrolytic capacitors - two on PSU, two on compressor board.
Since there i cannot find them, could i use 1uF electrolytic with parallel  56nF mkp/mkt/styroflex capacitor?

 

[abechap024]

I've found on the net some info, that UA7915C and UA7815C (both on my psu) are not the best option, that they sounds bad...
What do You think guys?
It's there any simple option to replace them with something better, if they really "sounds bad"?

Second thing are 1,5uF electrolytic capacitors - two on PSU, two on compressor board.
Since there i cannot find them, could i use 1uF electrolytic with parallel  56nF mkp/mkt/styroflex capacitor?

Hi,
DONT worry about changing the power regulators (7915, 7815). They just smooth the power they do not have a "sound" (outside of hocus-pocus audiophoolery sell you a 1000$ RF psycho-acoustic inducing wire circle)

Also you do not need to replace 1.5uf with 1.5uf. UNLESS it is in the sidechain circuit timing circuit. but probably replace all of them with 10uf or better if they are in the audio path blocking DC. Or you can upgrade the opamps to DC trimmed ones and omit them completely. The timing cap is easy to locate once you have the schematic.

 

[ln76d]

Thank You for reply!!

Hi,
DONT worry about changing the power regulators (7915, 7815). They just smooth the power they do not have a "sound" (outside of hocus-pocus audiophoolery sell you a 1000$ RF psycho-acoustic inducing wire circle)

So i was thinking good about that

Also you do not need to replace 1.5uf with 1.5uf. UNLESS it is in the sidechain circuit timing circuit. but probably replace all of them with 10uf or better if they are in the audio path blocking DC. Or you can upgrade the opamps to DC trimmed ones and omit them completely. The timing cap is easy to locate once you have the schematic.

Since i have no schematic, is truly hard to guess do they can be with higher values or not.
I wrote to Ashly, do they can send me service manual or schematic. Now i'm waiting.
I was thinking to replace them with 2.2uF.
I bought OPA2604 to replace tl072 and a new 4558 produced by JRC.
If i get schematic it will be easier to replace 2150A VCA to the newer one.
Now i'm confused, what do i need to change. THAT info's little bit incomprehensible for me right now

 

[abechap024]

The 2150 VCA has a sound all its own. If your going for "clean" I would switch to the 2180, but really the 2150 doesn't sound so bad especially considering the distortion is mostly second harmonic. Plus there is a bunch of confuzing crap about this and that resistor needing to be changed.


fortunately, if you can't get the exact schematic for this unit, each VCA compressor is essentially the same thing...Do some diggin on THAT application notes (go to their website) unfortunately its too much to try to explain here, and its been explained so many other times, and better than I could!

Basically you have your audio input circuity, then the audio splits and goes to the VCA and the RMS/Sidechain circuitry. The VCA side it goes to the VCA and then to the output, or makeup stage if they don't use the VCA for makeup gain (they probably do) the audio signal flow is super simple. IF you can trace that you know what capacitors you need to change to 10uf, 22uf, 47uf, 100uf however much your wallet and space can handle.

Sidechain it goes to some sort of circuitry that splits the AC sound into a DC voltage using diodes and opamps of some sort. (or if its really old school ; transistors) then it goes to the attack and release controls, makeup pots and then into the VCA control pin.

Hope this helps and haven't confused you more!

 

[ln76d]

The 2150 VCA has a sound all its own. If your going for "clean" I would switch to the 2180, but really the 2150 doesn't sound so bad especially considering the distortion is mostly second harmonic. Plus there is a bunch of confuzing crap about this and that resistor needing to be changed.


fortunately, if you can't get the exact schematic for this unit, each VCA compressor is essentially the same thing...Do some diggin on THAT application notes (go to their website) unfortunately its too much to try to explain here, and its been explained so many other times, and better than I could!

Basically you have your audio input circuity, then the audio splits and goes to the VCA and the RMS/Sidechain circuitry. The VCA side it goes to the VCA and then to the output, or makeup stage if they don't use the VCA for makeup gain (they probably do) the audio signal flow is super simple. IF you can trace that you know what capacitors you need to change to 10uf, 22uf, 47uf, 100uf however much your wallet and space can handle.

Sidechain it goes to some sort of circuitry that splits the AC sound into a DC voltage using diodes and opamps of some sort. (or if its really old school ; transistors) then it goes to the attack and release controls, makeup pots and then into the VCA control pin.

Hope this helps and haven't confused you more!

Thank You very much, i really appreciate Your help!

I got schematic from ashly service!
Later i'll add in better quality.
For now i have no much time to check everything, because i'm leaving to gig tonight, so if i'm back on sunday or monday i'll check schematic.
Now it's clear, how's vca is applied in circuit. It's easier to check with THAT instructions to replace 2150 with 2180.
I want to replace my 2150, because it isn't dbx or THAT and looks pretty cheap
There's few things changed in circuit since my CL50E (rev 0).
Quick looking i found changed one IC and few resistors.
Now's more fun

Cheers

Piotr

 

[ln76d]

I checked all differences in my CL50E. I marked them red on a schematic.
Probably it will be good to update my version to higher.
I marked 1,5uF capacitors on green. Do they really can be with higher capacitance in this part of circuit?
In circuit is also one 47uF bi-polar electrolytic cap (marked on blue).
Can i put instead a MKP or MKT capacitor? Do they have no different impedance or something else, what disqualify them?

Returning to the 2150A changing idea!
From the THAT notes i've found, that 2180LB will be best choice. Since is "Trimless" i need to remove R6,R7 and VR6. Do i must change something else too?
What's with other resistors and capacitors values? Should I stick to the values ​​given by Ashly or by THAT in case using 2180LB? For example R11 is two times lower than THAT provided.

 

[abechap024]

Looks like those 1.5uF are part of the release/timing circuit. So you don't want to change the value of those.

For 2180 I would either just put it in, or bend the trim pin out of the way instead of removing all those parts. Also I would get the 2180 and put it in before you start changing parts, and doing tests at each step of the way, that way you know what your changing. Sometimes its a compromise between the original circuitry and whats optimized for the THAT chip. But essentially they are drop in replacements.

If you have a PC download RMAA and do several tests with and without the compression engaged, and then switch the VCA to 2180A (or B) and then measure again.

You could upgrade the 47uf bi-polar cap if it is old to 47uf or a 100uf bi-polar. increasing the value makes for a better low end, though 220uf is probably as high as you would want to go and it isn't a huge difference.

 

[ln76d]

If someone has this compressor i really recommend to make restoration and upgrade!
What i did:

- changed all electrolytic capacitors for new one (huge improvement)
- changed three tl072 for opa 2604 (huge improvement)
- updated IC2 to JRC 2043 (positive audible difference)
- changed VCA 2150A on 2180LB (maybe not huge but positive and a little audible difference)

I've also changed all ceramic capacitors for NP0 type (it's only few), all 4558 to JRC4558DD, new toroidal power transformer with higher power, updated values of resistors to the newer version from schematic.

All in all, this compressor got new life! Sounds fantastic and clean!
Before surgery I liked it but now i love it
Really worth!

Thanks for all help!

 

[leigh]

I know this is an old thread, but I've gotta say thanks to Piotr for the mod ideas. I've had an Ashly CL-50e for about five years, and had never thought to crack it open. It's got a solid sound, but didn't really do much impressive in the "color" compression department, so it didn't see a lot of use.

I listened to a number of possible changes, but my mods wound up being pretty basic in the end. For the record, I have a Rev. 0 model, dated 5/89. In mine, IC201 (the input amp on the separate "jack card" PCB) was an NE4558. IC2, the only other chip in the main signal path besides the dbx VCA, was a TL072.

In general I don't go too crazy with opamp chip swapping, but with the specs on those chips, I figured they could be easily bested. (The NE4558, for example, specs as 2MHz bandwidth, 25 nV/√H input noise, 1 V/µs slew.) I wound up swapping both those ICs for an MC33078, chosen mostly because it was one of the few decent-for-audio dual opamp chips I had lying around.

I also tried swapping the dbx 2150A VCA chip for a THAT chip of the same model number. Differences were (as you would hope) extremely subtle, but I wound up thinking the dbx VCA sounded a little better, so I swapped it back in (and yes I re-set the VCA trim pot for minimum output THD each time I put in a new VCA chip).

At each step, I made test recordings of the changes. It's been a few weeks, so I'm probably ready to go back and listen more objectively now. If any differences seem surprisingly drastic, I can post some audio clips here.

cheers,
Leigh

 

[leigh]

Oh, and one more note about this Ashly compressor - I was impressed by how solidly it was built, and how easy it was to work with.

For DIY'ers wanting to experiment with designing VCA sidechains, the CL50E makes a perfect platform! As I mentioned, its style of compression always struck me as utilitarian, and not very colorful. But for cheap, you can pick one of these up, and the case, power supply, audio path, etc. is already in place for you. And there's a ton of empty space within the box, to add an additional circuit board. So, you could tap the input signal, run your own sidechain circuit, and then switch your own control voltage to the VCA chip, to play around with different sidechain designs.

 

[ln76d]

Try the THAT 2180, in my unit it was a really good improvement.
I think the next good step for this compressor could be 1:1 output transformer