Alctron CP540 Neve 2254/33609 Clone

This guy has arrived. It sounds amazing. I thought i could share some gut pics. Any idea for mods? It seems to be identical to GAP Comp54.

doesn't that have an ac wall wart?

They got warts.

Here's the video. I demoed it with pre73eq

How is the distortion when compressing a 40 Hz tone?

It depends on gain staging. If not pushed hard on the input it's fine and still compress a lot. Otherwise it can get pretty crunchy. As far as i know these Neves are known for saturating things, low end especially, even my software plugins do it. Unfortunatelly, i don't have original hardware to compare. I guess one can experiment with transformers. I actually prefer these over software because pretty non linear saturation. I guess i could try at least to try different input transformer.

Thanks.
I asked this, because I did some measurements on an original Neve 33609 compressor, and I found the following figures:

Compressor, 50 Hz, 6 dB gain reduction

100 mS - 2,66% THD
400 mS - 0,84% THD
800 mS - 0,49% THD
1500 mS-0,33% THD

Wow, thanks i will check it out! What is your input signal? 0 db 50hz? Or better, how many volts?

I think I used 1 volt as input signal. Ratio was 6:1.

I'd be interested to hear any more info or opinions on these.  Very tempted to pick up a pair but the low price makes it seem like a "too good to be true" kind of scenario.

nothing a different chassis can' t fix. I would also ditch the wallwarts  and a few things?

Matt C said:

I'd be interested to hear any more info or opinions on these.  Very tempted to pick up a pair but the low price makes it seem like a "too good to be true" kind of scenario.

Click to expand...

Well the price is officially 500 dollars. I got lucky with these samples. They are pretty much Golden Age models, as Alctron makes them as far as I know. I ordered two output Carnhils for both, and plan to have both output transformers inside and do proper tests and null tests to see what Carnhill actually does.

Some guys suggest changing electrolytics to  tantalums, as they were used in original Neves. However I am bit puzzled, as a lot of people change tantalums for regular ones in other gear. Have no idea honestly.

The thing sounds great stock anyways, I just thought it would be great idea to have different trany inside available with a flip of a switch for different flavor.   

Geoff Tanner, one of the Neve designers, always says 'do not replace the tants!!!'
("Those tants aren't there without a reason")
I know that opinions differ, but it seems they do change the sound.

is it the coupling caps in the originals that were tantalum?

I have "upgraded" output transformer to Carnhill with switch to go back to stock.

Huge difference? No. Better? No, rather slightly different flavour.

Carnhill has more low end, but just a tad. In the subs for the most part, 30-50hz.

However, stock Chinese is cleaner and has less distortion. Carnhill distorts sooner in the low end. Stock starts to saturate obviously when VU peaks at +8db, Carnhill at +4. Chinese has better high end response.

Coloration comes probably from harmonics, as both transformers have flat frequency response. These differences are hardly audiable, i had to perform null tests and loop 500ms of audio material on kick drums, hi hats, whole arrangements and switch back and forth to hear any difference.

I actually get almost the same effect when i send/return signal through Carnhill from my DAW and back into converters. This makes it great and cheap "warm" passive element. Sounds totaly different when primary and secondary are swapped tho. Reversed it makes +3 db bump at 40hz. But that might be interraction with Carnhill, input and output of my converters.

am i wrong , or seem that it is no longer available ?

Can anyone conform based on the pic of guts in the first post if this could be Igor's 2254c?

Looks remarkably similar. I can't find Igor's schematic, does anyone have it? By the way, is GAP Comp54 actually Igor's schematic?

I found Igor's schematic, and even though there are some differences it seems like the same thing. I will dig deeper when i get some extra time.

@Ruud, i was a bit slow with THD measurements, but i did get scary similar results.

100ms 2.79%
400ms  0.81%
800ms  0.428%
1500ms  0.368%

Even though it doesn't show, the cursor was placed at 50hz. I used soundcard and REW.

Thanks for the THD measurements! They show more or less the same as the 33609.
IMHO a distortion level of 0.81% @ 400 mS is high.

kingkorg said:

Can anyone conform based on the pic of guts in the first post if this could be Igor's 2254c?

Looks remarkably similar. I can't find Igor's schematic, does anyone have it? By the way, is GAP Comp54 actually Igor's schematic?

Click to expand...

Igor hybrid 54-609 seem no limiter section included
and the electron seem very similar
cheers