Superlux S502 MK2 test, teardown and improvements

[Recording Engineer]

This looks like a CMC6 clone, doesn't it? Anyone tried it?

View attachment 140345

https://a.aliexpress.com/_EzfjgHJ

Well I just now ordered pair… I want the bodies! Some M221b-inspired mics with Schoeps MK22 capsules might be fun! AMI T28 seems to be the only available option for these.

 

[bremusound]

So the question now is: who knows a commercially available black SDC with 20mm body, made by 797 Audio?

Jan

Studio Projects C4

 

[SubSpec]

Well I just now ordered pair… I want the bodies! Some M221b-inspired mics with Schoeps MK22 capsules might be fun! AMI T28 seems to be the only available option for these.

Definitely let us know, I'd been eyeing those too, interested to hear how they are

 

[Emmathom]

I think it has been discussed on the forum : a very good solution is Takstar CM63 + 3UAudio capsule(s) > 42€ + 120€ to get a really nice cardio SDC...

@Recording Engineer let us know please when you receive the 92€ Ali SDC mic (Schoeps look) and how it sounds with the chineese original caps.

 

[jp8]

I think it has been discussed on the forum : a very good solution is Takstar CM63 + 3UAudio capsule(s) > 42€ + 120€ to get a really nice cardio SDC...

Sure! There are a number of really usefull mods described in this thread, nicely summarized by @Voyager10.

You specifically mentioned to pair the CM-63 with the 3U capsules, but it yields a slightly different tonality when compared to the CM-60 + 3U combo, which I liked better. It's a bit flatter in the highs. I assume the differences are caused by the different back chamber and slots design. I'd suggest to also consider the Alctron T-02A instead of the CM-63, which I expect to sound identical to the CM-60.

You can hear the tonal differences in @joulupukki 's Blind Test (link below). Though both the CM-60 and CM-63 have slightly different KM84 style circuits, both circuuts are dead-flat in the highs, so I'd reason that tonal differences in the highs should be caused by the capsule/body combination.

Thread 'Four KM-84 Clones - Blind Test' https://groupdiy.com/threads/four-km-84-clones-blind-test.89135/

Having done the KM84 "project", the S502 Mk2 capsule similarities with a Schoeps MK4 triggered me to pick up cloning a CMC6 MK4 as the next project. Just not with a standard Schoeps circuit, but my own.

Jan

 

[Emmathom]

@jp8 your DIY seems very attractive... so after a "Jan S502 special circuit" we'll have a "Jan Schoeps custom build" ?

Great ! Oh, I forgot Xmas is approching (Santa Jan)

 

[jp8]

@jp8 your DIY seems very attractive... so after a "Jan S502 special circuit" we'll have a "Jan Schoeps custom build" ?

Great ! Oh, I forgot Xmas is approching (Santa Jan)

Thanks a lot for the kind words, @Emmathom !

The "S502 special circuit" should be credited to @MicUlli , though. The circuit that I had in mind for the Schoeps MK4 clone SDC has charge amplifier input, CMOS polarization voltage generator and improved Schoeps output stage. Not a 100% Schoeps clone. Has more headroom, somewhat lower noise and THD compared to the "standard" Schoeps circuit that we all know.

Jan

 

[Emmathom]

Thanks a lot for the kind words, @Emmathom !

The "S502 special circuit" should be credited to @MicUlli , though. The circuit that I had in mind for the Schoeps MK4 clone SDC has charge amplifier input, CMOS polarization voltage generator and improved Schoeps output stage. Not a 100% Schoeps clone. Has more headroom, somewhat lower noise and THD compared to the "standard" Schoeps circuit that we all know.

Jan

So, a kinda "to-do list" :

- use my S502 capsules for your DIY Schoeps circuit (but the right body has to be found for that) > what to do then with the mic without its capsules ? Waiting to find a mic out-of-order and use the capsules maybe...
- buy a S502 MkII and replace the original circuit by @MicUlli one (about 145€ + 35€)

Maybe resell my WA84 pair to finance that ? (lowest price brand new is 606€ so I could resell ~500€)
or keep them

 

[RCAguy]

This looks like a CMC6 clone, doesn't it? Anyone tried it?

View attachment 140345

https://a.aliexpress.com/_EzfjgHJ

Here’s a more readable response with the cardioid capsule - typical bass boost from proximity, but ragged >10kHz.

 

[Emmathom]

Here’s a more readable response with the cardioid capsule - typical bass boost from proximity, but ragged >10kHz.

Woa, a serious peak around 12kHz (+10dB !)

 

[MicUlli]

Hi All,
The S502 "repair kit" circuit schematic is now finished. Here is the circuit...
If you have a 502 1st version a lot of components become superfluous (the dcdc-converter is not needed)...

 

[Emmathom]

Hi All,
The S502 "repair kit" circuit schematic is now finished. Here is the circuit...
If you have a 502 1st version a lot of components become superfluous (the dcdc-converter is not needed)...

Hi @MicUlli
So for the S502 1rst version please tell us which components not to install.
But if I order 2 full kits I'd like to get all components for both boards in case of... (I could resell my 1rst version to buy a MKII)
Regards

 

[RuudNL]

for the S502 1rst version please tell us which components not to install.

Yes, that would indeed be good to know. (I have both versions)
I suppose the DC converter can be omitted.
Probably a link between the connections of the four 330K resistors and Vpol???

 

[MicUlli]

For the MK1 version components R9..R13, C8..C14, D3, D4 and T3 can be omitted. The MK2 version requires all components. Find attached a first picture of the board..
Regarding the components:
1. all resistors are thin film 1% 50ppm,
2. ceramic caps are of type C0G(NP0) 50V, exceptions are C13 and C14, which are of type X7R 50V,
3. elcaps are mounted on the bottom side of the pcb, size 5x11mm.

 

[jeremynothman]

View attachment 140392
Here’s a more readable response with the cardioid capsule - typical bass boost from proximity, but ragged >10kHz.

I especially like "Phase no good"