SE Electronics Z3300a

The SE Electronics Z3300a is often brough up in forums as being similar to a Neumann U47 FET.

How close do you think it would be with a Peluso CEK47 capsule? Maybe a transformer change too?

I modded a couple of Alctron mics (the same one as the Apex 460) with Cinemag transformers, Mullard tube, Dale resistors and Black Gate and other high end caps and they sounded great. I used them for a while like that and when I scratched together a few more £££'s I swapped the capsules for CEK12's and now they are truly awesome.

Pop it open and take some photos. I'm doubtful it would be in the same league as a Neumann, but it might be worth a look.

The capsules they use are not necessarily bad.

I don't have a Z3300a but I know they go really cheap used and the Peluso capsule I used in my other mics were excellent.

I've got a Z3300a. I'll post some pics of the innards tonight. I'm looking at the cinemag mic trannies, but I wouldn't know how to pick the right one, aside from the fact that it needs to be center tapped for phantom power. The choices are

CMO-5/200CT          5K:200CT (5 : 1)
CMO-2.65/200CT      2650 : 200 CT (3.64 : 1)
CMO-15/100CT        15K : 100 CT (12.2 : 1)

I do know the mic has a superhot output, so I'm thinking if I pick a tranny with a lower output, then I could probably get rid of the -10dB pad... Am I going in the right direction?

And I couldn't find any info about a CEK 47 capsule. Perhaps you meant the CEK 367?

I'm very much in doubt concerning peluso capsules. I know a guy who measured them in comparison to the chinese original and they spec the same, same curve same sound. I think the chinese capsules are pretty good. I mean some of them are very good ! I'm german, and typical for a German i don't have much patriotic feelings. I picked up a Gefell/Neumann mv691 with a m70 capsule. I changed them to 48 Volt. Either my capsule is shit or the m70 is crazy overrated, a chinese capsule from a mca sp1 sound better with the same curcuit.

btw the dale m7 sound very good !
nicholas

nicholas

  I have 3 m70 Ni capsules and three 48v modded 692 bodies.  Two of my m70s sound very good the other is bad.  I opened the capsule of the bad one and saw pinholes in the Ni diaphram and the the Ni was discolored.  It might be you have a bad capsule.  Can you borrow one to test?

Gus

Microtech Gefell and Siegfried Tiersch both do reskinning of those capsules.
(Maybe you already know, but anyway...)

The capsules you buy over eBay often have these small holes, seems to be an age thing.
The good ones I bought there were all Tiersch reskins.

It's the same problem with the other Gefell nickel capsule (M94) as well.

I find the M70 super on acoustic guitar and violin for example.
M94 I use as overhead or for distant miking.

Just for clarity in this thread:

M70 is a small nickel membrane capsule for the Gefell range of mic bodies (MV690, 691, 692)
M94 like M70 but with more hights.

Hope this helps,

Anders

I also found the Gefell SDC capsules (which I think are M70) in my PM750 and PM860 to sound nice.

The SE capsules seem to be ok from what I have heard so far, since I haven't heard a bad one yet.

jonesy said:

I do know the mic has a superhot output, so I'm thinking if I pick a tranny with a lower output, then I could probably get rid of the -10dB pad... Am I going in the right direction?

Click to expand...

Yes, as far as considering not over-driving a mic input is concerned. However, that's what mic preamp pads are for. The pads on mics allow you to drive more level in the mic amp circuit which will distort at a certain level (possibly before the transformer which will maybe overdrive in a more acceptable way).

The capsule in PM750 is actually a kind of M94.
You can actually use them on the other mic bodies in the SMS70 range but the'll be
oversensitive to loud sounds (use a pop filter) or connect a 10MOhm resistor between the backplate
and capsule housing just like in the real M94.

The capsule in PM860 is a totally other thing, difficult to use outside the mic body.
Its not a closed capsule housing and hums loud used elswere.

Roddy, did you try with other mic bodies?

Sorry if this is too off topic.

Regards,

Anders

By the way, the mic sounds pretty darned good as-is. I consider it a solid step up over the bottom feeders, but I've never heard any high end mics in action. IMO the problems with it are that its a little boxy in the low mids, and the highs can get sizzly. Its sitting right on the edge of very nice, though, and I'm thinking a key upgrade or two might take it over the top. I'd be interested to hear you guys' take on the innards. Anybody got a schematic?

ok, I  opened th m70 now. Doesn"t look so bad though. I"m going to clean the capsule and keep you posted. Thanks for the help.

Anders, When I ordered the reistors maybe we meet and check

nicholas

Without a schematic it's hard to make recomendations. But I'll tell you what I think I see on the pictures.

The PCB side on your first pictures is the DC converter part. The small metal box is probably an inductor or autotransformer. For pattern switching the diaphragms and backplate must be polarized properly. Usually that means that the front diaphragm is at 0V, the backplates for both halves (in most dual diaphrgm capsules the backplates are connected) are at 60V and the rear diaphragm is polarized at 0V, 60V or 120V for omni, cardioid or figure eight. Which means you have to generate up to 120V. That's what the rear PCB does.

The Front PCB is the acutal mic amplifier/impedance converter circuit. It is a two transistor circuit like in most chinese microphones. The first one (in the metal housing) is the FET input, the second one is a bipolar transistor in emitter follower configuration. The emitter follower output stage allows them to use a low inductance/low step down ratio transformer, which is cheaper than a good high step down ratio transformer that you'd need for a single FET circuit as found in classic FET microphones from the late 60s or early 70s.

Theoretically the additional bipolar output stage is a good idea. The way it is usually implemented (think MXL2001 circuit), it doesn't sound very good, though. I don't know about this mic.

Another issue is the use of a K67 style capsule without HF compensation. The K67 design has an inbuilt treble boost, which is supposed to be compensated by the mic electronics. That's how it is done in the U67 and U87 mics, for instance. Do a forum search, there were several threads about it.

While the capsules aren't quite the same quality as the ones from leading European manufacturers, I think the weakest part in SE mics is their amplifier electronics. The SE mics I've used so far were quite noisy, too.

Hey Nicolas!

DONT CLEAN THE M70 CAPSULE!

You'll destroy the extreme thin nickel membrane in no time.
(I did it myself once so I know) 

Careful blowing away dust may work.


Take care,

Anders

Sredna said:

The capsule in PM860 is a totally other thing, difficult to use outside the mic body.
Its not a closed capsule housing and hums loud used elswere.

Roddy, did you try with other mic bodies?

Click to expand...

Thanks for the info. I don't suppose anyone knows how to open the PM860 capsule? Mine seems dead.

I'e not had a chance to use the capsules for the PM750 mics on any other bodies. They sounded good though - plenty of treble without sounding harsh.

Interesting pictures

Compare the circuit to a schematic of a u87ai.  The DC to DC section uses a BJT and a FET and the amp section uses a BJT in the power supply section and a FET gain stage.

Can you take better pictures of both sides of each board and mark up the part values on the picture?

Do you know how to get the transformer ratio?  Disconnect one end of the primary side of the transformer from the PCB If you have a signal gen set it to say .100VAC at 100Hz and 1KHz then measure the output voltage.  The ratio is the output over the input voltage

The hole pattern looks like a 87 capsule pattern as best I can tell

Might be a copy of a 87 circuit

Gus said:

Can you take better pictures of both sides of each board and mark up the part values on the picture?

Click to expand...

Will do, sometime over the weekend. I've got a session tomorrow night, so probably won't be before then.

Gus said:

Do you know how to get the transformer ratio?  Disconnect one end of the primary side of the transformer from the PCB If you have a signal gen set it to say .100VAC at 100Hz and 1KHz then measure the output voltage.  The ratio is the output over the input voltage

Click to expand...

Well I don't have a multimeter yet (or a signal generator), but I'll see about getting one soon.

Gus is right, component-wise this could indeed be a U87AI knock-off.

On the other hand, the high output speaks against this theory (depending on what you'd call high output) and with the U87 HF compensation, this mic should not be overly bright. But then again, maybe they liked the very bright sound of the capsule and left the HF compensation out.

Yes pics of both sides of the PCBs would be useful in determining what this circuit is and how it could possibly be improved.

BTW: Here's a library of mic schematics: http://www.sdiy.org/oid/mics.html

15 years later and I have a similar challenge. Let me know what you think. I own an sE z3300a and I want to use the mic body and some of the components in order to make it into a Rode Classic 1, FET version, since.the sE is already a FET mic. I want to get it to sound like 95% of the sound of the Rode Classic 1, knowing that it doesn't have the Jensen transformer of the Rode or its Tube. I don't mind the mic staying a FET mic and don't really like any other of the Rode mics except the crispy high Classic 1, but I don't want to break the bank in buying an expensive Rode Classic 1, either. Can capturing the Classic 1 sound be done by just using the Rode Classic 1 capsule via a capsule swap? (See photo) The sE capsule is the center-terminated 67 type I think, and the Rode is the edge-terminated one. I also included photos of both frequency responses in Cardioid mode. Looking at the responses, they look similar but the Rode seems to have a 2db presence boost from 5-7 kHz. Let me know what you think I can do. Thanks!

jonesy said:

By the way, the mic sounds pretty darned good as-is. I consider it a solid step up over the bottom feeders, but I've never heard any high end mics in action. IMO the problems with it are that its a little boxy in the low mids, and the highs can get sizzly. Its sitting right on the edge of very nice, though, and I'm thinking a key upgrade or two might take it over the top. I'd be interested to hear you guys' take on the innards. Anybody got a schematic?

Click to expand...

Did you ever end up modding the sE z3300a?