SE ICIS mod

[B.A.D]

Hi there, I am trying to mod my SE Icis (the version wth -10 db pad and low cut) for higher SPL, so that i can record tenor sax. On alto sax and with the original tube, the icis is fantastic. Like, the alto sax mic. Too bad i do not have the test recordings i did some time ago. However, on tenor sax, it distorts quite a lot, and the -10 db pad doesn't help much.
The original tube is a chinese12ax7a, so i changed it with a jan philips 5752- a lower gain tube, and while it sounds very pleasant on my voice, alto sax sounds kind of lifeless, lacking low end. I haven't tried it on tenor sax yet. I guess because of the lower gain tube i need a transformer with lower turn ratio, but i don't know what turn ratio is the original one.
Does any one know ? Any help and ideas are greatly appreciated. Thanks in advance
Please keep in mind that i am "electronically challenged"

 

[Khron]

If high SPL is an issue, then the noise floor should not be much of a concern - as such, dropping the bias voltage going to the capsule should be a simple enough first step.

 

[B.A.D]

I just don't know how. Please tell me witch component to change, if you can, and the values too.
I know i am a pain with my ignorance...but this is a good way to learn something. Thanks

 

[Khron]

Well, considering i was not even aware this mic existed before seeing this thread, even *IF* i was able to tell you the "role" of the component(s) needing altering, that probably still wouldn't help you much (by your own admission).

I don't suppose you've considered at least posting some photos with the guts of the mic, at least..? Assuming / since i / we can't expect you to trace out the circuit...

 

[rock soderstrom]

Hey Khron, is your crystal ball broken?

Khron@work:

Crystal ball is broken now...

I mean really broken!!

 

[Khron]

Hey Khron, is your crystal ball broken?

No, I grew up poor, so i never had one :'(

 

[rock soderstrom]

No, I grew up poor, so i never had one :'(

DiY?

 

[Khron]

DiY?

Nah, i'm not quite that big a fan of polishing (my) balls... But back to the topic at hand..? (If you'll pardon the unfortunate wording)

 

[rock soderstrom]

But back to the topic

Unfortunately, all the graphics in this thread are no longer available...life could have been so easy.​

Thread 'SE Icis Condenser - Schematic And Photos' https://groupdiy.com/threads/se-icis-condenser-schematic-and-photos.30017/

i guess we need photos..

 

[B.A.D]

Here are some photos

 

[B.A.D]

Also, the bridging on photo number 2 was not done so good. It was very fragile and burning into the plastic. I added some solder, but didn't have the right solder iron, so now it looks terrible, and still burning into the plastic. I am aware of that, and will do a better job when i finally get the tools i ordered from AliExpress. In any case some little noise did go away...i believe.

 

[rock soderstrom]

Here are some photos

The circuit could be based on the CCDA head amp of the Apex 460.

Compare it with this schematic
.

 

[zero23]

I too have an old icis that i fiddled around with for much the same reasons, this mic can sound great for a female vocal but lacks body for anything else, I got it sounding a little nicer with a mullard ecc81 and a component upgrade, but still no great change in its voicing, still bass shy. I thought about changing the capsule but, for what its worth, i bought a different mic. it's a one trick pony.

 

[rock soderstrom]

There is some good information in the linked thread despite the lack of graphics.

If you want to mod the mic we need the schematic of the actual state.

 

[B.A.D]

I too have an old icis that i fiddled around with for much the same reasons, this mic can sound great for a female vocal but lacks body for anything else, I got it sounding a little nicer with a mullard ecc81 and a component upgrade, but still no great change in its voicing, still bass shy. I thought about changing the capsule but, for what its worth, i bought a different mic. it's a one trick pony.

Yes, i hear exactly the same thing. Very pleasant on a voice after changing the tube, but still no body. I tried it on female voice with a Genalex gold lion 12ax7- a very high gain tube. It worked nicely, sounding wide, and it takes eq well, but forget about anything loud. No sax with this tube
I do have an rk47 capsule form microphone parts, witch will give it some more body, but don't feel like installing it, unless i know that i can improve the SPL.
I have the feeling that a good transformer, with more of it in the overall sound of this mic will help with the body problem, and perhaps the SPL a little.
What components did you change? Do you happen to know the turn ratio of the transformer? Thanks in advance.

 

[B.A.D]

There is some good information in the linked thread despite the lack of graphics.

If you want to mod the mic we need the schematic of the actual state.

I emailed se electronics a long time ago, but didn't get a replay. I will try again.
I have read the thread, but will read it again now Am i correct in thinking that a lower gain tube and a transformer with a lower turn ratio will give it more transformer sound? Thanks again for the effort