T-bone sc400/sc600 Mod

Hello,

I started a precious post about modding a T-bone sct2000 and i got very great answers !

Though i've been kind of holding back to the mod and instead buy a cheap mic and mod until i understand things better and get something good out of it.

On Thomann.de there are those two microphones :

Sc400 : 57 euros

the t.bone SC 400 large diaphragm studio microphone with 6dB 100Hz low cut switch, Frequency Response: 30 Hz - thomann 20 Khz, cardioid, 48V Phantom Power required, Includes shockmount and soft case.

Sc600 : 77 euros

the t.bone SC 600 large diaphragm studio microphone - 1" diaphragm, 48 V phantom power needed, cardioid and thomann omnidirectional patterns, 30Hz-20kHz, max. SPL 138dB, 200 ohms, 100Hz/6dB lo-cut switch. Includes: shockmount and bag.

Reading a lot from Groupdiy i realized that the most important part for sound is Capsule and Transformer.

Many places sell capsule like microphone-parts.com or Peluso or even Dale M7,
though for a cheap alternative which one would you go for?

-I've heard lots of good from the RK-12 capsule that Microphone-parts sells.

As far as transformers :

Do any know which circuit those mics are based on?
I guess if they would be close to Neumann u87 what Ratio transformer would be best?

To get further i will need to place an order and get one of those two mics :
Sc400 or Sc600?

Thank you guys,

I hope to hear from whoever has done mods to these mics already !

Manu

Not familiar with these. The 450 looks more like the typical U87 inspired mics (95 euro) the 400 and 600 are probably similar circuit to the MCA-Sp1/MXL 990/Apex 435 (I think) FET, without transformer, I'm guessing.

I think I posted a genchinamic.pdf of that circuit in another thread. Depends on what you want to do. There are mods to that circuit. (Zapnspark -- I think I posted that as well)  If you do the full mod, you need to replace the FET and rebias. I'm only assuming it is that though, without seeing it hard to know.

The 450 would give you a good platform for a lot of mods, including Royer.

Hello,

I guess 450 then would be a better choice. It looks better manufacturing too !
95 euros is still very reasonable.

I will look at your schematics thanx a lot,
Iäve hard a lot about royer mod, will that be a good alternative or better trying to emulate 87 circuit...

Manu

Depending on what is inside the 450 you have a lot of options. If this is the transformer version (like MXL 2001 or Aurycle 460) you can delete some parts, and change the transformer for a T13 type transformer (AMI T13, Cinemag 2480, Marik 1/10) and get a U87 type circuit. You could replace everything and get one of Poctops U87 clone boards on the next run of them, or one of my Royer boards. I have a few on the black market. You could change the capsule. There are capsules available at a variety of price points.

Edit: http://www.elektroakustika.cz/t_bone_sc450.html

Looks the same as MXL 2001 or Aurycle 460. See matador's aurycle thread.  I do not speak Czech, but the page says Alctron, so perhaps this mic: http://www.alctron-audio.com/encpShow.asp?id=1725

that's an amazing link you found. Great to see what's inside of it.

Yes i will go through matador's aurycle thread and get back to you about it.

I have to check your royer boards too !

Thank you again,
Will get back to you tomorrow

Manu

I looked at the Aurycle thread, very nice built with Dave Thomas capsules...

I was wondering about building a akg 414 clone, with a c12 type capsule...

Would be nice to have a mic in that direction...

It's funny to see how the Aurycle or T-bone schematic is much simpler than a u87 one, though they are supposed to be U87 oriented clones...

There is a lot to do with the T-bone, that's promising...

Manu

If you compare the audio portion of the schematics they are quite similar. I do not know enough to know how the subtle differences matter. much of the complexity is the pattern switching.

85 euro for a 450:

http://www.thomann.de/de/blowouts_GF_mikrofone_HL_blowout.html

Ok !

Yes that one is cheap, though it's customer return, for 10 euros more you get a new one.

I will place my order whenever i can and try to write down a chematic for it !
Manu

How about this Schematic from the MXL 2001, hoping it's the same. What changes should be done to suit a 414 type of mic or u87.

Let's say RK-12 for the Capsule, or RK-47.
So with a T13 Transformer, what improvment in the circuit should be done to adapt to the right capsule, which Condo to change so the response is more flat and we can get rid of that Chinese 10khz boost and bring more around 4khz.

Thank you
Manu

There are many mods you can do. Matador (Aurycle), Royer,  or you could do the attached.  I'm not sure where I got this from, but you remove  some parts and change the transformer and maybe upgrade the 4.7uF capacitor.

The schematic lists a Cinemag 2480, but I should think a T13 or similar transformer would also work. I have not done this mod (yet.) I have another 2001 and may try this next. It is my understanding this circuit would work with a K67 type capsule. So you could leave the 32mm capsule installed  or get a different K67 style capsule.

Ok,

If i would do the Royer Mod, where would you find the PSU for it? i mean wouldn't it be easier to try that mod with a Tube T-bone?

Trying your mod coulb be cool, i also read how to rebias the FET, i guess most chinese mics are not properly biased and so you can end up with a good or bad microphone.

So you wouldn't try a U47 or C12 type capsule in there? ...

Manu

manulaudic said:

Ok,

If i would do the Royer Mod, where would you find the PSU for it? i mean wouldn't it be easier to try that mod with a Tube T-bone?

Click to expand...

I built the PSU with PCB I had made. Otherwise, the original Royer PSU is point to point wired voltage tripler. You could make your own PSU with either, or you could use the original microphone PSU. You may have to modify it to produce the voltage necessary for the Royer.

Trying your mod coulb be cool, i also read how to rebias the FET, i guess most chinese mics are not properly biased and so you can end up with a good or bad microphone.

Click to expand...

I do not have an oscilloscope (yet) to do this.

So you wouldn't try a U47 or C12 type capsule in there? ...

Click to expand...

I think Matador did in his Aurycle mods. I think it is all a matter of taste. If you have the time try different things and see what you like the best. I don't have any sophisticated test equipment to measure frequency response. And I like to do this kind of modding because it is enjoyable to me, and maybe I make a good microphone into a better microphone or if not, I learn something in the process. E.g. on the Royer mod I did, my PSU for whatever reason only gives me 70v under load. So that is about 40v on the capsule, and the microphone has a mellowness about it. I am finishing another PSU with higher voltage and I will try out and listen.

THanks,

I'm on the same boat, i also mod because it's  very nice hobby and like you said if something good comes out then that's a great feeling !

I will try to talk to Dave Thomas about it and see what he would recommend, maybe buy the transformer + Capsule from him...

Thank you again,
I will get on the Royer mod,

I think i will first build all the circuits and then when i feel like they are looking like something i will look for a mic body :
I was thinking of building it inside wood, that would be interested and unique...

Let's see.
Manu

hello
does anybody know the amperage and tension of the output of a bv8HR ? Thank you for your answer.
luc

Ehrm... If that's related to the Neumann BV8, that's a signal transformer, so your question doesn't make much sense, i'm afraid.

I'm pretty sure voltage / current / power ratings apply only (or mostly) to power transformers.

cielapeute said:

hello
does anybody know the amperage and tension of the output of a bv8HR ? Thank you for your answer.
luc

Click to expand...