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General Discussions => The Lab => Topic started by: gary o on April 25, 2006, 05:38:01 AM

Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: gary o on April 25, 2006, 05:38:01 AM
Hi folks...... I have a AKG Solid Tube mic that was my main mic in my home studio till it went wrong, I know its not best mic in the world {its just for vocals by the way}
 but im on a budget I had little go at repairing it but it will cost money too and I have been wanting to make a tube mic for a while, thought it wouldnt cost anymore than
n straight repair as I have some parts already, I did read somewhere that its not a good choice to DIY tho ???
Any suggestions or thoughts on the matter would be great.

Thanks...........................Gary O.
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: ChrioN on April 25, 2006, 05:44:03 AM
This won't exactly answer you question, but I know that there is a mod for it. Something about superiormod or suprememod. Makes the high end more noticable.
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: rodabod on April 25, 2006, 05:53:59 AM
I'd replace the circuit with a G7 and then see how it sounds.

There is a simple mod of removing some of the pop-filtering from the grill too. Search for it here.

You can buy the G7 PCBs via Paypal from Gustav in "The Black Market" and it is very well supported.

Have you tested the power supply volatges yet?
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: rodabod on April 25, 2006, 05:55:03 AM
Oh crap. Just remembered it is an electret capsule.

Wait around for more suggestions. Might suit a new capsule.
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: rodabod on April 25, 2006, 05:57:52 AM
http://www.groupdiy.com/index.php?topic=7096&highlight=akg+solidtube
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: rodabod on April 25, 2006, 06:00:18 AM
http://www.groupdiy.com/index.php?topic=709
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: gary o on April 25, 2006, 06:09:58 AM
Yeah is etectret capsule im not 100 percent sure about what that means regarding the G7 and other circuits...
So I can still use it as a quike fix I have an old AKG C28A tube mic that I dont use, I removed the CK1 cusle and basically connected it to the Solid Tubes capsule and it works.. and better than its original form, I think, but its a mess, was thinking I could remake the C28A circuit point to point inside thr Solids body, if I can find the right resestors for it that is.
Thanks for your thoughts so far guys keep em coming....


Cheers ..................Gary o.
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: rodabod on April 25, 2006, 06:15:06 AM
Quote from: "gary o"
Yeah is etectret capsule im not 100 percent sure about what that means regarding the G7 and other circuits...
So I can still use it as a quike fix I have an old AKG C28A tube mic that I dont use, I removed the CK1 cusle and basically connected it to the Solid Tubes capsule and it works.. and better than its original form, I think, but its a mess, was thinking I could remake the C28A circuit point to point inside thr Solids body, if I can find the right resestors for it that is.
Thanks for your thoughts so far guys keep em coming....


Well, electret capsules don't require a polarising voltage applied to them, unlike your C28 which will have something like 60V applied to it to get it to work.

I am actually surprised that the eletret capsule was ok whilst having a voltage applied. Someone will probably chip in here, but I thin something like a G7 with the polarising volatge ommitted might be good.

So you say you don't use your old AKG C28A? Interested in selling it?
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: gary o on April 25, 2006, 06:26:35 AM
So G 7 minus polar voltage or Royer simple circuit I wonder how they would compare to the C28A circuit which I read is practically a C12 circuit ??
Sorry :sad:  cant sell me C28 I get attached to things, I do use him a bit, I only paid 20 yes 20 pound for it came from the BBC so who knows who sung into it, iv seen loads of C28s being used by the beatles and such on old BBC shows.


Thanks .....................Gary O.
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: rodabod on April 25, 2006, 06:34:08 AM
Quote from: "gary o"
So G 7 minus polar voltage or Royer simple circuit I wonder how they would compare to the C28A circuit which I read is practically a C12 circuit ??


Well, a big part of the sound is in the capsule you use, and the housing of the microphone. I'm sure Gus, etc. can comment on the differences.

Quote
Sorry :sad:  cant sell me C28 I get attached to things, I do use him a bit, I only paid 20 yes 20 pound for it came from the BBC so who knows who sung into it, iv seen loads of C28s being used by the beatles and such on old BBC shows.
#

Ahh, that's ok. We are actually moving out of the BBC Scotland building in Glasgow at the moment, although I am still yet to find their secret stash of C28s, C12s and STC 4038s - I hope none of the old equipment goes to waste :razz: .
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: rodabod on April 25, 2006, 06:35:58 AM
Also, I'm not sure what sort of impedance your electret capsule will like to see.... Also, I wonder if it requires a different amount of amplification....

Someone here with experience with the Solidtube will be able to comment.
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: gary o on April 25, 2006, 06:47:36 AM
Those links you posted have given me hope thanks :grin: see what your saying about the sound, was wondering about the output tranformer if I can use the AKG for now at least.
Hey now leave no stone unturned there maybe a stash of something at the BBC, im sure you can make good use of it if you can find good luck....there mabe a Fairchild limiter being used as a paper weight in some office somewhere.... look for desk with bow legs, if you find 2 i'll swap 1 for the C28A haha :grin:


Cheers ..................Gary O.
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: ChrioN on April 25, 2006, 12:05:33 PM
Quote from: "rodabod"

There is a simple mod of removing some of the pop-filtering from the grill too.


I think that is the supreme-mod. Corny name for such a thing  :green:

 :guinness:
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: mikeyB on April 25, 2006, 04:18:32 PM
What's wrong with the mic - is it the psu - I've repaired 3 in the last year and it's ALWAYS the transformer crapping out andtaking the varistors with it!
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: gary o on April 25, 2006, 07:52:18 PM
Yeah is the transformer thats crapped haha, I like that, the brown thing technical arnt i is broke to is it a transformer of sorts or something to do with the bass roll off, its near the jumper plugs for mic and audio output, I only have scematics for the mic not the PSU, havent looked into price of transformer,do you know a rough price mikey B ..cheers


Thanks ...................Gary O.
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: mikeyB on April 26, 2006, 01:31:48 PM
No! - its not that - it's the big grey power transformer! Full circuit is available on akg site. Power transformer would cost £25 inc vat and pp. Get the circuit first and measure the output voltages before shelling out!
Title: AKG Solid Tube up for DIY what can I turn it into ???
Post by: gary o on April 26, 2006, 08:36:03 PM
Thanks MikeyB yeah the tran has gone for sure and so has the brown thing, whatever it is il go find that diagram, thanks once again.


Cheers .........................Gary O.