AKG SOLIDTUBE POWER SUPPLY

[Bernard75]

Hello,
I have two AKG SOLIDTUBE microphones but only one power supply.
I am looking for any idea for a "compatible" or "adaptable" power supply ? Power supply production for solidtube has been discontinued and there is no stock left...
Many thanks in advance,
Bernard
ps: any possibility to make a simple power supply from a battery + a resistor to adapt the impedance ? (might be a naïve thought...) In essence the power consomption is low ( needs an order of magnitude of 10 milliampères) and I need the microphone to work only a couple of hours in a row)

 

[Migs 31]

Hello,
I have two AKG SOLIDTUBE microphones but only one power supply.
I am looking for any idea for a "compatible" or "adaptable" power supply ? Power supply production for solidtube has been discontinued and there is no stock left...
Many thanks in advance,
Bernard
ps: any possibility to make a simple power supply from a battery + a resistor to adapt the impedance ? (might be a naïve thought...) In essence the power consomption is low ( needs an order of magnitude of 10 milliampères) and I need the microphone to work only a couple of hours in a row)

Hello Bernard,

I was in a similar situation once, but NOT with an AKG SOLIDTUBE. No.
It was a DIY Mic found without a power supply. But this is what I did anyway:

Bought The t.bone power supply from Thomann, also bought their 7 PIN XLR cable (sold separately).
And finally purchased a 6 PIN FEMALE XLR connector from RS.

Then I had to check all the voltages coming from the 7 PIN XLR/PSU (extremely careful).
After that I de-soldered the 7 PIN XLR Female on the cable, re-soldered all the small coloured cables to the correct pins of the new 6 PIN XLR. Checked all the correct voltages were going to the right places before trying with the mic. Connected the Microphone and voila! It worked nicely.

That is what I DID. Usual Disclaimer here!
This is a job better left to a skilled person in soldering/electronics.
Find a competent Tech. or a friend who is good with DIY/Electronics.

Hope this helps
M

 

[Bernard75]

Hello M
Yes great great help, many thanks and for the shematics.
I might try to go the same way with some help around.
Further to your post I just went on Thomann french site and found a T bone SCT 2000 which got a power supply looking indeed "similar" to the missing one of my AKG. Is it the one you used ?
Many thanks again,
Bernard

 

[Migs 31]

Hello M
Yes great great help, many thanks and for the shematics.
I might try to go the same way with some help around.
Further to your post I just went on Thomann french site and found a T bone SCT 2000 which got a power supply looking indeed "similar" to the missing one of my AKG. Is it the one you used ?
Many thanks again,
Bernard

Hi again,

Yes that looks like the one. But the Pattern Switch (Big Grey Pot) was not needed at the end.
That is used when you have a Double Diaphragm Mic, for Variable Polar Pattern use.
The HT voltage was around 176/180 Volts if I remember correctly and 6.3V for the heaters.
Yours (AKG Mic) probably runs on Higher Voltages (just my assumption). Need to check that first.
Options available, quickly done:

PSU-1 the t.bone PSU SCT 2000

PSU-2- the t.bone PSU Retro Tube II

CABLE XLR7- the t.bone XLR 7-pin Cable 10m

XLR6F- Code : i066 fiche xlr

XLR6F- RS:
https://fr.rs-online.com/web/p/conn...3685F6B6579776F72645F6170703D3230383531383126
I wish you success!
M

 

[Migs 31]

Oh !
I forgot, concerning the pins on those 7XLR and colour codings:

#Chuck D wrote:
"OK fine you made me go search the internets

Here it is

1. B+
2. Heater
3. Pattern Vari V+
4. GND
5. Out +
6. Out -
7. GND tied to pin 4"

Microphone parts.com agrees with that:

• XLR1: plate voltage to mic
• XLR2: heater voltage to mic
• XLR3: pattern voltage to mic
• XLR4: ground
• XLR5: balanced audio from mic
• XLR6: balanced audio from mic
• XLR7: ground

https://microphone-parts.com/products/tube-mic-power-supply?_pos=3&_sid=0b536651b&_ss=r
And from what I read on the Advancedaudio Canada forum. Colours:

Pin 1- Red
Pin 2- Yellow
Pin 3- Blue
Pin 4- White
Pin 5- Black
Pin 6- Green
Pin 7- White

But please take that with a lot of caution. Always check for yourself.
And don't believe everything that people say on the Internet
Good night!

M

 

[Bernard75]

Thank You !

From the look T bone is using "same" power supply with three mic: SCT 800/SCT 700/SCT 2000

SCT 800 and 2000 run same lamp: 12AX7B
SCT 700 run a 12AT7 (also named ECC81)

Wheras my AKG Solidtube would run an ECC83.

I will check if voltage are similar for these lamps and if all these T bone power supply have same part number.

Otherwise I might also try to find another power supply for another lamp microphone which run an ECC83 (on the assumption that the voltage from the power supply are not modified by the electronics of the mic itself).

And will not miss to check everything before to make any test !

Kind regards,
Bernard

 

[Migs 31]

Thank You !

From the look T bone is using "same" power supply with three mic: SCT 800/SCT 700/SCT 2000

SCT 800 and 2000 run same lamp: 12AX7B
SCT 700 run a 12AT7 (also named ECC81)

Wheras my AKG Solidtube would run an ECC83.

I will check if voltage are similar for these lamps and if all these T bone power supply have same part number.

Otherwise I might also try to find another power supply for another lamp microphone which run an ECC83 (on the assumption that the voltage from the power supply are not modified by the electronics of the mic itself).

And will not miss to check everything before to make any test !

Kind regards,
Bernard

Hi,

@Bernard75 wrote "SCT 800 and 2000 run same lamp: 12AX7B"

12AX7B and ECC83 are the very same valve/tube/lamp.
ECC83 is the name usually given in UK/EU and 12AX7 the name given in USA.
Same thing, just different names and many variations.

I own an SCT 2000 mic (which I hacked to Kingdom's Come) and put a Telefunken EF86 in...
It had indeed a very cheap Chinese 12AX7B crap/caca limited edition inside as stock.

M

 

[terry setter]

If you ended up with a supply that has a pattern select switch on it, you can take that voltage into the mic and use it to polarize your capsule (NOT as the voltage source for a second diaphragm). The pattern select switch then beomes a "trim" knob. Experiment with the voltage you deliver to the capsule and see what works in your mic. I have one I've wired like this that goes up to 140 V and down to 20, across the nine steps of the switch. The mic I use with it in has never had an issue with 140V, but if I put it in front of a loud sound source, I turn the "trim" way down, then bring it up until I'm happy. The higher the voltage (before the diaphragm "collapses", the less noise you'll have in your signal). Also, it lets you while-away the hours as you test for superior sonic characteristics of various polarization levels. Many say 60-63V is optimum, but I've also known people who preferred the sound they got at 130+V.

As per the color of the wires in your supply, I've see pin 2 as blue and 3 as yellow in many situations. A give away for the heater wire is that many of the better supplies use a larger gauge wire to supply the heater voltage/current.

 

[mlsebring]

Hello,
I have two AKG SOLIDTUBE microphones but only one power supply.
I am looking for any idea for a "compatible" or "adaptable" power supply ? Power supply production for solidtube has been discontinued and there is no stock left...
Many thanks in advance,
Bernard
ps: any possibility to make a simple power supply from a battery + a resistor to adapt the impedance ? (might be a naïve thought...) In essence the power consomption is low ( needs an order of magnitude of 10 milliampères) and I need the microphone to work only a couple of hours in a row)

Hello!
I'm just wondering what your solution was - I have a failed SolidTube PS and was wondering if I could finagle one from something existing and this thread sounded promising!

 

[commanderberti]

https://groupdiy.com/threads/solid-tube-powersupply-transformer-mod-2-switchps.86532/