renx
Well-known member
Hello everyone,
long time since my last post, I had and still have a LOT of work on my job so it took me a long time to diy something on the side but finally here it is.
I made something from the bottom of my heart, a microphone which is modular, it is a tube mic and at almost the same time solid state mic in a custom oak case with the most interesting PSU case.
Here it is...
The tube circuit is based around a EF806 pentode wired as a triode, the rest of the circuit is like the um57, like my older design. The transducer is the M7.
The yellow switch is used to add feedback to minimize the tube distortion and hope to leave only the transformer distortion and the transducer distortion of course.
Here is the side where the modules are connected. The hole in the PCB through which you can see the tube was made cause there was not enough space for the tube to fit in.
And the modules are basically different transformers to change the flavor of the tube sound and a solid state module based around AD's op467 quad opamp wired as an instrumentation amplifier with a differential output with a simple first order butterworth LP filter. The gain of the SS module is 1, and the sensitivity of the transducer is around 17.5mV/Pa@80V so the output level is pretty high!
On the following pics the transformers are Lundahl LL1538 and Cinemag CM-2461NiCo, I just MUST get one of the Sowters to add to this group.
Here is a pic with one of the modules in its place.
Next up is the PSU.
It is made out of PCB material, more precisely FR4 2.4mm thick.
It is soldered together and than lacquered at a car shop. It is very light and extremely strong and very very cheap. Fantastic for diy!!!
The front and back panels are also made of PCB material! In other words the whole PSU case is made at the same PCB manufacturing service provider.
I made this case after I ordered 5 aluminium cases which I planned to sand than anodize but it was just too much trouble compared with this.
The PSU has high voltage regulation for the 160V rail made of two LM317's (one for pre-regulation). And +6.3V and -6.3V rails for the opamp also with pre-regulation each. AN OVERKILL!
The PSU transformer is custom wound 30VA - 230V : 135V + 13V +13V
Some pics together with the mic.
And now the Case!
It is hand made out of Oak by my friend than colored brown-red to give it a Rosewood kinda look, after that it was lacquered with one of the best polyurethane lacquers (used in yacht interiors) in three layers for the deep shine.
The handle was CNC cut than hand rounded.
Front look.
Than I "killed my self" while I finally found a moisture repelling, no-particle-disposing sponge for the inside. It cost me an arm and a leg.
While designing the case I was thinking where to put the cables, should they be beside the mount? If so, the case would have to be bigger more heavier and more expensive.
Than I thought if I make the mic carrying board removable I could place the cable underneath the PSU.
And some final pics for the end...
All together it took me a little less than two years to complete this, lots and lots of failed tries.
At the moment I hired a pro photographer to take some pics, I am also making a web site, where I'll post some sound clips and comparisons with other mics.
Best regards to all, Renx.
long time since my last post, I had and still have a LOT of work on my job so it took me a long time to diy something on the side but finally here it is.
I made something from the bottom of my heart, a microphone which is modular, it is a tube mic and at almost the same time solid state mic in a custom oak case with the most interesting PSU case.
Here it is...
The tube circuit is based around a EF806 pentode wired as a triode, the rest of the circuit is like the um57, like my older design. The transducer is the M7.
The yellow switch is used to add feedback to minimize the tube distortion and hope to leave only the transformer distortion and the transducer distortion of course.
Here is the side where the modules are connected. The hole in the PCB through which you can see the tube was made cause there was not enough space for the tube to fit in.
And the modules are basically different transformers to change the flavor of the tube sound and a solid state module based around AD's op467 quad opamp wired as an instrumentation amplifier with a differential output with a simple first order butterworth LP filter. The gain of the SS module is 1, and the sensitivity of the transducer is around 17.5mV/Pa@80V so the output level is pretty high!
On the following pics the transformers are Lundahl LL1538 and Cinemag CM-2461NiCo, I just MUST get one of the Sowters to add to this group.
Here is a pic with one of the modules in its place.
Next up is the PSU.
It is made out of PCB material, more precisely FR4 2.4mm thick.
It is soldered together and than lacquered at a car shop. It is very light and extremely strong and very very cheap. Fantastic for diy!!!
The front and back panels are also made of PCB material! In other words the whole PSU case is made at the same PCB manufacturing service provider.
I made this case after I ordered 5 aluminium cases which I planned to sand than anodize but it was just too much trouble compared with this.
The PSU has high voltage regulation for the 160V rail made of two LM317's (one for pre-regulation). And +6.3V and -6.3V rails for the opamp also with pre-regulation each. AN OVERKILL!
The PSU transformer is custom wound 30VA - 230V : 135V + 13V +13V
Some pics together with the mic.
And now the Case!
It is hand made out of Oak by my friend than colored brown-red to give it a Rosewood kinda look, after that it was lacquered with one of the best polyurethane lacquers (used in yacht interiors) in three layers for the deep shine.
The handle was CNC cut than hand rounded.
Front look.
Than I "killed my self" while I finally found a moisture repelling, no-particle-disposing sponge for the inside. It cost me an arm and a leg.
While designing the case I was thinking where to put the cables, should they be beside the mount? If so, the case would have to be bigger more heavier and more expensive.
Than I thought if I make the mic carrying board removable I could place the cable underneath the PSU.
And some final pics for the end...
All together it took me a little less than two years to complete this, lots and lots of failed tries.
At the moment I hired a pro photographer to take some pics, I am also making a web site, where I'll post some sound clips and comparisons with other mics.
Best regards to all, Renx.