Tube Bottle-mic Alctron BV563 Mod.

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Rohan white

Member
Joined
Apr 26, 2017
Messages
19
Ive got a case of blues and some violet capsules I will be trying on this mic. I am going to get some pictures and trace out the schematics to get some advice on modifying one of these. An op on gearspace confirmed that they fit the standard cmv 563 bottle caps. Will report back when its delivered it could lead to a cheap route to start using those capsules in a tube body without forking out £1000's (I'm in Uk and am getting mine from Norway via Denmark..!
 
Someone should definitely make these bodies and capsules for the diy community (preferably a larger 47'ish size bottle). I've got some parts I've been looking to use for this someday (I already have a Vintage Telefunken 301/2 bottle with extra caps that could be put to good use).

Looking forward to hearing about your experience.
 
The Tbone retro II is fairly similar to the Alctron , although has the PSU with patern switching ,dual membrane capsule as well as HPF and att switches on the body .
A set of swappable M7 style headshells is a nice bonus with the BV 563 , but I can get pair of the t.bones for less than the cost of one Alctron . So Id always choose two complete mics over one with three capsules .

A 7025 is the wrong tube for a CMV563 , My guess is the circuit board is the same in both Alctron and Retro II , its probably for the bin but no reason not to reuse some of the components if you can .
 
Last edited:
So here's some pictures. It's a strange beast, any ideas what this circuit could be based on? I will try and trace a schemetic but I've no real experience in this. In terms of capsules the ones provided won't fit my blue microphone stage one, BUT my Violet capsules fit the alctron body fine. Weirdly, the blue capsules won't fit this body. The problem being that the lollipop base on the blues is slightly longer... If I just filed 1mm off the bottom of those blue lollipops they would fit fine fine, if only alctron had stuck their securing pin a tad higher it would have been fine.. Anyway here's some photos, I will check if the alctron capsules can fit the violet global pre but somehow I doubt it. The mission is on to mod this mic into something better. Im dying to use the lush sounding vin 47 and 67 capsules I have in a decent tube circuit so I'd be happy to rip the circuit out completely or mod it.
 
I took delivery of a pair of Retro tube II's today ,
each case is 8kg ,
the mic itself is 1450grams , the cradle around another 600grams
I second what was said in relation to the Alctron/Tbone bottle before , you'll want a substantial counter weighted mic stand if you wanna boom mount this monster ,
I didnt deploy the latex gloves and zircon encrusted tweezers and look inside yet
 
Just looking at the powersupply , all the switches and sockets are good quality , all the wires are heat shrinked where they meet the teminals ,
The LT is regulated in the usual way but theres an aditional passive RC smoothing stage so the regulator doesnt have to drop too much voltage , HT has 6 stage RC smoothing , 22uf 400v , all the electrolytics are 105c rated , theres a pair of zeners at the end of the chain .
The polar patern switch is white ceramic and feels very solid , .125w resistors make it very neat and tidy .
The PCB is through hole plated so should be easy to rework or repair if the need arrises .
Transformer has 9.5v and 175v windings .

The grounds from the PCB , mains socket and upper part of the enclosure are all starred to a common point on the chassis , the common chassis connection at the XLR sockets does create a small ground loop ,the wire connecting the XLR's ground to the pcb might not be required as long as there good contact between the metal xlr housing and chassis , the paint might need to be scraped away in the vicinity of the
mounting screws and toothed washers and nuts added at the back ,

The finish on the case work of the mic is nice , the PCB is marked BV-300a ,
Inside is the usual suspect Shuguang tube , I found these tubes often badly microphonic brand new out of a box , the one in the mic is no exception , swapping out for a decent UK/US/or EU made tube is probably well worth doing .

Finally the 7 pin xlr cable looks like it will last years , the connectors are a bit like the old Cannon type with grub screws ,
All in all Im very happy with my purchase , although I do plan to replace the electronics in the mic itself .
For the 210 euros you cant go wrong , the T.bone Retro PSU , is available as a seperate item from thomann for 69 euros . Actually I just checked Don audio ,their PSU box alone is over 150 euros, by the time you have the extra accesories like XLR connectors ,dial scale and other components your going to be spending well over 250 euros before your up and running .
 
Last edited:
Thanks for the input. I think building the UM92.1 is a bit beyond me as i just want to improve on the circuit here, maybe in the future though.. What bothers me is that the Bv563 is Cardioid only. Does this alter the circuit much? I was just gonna change the transformer, tube and remove the rf shielding capacitors and replace C8 with something better. I know this has been covered in many places but this circuit is slightly different from the Apex 460 and i especially want to get the capsule voltage to the correct level . I dont fully understand how the circuit works but im ok with keeping the plate follower and using bothe sides of the tube. I was gonna get a bv11 transformer , or possible the sowter equivalent as im in the UK.
This looks like the Alctron T190 board. It was nice sounding, but I built Oliver's version of the UM92.1 with a lovely BeesNeez M7.
 
Thanks for the input. I think building the UM92.1 is a bit beyond me as i just want to improve on the circuit here, maybe in the future though.. What bothers me is that the Bv563 is Cardioid only. Does this alter the circuit much? I was just gonna change the transformer, tube and remove the rf shielding capacitors and replace C8 with something better. I know this has been covered in many places but this circuit is slightly different from the Apex 460 and i especially want to get the capsule voltage to the correct level . I dont fully understand how the circuit works but im ok with keeping the plate follower and using bothe sides of the tube. I was gonna get a bv11 transformer , or possible the sowter equivalent as im in the UK.
Actually I think its a cathode follower type circuit, to be honest I don't know the practical difference between the two.
 
That appear to be the same circuit board that luke audio uses in their Al-y56.
This first photo is the Luke, the second the alctron t190 and the third is the alctron bv563 so i dont think its like the Luke, though they seem to be the same size.
im still wondering which components to change, though i would love to make the UM92.1 but would need help with the board and sourcing components in the UK.
 

Attachments

  • Screen Shot 2022-07-10 at 11.48.12.png
    Screen Shot 2022-07-10 at 11.48.12.png
    706.1 KB · Views: 21
  • Screen Shot 2022-07-10 at 11.52.13.png
    Screen Shot 2022-07-10 at 11.52.13.png
    328.8 KB · Views: 20
  • Screen Shot 2022-07-10 at 11.52.29.png
    Screen Shot 2022-07-10 at 11.52.29.png
    367.4 KB · Views: 19
Just looking at the powersupply , all the switches and sockets are good quality , all the wires are heat shrinked where they meet the teminals ,
The LT is regulated in the usual way but theres an aditional passive RC smoothing stage so the regulator doesnt have to drop too much voltage , HT has 6 stage RC smoothing , 22uf 400v , all the electrolytics are 105c rated , theres a pair of zeners at the end of the chain .
The polar patern switch is white ceramic and feels very solid , .125w resistors make it very neat and tidy .
The PCB is through hole plated so should be easy to rework or repair if the need arrises .
Transformer has 9.5v and 175v windings .

The grounds from the PCB , mains socket and upper part of the enclosure are all starred to a common point on the chassis , the common chassis connection at the XLR sockets does create a small ground loop ,the wire connecting the XLR's ground to the pcb might not be required as long as there good contact between the metal xlr housing and chassis , the paint might need to be scraped away in the vicinity of the
mounting screws and toothed washers and nuts added at the back ,

The finish on the case work of the mic is nice , the PCB is marked BV-300a ,
Inside is the usual suspect Shuguang tube , I found these tubes often badly microphonic brand new out of a box , the one in the mic is no exception , swapping out for a decent UK/US/or EU made tube is probably well worth doing .

Finally the 7 pin xlr cable looks like it will last years , the connectors are a bit like the old Cannon type with grub screws ,
All in all Im very happy with my purchase , although I do plan to replace the electronics in the mic itself .
For the 210 euros you cant go wrong , the T.bone Retro PSU , is available as a seperate item from thomann for 69 euros . Actually I just checked Don audio ,their PSU box alone is over 150 euros, by the time you have the extra accesories like XLR connectors ,dial scale and other components your going to be spending well over 250 euros before your up and running .
Would you happen to know what the voltage regulator (RP1) inside the power supply is for? And where the measurements are taken/calibrated?
 
Back
Top