gary o

Which BV8 transformer to buy ....
« on: May 10, 2012, 07:32:40 AM »
Building a 2nd U47 is mic I have Max MK47 its great... Im making a point to point version and am wondering how the different BV8 transformers compare......

http://www.tab-funkenwerk.com/id53.html

http://www.ebay.com/itm/BV8-P-Transformer-for-Chinese-upgrades-/170574212357?pt=LH_DefaultDomain_0&hash=item27b703ed05#ht_500wt_1413


http://www.aamicrophones.com/parts.htm

anyone try these options & have comparisons

Thanks for reading


manulaudic

Re: Which BV8 transformer to buy ....
« Reply #1 on: May 10, 2012, 07:44:21 AM »
Hello,

I will not be able to answer your question but would love to know which schematic are you using to do your point to point u47 and which tube...

Manu

gary o

Re: Which BV8 transformer to buy ....
« Reply #2 on: May 10, 2012, 08:08:32 AM »
Hi manu Im using schematic for the Mk47 kit two 6028 tubes wired in parallel .....just too couple hours to solder together just testing transformers I have in my junk box at the moment.

manulaudic

Re: Which BV8 transformer to buy ....
« Reply #3 on: May 10, 2012, 08:17:48 AM »
Ok, so the same schematic without the PCB then... Did you get the kit of bought the parts separately?

Based on Dave Thomas support and knowledge, i would assume his BV8 would be great.. But that's because he seems to be such a nice guy and know so much about mics...
Manu

gary o

Re: Which BV8 transformer to buy ....
« Reply #4 on: May 10, 2012, 08:43:03 AM »
Thanks Manu yes same but no PCB as I say I have the Kit done its great ....point to point version is made from junk from junk box all old second hand parts, sounds great just need another BV8 now ...I like the price of the the Dave Thomas BV8....thanks once again....

manulaudic

Re: Which BV8 transformer to buy ....
« Reply #5 on: May 10, 2012, 09:07:29 AM »
Sounds great !

Could you possibly send me the link for schematic of the MK47 mic?
I'd like to try P2P, seems like fun...

Manu

letterbeacon

Re: Which BV8 transformer to buy ....
« Reply #6 on: May 10, 2012, 09:11:58 AM »
Manu - here's a link the MK47 thread with the schematic: http://www.groupdiy.com/index.php?topic=41379.msg513821#msg513821

Gary - what body did you use?  How have you physicall contructed it in the case?  Tag strips?  I would love to see some pictures....

manulaudic

Re: Which BV8 transformer to buy ....
« Reply #7 on: May 10, 2012, 09:21:20 AM »
tHanks !!

Might be a stupid question but how is it wired with the two 6028?
The schematic is for the almost impossible to find Vf14..

Manu

gary o

Re: Which BV8 transformer to buy ....
« Reply #8 on: May 10, 2012, 09:21:24 AM »
Ha letter beat me to it Manu...enjoy....Thanks letter .....no tag strips its a lash up really just soldered components between the two tube holders look horrendus but but does the job, crammed it in the body of old AKG solid tube mic using lollipop head for basket at the moment its more of an experiment  than a build really to see how it sounded with a T14/1 that I have plus some junk transformers that didnt really work.......I was also comparing MK47 electronics to Ela M251 that I knocked up in the same way using same capsule RK47 in a lollipop head....

gary o

Re: Which BV8 transformer to buy ....
« Reply #9 on: May 10, 2012, 09:23:44 AM »
Hi Manu on schematic the VF14r is a representation of the two 6028 that are wired in parallel.......if you have a go  make sure you wire your heaters in series tho


letterbeacon

Re: Which BV8 transformer to buy ....
« Reply #10 on: May 10, 2012, 09:54:25 AM »
I hate to say it mate but -pics or it didn't happen!

I'm thinking of getting that Aurcycle tube mic body and P2Ping something together in that.  It's annoying that you have to buy their whole kit though and not the body separately!

manulaudic

Re: Which BV8 transformer to buy ....
« Reply #11 on: May 10, 2012, 10:22:27 AM »
Ok ! Gary O,

I guess i have to understand a bit more about Tube mic design before i start wiring my own P2P one, i think i get the idea of wiring them in paralel but in the schematic it doesn't tell wich branch is connected (branch number 1-8). That said i should look more into Tube and Tube designs...
Sorry for taking this subject somewhere else and thank you for your help !

good luck with the project, i might just stick with a simple elam 251 project or Royer Mod.

Manu

gary o

Re: Which BV8 transformer to buy ....
« Reply #12 on: May 10, 2012, 12:09:45 PM »
It didnt happen Letter that made me chuckle......maybe a crappy video later I have to teach some Tango this eve should be fun..... couldnt you  buy a really cheap mic to gut & can use some parts....

Manu no problem take subject where you like its cool.....7 pins on 6028 check tube data to see which pin is what part of tube.....connect both tubes in parallel pin 1 to pin and so on but not the filiments pins 3 & 4 , filiments are 20V each wire in series one end connects to cathode resistor 27R other end to large wattage 1500 R which drops the 105V supply down to 36 ish for the two filiments in series....hope that helps...

Im mess with two Ela m251 circuits at the same time just trying to see / hear which is best.....for my own rock n roll use they sound as good as each other.... have fun...

letterbeacon

Re: Which BV8 transformer to buy ....
« Reply #13 on: May 10, 2012, 01:07:28 PM »
It didnt happen Letter that made me chuckle......maybe a crappy video later I have to teach some Tango this eve should be fun..... couldnt you  buy a really cheap mic to gut & can use some parts...

I could, but I really want a U47-esque headbasket to go with the circuit.  The Aurcycle kit converts to about £110 including postage, which isn't too bad compared with Skylar's bodies.  It's just a shame that you're paying a lot in shipping when I only want the mic body!

How much space is need in the body to fit the two tubes in?  I think the Aurycle is a bit thinner than a U47.

I've got a couple of 1uF Russian PIO capacitors lying around, although they're only rated at 160V.  Do you think that's too close to the 105V B+?
« Last Edit: May 10, 2012, 06:38:42 PM by letterbeacon »

gary o

Re: Which BV8 transformer to buy ....
« Reply #14 on: May 10, 2012, 08:21:36 PM »
Is there a U47 esque head basket then .....Mmm 110 fair bit of dosh for that ...... I think you PIO caps should be ok there voltage at that cap in circuit measures 45V on mine my supply is 107V.....my PIO that came with kit stinks I think it leaks it smells poison if you no what I mean....

has skylar got any B stock bodies cheaper maybe or just the basket.....

micaddict

Re: Which BV8 transformer to buy ....
« Reply #15 on: May 11, 2012, 04:00:41 AM »
 Nope.  :(

letterbeacon

Re: Which BV8 transformer to buy ....
« Reply #16 on: May 11, 2012, 04:33:09 AM »
Is there a U47 esque head basket then .....Mmm 110 fair bit of dosh for that ......

The £110 is for the kit, which includes a power supply and shipping.  Here's a link to the page: http://www.aurycle.com/aurycle-a5500-large-diaphragm-tube-condenser-diy-microphone.html

Quote
my PIO that came with kit stinks I think it leaks it smells poison if you no what I mean....
I've got a spare 1uF 160V PIO.  If you PM me your address I'll post it off to you.

gary o

Re: Which BV8 transformer to buy ....
« Reply #17 on: May 11, 2012, 06:22:49 AM »
Wow thanks letter I will PM ya .......I been away from here for while I missed your BA2A, I just had a look wow that looks beautiful! proper olds school love it real iron so jealous bet it sounds sweet.... havent read the whole thread yet just looked at the porn but will read .. do you like the sound...

Ah yeah thats the apex 460/nady/Tbone STC800 in kit form ....I think the T bone is £150 I think you get spider and ali case with it not sure......

You have read all the stuff about the U47 head basket then & how it effects the sound.......I bought Skylars mic body and head basket/grill  the thing is beautiful but to my humble rock n roll ears its doesnt sound much different to my capsule in other baskets not that i tried loads....Im sure its doing something and its as Skylar intended to be the same as the U47.....but when you read about it you kinda expect a huge difference for the better & really its just a knats cock different.....from my humble experiments with mics for my ears I would say a mic is 85% capsule

Sorry didnt answer the 6028 tubes are small 7 pin tubes depending how you arrange if you do point to point Im sure they would go in the auricle body....

letterbeacon

Re: Which BV8 transformer to buy ....
« Reply #18 on: May 11, 2012, 06:48:54 AM »
Wow thanks letter I will PM ya .......I been away from here for while I missed your BA2A, I just had a look wow that looks beautiful! proper olds school love it real iron so jealous bet it sounds sweet.... havent read the whole thread yet just looked at the porn but will read .. do you like the sound...
I love it, it sounds great.  I've been so busy with work at the moment that I haven't had a chance to put it through its paces yet, but the short recordings I have made sound great.  I think I'm going to try and twist the heater wires a bit tighter though, try and get rid of the last tiny remnants of hum.

Quote
You have read all the stuff about the U47 head basket then & how it effects the sound.......I bought Skylars mic body and head basket/grill  the thing is beautiful but to my humble rock n roll ears its doesnt sound much different to my capsule in other baskets not that i tried loads....Im sure its doing something and its as Skylar intended to be the same as the U47.....but when you read about it you kinda expect a huge difference for the better & really its just a knats c**k different.....from my humble experiments with mics for my ears I would say a mic is 85% capsule

Sorry didnt answer the 6028 tubes are small 7 pin tubes depending how you arrange if you do point to point Im sure they would go in the auricle body....
Very interesting... thank you.


 

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