Phrazemaster

Can't give you a definitive list, but I used a real AC701K with Dany's board. All I did was adjust the PSU heater to 3.85V. It was hard to calibrate it but it does sound terrific!
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useme2305

what do you mean by adjust the PSU heater to 3.85V?
i thought danny's boards are ready for the AC701?

Phrazemaster

His boards are for using a 5840 sub-mini tube. The 5840s use a 6.2V heater.

You'll blow your AC701 very quickly at anything over 4V on the heater.

The good news is that's easy to adjust the PSU. The bad news (for me) was I had a heck of a time setting the other voltages - not sure why. Dany told me I had a gremlin in the mic after he helped me troubleshoot, so I rebuilt it with a new board and got it working. You'll have to figure out how to wire the AC701 because Dany's instructions are for the 5840.

Do NOT wire up the AC701 and turn on the mic without  having first gotten your PSU heater voltage calibrated with a dummy load to 3.8 ~ 3.9V. If memory serves the dummy load was 40K but look through this thread and Dany already answered this one.

Good luck!

Mike
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useme2305

oh, i didn't know that. thanks for clearing that up.

Phrazemaster

Welcome :)
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useme2305

has anyone tried a 6S6B with these boards? i saw a youtube video from tubemictests where they tested a Flea vs Vintage and i think the Flea had the 6S6B and it definitely sounded close as hell, just a tad darker. very cool!
« Last Edit: April 27, 2017, 05:26:10 AM by useme2305 »

Hi,
  Thanks for the information about the power supply.

 With other projects Dany has posted a schematic of his circuit which has helped me compare both the part labels and part values with the original circuits.

 In this instance, where I am sure to not use the original tube and will almost certainly swap it with a 5840 I am especially curious to understand what other components have been adjusted to make the system work well.

 Ideally I would look at Dany's schematic and compare each part for part label nomenclature and value.

useme2305

i second the request for a schematic of Dany's version. would be really helpful.


THANK YOU!  :)


Hi Dany,
 I drew a schematic for the D-49c circuit, and would like to know if you think it looks correct. I will make any edits and replace it with a clean copy if you can take some time, look it over and make suggestions.

 I am wondering about the styroflex caps; C1 and C6, It seems like those are rated at 630vDC because that is value of the items you can supply.
 If someone wanted to use some other type of cap what is the minimum voltage rating for these two positions?

edit: I removed the schematic because it was never confirmed to be correct.

 Thank you.
« Last Edit: July 04, 2017, 03:55:58 PM by trans4funks1 »

Phrazemaster

Transfunk - awesome work! What program did you use to generate this schematic?
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 Thanks. I draw by "hand" in Adobe Illustrator.

 Having all the info on a schematic helps me understand what is going on, and I enjoy making the drawings.

Phrazemaster

Great work!  :D
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useme2305

great work trans! thanks!
« Last Edit: May 01, 2017, 05:14:21 AM by useme2305 »

Hi Dany,
 I drew a schematic for the D-49c circuit, and would like to know if you think it looks correct. I will make any edits and replace it with a clean copy if you can take some time, look it over and make suggestions.

 I am wondering about the styroflex caps; C1 and C6, It seems like those are rated at 630vDC because that is value of the items you can supply.
 If someone wanted to use some other type of cap what is the minimum voltage rating for these two positions?


 
 Thank you.

Hi Mike thanks For doing That ,
i will try to take some time to revise this nice drawing , lately i have been so swamped.
about the caps C6 should be minimum 2X plate voltage and the polarisation caps Pol X2 at least ,
i do supply really small package 630V indeed so there is no issue there ,
you are doing miracle with those drawing ,
Thanks a bunch ,
Best,
DAn, <



I want to work on the D-49B schematic as well as a depiction of the original M49, but before I move on I would like to learn if anyone has noticed any required edits or revisions.

If anyone can please double check the schematic I have drawn against the originals I will greatly appreciate it.

I have checked them myself by following all the connections on both Dany's and the original Neumann schematics, but would like a second pair of eyes to scrutinize the work before I remove the preliminary notice and prepare drawings of the other two versions.

Thanks very much! :-)

adrian

hello,
does someone know how to wire the AMI Bv11r?
there are 4 wires : 1 yellow, 1 red, 1 grey and 1 violet and I don’t wich one is wich?
there isn't spec on their website so I'm a little bit confused :o
any idea?

Hello Adrian,
Inside lid of transformer box should be the data sheet.
Red + Violet = Pri
Yellow + Grey = Sec

Email Atelier Magnetics if you need further assistance. [email protected]

adrian

thanks a lot Bonnie! ;)
there wasn't data sheet in the box but thanks to you I can finish my project!



 

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