D-EF47 Tribute To Oliver Archut U47 Build Thread.

dasnevestheo · Mar 12, 2021

Yeah I know that's why I'm pissed ! City sound pro sells some but it's pricier and lead times are very long/
Plus, he's asking me for my U47 serial number to put an order (I can always cheat with that but, makes it weird idk...).

Delta Sigma · Mar 12, 2021

I think Beesneez K7 is a fantastic capsule. Personally, I'm not as big of a fan of their M7 (in my M49b) but it still sounds great. I want to try another capsule in my M49 but I'd rather one of Dany's M7s than a Sennheiser. I have a pair Maiku K47s. They sound nice but just aren't in the same league as the Beesneez K7. Hopefully Ben/Veronica start getting back to people and we see their capsules in builds around here soon.

Saving up my pennies for one of Dany's M7s. Just waiting for my modeling career to finally take off...

Purplenoise · Mar 12, 2021

Delta Sigma said:
I think Beesneez K7 is a fantastic capsule. Personally, I'm not as big of a fan of their M7 (in my M49b) but it still sounds great. I want to try another capsule in my M49 but I'd rather one of Dany's M7s than a Sennheiser. I have a pair Maiku K47s. They sound nice but just aren't in the same league as the Beesneez K7. Hopefully Ben/Veronica start getting back to people and we see their capsules in builds around here soon.

Saving up my pennies for one of Dany's M7s. Just waiting for my modeling career to finally take off...

I have Danys m7 in my 49. It sounds awesome. I prefer it to an original Neumann k47 I had there before.

dasnevestheo · Mar 12, 2021

Does anyone here have some thoughts one sonic differences between Dany's D7 and Beesneez K7 ?
They both seems to be awesome but I'm having trouble making my mind.
Sorry I feel like I'm hijaking this thread :/

Purplenoise · Mar 12, 2021

dasnevestheo said:
Does anyone here have some thoughts one sonic differences between Dany's D7 and Beesneez K7 ?
They both seems to be awesome but I'm having trouble making my mind.
Sorry I feel like I'm hijaking this thread :/

Look for differences between k47 and m7 capsules. Usually a k47 has a little more emphasis between 1 and 3k and m7 between 2 and 5k...roughly. Very similar though with a k47 a little more lean in the low mids and with a touch more air. You should also remember that a mic is the synergy of many parts so depending on the rest of your components one might work better than the other...for your ears.

Delta Sigma · Mar 12, 2021

dasnevestheo said:
Does anyone here have some thoughts one sonic differences between Dany's D7 and Beesneez K7 ?
They both seems to be awesome but I'm having trouble making my mind.
Sorry I feel like I'm hijaking this thread :/

This is an easy one. Buy both and hide your credit card statement from your spouse.

dasnevestheo · Mar 12, 2021

hahaha yeah would do that if capsules were the sort of thing you'd buy second hand but it's obviously not

Unless I'm wrong

Purplenoise · Mar 12, 2021

Delta Sigma said:
This is an easy one. Buy both and hide your credit card statement from your spouse.

Haha...yup....this tactic keeps me alive...so far

Ricardus · Mar 12, 2021

I heard Dany is out of these boards. Hopefully he restocks soon. This will be my next mic build.

JMPGuitars · Mar 13, 2021

Purplenoise said:
Tried an amperex ef184. I got to say it sounds really good, less midforward around 2k and more extended highs and lows. That was a quick test but I think I prefer it. This particular ef184 is a little microphonic around 10/11k but not audible unless maybe I record drums. Vf14s were a little microphonic too so maybe it’s a good thing haha.
H+ at 5.05v

——a little update——

After using it in a couple of sessions and bringing up the h+ to 5.1v to achieve proper bias I got to say I really like the ef184. It works really well with the k47 capsule and it sounds really close to an original u47. Density, fullness yet really smooth. Smoother than ef800 with k47.
Now since I really liked the mic with ef800 and m7 and found it to be really smooth and big sounding I have a feeling that the ef184 might be a better match for k47 and ef800 a better match for m7 capsules. Just a feeling but I can’t say unless I try it.
Now the next thing is to figure out the way to calculate the best value for the 100k plate resistor in this build. If someone wants to school me on this it would be greatly appreciated.

I finally received my EF184 RFT tubes today. I haven't swapped tubes in the mic yet, but I did a quick trace comparison with EF800, EF80, and EF184. Quick observation is that EF800 pushes slightly higher current than EF80, and EF184 is much higher current than the other two. If anybody wants me to do a specific test, let me know. I will eventually do some recording comparisons between the 3 to see how I like them.

Purplenoise · Mar 13, 2021

JMPGuitars said:
I finally received my EF184 RFT tubes today. I haven't swapped tubes in the mic yet, but I did a quick trace comparison with EF800, EF80, and EF184. Quick observation is that EF800 pushes slightly higher current than EF80, and EF184 is much higher current than the other two. If anybody wants me to do a specific test, let me know. I will eventually do some recording comparisons between the 3 to see how I like them.

Is there a way to compare impedances? I am looking forward to hearing your impressions when you try the ef184. I got an rft as well. It sounds a little different than the amperex. The amperex is cleaner and more defined while the rft has a more smoky kinda “diffused” sound. Both sound great to my ears.

JMPGuitars · Mar 14, 2021

Purplenoise said:
Is there a way to compare impedances? I am looking forward to hearing your impressions when you try the ef184. I got an rft as well. It sounds a little different than the amperex. The amperex is cleaner and more defined while the rft has a more smoky kinda “diffused” sound. Both sound great to my ears.

Ohhh, I like that description. That smoky old school sound is exactly what I'm looking for.

Compare impedances of what? Anodes? Almost all tube traces are comparing different situations for specific currents or voltages. There is a quick test function on the uTracer, but it hates these pentodes. I'm hoping someday that improves so I can get Ra, gm, and mu readings quickly with it.

Purplenoise · Mar 14, 2021

JMPGuitars said:
Ohhh, I like that description. That smoky old school sound is exactly what I'm looking for.

Compare impedances of what? Anodes? Almost all tube traces are comparing different situations for specific currents or voltages. There is a quick test function on the uTracer, but it hates these pentodes. I'm hoping someday that improves so I can get Ra, gm, and mu readings quickly with it.

If you like that sound you should try this also as an output cap.
https://www.ebay.com/itm/133165931159
Rft 0.47uf 400v MP capacitors

innercityman · Mar 17, 2021

Hi everyone,

I will soon start to build this mic for a friend, almost ordered everything except tube and PCB kit as it's out of stock ATM. I've chosen the AMI BV8R transformer and the Beesneez body kit with their M7 capsule. I'd like to get your opinion about the best tube for this project, considering that money is not a problem for my friend, he just wants the best.

Thanks

shabtek · Mar 17, 2021

this circuit could be done point-to-point. chunger/matador has a generic pcb that allows teflon turrets (if you are in to that). studio939 store also has rubber holders for ceramic sockets; it would take some creativity to mount a pair. I have only used the dual triode with 40v filament 407A for a parallel triodes circuit, easier to mount and wire 1 bottle

did you already get the body/capsule? when did you order?

innercityman said:
Hi everyone,

I will soon start to build this mic for a friend, almost ordered everything except tube and PCB kit as it's out of stock ATM. I've chosen the AMI BV8R transformer and the Beesneez body kit with their M7 capsule. I'd like to get your opinion about the best tube for this project, considering that money is not a problem for my friend, he just wants the best.

Thanks

innercityman · Mar 17, 2021

this circuit could be done point-to-point. chunger/matador has a generic pcb that allows teflon turrets (if you are in to that).

I've build an MK47 which is really close to the D-47 and uses two 408A/6028 tubes but not available anymore. I'd like to build the D-EF47 which gives more choice of tubes and my friend wants a Telefunken NOS tube on it. You can't find any Telefunken 408A tubes, I guess they even never produced some.

did you already get the body/capsule? when did you order?

Yes I did, as described in my previous message, I've chosen Beesneez body and capsule (M7) and AMI BV8R transformer. I've ordered everything 2 or 3 days ago.

So if I wasn't clear enough, my question is... What is the best tube option for this D-EF47 ? EF800 ? EF802 ? EF80 ? And is it worth to choose an S (low noise) series like the EF802S for example ? Would an EF806S work ?

Purplenoise · Mar 17, 2021

innercityman said:
I've build an MK47 which is really close to the D-47 and uses two 408A/6028 tubes but not available anymore. I'd like to build the D-EF47 which gives more choice of tubes and my friend wants a Telefunken NOS tube on it. You can't find any Telefunken 408A tubes, I guess they even never produced some.

Yes I did, as described in my previous message, I've chosen Beesneez body and capsule (M7) and AMI BV8R transformer. I've ordered everything 2 or 3 days ago.

So if I wasn't clear enough, my question is... What is the best tube option for this D-EF47 ? EF800 ? EF802 ? EF80 ? And is it worth to choose an S (low noise) series like the EF802S for example ? Would an EF806S work ?

I have tried ef800, ef802 and ef184. They all sound good. With ef802 and ef184 I dropped the 100k plate resistor to 51k and the play better in this circuit.
Ef800 and ef802 by telefunken are very quiet and I didn’t have issues with microphonics. The ef184s can be microphonic. The ones with the mesh less so I believe. My preference for 184 is amperex. Also for the 184 I raised the b+ to 110v and h+ to 5.2v.
The ef800/802 works great with m7 style capsules. With k47 I am between 802 and 184 with the 184 sounding more “vintage”

rmburrow · Mar 17, 2021

I don't believe Telefunken built any 407A/408A type tubes. The 407A was a dual medium mu triode like the 2C51 with a 40 volt heater. The 408A was a pentode with a 20 volt heater...both types were built by Western Electric and used in early telephone repeaters. The late Oliver Archut and I had a long phone conversation about tubes used in microphones...the purists said nothing but the VF14 was acceptable...both Oliver and I agreed the old AR47 kit for the U47 (with the 13CW4 nuvistor) was not good...the general consensus was that a lot of those tubes would work, but few approached the "sound" using a VF14... Oliver mentioned the high cost of AC701's and VF14's, and his development of the U47 circuit could have been a "work around" for an expensive VF14...Oliver seemed to like the triode connected 5840 concerning the AC701...self noise of these tubes is always an issue..

innercityman · Mar 17, 2021

I have tried ef800, ef802 and ef184. They all sound good. With ef802 and ef184 I dropped the 100k plate resistor to 51k and the play better in this circuit.
Ef800 and ef802 by telefunken are very quiet and I didn’t have issues with microphonics. The ef184s can be microphonic. The ones with the mesh less so I believe. My preference for 184 is amperex. Also for the 184 I raised the b+ to 110v and h+ to 5.2v.
The ef800/802 works great with m7 style capsules. With k47 I am between 802 and 184 with the 184 sounding more “vintage”

Thanks for all the details...

JMPGuitars · Mar 29, 2021

Purplenoise said:
If you like that sound you should try this also as an output cap.
https://www.ebay.com/itm/133165931159
Rft 0.47uf 400v MP capacitors

I ordered them on the 15th, and I'll still probably be waiting another month for them to show up. I'll probably wait until then to test other things like the EF184. I hate how annoying it is to take apart the U47 body, and I love how it sounds anyway with the EF80...so laziness wins.

D-EF47 Tribute To Oliver Archut U47 Build Thread.

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