emrr

For your amusement: WE 141-A preamp clone
« on: July 07, 2008, 01:43:58 AM »
Here's an example of the Western Electric 141-A preamp circuit I hacked into a recipe box years ago.  Wish I had better pics of it.   No WE 618-B here; using a 1960's era Gates Radio / Triad input transformer.   I went with a pot for fully variable NFB gain control, versus the original (3) 10 dB steps, and added an input pad.    Pretty nice high gain circuit that more people should try, given the low parts count and cathode follower output stage.  


Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g


Viitalahde

For your amusement: WE 141-A preamp clone
« Reply #1 on: July 07, 2008, 02:05:32 AM »
:thumb:

Proper!

rafafredd

For your amusement: WE 141-A preamp clone
« Reply #2 on: July 07, 2008, 12:39:29 PM »
mmm.... Do you have schematics? I have some of those gates input transformers... How does it sound in this circuit?

emrr

For your amusement: WE 141-A preamp clone
« Reply #3 on: July 07, 2008, 01:01:59 PM »
Don't remember; I sold this 5-6 years ago.  Any standard mic to grid input will work.  The lack of output transformer definitely makes the bottom tighter.   Having a NFB based volume control, the tonal color does shift dramatically with adjustment end to end.    

circuit
« Last Edit: January 29, 2011, 04:20:37 PM by emrr »
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g

rafafredd

For your amusement: WE 141-A preamp clone
« Reply #4 on: July 07, 2008, 02:13:13 PM »
wow, that´s an interesting circuit!

b2

For your amusement: WE 141-A preamp clone
« Reply #5 on: July 09, 2008, 06:53:58 AM »
Hi, :grin:

Yes ,it's an interesting schemo but it's seem to be very difficult to find information about the WE 618 transformer that is used in this preamp.did you have some information about it or what kind of transformer ratio could I used
instead of the WE 618?? It's seem to be a high gain preamp 40dB to 70dB,may be nice for ribbon mics :thumb: !

Best Regards,Bruno. :thumb:

emrr

For your amusement: WE 141-A preamp clone
« Reply #6 on: July 09, 2008, 11:48:40 AM »
'Mic to grid' is really all one needs to know.  The sec is 30K, which no one makes anymore.   Very little difference in practice from either 15K or 50K.
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g

b2

For your amusement: WE 141-A preamp clone
« Reply #7 on: July 10, 2008, 03:43:41 AM »
Hi, :grin:

Thank's for the reply,I was in this idea cause I've got interesting oep transformer from radiospares (x187b)which is done for 600/200 to 47k,so I m building  with and in my local old electronics store I've found 4 6j7 ,I've got 12sn7 instead of 6, but.. :thumb:

Good caps+tubes+ glass of red wine and all this gone right :green:


Best regards,Bruno :thumb:

emrr

For your amusement: WE 141-A preamp clone
« Reply #8 on: July 10, 2008, 11:48:47 AM »
Sounds like the right parts pile; have fun!
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g

For your amusement: WE 141-A preamp clone
« Reply #9 on: July 12, 2008, 09:49:29 AM »
Where dies the wire below R3 in the schematic go?  It goes off the top of the page?

Tim


gary o

Re: For your amusement: WE 141-A preamp clone
« Reply #10 on: January 07, 2009, 10:07:15 PM »
Wow , lush thats what I call DIY.....also would love to see the feedback path would like to knock one of these up, thanks for posting.


bluesbaz

Re: For your amusement: WE 141-A preamp clone
« Reply #12 on: January 29, 2011, 12:34:17 PM »
can someone get this schematic back up. Everything online has the top half cut off. 

emrr

Re: For your amusement: WE 141-A preamp clone
« Reply #13 on: January 29, 2011, 01:40:00 PM »
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g

bluesbaz

Re: For your amusement: WE 141-A preamp clone
« Reply #14 on: January 29, 2011, 02:08:48 PM »
Thanks!! I just thought there was some kind of flying lead freak show happening over the top of this circus.
-s

dustbro

Re: For your amusement: WE 141-A preamp clone
« Reply #15 on: January 29, 2011, 07:06:03 PM »
What's going on with pins 7+8 on the 6SN7? Havent seen anything like that before.
Does pin 1 of the 6J7 go to ground?
What's the note on R15?

Your box looks awesome!
« Last Edit: January 29, 2011, 07:25:21 PM by dustbro »

bluesbaz

Re: For your amusement: WE 141-A preamp clone
« Reply #16 on: January 29, 2011, 08:31:01 PM »
I would love to know what the comment on r15 says I'm guessing some type of gain setting. As for 7&8 of the 6sn7 thats just some fancy-ass heater artwork. 

emrr

Re: For your amusement: WE 141-A preamp clone
« Reply #17 on: January 29, 2011, 10:19:25 PM »
R15 strap dependent on need (or not) of 600 ohm load capability.
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g

dustbro

Re: For your amusement: WE 141-A preamp clone
« Reply #18 on: January 29, 2011, 11:07:01 PM »
thanks!  Is R15 + R16 620K or 820K? It's hard to tell on the scan.
Is C6 (50uF) electrolytic?
TIA
« Last Edit: January 29, 2011, 11:57:16 PM by dustbro »

dustbro

Re: For your amusement: WE 141-A preamp clone
« Reply #19 on: January 30, 2011, 02:00:04 AM »
I wanna give this circuit a try. Can you guys look over my layout for any errors? (sorry, I'm not a P2P guy  :-[)