Hi, I started a thread long ago about this here http://www.prodigy-pro.com/diy/index.php?topic=5743.msg68460#msg68460 and it resulted in nice discussions...
14757
Eric Benjamin
ericbenjamin2
Apr 26, 2011 8:55 pm
Greg, You don't say why you want to make the conversion, but for me it would be the possibility of gaining the performance of a really good transformer without...
14758
chickennerdpig@...
jackguernsey
Apr 27, 2011 9:33 am
Hello, It's indeed not too practical to try to skip the transformer. The combination of transformer followed by an active circuit seems to be both the most...
14760
Greg Macmillan
groova23223
Apr 27, 2011 10:26 am
Hi Ercic, thank you for the reply and info, and sorry to take so long to get back. I was really just thinking about the possibility of converting some cheaper...
14761
LESLIE WATTS
wattsfurniture
Apr 27, 2011 12:11 pm
Well the prodigy thread mentioned was a classic. PRRs circuit ended up being a long tailed pair using the 6.81k phantom resistors as collector resistors. To...
14762
zephyrmic
Apr 28, 2011 3:19 am
I am also interested in ribbon mics, and providing a booster circuit. A couple of questions: 1. In the PRR circuit what about using 2SC3329 transistors? Low...
14763
chickennerdpig@...
jackguernsey
Apr 28, 2011 11:03 am
Hi, ... Sure, go ! :-) And please do it especially there; it would be a pity if new info landed elsewhere in a new thread that various people then might not...
14764
LESLIE WATTS
wattsfurniture
Apr 28, 2011 11:46 am
Typically current sources are used in the tail because common mode rejection ratio is directly related to tail resistance, and a current source has ideally ...
14765
Mark Fitzsimons
greenmanhumming
Apr 28, 2011 11:57 am
I think that PRR bipolar circuit is better than a fethead, certainly lower output Z. not sure about a cloudlifter, i don't know what it consists of. most of...
14766
DRF
polititle
Apr 28, 2011 12:55 pm
on the topic of ribbon mics I am putting one together I have a 50:50K mic transformer from an old system. would this work as the transformer? thanks very much...
14767
dbranton@...
dbranton...
Apr 28, 2011 11:45 pm
Hi Everyone, I will shortly embark on building my first microphone, based on the Alice schematic. I have three questions. 1) I'm thinking of using the SMD...
14768
Richard
ricardo_lee
Apr 29, 2011 1:39 am
I've put a very headbanging circuit in my Ricardo Files directory. It won't do what you want, Greg, cos it has low maximum output and 20dB gain but it has...
14769
Roger
krokavadet
Apr 29, 2011 8:38 am
... Hi Dave, In many microphones the FET is some distance from the capsule. My own Nakamichi microphones have the FET about 20-30 mm from the capsule. You can...
14770
LESLIE WATTS
wattsfurniture
Apr 29, 2011 2:02 pm
Neat! But really...I wish you'd stop holding back on using phantom current...use all you want!! :^D I threw it up on quickie 5spice with 2N4401...will get the...
14771
LESLIE WATTS
wattsfurniture
Apr 29, 2011 2:07 pm
Never mind the offset on the transformer...I just misread the graph. Too many squiggly lines. Now to muck up the transistors... Les ... From: LESLIE WATTS To:...
14772
Mike
mikewalzy
Apr 29, 2011 3:21 pm
Does anyone have schematics for Daking Mic Pre One?...
14773
Mike Rooke
picnet2
Apr 29, 2011 7:44 pm
http://www.crystal-radio.eu/entrafometing.htm Shows how to measure the impedance of a transformer - but is this also applicable to a ribbon transformer? since...
14774
Richard
ricardo_lee
Apr 29, 2011 8:52 pm
... Er.r. The ribbon itself is about 0R2 and the primary should be much less than that in a good transformer, say below 0R07 I explain this in detail in a...
14775
RSN
ron.novy
Apr 29, 2011 10:46 pm
Well I'm no guru, but your circuit works well in simulation. I'm using the 2n4401 here as well. There is low distortion and high gain but the signal to noise...
14776
Richard
ricardo_lee
Apr 29, 2011 11:04 pm
... I would just assume floating 300R source for AC simulations and the DC of the trannie for DC; say 15R Are you assuming the usual 2k Mixer i/p? Modest...
14777
Richard
ricardo_lee
Apr 30, 2011 1:16 am
My thanks to Les & Ron for their efforts with SPICE. I need to say that I don't use SPICE cos in da old days, I wrote my own Circuit Analysis package and have...
14778
RSN
ron.novy
Apr 30, 2011 6:07 am
... Arg... Should have mentioned that it's PRR's circuit with capacitors removed. I don't like those evil caps either......
14779
RSN
ron.novy
Apr 30, 2011 6:43 am
... Ahh... This is my mistake. I took the measurements using an 'ideal' transformer with no resistance or other parameters. Fixed that and now I get about the...
14780
Richard
ricardo_lee
Apr 30, 2011 9:05 am
... Don't worry about it. Guru or not, SPICE simulations are better than my pontificating if not as good as soldering iron stuff. What current did you get on...
14781
Mark Fitzsimons
greenmanhumming
Apr 30, 2011 10:26 am
you should model with "real world" achievably (mis)matched transistors and see what transformer current you get... even a slight mismatch seems to result in...
14782
LESLIE WATTS
wattsfurniture
Apr 30, 2011 10:50 am
I think there is a lot of utility to boosters because many mic pres out there just don't have the noise performance of a Cohen or THAT configuration. Or just...
14783
Greg Macmillan
groova23223
Apr 30, 2011 11:30 am
Hi Richard and other mic builders, Wow all this info is a bit much for me ATM I haven't got a chance to try any of these circuits. I'm finding it bit hard to...
14784
RSN
ron.novy
Apr 30, 2011 11:36 am
... I'm just toying for now, but about ready to just order a bunch of parts. Could probably order enough for 5 or 10 of these for well under $20US... ... ...
14785
Richard
ricardo_lee
Apr 30, 2011 7:25 pm
I've updated Ribbon2.gif in my Files directory. D1/2 prevent Q1/2 Vbe from Zenering and "some" protection to the ribbon. Bias chain tweaked to allow 4x hfe...
14786
LESLIE WATTS
wattsfurniture
Apr 30, 2011 10:30 pm
... It's gotta be goof proof for sure. Musicians are gonna be drunk/stoned much of the time, and if there's a switch they'll flip it...the wrong way. And...
