Svart
Well-known member
Flatpicker,
would you say that FET circuit would be more useful for vocals or for instruments?
would you say that FET circuit would be more useful for vocals or for instruments?
What were those MXL mics that people liked to modify?
- Thread starter Svart
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Svart
Well-known member
I'm looking for something for overheads. I guess the original question has turn into this: would the 2001's be better or the 2003's for *improvement* and use in this situation? or are the capsules the same and just build that FET stage for them?
Capsules and grill are not the same. 2003 has a more open grill and what looks like a 797 audio 3 micron capsule. The 2001 has a 6 micron not 797 audio IIRC. With good electronics behind the capsules it becomes a taste issue. To mod the 2001/v67 you need to install new electronics IMO. The 2003 is a much better microphone with just a few part changes.
Maybe the best thing would be to buy two SP b1s for overheads.
Maybe the best thing would be to buy two SP b1s for overheads.
Svart
Well-known member
I was thinking SP B1 also but I have one C1 already and for that i could buy another C1 and have dual purpose mics, but that just wouldn't be DIY would it? :grin:
Flatpicker
Well-known member
[quote author="Gus"]Tim
tell them the story I think you would be better at it.[/quote]Heh, heh?
A few months ago I finally got around to modifying my MXL V93M (The Mars Music store version of the MXL 2003) via a cap upgrade Gus came up with. Gus had previously performed the same mod to his 2003 and was anxious to see if mine would sound like his.
I had recorded ?before? and ?after? clips of my wife singing ?Over The Rainbow? and sent the mp3s to Gus so he could compare them. After hearing them he immediately called me up and said ?You?re not going to believe this, but my wife sings the same song to test my mics and she sounds exactly like your wife!? He went on to say that his wife heard him playing the clips, thought it was herself and ask him ?When did we record that??
I think we?ll have to play ?The Twilight Zone? theme song to that one. :green:
I can put the clips back up and post a link if anyone wants to hear them.
tell them the story I think you would be better at it.[/quote]Heh, heh?
A few months ago I finally got around to modifying my MXL V93M (The Mars Music store version of the MXL 2003) via a cap upgrade Gus came up with. Gus had previously performed the same mod to his 2003 and was anxious to see if mine would sound like his.
I had recorded ?before? and ?after? clips of my wife singing ?Over The Rainbow? and sent the mp3s to Gus so he could compare them. After hearing them he immediately called me up and said ?You?re not going to believe this, but my wife sings the same song to test my mics and she sounds exactly like your wife!? He went on to say that his wife heard him playing the clips, thought it was herself and ask him ?When did we record that??
I think we?ll have to play ?The Twilight Zone? theme song to that one. :green:
I can put the clips back up and post a link if anyone wants to hear them.
Flatpicker
Well-known member
[quote author="Svart"]Flatpicker,
would you say that FET circuit would be more useful for vocals or for instruments?[/quote]I think the modified 2003 sounds good on either one. The main difference I hear between the 2003 and 2001 using simular circuits is that the 2003 is more clear and transparant in the lows and mids. I haven't used the B1, but compared to a B3, the modified 2003 sounds a little clearer to me.
would you say that FET circuit would be more useful for vocals or for instruments?[/quote]I think the modified 2003 sounds good on either one. The main difference I hear between the 2003 and 2001 using simular circuits is that the 2003 is more clear and transparant in the lows and mids. I haven't used the B1, but compared to a B3, the modified 2003 sounds a little clearer to me.
Svart
Well-known member
so would those mods just include *better* parts or an actual change in design?
synthi
Well-known member
I just bought a MXL V67G, do you know what specified parts are subject to change for improving the specs?
Thanks!
Synthi.
Thanks!
Synthi.
Plexibreath
Well-known member
Which would be the best MXL model to use as a starting point to build a Fet47 clone?
Kelley
Kelley
synthi
Well-known member
thanks gus, do you know what would be the best transformer to replace the stock one?
Synthi
Synthi
G
Guest
Guest
Flatpicker, Gus, others,
Did this thread shift to another?, did the pics/diagrams/schem/pcb ever materialize?
(sorry I'm late to the party)
Did this thread shift to another?, did the pics/diagrams/schem/pcb ever materialize?
(sorry I'm late to the party)
mhelin
Well-known member
This is old thread but I happened to note a thing here the other day when going through all the related posts here:
[quote author="Flatpicker"][quote author="Gus"]Tim has a nice redrawn schematic of the fet microphone circuit...[/quote]Here it is:
[/quote]
The 2N3819 pinout in the picture doesn't seem to be correct, it should be (1) S, (2) G and (3) D (TO92). Also I think Brent Casey once suggested
replacing the 2SK170 by 2N3819 with the drain and source leads reversed (!! maybe it will correct the bias problems too with this circuit !!) and with 500M resistors instead of 1G (that "mod" was for MXL2001 circuit with 2SK170, I think Brent had a job at that time @MXL and was revising the circuit all the time). Oh, and he promised 11-14 dB noise spec with that mod (the post is somewhere on HR.COM, actually it's not posted by Brent but anyway).
But this (KM84) circuit hasn't got the PNP driver 2001 used ...
-Mikko
[quote author="Flatpicker"][quote author="Gus"]Tim has a nice redrawn schematic of the fet microphone circuit...[/quote]Here it is:
The 2N3819 pinout in the picture doesn't seem to be correct, it should be (1) S, (2) G and (3) D (TO92). Also I think Brent Casey once suggested
replacing the 2SK170 by 2N3819 with the drain and source leads reversed (!! maybe it will correct the bias problems too with this circuit !!) and with 500M resistors instead of 1G (that "mod" was for MXL2001 circuit with 2SK170, I think Brent had a job at that time @MXL and was revising the circuit all the time). Oh, and he promised 11-14 dB noise spec with that mod (the post is somewhere on HR.COM, actually it's not posted by Brent but anyway).
But this (KM84) circuit hasn't got the PNP driver 2001 used ...
-Mikko
Mikko
The 5.6 should be a 56K. The circuit is the neumann 84 type one with some not needed parts removed.
The 3819s source and drain are interchangeable.
The FET microphone circuits don't have a bias problem. Fets have specs that vary alot so with simple circuits you need to select the fet. I check voltages with a circuit fragment and IDSS at working VDS in the circuit voltage supply.
The added PNP transistor(in a lot of china microphone circuits) is to allow the use of a 2:1 output transformer.
The 5.6 should be a 56K. The circuit is the neumann 84 type one with some not needed parts removed.
The 3819s source and drain are interchangeable.
The FET microphone circuits don't have a bias problem. Fets have specs that vary alot so with simple circuits you need to select the fet. I check voltages with a circuit fragment and IDSS at working VDS in the circuit voltage supply.
The added PNP transistor(in a lot of china microphone circuits) is to allow the use of a 2:1 output transformer.
Flatpicker
Well-known member
[quote author="Gus"]The 5.6 should be a 56K...[/quote]Ha! That'll teach you to compliment my circuit drawing! :razz: :wink: I'll fix that as soon as I can get to it.
BTW Mikko, thanks for bringing this up because it's probably the best non-tube mod you can do to a Chinese mic of this type - Buy a bunch of FETs (you have to select them like Gus has so often explained and your yeild will be small) and a good 7:1 - 10:1 transformer, and be done with it. I'd bet you could even get away with building it on the existing board.
BTW Mikko, thanks for bringing this up because it's probably the best non-tube mod you can do to a Chinese mic of this type - Buy a bunch of FETs (you have to select them like Gus has so often explained and your yeild will be small) and a good 7:1 - 10:1 transformer, and be done with it. I'd bet you could even get away with building it on the existing board.
Flatpicker
Well-known member
[quote author="Gus"]The added PNP transistor(in a lot of china microphone circuits) is to allow the use of a 2:1 output transformer...[/quote]...with laminates made from scrap Chinese car bumpers. :green:
mhelin
Well-known member
How about paralleling the bunch of FETs? It should lower noise but aren't there any drawbacks in this circuit (lowered input impedance, increased power consumption etc.)?
MXL2001/V67 are pretty expensive here in Finland/EU., aren't there any cheaper alternatives? I've seen some Alctron made mics, OEM (also Thomann sells them) and the TSM MT87s which also has a transformer (though it shouldn't matter if you get the LL1363 which is already canned). Wasn't the MXL capsule different than others, at least the 2003 one needs higher voltage? At least they are supposed to be better?
Alctron shop in Germany: http://www.microphonics.de/deeplinks/hsmc001.htm
TSM MT87s images:
http://www.groupdiy.com/index.php?topic=6582&highlight=tsm
MXL2001/V67 are pretty expensive here in Finland/EU., aren't there any cheaper alternatives? I've seen some Alctron made mics, OEM (also Thomann sells them) and the TSM MT87s which also has a transformer (though it shouldn't matter if you get the LL1363 which is already canned). Wasn't the MXL capsule different than others, at least the 2003 one needs higher voltage? At least they are supposed to be better?
Alctron shop in Germany: http://www.microphonics.de/deeplinks/hsmc001.htm
TSM MT87s images:
http://www.groupdiy.com/index.php?topic=6582&highlight=tsm
Parallel fets have higher input capactance. And it might be hard to match them. The 3819 type ones have lower input cap than a 170.
You can adjust the source resistor I have seen 2.2k to 10K used in older u87s I have worked on.
The mxl2003 has what looks like a 34 mm 797 audio capsule in it.
I don't know about the other microphones like the Alctron. They might be the same microphone like a MXL etc. with a different name. It is hard to tell with china built microphones who makes what microphone or what parts are made by what company.
I have a few nadys and MXLs the MXL microphones/32mm capsules(about 20) seem to be built/tested better than the three nady microphone/32mm capsules I have.
You can adjust the source resistor I have seen 2.2k to 10K used in older u87s I have worked on.
The mxl2003 has what looks like a 34 mm 797 audio capsule in it.
I don't know about the other microphones like the Alctron. They might be the same microphone like a MXL etc. with a different name. It is hard to tell with china built microphones who makes what microphone or what parts are made by what company.
I have a few nadys and MXLs the MXL microphones/32mm capsules(about 20) seem to be built/tested better than the three nady microphone/32mm capsules I have.
Flatpicker
Well-known member
[quote author="Gus"]...The 5.6 should be a 56K...[/quote]Fixed.
(Gus - I looked at the original drawing you sent me and sure enough, there is a dot between the "5" and the "6". Must have been a slip of the pen. :wink: )
(Gus - I looked at the original drawing you sent me and sure enough, there is a dot between the "5" and the "6". Must have been a slip of the pen. :wink: )
