MXL 603s... crappy capsule?

[Marik]

Brad,

Thank you for checking the trafo.

[quote author="lampas"][quote author="Marik"]Today I put into 603 a 6111 tube, wired as a direct coupled CF. The output trafo is a 1:10.5 Cinemag 2840, which is just the right size to fit the body. As I thought and said before, the capsule is actully very very good and I like the mic.[/quote]


Would you post schematic for it ? [/quote]

As I have said before, I still need to do some testing. I am struggling with the idea of having direct copuled CF and using 1:10 trafo, instead of getting signal straight from anode. They definitely sound different and I am still to deside which one to choose. In fact, I like the best "straight" CF with 1:10 trafo, but signal becomes way too low, bordering with unusable for many applications.
I guess, I should not mention things until I thoroughly test them out, but on the other hand, it probably gives ideas to folks, who like to try things themselves and deside what's good and what suits the best their applications...(???)

 

[bradzatitagain]

[quote author="Marik"]Brad,

Thank you for checking the trafo.

[quote author="lampas"][quote author="Marik"]Today I put into 603 a 6111 tube, wired as a direct coupled CF. The output trafo is a 1:10.5 Cinemag 2840, which is just the right size to fit the body. As I thought and said before, the capsule is actully very very good and I like the mic.[/quote]


Would you post schematic for it ? [/quote]

As I have said before, I still need to do some testing. I am struggling with the idea of having direct copuled CF and using 1:10 trafo, instead of getting signal straight from anode. They definitely sound different and I am still to deside which one to choose. In fact, I like the best "straight" CF with 1:10 trafo, but signal becomes way too low, bordering with unusable for many applications.
I guess, I should not mention things until I thoroughly test them out, but on the other hand, it probably gives ideas to folks, who like to try things themselves and deside what's good and what suits the best their applications...(???)[/quote]

Marik, 6021 will give you 75% more gain than 6111 IIRC, also twin triode seperate cathodes. Let's see what the book says...6.3 filament, 30mA, 165V plate max, 100V typical, capacitances are close enough to be identical, plate resistance and mu a little lower. GE manual states "amplification factor" of 6111 = 20, 6021= 35, that's probably for each triode seperately (?). $5 new/$2.50 used at www.tubesontheweb.com, Phil Frakes in OK, the guy that invented that computer interface box for the Hickok Card-o-Matic testers. (leave a few new ones for me, por favor!)

Matbe there's a good book to refer folks to that describes various tube circuits and their uses, direct coupled CF, White CF, resistance coupled, etc., etc. Some kind of tube circuit primer. And there's also TubeCAD, that's an education in itself.

 

[bradzatitagain]

Marik: What if you paralleled the triodes?

A general capacitor question for anybody out there: Aside from size constraints, wouldn't mylar caps be as good as polystyrene caps in mic circuits? Is it low DC leakage we're looking for as well as replacing 'lytics in stock circuits with cheapo parts?

An answer my own book question, BTW, Bruce Rozenbilt's
"The Beginner's Guide to Tube Amplification." And "Audio Reality" is a good read too.

 

[Marik]

Marik, 6021 will give you 75% more gain than 6111 IIRC, also twin triode seperate cathodes.

That's exactly why I did not want to use 6021 (which I also have)--to keep smaller core output trafo out of saturation. Strictly speaking, this Cinemag 1:10 trafo is not the best ratio for both tubes. For 6111 it should be roughly like 1:4.5, and for 6021--1:5.7, but it is what I had. Probably later I will try to wind my own, with proper ratio, or ask Tom at Cinemag for a custom one.

Matbe there's a good book to refer folks to that describes various tube circuits and their uses, direct coupled CF, White CF, resistance coupled, etc., etc. Some kind of tube circuit primer. And there's also TubeCAD, that's an education in itself.

Have a look at Valve Amplifiers by Morgan Jones, 2nd edition. And of course, Radiotron 4th edition is a must.

Marik: What if you paralleled the triodes?

I don't like paralleled tube sound.

 

[Flatpicker]

[quote author="Gus"]Do you want him to hold yor hand as well?[/quote]Isn't that an old Beatles song? ("I wanna hold yer haaaannndd...." Oh, nevermind.) :razz:

 

[Guest]

Marik Wrote:
I guess, I should not mention things until I thoroughly test them out, but on the other hand, it probably gives ideas to folks, who like to try things themselves and deside what's good and what suits the best their applications...(???)

I enjoy seeing the thought process, it definetly gives me ideas and I apreciate you sharing. Now if I only spent more time with mics and less on hurricane cleanup! Time for a :sam:

 

[bradzatitagain]

[quote author="Marik"]

Marik, 6021 will give you 75% more gain than 6111 IIRC, also twin triode seperate cathodes.

[quoteThat's exactly why I did not want to use 6021 (which I also have)--to keep smaller core output trafo out of saturation. Strictly speaking, this Cinemag 1:10 trafo is not the best ratio for both tubes. For 6111 it should be roughly like 1:4.5, and for 6021--1:5.7, but it is what I had. Probably later I will try to wind my own, with proper ratio, or ask Tom at Cinemag for a custom one. [/quote]

Just got an email from David Geren at Cinemag, quoting $50 each for a custom wind, minimum order 100. Elsewhere here I've read reports to the contrary, custom batches as small as 12, less than $40 per. ??? I'm guessing they have inconsistent communications. I can never figure out why you gotta beg some people to give them your money, y'know?

 

[ebartlet]

I have a pair of MXL600's. I know the capsule is different. does anyone know if the circuit is the same? Are 603 capsules available?

 

[Flatpicker]

[quote author="ebartlet"]I have a pair of MXL600's. I know the capsule is different. does anyone know if the circuit is the same? Are 603 capsules available?[/quote]I'm not sure of either, but I bet the guys at MXL could give you answers to both. Give them a call and you probably want to talk to "Scott" when you do. Let us know what you find out! :grin:

 

[bradzatitagain]

[quote author="ebartlet"]I have a pair of MXL600's. I know the capsule is different. does anyone know if the circuit is the same? Are 603 capsules available?[/quote]

I recently rcvd a reply from MXL re: capsule sales. They said capsules are not available seperately as they are the main cost to them in the mic.

 

[bradzatitagain]

[quote author="Marik"]

That's exactly why I did not want to use 6021 (which I also have)--to keep smaller core output trafo out of saturation. Strictly speaking, this Cinemag 1:10 trafo is not the best ratio for both tubes. For 6111 it should be roughly like 1:4.5, and for 6021--1:5.7, but it is what I had. Probably later I will try to wind my own, with proper ratio, or ask Tom at Cinemag for a custom one.
[/quote]

Marik, what instruments/amps have you recorded w/ the mic so far? What do you think would overload the transformer, &/or what would your intended use be for this particular mic, i.e., spaced pairs, etc etc?

 

[Marik]

[quote author="bradzatitagain"]

Marik, what instruments/amps have you recorded w/ the mic so far? What do you think would overload the transformer, &/or what would your intended use be for this particular mic, i.e., spaced pairs, etc etc?[/quote]

It is hard to answer your question, as as often, I did it, listened and moved on. I did not make any extensive experiments, and checked it only on my voice and acoustical guitar. Later I will probably try my piano to see its overload capabilities.
BTW, if you are interested, I can post some guitar clips.

 

[Guest]

I am Marik! Hearing with your own ears is always the best judgement. Thanks!

 

[Sleeper]

I'm just switching the caps on my 603s this afternoon, looking through mouser catalog, does anybody have a part # for the 1uf films.
You all were right when you said this was a tough fit, these things need to be tiny.
Thanks
Sleeper

 

[BradAvenson]

Check out this part. (on mouser)

5989-100V1.0

Its one of the smaller film caps avaliable. I don't know what they used in that mod, but this one may work.

 

[Sleeper]

Thanks Brad,
I missed that page, that's smaller than everything else by about 5mm
that looks like it just might do it.
:thumb:
Thanks
Sleeper

 

[Flatpicker]

[quote author="Sleeper"]I'm just switching the caps on my 603s this afternoon, looking through mouser catalog, does anybody have a part # for the 1uf films...[/quote]1uF? In a 603? Last time I looked there wasn't room for anything bigger than the Panasonic 0.22uF miniature metal films. Did I miss something here?

 

[Sleeper]

Hey Tim,

I'm pretty sure the stock cap was marked I played with MXL603 a lot. To make it sound more or less presentable you should change all the signal caps for good quality polystyrenes, or polypropilenes. One from capsule--use around 1000pf polystyrene.
If you want to get a better bass, you should use for signal caps from FET (two 0.22Mf) at least 1Mf, and finding right size films to fit might be tricky. If you absolutely cannot find them, try 2.2Mf small Black Gates there

It's trick all right... but i think it can be squeezed. I'll know tommorrow if the part Brad suggested fits, cause it's on the way.
The stock one says 1000 on the side so I assume its also 1Mf/uf

Kelly

 

[Gus]

I don't know of any 1uf films that can fit. The biggest I fit was .47uf at 50V PETS. for the .22ufs in Nady cm90s

 

[Flatpicker]

Hi Sleeper,
I?m betting the ?stock? one marked 1000 that Kelly refers to is 1000pF, and I agree 100% that polystyrene rules here between the capsule and the FET. As for the .22uFs, I have to agree with Gus ? larger metal films won?t fit. Also, in this part of the 603?s circuit, I think that .22uf may be large enough (unless you are trying to ?accurately? record a thunderstorm or something :wink: ).

I?ve never tried the Black Gates, but those Panasonic metal films are great caps for audio as far as I can tell, and in this case quality is better than larger values, IMHO. I?m not trying to slam the BG?s ? just saying give the Pan 0.22s a try. Gus modified his 603s this way, loaned them to a studio to try, and now he can?t get them back! That says something right there?