MXL 960 Mod Ideas?

P

pylet2000

New member
Hello all,

I just got my MXL 960, swapped in a Telefunken 12AT7, and am really impressed with the results. My only comparison condensor mic is an MXL 992 using a Digi 002, and this tube upgraded 960 is a good bit better with much less high end garbage and better image presentation. Very cool for $179! :)

I build guitar amps, and figure modding this to be a very clean simple pattern mic would be great fun and a great intro into building/modding mics. What mic would you guys/gals suggest building into this 960?

I have the idea that it's possible to put in a good Peluso capsule, use an appropriate Cinemag transformer, and come up with a simple circuit for the tube running at the voltages supplied by the 960 power supply. Add in a couple of nice poly caps, and I should be able to get a very nice single pattern mic, correct?

Thanks in advance for any details!
 
I'm sorry, I didn't mean to steal very well deserved thunder or suggest the idea is original to me. :o Certainly not. I worded my original post very poorly. My apologies. :( (Insert groveling here.)

I'm new to tube mics, and come humbly seeking knowledge and guidance from the wiser members. I can take my questions over to the spirit of 47 thread. The parts and general schematic I had in mind are different enough to not really be a 'spirit of 47' mic though, and I didn't want to gum up or hijack that thread. :(

I'd like to use the Peluso CEK-89 single sided capsule to keep the mic single pattern, and use a 12AT7 because I have a lot of decent NOS ones. I'm not quite sure which transformer to use though. Should I do the cathode follower and then an appropriate transformer, or just find a good transformer and skip the cathode follower? Is it beneficial to run the two triodes in parallel? Is there a general schematic anywhere for a simple single pattern mic like this?

Sorry for all the newbie questions, and I'm really sorry for my poorly worded intial post... :o
 
pylet2000 said:
I'm sorry, I didn't mean to steal very well deserved thunder or suggest the idea is original to me. :o Certainly not. I worded my original post very poorly. My apologies. :( (Insert groveling here.)

I'm new to tube mics, and come humbly seeking knowledge and guidance from the wiser members. I can take my questions over to the spirit of 47 thread. The parts and general schematic I had in mind are different enough to not really be a 'spirit of 47' mic though, and I didn't want to gum up or hijack that thread. :(

I'd like to use the Peluso CEK-89 single sided capsule to keep the mic single pattern, and use a 12AT7 because I have a lot of decent NOS ones. I'm not quite sure which transformer to use though. Should I do the cathode follower and then an appropriate transformer, or just find a good transformer and skip the cathode follower? Is it beneficial to run the two triodes in parallel? Is there a general schematic anywhere for a simple single pattern mic like this?

Sorry for all the newbie questions, and I'm really sorry for my poorly worded intial post... :o
Click to expand...

I think you could end up with quite a decent mic going that route.

What schematic did you have in mind? 12AT7 is not the greatest tube for mics IMO, but I've used them and never found them too objectionable. 12AY7 is better, especially a good GE. Anywhere from a 10.5:1 to a 12:1 transformer works with that tube. In most mic applications only one side of a dual triode is used, although Actron used both sides in the Apex 460 design in a cathode follower so they could use a lower ratio transformer. Most folks here found the mic was better sounding without the cathode follower.

I'm looking at an old schematic that was designed in 1963 around an EF86 that I was thinking of trying.
 
PhilGood said:
Finally SOMEBODY got it!:D
Click to expand...

Excellent! :)

And thanks for the answers to my many questions.

I have a few decent GE 12AY7's as luck would have it. I can see why they might work better, too. Generally a sweeter sound than the 12AT7. Is there a saturation possibility in the transformer that we should be mindful of, thus encouraging the use of the medium-lower gain tubes? Running the two triodes in parallel would halve the impedance ratio required of the transformer while only amplifying the signal by about 30% more than the single triode. If there is a saturation concern, maybe a 12AU7 could be used in this mode. Is there any benefit to this? My non electrical-engineer brain seems to be thinking that having lower ratio transformers would be better for signal preservation. Strike me wrong if there is no benefit.

I haven't really found many schematics for tube mics out on the web. I guess when I stated "the schematic I have in mind", it's more the overview I have in my brain. I've really gotta work on the post clarity thing. :o

I started working on drawing up the rough schematic I was thinking about, and it was about the same overview as a U47 with a different tube and simpler capsule. Very similar to what PhilGood's "Spirit" mic is! So really this is a variation of the "spirit of 47" and does indeed belong over there. You might call it a "Spirit Lite." My subsequent questions/newbie babbling will go over there. I thought it was different because of the different capsule and tube, but really it's not...

I think I could figure out how to get this simpler "Spirit of 47" to work, but here's a final question for the folks that have spent a lot of money on building and modding mics: Am I better saving my money for the full blown true "Spirit of 47" mic plans with the multi pattern M7 capsule and PhilGood engineered circuit? Or should I make this simpler version, learn a few cool things, and see where I end up from there?

Are mic mods as addictive as guitar amp building? Gauging by PhilGood's arsenal and knowledge, I'm thinking so... :)
 
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pylet2000 said:
Excellent! :)

And thanks for the answers to my many questions.

I have a few decent GE 12AY7's as luck would have it. I can see why they might work better, too. Generally a sweeter sound than the 12AT7. Is there a saturation possibility in the transformer that we should be mindful of, thus encouraging the use of the medium-lower gain tubes? Running the two triodes in parallel would halve the impedance ratio required of the transformer while only amplifying the signal by about 30% more than the single triode. If there is a saturation concern, maybe a 12AU7 could be used in this mode. Is there any benefit to this? My non electrical-engineer brain seems to be thinking that having lower ratio transformers would be better for signal preservation. Strike me wrong if there is no benefit.

I haven't really found many schematics for tube mics out on the web. I guess when I stated "the schematic I have in mind", it's more the overview I have in my brain. I've really gotta work on the post clarity thing. :o

I started working on drawing up the rough schematic I was thinking about, and it was about the same overview as a U47 with a different tube and simpler capsule. Very similar to what PhilGood's "Spirit" mic is! So really this is a variation of the "spirit of 47" and does indeed belong over there. You might call it a "Spirit Lite." My subsequent questions/newbie babbling will go over there. I thought it was different because of the different capsule and tube, but really it's not...

I think I could figure out how to get this simpler "Spirit of 47" to work, but here's a final question for the folks that have spent a lot of money on building and modding mics: Am I better saving my money for the full blown true "Spirit of 47" mic plans with the multi pattern M7 capsule and PhilGood engineered circuit? Or should I make this simpler version, learn a few cool things, and see where I end up from there?

Are mic mods as addictive as guitar amp building? Gauging by PhilGood's arsenal and knowledge, I'm thinking so... :)
Click to expand...

You know, in going over this, maybe this is another check for leaving the mic as-is. Harvey has already said this is a fine mic in it's own right, so why mess with it? I only wanted to use the body (typical for me:D) but still, the only back-draw I see to the mic as-is is the possibility of someone laying into it hard and being sibilant. Other than that the mic is smooth and even! It's really quite good!

My mod added a dimension that has "That sound" (classic studio sound), which is what I was going for, but the mic was in the ballpark already. I'd say the capsule, since it's 90% of the sound, is on par with the Peluso CEK-89, so why waste money on that. Upgrade to the PK67 or even the PK47 and get a more usable sound!

The 960 uses both sides of the tube, so maybe you could add a transformer in place of the TL sound if iron is your thing.

There's all sorts of possibilities, but the fact remains: Marshall has made a good mic! Maybe just enjoy it!

Give it it's props!
 
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