Flatpicker
...
Yes but you are not allowed to tell what it is because its secret!Brent Casey said:
V67g mods anyone?
- Thread starter usernamebob
- Start date
travelin travis
New member
I like secrets.........go ahead and spill it.
usernamebob
New member
Okay... I emailed cinemag and he sent me back an email regarding what I would need to do
Hey, I recently posted a question on the homerecording.com forums about mods to mxl v67 mics ( http://www.homerecording.com/bbs/showthread.php?t=151857), and was told that I should talk to you about getting replacement transformers. So I was just wondering if you make any aproprately spec'd transformers, and if so what sort of price I would be looking at to get them shipped to Australia, Thanks
Bob
Dear Bob;
Thank you for contacting us about the replacement transformer problem. I took a look at the thread and have these comments:
We do not have the engineering information on the MXL microphones. Thus, we cannot simply give you a CineMag part number for your replacement transformer. These usually have fairly large bodies, so fitting in a transformer should be no problem. From what we have seen inside these microphones in the past, they usually use Chinese transformers. They will have metric sized laminations. This means that you probably will have to make some mechanical modification in order to accommodate something else.
In order to figure out what you need for any replacement transformer, we must start with the turns ratio. You can get this by unloading the secondary and putting a meter across it. Feed a signal of a known amplitude into the primary. The voltage ratio of the unloaded transformer is the turns ratio. Next, determine if it is phantom powered. (Tube microphones mainly are not, but solid state ones often are.) Finally, give us an idea of how much room you have for the replacement transformer. Large usually is good because there is more core and low frequency maximum signal level goes up.
The comments in the thread about the choice of coupling capacitors is accurate. The type of capacitor makes a big difference and is especially so with tube circuits. Higher capacitance also helps by extending the low frequency cutoff and phase shift. However, with high impedance sources you do have to pay attention to the inductance of a wrapped capacitor.
There was some talk in the thread about contacting lamination companies for samples so that you can re-laminate existing transformers. Laminations are annealed. Every high quality transformer company works with its lamination vendors to develop annealing processes to deliver the best characteristics they can. When you ask for a pinch of something you may or may not get professional audio grade laminations. Probably you will not. These high performance annealing processes are proprietary for each transformer company. No lamination company will compromise its OEM relationships to provide samples.
Mention was made of Royer microphone modification kits. They often call for a "direct box" transformer. Dave Royer is a fellow member of the Hollywood Sapphire Group and we know him well. We do have the CM-DBX (which out-performs the Jensen part) for US$45.82. However, we specifically designed a vacuum tube output transformer which is hum-bucking for that purpose. It is the CM-2480. Its turns ratio is intentionally less and gives a "hotter" signal. It sells for $41.63.
We do ship anywhere in the world that has postal service, UPS, Federal Express, etc. Of course shipping, insurance and handling charges depend on the weight, value and method of shipment.
Give me a bit more information on what you are looking for and we will be most happy to help out. Thanks for the inquiry!
Best regards,
David Geren
Vice President
CineMag, Inc.
Hey, I recently posted a question on the homerecording.com forums about mods to mxl v67 mics ( http://www.homerecording.com/bbs/showthread.php?t=151857), and was told that I should talk to you about getting replacement transformers. So I was just wondering if you make any aproprately spec'd transformers, and if so what sort of price I would be looking at to get them shipped to Australia, Thanks
Bob
Dear Bob;
Thank you for contacting us about the replacement transformer problem. I took a look at the thread and have these comments:
We do not have the engineering information on the MXL microphones. Thus, we cannot simply give you a CineMag part number for your replacement transformer. These usually have fairly large bodies, so fitting in a transformer should be no problem. From what we have seen inside these microphones in the past, they usually use Chinese transformers. They will have metric sized laminations. This means that you probably will have to make some mechanical modification in order to accommodate something else.
In order to figure out what you need for any replacement transformer, we must start with the turns ratio. You can get this by unloading the secondary and putting a meter across it. Feed a signal of a known amplitude into the primary. The voltage ratio of the unloaded transformer is the turns ratio. Next, determine if it is phantom powered. (Tube microphones mainly are not, but solid state ones often are.) Finally, give us an idea of how much room you have for the replacement transformer. Large usually is good because there is more core and low frequency maximum signal level goes up.
The comments in the thread about the choice of coupling capacitors is accurate. The type of capacitor makes a big difference and is especially so with tube circuits. Higher capacitance also helps by extending the low frequency cutoff and phase shift. However, with high impedance sources you do have to pay attention to the inductance of a wrapped capacitor.
There was some talk in the thread about contacting lamination companies for samples so that you can re-laminate existing transformers. Laminations are annealed. Every high quality transformer company works with its lamination vendors to develop annealing processes to deliver the best characteristics they can. When you ask for a pinch of something you may or may not get professional audio grade laminations. Probably you will not. These high performance annealing processes are proprietary for each transformer company. No lamination company will compromise its OEM relationships to provide samples.
Mention was made of Royer microphone modification kits. They often call for a "direct box" transformer. Dave Royer is a fellow member of the Hollywood Sapphire Group and we know him well. We do have the CM-DBX (which out-performs the Jensen part) for US$45.82. However, we specifically designed a vacuum tube output transformer which is hum-bucking for that purpose. It is the CM-2480. Its turns ratio is intentionally less and gives a "hotter" signal. It sells for $41.63.
We do ship anywhere in the world that has postal service, UPS, Federal Express, etc. Of course shipping, insurance and handling charges depend on the weight, value and method of shipment.
Give me a bit more information on what you are looking for and we will be most happy to help out. Thanks for the inquiry!
Best regards,
David Geren
Vice President
CineMag, Inc.
Marik
Pro Microphone Design
PhilGood said:
Phil,
I see you are in LA. You could just give Dave and Tom a call, ask nicely, stop by their place--if they have time they would be able to take complete measurements of the transformer. Otherwise, if you want, you can send to me and I will measure its ratio and inductance. PM me.
Marik
Pro Microphone Design
PhilGood said:
No. I suspect you are talking about static resistance. The actual impedance is much more complex and involves resistance, frequency, etc. To measure the voltage ratio you need signal generator and voltmeter. The impedance ratio will be square of the value.
usernamebob
New member
okay, so from looking through here are some posts on another message board... it seems I should do the following..
swap out c2 for a polystyrene of the same value, someone also mentioned swapping out C4 and C8 for panasonic hv's, c6 with a nice film cap and c3 with a .47 metal film or metalized polyester
and then either get a replacement transformer from cinemag if that comes through or relaminate the current transformer.
The other mod I've read about (and done) is to line the inside of the body with leukoplast tape (adhesive bandage) to deaded the reasonance. Are there any other non electrical mods that are worth doing to these mics?
swap out c2 for a polystyrene of the same value, someone also mentioned swapping out C4 and C8 for panasonic hv's, c6 with a nice film cap and c3 with a .47 metal film or metalized polyester
and then either get a replacement transformer from cinemag if that comes through or relaminate the current transformer.
The other mod I've read about (and done) is to line the inside of the body with leukoplast tape (adhesive bandage) to deaded the reasonance. Are there any other non electrical mods that are worth doing to these mics?
PhilGood
Juice box hero
OK, just got a reply from Dave
Quote:
Dear Phil;
Tom and I are in this business to encourage people to use high
performance pro-audio grade transformers. (If it was just for the
money, we would be doing something else.) Just give us a call and set
up a time to come by. Otherwise, you could send it over via UPS. We
will be happy to characterize the transformers and see if we can solve
the problem.
Best regards,
David
I will set up a time to take it there later this week. Its too far away from me to just rush over unless my schedule changes.
Phil
Quote:
Dear Phil;
Tom and I are in this business to encourage people to use high
performance pro-audio grade transformers. (If it was just for the
money, we would be doing something else.) Just give us a call and set
up a time to come by. Otherwise, you could send it over via UPS. We
will be happy to characterize the transformers and see if we can solve
the problem.
Best regards,
David
I will set up a time to take it there later this week. Its too far away from me to just rush over unless my schedule changes.
Phil
usernamebob
New member
awesome, it's good to see some good peolpe in this buisiness not just trying to get rich
usernamebob
New member
well I actualy just meant in the general audio buisiness 
Flatpicker
...
Oops! I just noticed that I posted the ratios backwards. Should be 2:1 and 7:1.Flatpicker said:
paddyponchero
New member
PhilGood said:
Hi Phil,
Glad you're still at it, I'm in the middle of my last exams ever (bit of an eternal student). Lundahl may be worth a look, maybe the LL1532? Good luck with it anyway
Paddy