iprovlek

Re: G7 Capsule Recommendations Please!
« Reply #60 on: December 11, 2018, 01:28:52 AM »
G7 sound much much better with 1:10 trannies....

Beyers are very good in this circuit!!! I didn't ever try Lundahl in G7....but try Beyers and Pikatrons 1:10 and bought sounds great!!!



Re: G7 Capsule Recommendations Please!
« Reply #61 on: December 11, 2018, 03:32:14 AM »
But the sample the  OP posted of the unmodified  g7 sounds  fabulous in his application, so  the transformer cannot be so bad...

ln76d

Re: G7 Capsule Recommendations Please!
« Reply #62 on: December 11, 2018, 06:55:55 AM »
If i remeber correctly the main problem was with sibilants?!? Here transformer change don't make anything. Lundahl is truly transparent, it's a fact. If change transformer in this circuit then rather not for "mojo" reason but ratio. Yes, 10:1 Beyer is pretty great for this circuit. Generally higher ratio works here good, but you need to remember that it will reduce sensitivity.
If you still have the problem with input topology and can't find solution, then back to the original input topology (are you using omni and fig.8 patterns at all?) and change polarisation voltage.
If you truly don't need fig.8 and omni, the wire it for true cardioid (without use of back diaphragm) - here you will get great senstivity and repsonse from transducer. If you would like to go back to original topology then keep 100M at the grid.
« Last Edit: December 11, 2018, 08:33:12 AM by ln76d »

Freddy G

Re: G7 Capsule Recommendations Please!
« Reply #63 on: December 11, 2018, 08:04:05 AM »
If i remeber correctly the main problem was with sibilants?!? Here transformer change don't make anything. Lundahl is truly transparent, it's a fact. If change transformer in this circuit then rather not for "mojo" reason but ratio. Yes, 10:1 Beyer is pretty great for this circuit. Generally higher ratio works here good, but you need to remember that it will reduce sensitivity.
If you still have the problem with input topology and can't find solution, then back to the input original topology (are you using omni and fig.8 patterns at all?) and change polarisation voltage.

Yes, Thanks. I will go back to original input topology. What difference should I expect to hear with lower polarization voltage?
PRR wrote:
Use #18 wire for rock-n-roll, #16 wire for classical.

ln76d

Re: G7 Capsule Recommendations Please!
« Reply #64 on: December 11, 2018, 08:35:35 AM »
Yes, Thanks. I will go back to original input topology. What difference should I expect to hear with lower polarization voltage?

I updated previous post in the meantime.
Lower senstivity definately but it should be less sibilant  - if not, then Dale capsules are much different than Neumann M7.

Freddy G

Re: G7 Capsule Recommendations Please!
« Reply #65 on: December 11, 2018, 08:41:29 AM »
cool! Will leave 100M at grid. yes, sometimes I do use omni and fig 8.
PRR wrote:
Use #18 wire for rock-n-roll, #16 wire for classical.

ln76d

Re: G7 Capsule Recommendations Please!
« Reply #66 on: December 11, 2018, 08:58:18 AM »
For polarisation voltage mod i strongly suggest to use described by me method with extra wire from PSU to get backplate polarisation voltage.  Just resign from separated heater ground and make new connection. You can then easily setup most optimal polarisation voltage for your needs.

mhelin

Re: G7 Capsule Recommendations Please!
« Reply #67 on: December 12, 2018, 05:38:15 AM »
Regarding polarisation it would be nice if someone designed a simple HV window comparator circuit to switch the back diaphragm automatically off using a relay (like the RS Pro 291-9631) when the cardioid pattern is selected on PSU.

You just need a couple of 2N5551's and 2N5401's for the job, two discrete comparators with combined output to relay using the basic schematic from http://sound.whsites.net/articles/comparators.htm#s5

I guess it would work even without the current mirror using bare resistor on top of the differential pair, simulation would tell.
Mikko

ln76d

Re: G7 Capsule Recommendations Please!
« Reply #68 on: December 12, 2018, 07:14:30 AM »
Regarding polarisation it would be nice if someone designed a simple HV window comparator circuit to switch the back diaphragm automatically off using a relay (like the RS Pro 291-9631) when the cardioid pattern is selected on PSU.

You just need a couple of 2N5551's and 2N5401's for the job, two discrete comparators with combined output to relay using the basic schematic from http://sound.whsites.net/articles/comparators.htm#s5

I guess it would work even without the current mirror using bare resistor on top of the differential pair, simulation would tell.

For this you need just relay (5V for example) and rotary switch with two sections but it can't be used in original G7 input topology - only with M49 type of input.

 

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