gefell um900 grill and mount for g7 mic?

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

seavote

Well-known member
Joined
May 31, 2006
Messages
1,085
Location
Long Beach,New York
i'll be starting a g7 soon. right now im messing with bodies and grills. i'd like to make a grill similar to the gefell um900 and mount the capsule away from the mic body like the um 900. im stuck with the body shape as im using the standard gyraf by gustav pcb.(although i'm going to try to go as small as possible and taper the top of the mic body) i have a question about connecting the capsule to the circuit. i thought i read (maybe not) that there is some problem( or potential problem) the longer the leads that connect the capsule to the mic circuit are. if so can i compensate for this in any way? gefell seems to have done this sucessfully.
 
The capsule should indeed be as close to the amp as possible because of the high impedance. What distances are we talking about? 5 cm? 20 cm? I'm not familiar with the um900, only seen it on pictures.

/Anders
 
[quote author="seavote"]i'll be starting a g7 soon. right now im messing with bodies and grills. i'd like to make a grill similar to the gefell um900 and mount the capsule away from the mic body like the um 900. im stuck with the body shape as im using the standard gyraf by gustav pcb.(although i'm going to try to go as small as possible and taper the top of the mic body) i have a question about connecting the capsule to the circuit. i thought i read (maybe not) that there is some problem( or potential problem) the longer the leads that connect the capsule to the mic circuit are. if so can i compensate for this in any way? gefell seems to have done this sucessfully.[/quote]

Well, If you are crazy enough and have excellent machining skills you could try the UM900 type of body :razz:
I would say, it depends on what capsule you are using. If it is a Chinese stuff it might be probably not worth of going for all those complications.

I am not sure how Gefell got around the "long leads" problem, but IIRC, they are using miniature tube, so most likely they mount it in the body "mouth", i.e. close to the grill.

If you want to use G7 PCB, you could mount the tube separately (again, close to the "mouth") and then connect pins to the PCB with wires.

When you design the grill, remember, it is not anly a filter, but also a resonator chamber, with all reflections, diffractions, standing waves, etc. There are three ways of fighting it--1) avoid parallel surfaces, 2) absorb the energy 3) redirect the energy. Don't dismiss capsule saddle construction (or holder, or pedestal, or whatever else they call it).
 
yes, gefell uses very interesting pedestals in their single body mics, a non linear, conical shaped part that is isolated from the body by high density silicone. A very elegant and simple design. the grills are not parallel either. they use a single solid conductor from the capsule to the electronics.

Not sure how they do it with the separated capsule designs but I expect they did their math and the grills are a specific distance, a specific mesh size etc. Don't underestimate the little things that could make a huge difference.
 
[quote author="Svart"]Don't underestimate the little things that could make a huge difference.[/quote]

Hahaha :grin:

I learnt it very young from my pino Professor, whos favorite line was:

"The difference between good and excellent is the same as the difference between excellent and great, which is the same as difference between great and immortal. This difference is... VERY LITTLE ".
 
i'm only working off pictures of the mic . but using proportions(the grille is 75 mm) i'd say the distance from capsule to the pcb is about 40 mm. what would the problem be . low signal?, rf interference? i'm building two g7s so i'll build one "traditional" g7 body and then experiment with the other. i'd like to use peluso's for both but i'll experiment with a cheaper capsule. i'll definitly post results(dont hold your breath i have other projects to finish) i'm curious though i thought the peluso cek-12 was adouble sided capsule. the peluso web site doesn't state it either way. they do how ever advertise the cek 367 as a double sided capsule. is this the capsule i should be using for the g7?i want omni cardiod and fig 8. i need a double sided capsule for this circuit no?? i believe some people have done the g7 with single sided capsule is this only a financial decision? or an aural one?
 

Latest posts

Back
Top