SCT-700 Tube Mic Modding (Caps/Tube) Mic not working?! Pictures inside

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Maliq

Well-known member
Joined
Apr 23, 2012
Messages
65
Hello and Greetings,
I'm back after a long time, and as soon as I got back into Soldering and Modding, trouble starts. Back then i successfully modded my T-Bone SCT 2000 mic, changed one cap with a low tolerance Polypropylene, removed two more caps for a cleaner preamp, and changed the tube and capsule and gave it a new paint job. The mic sounded so great that many clients in my Studio got curious and wanted to try out this mic, and they loved the sound (mids/smooth highs and all that).

Anyway, so I thought, OK, lets mod the lil. Brother too, the SCT-700, it should be as easy as modding the SCT-2000... yeah right

Trouble starts with the fact that the Tube is soldered..ouch, but OK..why not, lets learn something. The mic is a lil. bit smaller as the SCT-2000 means not so much space inside.. ok..Sill something I can deal with, and I was so curious that I thought, let's change more Caps and the Tube. What a pain in the A** cause you need to desolder the tube to work on the caps.

I know, many will say: Look you might not hear any changes in changing the Caps, most critical for a different sound is:
1. Capsule. 2.Tube. 3. Output tranny.. I know, but I always do sound checks after each step and I'm way to curious I just wanne learn and find out.

So far, I desoldered 2 caps (C8 and C9 - same as in the SCT-2000). Then I replaced the Tube with a Electro Harmonix 12AY7EH/6072a, replaced one Electrolyte (same as in the SCT 2000) and replaced 2 more caps with Polypropylene Caps plus the one feeding the Capsule. My solder joints are ok, i cleaned the whole board with Isopropyl (99.9% Alcohol). Soldered the old Capsule back in.. fired the mic up and....Suprise.. not working !!!!.

All i heard in my Headphones was the metallic sound when i hit the Grill with my Fingers.

So, all I can do for now is ask you guys and show you some pictures so you can see what I exactly did and maybe, one of you will say, oh look you can't do this and that and this might be the mistake.

The Original Circuit
108ixox.jpg


Moddified Circuit, I used Polypropylene Caps with pretty low tolerance (bellow 10%)
xpphnd.jpg

6yh0k9.jpg


Moddified Circuit: Underside (Solder Joints)
mkdqow.jpg


New Tube:
amxn3m.jpg


New Tube: Top, Solder joints
2q0txk2.jpg
 

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