C12 build Apex 460 donor

[Ampzone]

Hello fist post here Just "finished" an APEX 460 build with the mic-parts CK12 capsule and typcial changes to C8 .1uf Solen,C6,R7,C4 polystyrene...c5,c3 4700pf silver mica. pins 6-9 to ground. Tab T14 tranny.  Solen,Elna caps.  NOS GE tube.  I used the stock board.  My problem is the sound is very thin and distorted.  Does anyone have voltages for the pins? Also remembered I removed C9/C10 altogether, just cut them off.  C7 also cut off.  Pin 5 is empty. 

Thanks for any help in advance.

 

[dmp]

C8 should be 1uf (not 0.1uf)
Post your actual build schematic since you probably have other problems (C8 will cause a HPF, not distortion)

 

[Ampzone]

I used this setup...

http://www.mark-o-matic.com/apex-460-mod.html

schematic/layout
https://www.google.com/search?q=apex+460+mod&rlz=1C1DVCJ_enUS407US434&espv=210&es_sm=122&source=lnms&tbm=isch&sa=X&ei=K8h6UrjKC8-jkQeTm4HIDQ&ved=0CAkQ_AUoAQ&biw=1920&bih=955#facrc=_&imgdii=_&imgrc=435J586y8WyURM%3A%3BPfTR2yLgnadSaM%3Bhttp%253A%252F%252Fwww.mark-o-matic.com%252Fmedia%252Fapex460-c12-mod.jpg%3Bhttp%253A%252F%252Fwww.mark-o-matic.com%252Fapex-460-mod.html%3B1500%3B1000

 

[Ampzone]

Voltages are 75v on pin 1. 6.3v on pin 4. 1.5v on pin 3.

 

[dmp]

Those voltages look reasonable, but you might want to try a different tube.
It would be easier to help if you posted your actual build details or pics. All the R and C values.

 

[Ampzone]

Could the polarity of the capsule be wrong?  The CK12 mic-parts capusle has 3 wires one off blue two off white.  The blue went to C4 the other two went to R11 & then ground.  I did swap the tranny to a T14 Tab. Not 100% sure that is correct either.

I will try another tube

 

[Ampzone]

Switched tubes no difference. I do Have some more test numbers.  Between pin 5-6 on the XLR connector the reading is 20ohm.  Between ground and pin 1 of the tube socket it reads 0.925k ohms.  I wanted to check to see if the T14 TAB tranny is hooked up correctly. I think it may be.

Really stumped on this one.  One area I am not clear on is where the new mic-parts CK12 capsule leads go, here I am guessing. 

Any ideas?

 

[pasarski]

This caught my eye because I'm also in a middle of C12'ish build and the mic was already working for a short period, but then suddenly went thin, quiet and distorted sounding. After couple of days trouble shooting (I luv it) found out the problem was the AMI T14 tranny. Touching the yellow wrap on the spot where two of the leads go introduced all kinds of funny noises and eventually made the mic go totally quiet so I suspect there's something wrong with the leads. I'm not sure if my mounting method (two cable ties) did the damage but if so, damn these are delicate.