Royer mod for NT1 is a No Go!

[mhelin]

[quote author="Gus"]
I think you might be reading the resistors wrong are they Blue 1% metal film with 4 color bands for value?
[/quote]

So I thought. These resistors have 5-band markings, the last and widest is always brown (=> 1% tolerance).

The 200 ohm is red, black, black, brown, brown. Ok, if the brown is not brown but red then it's 2k. Also if the orange I saw on "10k" resistor was really yellow then it's 100k. Maybe it's better to measure them. Got to go searching for the schematics...

 

[mhelin]

I wasn't color blind, but the 5-band code is read differently. Red, black, black, brown, brown = 2 0 0 x10 (the first brown is just a multiplier, but now there are three numbers before it) = 2000 ohms, 1% (the latter brown). The other resistors were 100k like Gus suggested. Has anyone tried the 2SA1084 transistors in other mic amps (like mxl603s)? Would they be an improvement?
--
Mikko

 

[nacho459]

Just so you know, since this thread has been revisited, I sold the NT1 a few months ago. but I'm sure there are other people out there who would want to mod this thing. So cary on. :wink: :guinness:

 

[mhelin]

Ok, I completed the action with my NT-1. I'd say the difference was not big. I removed the HF-disk mentioned in GT convertible thread, swapped the 1000pf polyprop cap to polystyrene (I think this is not what you should do as both are pretty much as good), replaced the 0.1 uF polyester caps with 1 uF pps caps, and removed the 470 pf (bypass/lowpass) caps before the 1084's and also removed the SMD caps in output stage. Wasit worth it? I'd say yes, but there isn't enough openess in the high end as with my SP C1. I may yet try replacing the J105 FET with 2N3819 which has a little bit less capacitance. Removing the HF disk maybe is the first and most important thing to do with this old NT-1 model. Also I still think that the capsule (not a 797 model in this old one) and the grille still are the limiting factors. If you could do something to the capsule like tune it to higher frequency it might be better. Or remove the inner mesh from the grille. I think it's not worth putting the tube there after all (Royer mod), but by doing these mods you can make subtle changes to NT-1's tone. NT-1A is different story after all, it seems to have a better capsule (797 one).