Group Buy Interest?

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redddog said:
I've got 8 pres and 2 1200s coming. I'm scared to death I won't be able to cover the shipping.
Click to expand...

I don't mean to be a vulture, but seriously, if you're overwhelmed by the shipping, I'll take a pair of pres plus the shipping to you & to me off your hands...
 
81 buzz problem solved

From zmix on Prodigy and PSW:

I just wanted to post an update to the TNC 81 humm problem.

I solved it today, and it was exactly as I had theorized:

The amplifier circuits in the EQ sections were oscillating, leading to RF induced hum and overheating.

I swapped out the output transistor pair in each of the EQ amplifier circuits and voila... no noises, no hum, no problems...

To Sum up:

NOT powersupply related
NOT grounding related
NOT layout related
NOT induced EMI related
NOT wiring related.

* Attachment: Picture 49.jpg
(Size: 51.15KB, Downloaded 29 time(s))

- Chuck Zwicky

So, all we need is for the good people at Prodigy to provide us with a "transistor swap for idiots guide", and a source for parts.:D
 
With Chucks permisson, this is a little more in depth


"
The TnC 81 hum problem was exactly as I had theorized:

The amplifier circuits in the EQ sections were oscillating, leading to RF induced hum and overheating.

Chance sent me some NTE substitutions for the for the parts I requested, I swapped them out and everything is running absolutely perfectly.

I do NOT recommend that these parts (NTE-186 and NTE-187) be used under any circumstance except with an expert repair person installing them because the pinouts do NOT match the actual part and it requires some pretty dicey crossing of the leads to fit them into the board... not a good bet for reliability.


To Sum up:

NOT powersupply related
NOT grounding related
NOT layout related
NOT induced EMI related
NOT wiring related

Also, NOT manufacturer error... the part in the schematic is the part used, and it is simply the wrong part for the circuit. the fix will be to order the correct parts for each of the 4 EQ boards ( Q4 must be a BC461 - 6 and Q5 must be BC441 - 6). The input board and HP / LP boards are fine as they are..



Let me know if I can be of any further assistance in sorting this out."
 
chance said:
I do NOT recommend that these parts (NTE-186 and NTE-187) be used under any circumstance except with an expert repair person installing them because the pinouts do NOT match the actual part and it requires some pretty dicey crossing of the leads to fit them into the board... not a good bet for reliability.

( Q4 must be a BC461 - 6 and Q5 must be BC441 -
Click to expand...
swee-ee-eet! But are BC461 and BC441 (as opposed to NTE-168 and NTE-187) pin compatible replacements?

And thanks for the clips drbill -- takes the edge off, indeed! :D
 
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I've been watching the threads on the other two forums concerning the solutions to the issues with the 81's. I haven't seen any mention of problems with the 73 or the 84. Is anyone aware of any problems with these two units? I just want to stay on top of what's going on. Thanks.

Paul:D
 
P. Glaser said:
I've been watching the threads on the other two forums concerning the solutions to the issues with the 81's. I haven't seen any mention of problems with the 73 or the 84. Is anyone aware of any problems with these two units? I just want to stay on top of what's going on. Thanks.

Paul:D
Click to expand...

The only problem with the 73's is that everyone wants more.
 
Okay...

chance said:
With Chucks permisson, this is a little more in depth


"
The TnC 81 hum problem was exactly as I had theorized:

The amplifier circuits in the EQ sections were oscillating, leading to RF induced hum and overheating.

Chance sent me some NTE substitutions for the for the parts I requested, I swapped them out and everything is running absolutely perfectly.

I do NOT recommend that these parts (NTE-186 and NTE-187) be used under any circumstance except with an expert repair person installing them because the pinouts do NOT match the actual part and it requires some pretty dicey crossing of the leads to fit them into the board... not a good bet for reliability.


To Sum up:

NOT powersupply related
NOT grounding related
NOT layout related
NOT induced EMI related
NOT wiring related

Also, NOT manufacturer error... the part in the schematic is the part used, and it is simply the wrong part for the circuit. the fix will be to order the correct parts for each of the 4 EQ boards ( Q4 must be a BC461 - 6 and Q5 must be BC441 - 6). The input board and HP / LP boards are fine as they are..



Let me know if I can be of any further assistance in sorting this out."
Click to expand...

Not to be obtuse, but what is the way ahead for those of us not experienced at doing mods?

Don't get me wrong, I'm glad the problem is sorted...I'm just going to need detailed instructions on what to actually do to both order and (especially) actually replace those particular pieces of electronic "stuff" on the boards.

Again - thanks to all those who are troubleshooting this problem...what a wealth of knowledge exists on these boards!

Jay
 
vicenzajay said:
Not to be obtuse, but what is the way ahead for those of us not experienced at doing mods?

Don't get me wrong, I'm glad the problem is sorted...I'm just going to need detailed instructions on what to actually do to both order and (especially) actually replace those particular pieces of electronic "stuff" on the boards.

Again - thanks to all those who are troubleshooting this problem...what a wealth of knowledge exists on these boards!

Jay
Click to expand...
OK. First, you open the case. Next you fire up a blow torch. Then close your eyes and have at it! When the smoke has cleared, your problem is gone (literally) :D

I'm kidding...there should be detailed instructions forthcoming shortly.
 
WOW!!!!!!

I recieved my items today and am very impressed. The microphones were packaged very well, have good weight and so far are sounding good.

The first thing I did was take a couple of them apart to see what we have to work with on the inside. The ACM1200's and 6802t's have plenty of room for mod's :) I am excited to see what they already have instore for the 1200's/

New Microphones 003.webp
New Microphones 013.webp

I picked up a couple fo the 310's as well, these are the only ones I have plugged in, but so far they have a decently low noise floor and work. I should have an acoustic guitarist over tomorrow and we will compare these against some other farmiliar microhones in my collection.

New Microphones 006.webp
New Microphones 011.webp


Chance!!!!! Great job. You should get a Grammy for this.
 
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Yes, +1 on those 310 samples. I have a pair on the way - I'm hoping to hear good things!
 
there are some 310 samples up from last time. Not sure how easy they are to find, but they're here.
 
here's um, one of them - a uke in a mix.

https://homerecording.com/bbs/showthread.php?t=257516

I'm having a hard time with the search function, but I know there are some very enlightening bluegrass tracks somewhere in the microphone forum as well (maybe in this very thread?)

edit: cannabis posted a link two posts from now. I encourage you to read the whole thread, too - I think you can access it by clicking on the thread name in the upper right corner of the post
 
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