TNC ACMP-73 for sale - Fantastic condition....

[vicenzajay]

Jon...and Moresound

The only truly horrible thing about the 81s was the gain pop causing excess power in the emitter resistor. That was a fire hazard. Easy solution, stuff in a 3W resistor; hard solution, fix the gain pop. If the 73 lacks that problem, and is otherwise quiet, no worries.

The gain pop is the same for all the units....again, the threads here and elsewhere (gearslutz/prodigy-pro) describe this in detail. So this unit has the gain pop at the 7 o'clock position. Mitigated by cutting the trace or the resistor. I have not yet cut the trace but have had zero issues just not using that position or going "through" it when setting gain.

This unit is easily quiet enough for any tracking (to me) - noise floor rises about 5 db from -98-100db or so to -93 to -95db or so with EQ engaged (i.e. completely usable even with high freq EQ generously dialed in)...the worst units were the 81's - again described quite thoroughly in threads here and elsewhere at great length...Antichef did a very nice job with pictures, etc. showing how inferior the 81's construction/ground plane/etc. actually were. Even with that, these units have re-sold very quickly and are quite appreciated by many....in fact you can find WTB posts over on gearslutz/etc. quite often.

To the OP - let me know if you want to change your mind...the 73's and 84's sell very quickly, and I had plenty of bites last night and this morning over the unit as listed here and elsewhere. I would advise reading all the threads on these...they will help set your expectations as well as give you the history of the different units. The gain pop does exist...every single unit in the group buy had/has it unless you cut a trace (documented here...this loses you one gain position, but that's certainly not a showstopper, or even annoying for that matter, given the output gain trim's generous range) or, as Jon says, put a resistor in there.

 

[crazydoc]

The units are certainly usable even with the gain switch problem. If you can remember to zero the output gain or switch to the line setting each time you rotate from position 6 to 7 in the mic setting, you won't damage the anything (power amp, monitors) connected. However, the voltage spike is present in the first stage of the preamp whether it is in mic or line position, and is present in mic position at the output transistor, even with the output zeroed. Increasing the wattage of the emitter resistor will probably keep it from burning, but won't change the "gain pop." Over time it's hard to tell how other components will stand up to repeated voltage/current surges.

The easiest fix by far is the one described in the link I posted above. I myself did two different electromechanical fixes in two of my units (an 81 and a 73) which break the connection at position 6 before making the connection at 7, thus eliminating the oscillation/spike. However, this was a tedious and meticulous process involving disassembly of the switch and drilling and tapping a 2-60 hole in the end of the switch shaft.

In any case, they are good sounding units, and certainly worth the asking price even with no fix.

 

[moresound]

The gain pop is the same for all the units....again, the threads here and elsewhere (gearslutz/prodigy-pro) describe this in detail. So this unit has the gain pop at the 7 o'clock position. Mitigated by cutting the trace or the resistor. I have not yet cut the trace but have had zero issues just not using that position or going "through" it when setting gain.

This unit is easily quiet enough for any tracking (to me) - noise floor rises about 5 db from -98-100db or so to -93 to -95db or so with EQ engaged (i.e. completely usable even with high freq EQ generously dialed in)...the worst units were the 81's - again described quite thoroughly in threads here and elsewhere at great length...Antichef did a very nice job with pictures, etc. showing how inferior the 81's construction/ground plane/etc. actually were. Even with that, these units have re-sold very quickly and are quite appreciated by many....in fact you can find WTB posts over on gearslutz/etc. quite often.

To the OP - let me know if you want to change your mind...the 73's and 84's sell very quickly, and I had plenty of bites last night and this morning over the unit as listed here and elsewhere. I would advise reading all the threads on these...they will help set your expectations as well as give you the history of the different units. The gain pop does exist...every single unit in the group buy had/has it unless you cut a trace (documented here...this loses you one gain position, but that's certainly not a showstopper, or even annoying for that matter, given the output gain trim's generous range) or, as Jon says, put a resistor in there.

NO,NO send it right out jay! this little snafu on the unit is no big deal.

 

[antichef]

moresound - good move. Do you play electric guitar? If so, when you get the 73, plug your guitar through DI, and just run the 73 dry into your DAW or whatever. You won't be able to put the guitar down - I mean it.

I'm using mine for kick and snare right now, although I might swap in my 81s for that duty and pull the 73s back out for vox and DI guitar and bass.

 

[moresound]

Yup, I play a lot of instruments.
Electric guitar straight in huh? I can't wait. Do you drive it hard?
Bass and vocals.
I'm getting it primarily for vocals! To bad it's only one that I'm getting Wish I could get a few more ~ so as I could have them dedicated.

Do you think that the GA 73 is a close resemblance to the TnC ?

I always hate purchasing anything to do with audio in singles. I have just about two of every thing if not more of the stuff that I really like.
Let me know when you'll sell me yours....listen to me, and I've not even heard it yet ....just going by what I hear from the people here at HR that I respect.
Thanks Guys.

 

[rty5150]

i love to di bass with it!

love micing guitars with them, too! vocals sound great with them as well. i love these things. i will have a pair of each type once i get the 84 from rightonmusic.

if i had a rack of 4-6 84's i would be a pretty happy camper. i love the eq's on these things.

 

[moresound]

i love to di bass with it!

love micing guitars with them, too! vocals sound great with them as well. i love these things. i will have a pair of each type once i get the 84 from rightonmusic.

if i had a rack of 4-6 84's i would be a pretty happy camper. i love the eq's on these things.

Do you have a link?

 

[vicenzajay]

Good to hear!

i love to di bass with it!

love micing guitars with them, too! vocals sound great with them as well. i love these things. i will have a pair of each type once i get the 84 from rightonmusic.

if i had a rack of 4-6 84's i would be a pretty happy camper. i love the eq's on these things.

Glad my 81s found such a good home....I'm keeping my one remaining 73...wonderful on bass (as you say) and vocals and electric guitar. I just need to find one 84 to complement it....if you run into an extra after you find your rack, let me know.

Jay

 

[antichef]

I have yet to read a controlled side by side comparison of the GAP Pre73 and these ACMP pres, but some have said that the preamp circuits are similar (even identical), and they seem to come out of the same general area (not sure if it's the same factory), so we might assume the parts are sourced from the same place. Of course, the Pre73 doesn't have an EQ, although I heard they're about to start selling one (separately). The EQs in the 73s and the 81s (after you make the hum go away) seems nice to me, but I'm an in-the-box person and so don't have occasion to actually use them too much.

I have run mixes through the 81s with some EQ (nothing I couldn't have done with the 73s, I bet) and like the result.

I'm *not* planning to sell mine anytime soon, sorry

It is advisable to do something about the pop problem, since when the pop is happening, there's an unhealthy amount of juice being sent through a resistor that's not rated to handle it - if the switch were to remain in the pop position or somehow get stuck there, it would probably "let the smoke out of" that resistor, which actually happened to one of us here.

 

[moresound]

Thanks anti ....I'll try not to let the smoke out of the unit.

 

[dgatwood]

Right. The easy fix is to just replace the resistor in question with a 3W (or larger) wirewound resistor. No big. You can probably get the part at the Rat Shack. I got mine at Fry's.

 

[moresound]

Right. The easy fix is to just replace the resistor in question with a 3W (or larger) wirewound resistor. No big. You can probably get the part at the Rat Shack. I got mine at Fry's.

Thanks dgatwood just that one huh? Ok I'll look in to. how much larger than 3w can one go?

 

[crazydoc]

Replacing that resistor isn't going to fix anything - it will just keep that resistor from frying. You'll still have the "gain pop" voltage/current spike and all the rest of the potential damage it entails.

 

[mshilarious]

Thanks dgatwood just that one huh? Ok I'll look in to. how much larger than 3w can one go?

10W . . . 50W . . . 100W . . . or parallel a whole bunch of them. The question is how big do you need to go? And of course crazydoc's comment.

 

[moresound]

10W . . . 50W . . . 100W . . . or parallel a whole bunch of them. The question is how big do you need to go? And of course crazydoc's comment.

Ya I see crazydocs comment MSH...Is there a place to send this unit out to and properly address this issue? Or just move the 6th resister to the 7th position and be done with it by having a null at that position on the input dial?

 

[crazydoc]

To my knowledge there is no "proper fix" commercially available currently, though it is possibly being worked on.

Easiest by far is moving one end of a resistor. This can be done without removing the board from the unit. You lose one gain position, but this is of minimal importance.

 

[moresound]

To my knowledge there is no "proper fix" commercially available currently, though it is possibly being worked on.

Easiest by far is moving one end of a resistor. This can be done without removing the board from the unit. You lose one gain position, but this is of minimal importance.

Thanks crazydoc I'll try that resistor move ----the only problem being that it's already in the studio and has been put to work sense it got here, WHAT A GREAT UNIT, also what I've noticed so far is that I may not need to go past the 7 o'clock position! But I haven't used it with a ribbon as yet.

 

[kidvybes]

I have yet to read a controlled side by side comparison of the GAP Pre73 and these ACMP pres, but some have said that the preamp circuits are similar (even identical), and they seem to come out of the same general area (not sure if it's the same factory), so we might assume the parts are sourced from the same place. Of course, the Pre73 doesn't have an EQ, although I heard they're about to start selling one (separately).

...actually they will be offering a companion compressor, the COMP-54, based on the Neve 2254/64 models...it seems they put the PREQ-1 (similar to the ACMP version with EQ) on the backburner...IMHO, a good useable compressor would be more desireable...the COMP-54 is due to ship in late August and GAP offers a 1U rack shelf for combining the PRE-73 & COMP-54 for racking...

 

[vicenzajay]

Yep...

it's already in the studio and has been put to work sense it got here, WHAT A GREAT UNIT

Lovin' the one I still have. Glad you like the unit, Henry!

Really a quality pre - and as we discussed in the pm I sent, your unit and mine both have noise floors (WITH EQ engaged) below that of my two-channel Neotek Series 1E pair of pres. Really, really nice box.

I was able to find an ACMP-84 for a good price as well....so I have one of those on the way in. Should be completely set for pres at this point, and I'm looking forward to the 84 EQ as an available option as well.

 

[moresound]

Lovin' the one I still have. Glad you like the unit, Henry!

Really a quality pre - and as we discussed in the pm I sent, your unit and mine both have noise floors (WITH EQ engaged) below that of my two-channel Neotek Series 1E pair of pres. Really, really nice box.

I was able to find an ACMP-84 for a good price as well....so I have one of those on the way in. Should be completely set for pres at this point, and I'm looking forward to the 84 EQ as an available option as well.

Oh yeah....have been matching the TNC pre up with a klark Tecnics compressor and the combo works well!