Frank Einstein
New member
- Joined
- Mar 14, 2009
- Messages
- 1
In keeping with Fester's cloak and dagger approach, I'll also post something under a pen name.
Transformers - Don't use the same types that are in the reissue unless you want a T.H.D. box.
Some history as best as I recall - Several years ago there were a couple of pairs of EMI TG12413 mastering compressors floating around that had been re-packaged into a 1 space chassis by David Manley. Each rack contained the original circuit cards, switches etc and the Ernest Turner meter. To the package David had added input and output transformers (possibly Sowter? can't remember) because the original module didn't have any. Anyway, the Chanandler people ended up with one of these racks and used it as a basis for the "reissue".
Trouble was that they used their Neve mic input (1272/1073) transformer on the input and a Neve type step up on the output. They went as far as to strap both transformers in parallel on the primary for even more gain that wasn't even needed in the first place. Was/is this madness, incompetence, inspired genius? It's your music, you decide...
Anyway, the internal gain structure of the thing was now completely shot in my opinion, not to mention a loading issue from putting line level inputs into a 300 ohms (actual) mic input. I'll go on - the original threshold control was now pretty useless unless you were the sort of person who likes everything pumping madly away or reduced to a pulp. To overcome this, Mr C came up with a couple of "mods" !
1/ A different method of adjusting threshold which was in the form of a simple pot on the input trasformer secondary. Their unit worked better with this form of threshold adjust but was hardly what you'd now call a reissue.
2/ I do believe the extra distortion was turned in to the T.H.D. "feature".
You can have a unit much closer to a real TG12413 by either using line level 1:1 (or so) transformers or just leaving them out alltogether like on the TG12413. I've done both. I would also opt for reverting to the original "Hold" circuit.
Adjust in situ resistors - I've seen lots of the Chanandler-Bing units and they all had exactly the same values here. Obviously no "adjusting in situ" was done. They simply copied what was in the David Manley racked pairs. I'm not sure if many know but they didn't get access to original EMI docs until many years after they had been building these reissues so there are lots of units out there that were built without actually having a schematic on hand. Maybe they now have their hands on the proper calibration procedure and build them accordingly - who knows?
The values posted above look about right to me - a good place to start anyway.
Good luck, it CAN be done
No doubt I'll now be flooded with offers to sue me :
Transformers - Don't use the same types that are in the reissue unless you want a T.H.D. box.
Some history as best as I recall - Several years ago there were a couple of pairs of EMI TG12413 mastering compressors floating around that had been re-packaged into a 1 space chassis by David Manley. Each rack contained the original circuit cards, switches etc and the Ernest Turner meter. To the package David had added input and output transformers (possibly Sowter? can't remember) because the original module didn't have any. Anyway, the Chanandler people ended up with one of these racks and used it as a basis for the "reissue".
Trouble was that they used their Neve mic input (1272/1073) transformer on the input and a Neve type step up on the output. They went as far as to strap both transformers in parallel on the primary for even more gain that wasn't even needed in the first place. Was/is this madness, incompetence, inspired genius? It's your music, you decide...
Anyway, the internal gain structure of the thing was now completely shot in my opinion, not to mention a loading issue from putting line level inputs into a 300 ohms (actual) mic input. I'll go on - the original threshold control was now pretty useless unless you were the sort of person who likes everything pumping madly away or reduced to a pulp. To overcome this, Mr C came up with a couple of "mods" !
1/ A different method of adjusting threshold which was in the form of a simple pot on the input trasformer secondary. Their unit worked better with this form of threshold adjust but was hardly what you'd now call a reissue.
2/ I do believe the extra distortion was turned in to the T.H.D. "feature".
You can have a unit much closer to a real TG12413 by either using line level 1:1 (or so) transformers or just leaving them out alltogether like on the TG12413. I've done both. I would also opt for reverting to the original "Hold" circuit.
Adjust in situ resistors - I've seen lots of the Chanandler-Bing units and they all had exactly the same values here. Obviously no "adjusting in situ" was done. They simply copied what was in the David Manley racked pairs. I'm not sure if many know but they didn't get access to original EMI docs until many years after they had been building these reissues so there are lots of units out there that were built without actually having a schematic on hand. Maybe they now have their hands on the proper calibration procedure and build them accordingly - who knows?
The values posted above look about right to me - a good place to start anyway.
Good luck, it CAN be done
No doubt I'll now be flooded with offers to sue me :
