khstudio
Well-known member
Has anyone tried (LISTENED TO) setting up the "Gain" stages to be more like the original Neve 2254a/e?
I have & I like it... it is a little more "Colored" but in a good way IMHO.
The way it is now, the output (183.110) isn't driving nearly as hard as the original (version A/E)... this "could be" the reason some say they hear a difference... it is "close" to the the older 2254 (no suffix) but missing the input pad.
NOTE: it is NOT BAD the way it is now so if you're happy, don't sweat it.
The mod is fairly simple to try... but not perfected yet (I'll explain later) this is why I'm starting this thread.
I know of a least one other "Clone-commercial product" that does it like I'm trying to.
The MOD:
Set the output gain resistor in 2nd gain stage (183.110) to 91ohm OR just turn the switch to +20dB... this = 100ohm on Igors.
Next, remove the 2x 5k6 resistors (voltage divider) R27 & R64. Put a 470R resistor in the R64 pad that goes to GND.
Connect pot (5k-10k... original is 5K but read below) top of pot goes to "P" on the schematic, bottom goes to "V" which is GND & the wiper goes to "L" (next gain stage, 183.110)
That's about it except there's about +4dB of gain that I just can't trim out with the "GAIN Trimmer"... even after changing the Trimmers surrounding components back to stock.
NOTE: Study the original schematic & docs to understand & see what I'm trying to do here.
You must have some knowledge of the original circuit or you won't get it. IF you'd like to try the MOD & don't understand what you're doing... PLEASE, wait until it's completely "Debugged"
OK... so I don't have to retype what happened after the mod - Here's an email I sent to a friend that is trying to do the same thing:
EMAIL #2
DISCLAIMER: I think IGOR did a GREAT job putting this together... I know he invested a lot of his time & energy into this & just want to say "Thank you". This thread is NOT meant to discourage other builders OR disrespect Igors efforts.
I have & I like it... it is a little more "Colored" but in a good way IMHO.
The way it is now, the output (183.110) isn't driving nearly as hard as the original (version A/E)... this "could be" the reason some say they hear a difference... it is "close" to the the older 2254 (no suffix) but missing the input pad.
NOTE: it is NOT BAD the way it is now so if you're happy, don't sweat it.
The mod is fairly simple to try... but not perfected yet (I'll explain later) this is why I'm starting this thread.
I know of a least one other "Clone-commercial product" that does it like I'm trying to.
The MOD:
Set the output gain resistor in 2nd gain stage (183.110) to 91ohm OR just turn the switch to +20dB... this = 100ohm on Igors.
Next, remove the 2x 5k6 resistors (voltage divider) R27 & R64. Put a 470R resistor in the R64 pad that goes to GND.
Connect pot (5k-10k... original is 5K but read below) top of pot goes to "P" on the schematic, bottom goes to "V" which is GND & the wiper goes to "L" (next gain stage, 183.110)
That's about it except there's about +4dB of gain that I just can't trim out with the "GAIN Trimmer"... even after changing the Trimmers surrounding components back to stock.
NOTE: Study the original schematic & docs to understand & see what I'm trying to do here.
You must have some knowledge of the original circuit or you won't get it. IF you'd like to try the MOD & don't understand what you're doing... PLEASE, wait until it's completely "Debugged"
OK... so I don't have to retype what happened after the mod - Here's an email I sent to a friend that is trying to do the same thing:
EMAIL #2
well, I'm tired. everything was looking good & all I thought I had left to do was adjust Igors V-Divider to the SC but I can't seem to adjust the (Unity-GAIN) Trimmer... it's a little too loud. (aprox = 4dB)
I've tried using the real Neve values in that spot but no go... not sure what's going on. Only thing I can think is that the GAIN coming INTO the 1st stage is hotter than normal the way Igor has it set up.
I think _____ pulls his SC prior to the 1st amp stage similar to the original... maybe a slight drop in gain where that divides? Not sure without seeing a schematic marked up with VOLTAGES or dBu NOT dBm.
I have notes & voltages documented... especially the ones going to the SC =measured with unity input (.774v), IGORs stock circuit - just to make sure I can get it back to that spot AFTER these mods.
BTW... with the 10k pot installed & can easily get UNITY thru the unit but it goes back to the "26dB" Range.
Setting the 183.110 Gain stage resistor to aprox. 220ohm get VERY CLOSE & is probably what I may end up doing.
As you told me, Geoff Tanner recommends not going under 220ohm anyway because it can limit frequency range... BUT I do like the "Sound" of it "Driving" more!!! (using the 91 or 100 ohm)
I wish you could get into your unit for me sometime soon to take some measurements.
I'm not sweating it that much.... I can see my options, just would like your input &/or voltages.
Hey, 1 more thing - What is R60, 18k* doing on Igors schematic?
I do have it installed & even lifted one side to see if it would help my gain issue but nothing happened... not on any Neve schematic as far as I can find.
DISCLAIMER: I think IGOR did a GREAT job putting this together... I know he invested a lot of his time & energy into this & just want to say "Thank you". This thread is NOT meant to discourage other builders OR disrespect Igors efforts.
