no iron required here folks!
impedance mismatch
- Thread starter bluebird
- Start date
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bluebird
Well-known member
I'm waiting for the day you tell us your second floor fell through...to much iron to much weight. :shock:
bluebird
Well-known member
So I took the pre to the studio and did some comparisons to my 1272's on kick and snare.
the langevin really lacked and didn't stack up to well to the 1272's.
I didn't expect it to sound as good but I thought it would be a little tougher to tell the difference.
the Langevin lacked low end and PUNCH. I could actually feel the ns-10 punching with the 1272's on the kick. I could here the attack very well. the langevins almost sounded farty. not so much that I could tell without reference to another pre, not like it was broke.
now, is this just the nature of the circuit? that is just not that fast? or is there more I can do make it sound better?
I'm using a 30uF mylar cap now instead of the original 50uF lytic. for the output cap before the TX. I would not think this would matter too much...
would it?
the langevin really lacked and didn't stack up to well to the 1272's.
I didn't expect it to sound as good but I thought it would be a little tougher to tell the difference.
the Langevin lacked low end and PUNCH. I could actually feel the ns-10 punching with the 1272's on the kick. I could here the attack very well. the langevins almost sounded farty. not so much that I could tell without reference to another pre, not like it was broke.
now, is this just the nature of the circuit? that is just not that fast? or is there more I can do make it sound better?
I'm using a 30uF mylar cap now instead of the original 50uF lytic. for the output cap before the TX. I would not think this would matter too much...
would it?
bluebird
Well-known member
Bump :grin:
Mark Burnley
Well-known member
Yea,
I agree with Butta- maybe lose the output pot altogether? As soon as you apply any attenuation it's effectively placing a resistor in series with the transformer primary, and the subsequent loading effect will definitely affect the output.
Try placing the output level pot at max, and listen to the sound of the pre. Then back it down a bit, and make up the gain, and see what happens. If you have had the output pot at say 60%, and you've relied on the preamp to boost the gain from the mic, it's possible that the stretched-gain of the pre has caused bandwidth-limiting, and combined with the series-load of the pot on the output stage, has caused a "darker" sound.
An output transformer in a circuit like this must be driven from a low impedance source.
Mark
I agree with Butta- maybe lose the output pot altogether? As soon as you apply any attenuation it's effectively placing a resistor in series with the transformer primary, and the subsequent loading effect will definitely affect the output.
Try placing the output level pot at max, and listen to the sound of the pre. Then back it down a bit, and make up the gain, and see what happens. If you have had the output pot at say 60%, and you've relied on the preamp to boost the gain from the mic, it's possible that the stretched-gain of the pre has caused bandwidth-limiting, and combined with the series-load of the pot on the output stage, has caused a "darker" sound.
An output transformer in a circuit like this must be driven from a low impedance source.
Mark
Bjorn Zetterlund
Well-known member
I reckon that output stage still looks a bit funny; I really don't know much about transformers, but it seems like if you attenuate with the fader you end up with a fairly high impedance driving a 600:600 transformer, which as far as I know is not the best way to drive them. Am I wrong?
Bjorn
...ah, looks like I didn't read the second page of this thread before posting. Like I said earlier, NQ4TS. Still, looks like I agree with the Burnmeister on this one!
Bjorn
...ah, looks like I didn't read the second page of this thread before posting. Like I said earlier, NQ4TS. Still, looks like I agree with the Burnmeister on this one!
bluebird
Well-known member
Thanks guys...
I did some more tests with kick and snare through a d112 and a 57... It seems I was driving the inputs of the pre to hard.
I put the input transformer back to 1:3. and it helped alot.
when I engaged the pad it sounded alot better. it even came close to the Neve 1272...as far as my retarded ears can tell.
the Neve had a bit more presence and a lower noise floor. the Neve attack was still stronger, but all in all I was happy with the sound of the Langevin.
I'm beginning to understand why people like the Neve stuff so much. its really great doing all these listening tests. I'm learning so much about different micpre sounds, and what over driving them does, noise floor, you know, stuff.
SO the output is 2K. I want to interface that to 600. would a mic TX backwards, say a 150:600 be more of a mach than a 600:600? having the 600 ohm winding connected to the 2K output of the transistor and the 150 going to the XLR?
I did some more tests with kick and snare through a d112 and a 57... It seems I was driving the inputs of the pre to hard.
I put the input transformer back to 1:3. and it helped alot.
when I engaged the pad it sounded alot better. it even came close to the Neve 1272...as far as my retarded ears can tell.
the Neve had a bit more presence and a lower noise floor. the Neve attack was still stronger, but all in all I was happy with the sound of the Langevin.
I'm beginning to understand why people like the Neve stuff so much. its really great doing all these listening tests. I'm learning so much about different micpre sounds, and what over driving them does, noise floor, you know, stuff.
SO the output is 2K. I want to interface that to 600. would a mic TX backwards, say a 150:600 be more of a mach than a 600:600? having the 600 ohm winding connected to the 2K output of the transistor and the 150 going to the XLR?
