Hi all,
My horn speakers are very efficient and I'm getting a small amount of hum coming through from my Sun 2a3 amp. Will I loose any sound quality if I put a simple fixed LPad on them to lower efficiency a bit? It's not bad but we're always looking for improvements. With drivers and xover the impedance is around 16ohm and I wouldn't mind dropping this a bit through the LPad if possible.
Main thing is I don't want to loose any of the 2a3's beautiful music.
Thoughts please.
Cheers
My horn speakers are very efficient and I'm getting a small amount of hum coming through from my Sun 2a3 amp. Will I loose any sound quality if I put a simple fixed LPad on them to lower efficiency a bit? It's not bad but we're always looking for improvements. With drivers and xover the impedance is around 16ohm and I wouldn't mind dropping this a bit through the LPad if possible.
Main thing is I don't want to loose any of the 2a3's beautiful music.
Thoughts please.
Cheers
Lpads do not change the signal quality, only level.
However, they do not separate signal from hum, they attenuate both.
You should work on eliminating hum some other way.
However, they do not separate signal from hum, they attenuate both.
You should work on eliminating hum some other way.
Instead of Lpad, have you tried current drive with resistor in series with the speakers? Like NP does?
The noise doesn't increase with volume that why I thought LPad might work.
So just a resistor in series? Simple as that? Might try it, nothing to loose.
So just a resistor in series? Simple as that? Might try it, nothing to loose.
Yup, simple as that.
It will force you to turn the volume higher, but if the hum is constant, not depending on the volume setting, this may help.
Start with 8, go up to 30 ohm and see.
Good luck.
I'm with the fix the hum bunch, actually.
Your amplifier's output is pretty modest. I personally would increase the size of the 47 µF ÷ 500 V capacitor (following the choke, on the right) to a 220 µF device; while changing devices, I'd also change the 'front end power supply capacitor' from its 47 µF at 350 V to 470 µF, 350 V. They're only about $6.00 ea on Mouser.
That is, of course, if I got the right Sun 2A3 schematic.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
Your amplifier's output is pretty modest. I personally would increase the size of the 47 µF ÷ 500 V capacitor (following the choke, on the right) to a 220 µF device; while changing devices, I'd also change the 'front end power supply capacitor' from its 47 µF at 350 V to 470 µF, 350 V. They're only about $6.00 ea on Mouser.
That is, of course, if I got the right Sun 2A3 schematic.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
Thanks guys, not sure I get which ones to change. One is saying increase capacitors and someone else says reduce to give the 5u4 a break.
The first cap after the tube rectifier (5U4) needs to be within the specs of a 5U4....going bigger stresses the tube and it can arc over......sometimes toasting the tube. Going smaller makes life for the 5U4 easier....it's been years but I think that a 47uf after the 5U4 is well within spec for typical 2A3 B+ voltages.
The caps after the first one can get larger to potentially reduce hum and make a stiffer power supply.
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