gingermrkettle
Deep vein trombonist
As Blumlein noted way back ago, resistive loading is effectively electromechanical damping of cantilever motion, the lower the resistance the higher the current so the higher the damping effect.
Phono Amp Capacitor Type Choice.
- Thread starter seyles
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- capacitors phono amp
And how does that (undoubtedly valuable) research relate to how an MC cart sounds, at different loadings?
Which, shirley ... is the important issue?
gingermrkettle
Deep vein trombonist
Lack of air and space = overdamped by too low a resistance
Loose and wooly bass = underdamped by too high a resistance
Loose and wooly bass = underdamped by too high a resistance
Aah, OK - thanks.
I can understand that - but it's the first time I've seen a direct relation between loading value and 'air' vs. 'woolly bass'.
It should not be forgotten that Herr Lucaschek ("Mr Benz") makes an MC phono stage which only offers 47k - as he believes his wood-bodied carts sound best with this loading!
gingermrkettle
Deep vein trombonist
Which it won't be for MC carts which is what we were talking about.
davidsrsb
pfm Member
That's the figure I read for the HOMC DL-110. There is only one way to get > 1mV level output and that's lots of fine wire.
LOMCs are a different ball game.
seyles
Retired Child
Well, there seems to be a difference of opinion on the resistive loading for the cartridge, from 1K to 16K; I will give it a try with loading plugs and see what I hear (no way of measuring the response and no idea of how to do it).
I have ordered some resistors and capacitors to replace components on the output stage C7 & R10, increasing R10 to 220K to increase the low frequency response, C7 is the same value, but polypropylene.
Hopefully they'll arrive tomorrow and I'll get the soldering iron out.
I have ordered some resistors and capacitors to replace components on the output stage C7 & R10, increasing R10 to 220K to increase the low frequency response, C7 is the same value, but polypropylene.
Hopefully they'll arrive tomorrow and I'll get the soldering iron out.
seyles
Retired Child
Time for an update; I replaced the C7 capacitors R10 resistors and had a quick listen, nothing night and day, but maybe a little more detail and a slight increase in the low bass.
I have some old Naim 322/4 boards in a Box with a 24v 5A linear power supply, so thought I'd put them against each other; hard to judge as i, it takes a while to swap over, ii, the output levels were about 12dB different and iii, it wasn't blind etc.
I decided to rip a couple of tracks using each of the phono stages, so I could level match and compare quickly and this showed up an additional problem:
The above is a single channel and shows clipping in the negative side, it's the same for both channels.
So now I need to work out if the pre-amp is clipping or if the A-D convertor's input is clipping.
I'm making up some 6dB attenuated leads and will check when I get some time later in the week.
I have some old Naim 322/4 boards in a Box with a 24v 5A linear power supply, so thought I'd put them against each other; hard to judge as i, it takes a while to swap over, ii, the output levels were about 12dB different and iii, it wasn't blind etc.
I decided to rip a couple of tracks using each of the phono stages, so I could level match and compare quickly and this showed up an additional problem:
The above is a single channel and shows clipping in the negative side, it's the same for both channels.
So now I need to work out if the pre-amp is clipping or if the A-D convertor's input is clipping.
I'm making up some 6dB attenuated leads and will check when I get some time later in the week.
Did you use same values as on the schematic?
Just a word of warning for Tants from parts experience and with Naim Audio, these cap should not be used in Audio and never in signal path, the sod act like a crap diode, blow up well, we used them in Magnum amps very bad idea, life far to short.
Also had problems in Jump Jet with the PTR377 Transmitter the Tants caught on fire and pilot ejected, whoops.
PLEASE DO NOT USE
Wima do some 16V-35V Polycarb cap these are great try them.
I use 10uF 16V in my pre as DC blockers.
Another tip Polystyrene cap have colour band one end that is the outer foil so solder to lowest impedance i.e. Zero or output , reduces noise pick up humm etc.
I hope this helps?
Also had problems in Jump Jet with the PTR377 Transmitter the Tants caught on fire and pilot ejected, whoops.
PLEASE DO NOT USE
Wima do some 16V-35V Polycarb cap these are great try them.
I use 10uF 16V in my pre as DC blockers.
Another tip Polystyrene cap have colour band one end that is the outer foil so solder to lowest impedance i.e. Zero or output , reduces noise pick up humm etc.
I hope this helps?
seyles
Retired Child
Thanks for the input, lots of good information, the tants on the board are only on the power supply, not in the signal.
Well I tried out the attenuated leads and all the clipping has gone via the A to D, so it seems the phono stage wasn't clipping, it was the input of the A to D.
The power rails on the Phono amp are +/- 15v, so it has lots of headroom and is probably running very hot (especially as it's over 2v p/p with a HOMC).
As the Phono stage isn't clipping and the eventual location will be on a wall bracket ~5m+ away from the rest of the system, I won't change the gain on the circuit board, I'll use attenuators at the main system so the signal is kept high as it travels the 5m.
Now I'm going do some comparisons with the Naim boards; I have fond memories running the Naim boards through a Magnum IA-150, definitely better than the on board stage.
Well I tried out the attenuated leads and all the clipping has gone via the A to D, so it seems the phono stage wasn't clipping, it was the input of the A to D.
The power rails on the Phono amp are +/- 15v, so it has lots of headroom and is probably running very hot (especially as it's over 2v p/p with a HOMC).
As the Phono stage isn't clipping and the eventual location will be on a wall bracket ~5m+ away from the rest of the system, I won't change the gain on the circuit board, I'll use attenuators at the main system so the signal is kept high as it travels the 5m.
Now I'm going do some comparisons with the Naim boards; I have fond memories running the Naim boards through a Magnum IA-150, definitely better than the on board stage.