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How important is ext. adj. for cartridge loading

Hello Folks,

A New Phono Preamplifier will soon be introduced - MSRP around $1750 - $2000

A small "focus group" questionnaire - On a Phono Preamplifier how important is it to you that MC cartridge loading is adjustable from the front panel of the amplifier? How often do you "fiddle" around with loading ? Enough to warrant the cost increase, probably about $200 for the additional switches faceplate machining etc. pricing the preamp towards the higher end of projected price?

Same goes for MM/MC switching Would external selection be preferable to a internal Jumper setting ?

Is a MUTE function desirable on the front panel as well?

MC loading is at 100, 220, 330, 500 Ohms and 47K Ohms, do you think these are OK or would you like other values?

We have designed the unit so it can be used as a fully differential unit as well with one balanced input and one balanced output, you'd need two of them for stereo, do you find this desirable? Would you prefer this mode of operation to be selectable from the outside (switch on back) or would internal jumper selection be enough?

Thanks in advance for your thought on these questions

Peter
128x128pbnaudio
lewm
13,199 posts
 
100R, 1K, 47K, 100K resistive loading, switchable from the front or rear panel. There is really not much difference in sound for loads between 100R and 1k, IMO. You could add 10K, if space permitted.
Switchable capacitative loading would be nice too, for MMs. For example, zero, 100pF, 250pF.
Switchable phono gain, between, e.g., 40 to 50db and 58 to 65db, would be icing on the cake.
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drrsutliff
863 posts
 
Avaliable MM Loading of 20K, 47K, and 100K. These would realy set this unit apart for those with HOMC, MM, and MI. Rear switch for the MM to MC would be best as previously noted. External access, front or back, for all adjustments since many individuals change cartridges often and opening the unit for each change may not desirable. Ultimatly quality components over all these convenience choices.
nikturner920
144 posts
 
Mono Switch, even on the back, would be a great feature.

Not that I listen to that many true mono records, but there are a large number of early stereo rock and jazz records with horrible L-R pan that sound great in mono.

I would have preference for exterior loading but putting them in the rear is fine if that is cheaper.
dgarretson
2,599 posts
 
As a middle ground option, consider switching on PCB via in-line micro-toggle switches as per BAT VKP10. This is more convenient than jumpers and keeps the signal path short, albeit degraded by switch contacts.
tonywinsc
583 posts
 
I have the ARC SP-15. It has front panel switchable impedance loading. It is a nice convenience having it there, but the only time I turn that knob is when I change cartridges. Once the cartridge loading is dialed in, no need to change it. I fiddled with cartridge loading years ago, but each cartridge has an optimum setting and just doesn't sound right when using other values- at least to me. I'd say it is desirable and a priority to have an easily adjustable knob. It is a secondary priority to have it on the front panel vs. the rear panel. The rear panel would be kind of a pain, but still better than soldering in resistors.
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