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
Thanks for your insightful answers - please keep them coming.

A few questions was raised - Ill try to answer them

Reason for rise in cost for adjustable selectors is of course cost of parts and the time it takes to install them - A 3/8 " Aluminum faceplate with holes etc for knobs switches cost more than a blank one because of increased machining time etc. they are made with a CNC Mill.

The unit is to be produced "in house" like all our other products and deliberately targeted to a lower price point than our Olympia Amplifiers, but of course with technology influence from them.

This is not a "Hollow State" Amplifier but a Solid State amplifier. Active devices are all FET devices - input is based upon the Toshiba 2SJ74 and its mate the 2SK170. Output is the Hitachi 2SJ79/2SK216. It's a 2 amplifier approach with the first amp having 20 or 40dB of gain depending on feedback resistor setting (MM/MC). The second amp have 24dB of gain at 1kHz and active bass boost to RIAA standards. A R/C network between the two amps provides the RIAA roll off.

Gain is set at 44dB MM and 64dB MC, as a mono block gain is 50dB and 70dB respectively.

The Amplifier is set up in Dual Mono configuration with two identical channels each with their own power transformer, on board discrete DC power regulators etc. Parts quality is very high, Dale RN60D 1% Metal film resistors throughout, Nichicon UHE series capacitors, 1% Panasonic Polypropylene film capacitors Etc.

Regarding Mono - The admittedly few Mono carts I've experienced have all had two outputs so using them with a Stereo amp was straight forward.

I have cosen only one Capacitive loading 220pF but it can be disconnected with a internal jumper making it "zero" , maybe 100pF could be added as well.

Input for several Turn Tables is a good idea - but I feel that adding a switch in series (which is how it would have to be accomplished) with the very low signal form the cartridge is not advisable.

Thanks again for your valuable input it is greatly appreciated.

Peter
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Just my thoughts. An Aesthetix Rhea meets my needs almost perfectly. The "almost" is due to absence of a mono switch on both my phonostage and linestage.

Essential to me are:
* multiple inputs (preferably 3, at least 2)
* variable loading
* variable gain (My "standard" settings are 38dB MM and 56dB MC)

Front-panel access is not that important, tho I confess that being able to do everything from the remote is a nice convenience.
Front panel loading is certainly nice and allows you to adjust on the fly to improve the sound of any given record. Rear panel RCA plugs are a bit less friendly, but still allow an easy enough adjustment. Pulling the top and replacing a resistor sucks.
Just to clarify, my desire for a mono switch is not for running a mono cart but for playback of stereo LPs (early stereo late 50s - mid 60s) that sound better in mono. Like Dopogue I lack this on my phono and line stages.

In general replacing resistors and moving jumpers sucks, micro-toggle switches at a minimum if you go internal for the settings.