How important is ext. adj. for cartridge loading

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.

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.

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.

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