Matching Sumiko SHO and Pass Labs Aleph Ono


My new PASS ALEPH ONO mates a SUMIKO SHO cartridge (2.4 mV output, 47k Ohms) with a PASS ALEPH P (the later one with the LEDs). At first, with ONO's standard MC settings, the SHO was almost too loud at the very lowest preamp volume/gain setting...and also got very shrill/grainy/distorted with energetic female singing, instrumental attacks, etc. I changed ONO's internal setting to MM and 100 pF...now sound is very smooth and relaxed, maybe a bit less detailed...but I use up ALL the volume/gain control on my ALEPH P getting the sound levels I like. Though PASS manual doesn't mention anything, are there any other MM gain adjustments inside the ONO I can make...so I can have some semblance of "preamp control" over sound levels I really don't want to change to bigger amps (Pass Aleph O's) or more efficient speakers (Alon V's). Thanks.
128x128nnauber
Run a balanced cable (XLR to XLR) from the Ono to the Alpeh P. This should give you 6 DB more gain, and probably a better sound to boot. Don't worry about turning the volume control all the way up on the P, you can't hurt anything.
The SHO is designed to work into your MM input on the Ono. The MC input is far too high in gain for it. This is why you had the terribly high volume output when you used it. Unfortunately, it seems that the SHO output is too low for the gain in the MM input of the Ono, and that is why you are not getting enough volume output from it. The normal MM inputs are designed to work with about 4mv output from the cartridge. You only have 2.4mv. This is typical for a high output MC.

The follwing is a re-print lifted from the Pass website Aleph ONO user's manual.

Disconnect power before opening cover.
On the main board you will see a set of DIP switches which are used to alter the inputconnections.Two switches, S1 and S1A, are used to select moving coil and moving magnet inputs.Positions 7 and 8 are labeled MC and MM. Select one only by depressing the switch towardthe silk screened label, which is the ON position of the switch.On these same switches, positions 1 through 3 are used to select the capacitive loading ofthe moving magnet cartridge input. You may select 100 pF, 200 pF, and 330 pF, or anycombination of these values, which are additive, for a maximum of 630 pF, or no capacitanceby simply leaving the switches in the off position. Two additional blank positions 4/CX and5/RX are available for you to solder your own loading values onto the main board. Position 6allows 1000 ohm loading of the moving magnet stage for use with some cartridges.Switches S2 and S2A are used to adjust the resistive loading of the inputs for low outputmoving coil cartridges. Switch positions 1 through 8 will load the input from 10 ohms up to1000 ohms in roughly binary steps. The switches and resistors are in parallel, so placingmore than one switch in the "on" position loads the cartridge with the two resistor values inparallel. Placing all resistors "on" will give approximately 5 ohms loading.The preamplifier is shipped with the moving coil stage enabled, with the higher gain setting(69 dB single ended, 75 dB balanced) and a 100 ohm input load. To obtain 4 dB lower gain,locate the jumper connectors for each channel next to the two large capacitors near theswitches. With the jumpers in place, the moving coil gain is the lower value. There is asecond set of jumpers on the board for additional gain adjustment of the MC stage. Theseare to the right of the first set of jumpers. Installing these decreases the gain 10dB. Either orboth sets can be used together for -4, -10, or -14dB from max. The board is marked on thesilk screen.When you are done adjusting the input gain and loading,replace and tighten the cover before reconnecting the AC linepower.
--------------------------------------------------------------------------------