Alice Phonopak phono stage - jumper settings?

[paulfromcamden]

I bought a second hand Alice broadcast phono stage to compare against my EMO stage.

Obviously before plugging it in I took the lid off to see what it looks like inside 



I noticed there are three jumpers marked LK1 LK2 and LK3



Does anyone know what these are for? I've not been able to find a manual online.

I can see the current Phonopak2 flyer states it has selectable input capacitance and selectable high pass filter so I guess these could be the same functions 

[wer]

Will have a look when i get back home, might still have some documentation.

[paulfromcamden]

Thanks Wer!

[wer]

Apparently there was a version where jumpers were available, both for changing RIAA to IEC playback equalization and three for capacitative loading. I have this information from a German sound engineer.

[paulfromcamden]

Thanks Wer - that's interesting. I emailed Alice a little while back but haven't heard back...

[Dave Gregg]

Regarding the Alice Phonopak, There are two sets of jumpers with two functions.

One set inserts (or bypasses) a 20Hz High Pass Filter (HPF). Its purpose is to remove very low frequency signals, often caused by record warps and rumble from bearings. If bearings are good and the cartridge/arm combination is good, it shouldn't be needed and should be bypassed. A combination of high-compliance cartridge and medium to high mass arm can produce a lot of low frequency signal content when playing a slightly warped record. This will be seen when the woofers of your loudspeakers are wobbling violently back and forth. The HPF will solve this, but it's better to get the cartridge/arm combination right.

The other set of jumpers have three settings, 68, 100 and 180 (pico Farads). These set the capacitive loading of the signal from the cartridge. Most cartridges need about 200 to 400 pico Farad loading to produce best high frequency sound. Typically, the cable from the record deck will provide a couple of hundred pico Farads (more if cable is long) and these jumpers will optimise this. Best done by ear. Whatever sounds best, is best! If high frequecies are dull, reduce the capicitance, if overly bright, increase the capacitance.

Hope this helps, kind regards to all,

Dave Gregg

PS German Sound Engineer's advice is quite incorrect. The equalisation in the Phonopak is very accurate and correct RIAA.

[paulfromcamden]

Thanks Dave! 

I'm wondering now if I kept the Alice stage or the EMO... I know I have one stashed away somewhere.