Superline plus Hicap2 fault

Posted by: vintageaxeman on 04 December 2017

Had no problem with my Superline/Hicap2 until today, when a very deep sounding rumble (like a steamroller going over speed bumps in the next street) sounded through my system today. Seemed to cause an HF distortion which sounded like my cartridge mistracking badly. Gets very loud if the volume is turned  up.... and disappears from my system if I turn just the Hicap2/Superline off. Also, immediately following the switch-off, I can hear what sounds like caps discharging (pop, pop, pop) about 5 times, coming through both speakers. Any (and cheapest) suggestions please folks? Thank you, David

Posted on: 05 December 2017 by Richard Dane

Is it the same whether the tonearm leads and earth wire are disconnected from the Superline?

Posted on: 05 December 2017 by vintageaxeman
Richard Dane posted:

Is it the same whether the tonearm leads and earth wire are disconnected from the Superline?

Hi Richard. Just tested this afternoon. No, the 'deep pulsing' noise isn't there if the phono cables and lead aren't connected.

I have also found that if I touch the top-plate, even momentarily, it can cause this noise to happen, or if I hold my finger ON the turntable top-plate (or in fact ANY metalwork on the LP12, tonearm or even the Superline itself), it goes away.   If I disconnect the earth lead on the tonearm cable, from the rear of the superline, there is a VERY loud hum through the speakers.   So it seems that it is something at the turntable end which is causing it....  To me it sounds like something isn't wired up properly, but it had all been working beautifully for months, so I find it a bit of a conundrum....

Just in case you need to know...The LP12 has a Mober DC motor unit and an Ittok/Akiva...the Ittok was rewired professionally a year or so ago, and the tonearm cable has been working perfectly since I bought it at about the same time.

Thank you, David

Posted on: 05 December 2017 by Richard Dane

Hmm.. yes, it does sound like something at the TT end is the culprit here.  I don;t know anything about the Mober DC motor.  I would suggest you contact an LP12 specialist and take things from there. Quite a few who are Naim dealers too...

Posted on: 05 December 2017 by The Strat (Fender)

I had a similar thing to this when we first installed the Vetere PSU on my Roksan.  It was easily sorted but don’t ask me how but as Richard says you need an LP12 dealer to have a look. 

Posted on: 05 December 2017 by vintageaxeman

Thanks! Tomorrow I will disconnect the power supply and see if the problem persists...Cheers, David

 

Posted on: 15 December 2017 by vintageaxeman

When I increased the Superline's input capacitance to 1uF, the motorboating noise problem disappeared. Peter of Cymbiosis recommended changing the capacitance value, so many thanks to him as well as to any of you who offered advice.

Peter said he had come across similar problems a number of times previously.