It's easy to insert a phase reversal switch between the tone-arm and the
pre-amp. I had the engineers at CHFI make me one on the turntable I was using
for transferring 78s (never mind how I managed to justify that!) and had
another engineer at CJRT do one for the Technics (this was portable). Later
when I was getting my old Dynaco pre-amp serviced I had the repairman do a
phase reversal in it..he just used the tape loop switch, which wasn't ever
Robert Hodge wrote:
> In the spirit of options , I offer these thoughts.
> Some years ago I wired a 16 inch Pickering tonearm with a phase
> inversion switch. The DPDT switch is mounted in the channel in the
> tonearm portion of the assembly and consequently avoids adding mass to
> the cartridge mount. The switch is a subminiature " MICRO" type that
> easily fits into the channel. The hole for the toggle was located above
> a cutout in the arm making installation very easy.
> The bearings in the pivot were removed and cleaned/ lubricated with a
> very thin grease . The needle bearings for the pickup were cleaned and
> left dry.
> Completly trouble free service for the last twenty or more years.
> Why not ( If you have a second cartridge to spare ) wire a second head
> shell with the phase invertion already installed ? I'm guessing that
> your tonearm has a socket and that the shell isn't hardwired into the
> arm assembly.
> Please excuse me if I sound insulting as it isn't meant to be in any
> way shape or form.
> Best !
> Bob Hodge
> Robert Hodge,
> Senior Engineer
> Belfer Audio Archive
> Syracuse University
> 222 Waverly Ave .
> Syracuse N.Y. 13244-2010
> 315-443- 7971
> >>> [log in to unmask] 5/27/2006 7:54 PM >>>
> Thanks Marcos.
> ----- Original Message -----
> From: "Marcos Sueiro" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Saturday, May 27, 2006 7:57 AM
> Subject: Re: [ARSCLIST] lateral cut switch
> > Here is a good explanation of the principle (3rd paragraph) and how
> to do
> > it.
> > <http://perso.wanadoo.fr/jlf/erepro2.htm>
> > --On Friday, May 26, 2006 1:40 PM +0200 George Brock-Nannestad
> > <[log in to unmask]> wrote:
> >> From: Patent Tactics, George Brock-Nannestad
> >> Hi Phillip and Graeme,
> >> you posted:
> >>> On 26/05/2006 you wrote;
> >>> ph> Cool cartridge/headshell modification. I never would've
> >>> ph> thought of this. Now how does it work (so I can do it)?
> >>> I wouldn't recommend you do this, it raises the mass of the
> >>> by some considerable degree (the switch probably weighs more than
> >>> headshell) and this is not a good idea at all. Far better to
> >>> the switch further down the line.
> >> ----- actually it is a good idea. It enables the reversal of
> polarity of
> >> the floating (non-grounded) coil in a stereo pickup, thereby
> >> summing to vertical instead of horizontal. I have used it for 30+
> >> only, precisely because of the mass you mention, Graeme, mine is a
> >> switch I obtained from a company that manufactures hearing aids,
> with no
> >> metal, except for switch blades and contact points (gold, rather
> >> silver). The rest is plastic. Soldering needed precision work. I
> >> not have a preamplifier that permitted doing reversal at the time.
> >> Kind regards,
> >> George
> > Marcos
> > http://tinyurl.com/kqdbk