Does anyone have a diagram (or photo) of a st 70 wired with 2 post speaker connections (replacing original 4,8 & 16ohm taps) all I have is a multimeter and a soldering iron so go slow! I am assuming I would use the 8ohm wires???? Thanks for your help!!
3 posters
Wiring new speaker posts
Michaelbenson- Posts : 1
Join date : 2018-01-14
Age : 68
Peter W.- Posts : 1351
Join date : 2016-08-07
Location : Melrose Park, PA
Michaelbenson wrote:Does anyone have a diagram (or photo) of a st 70 wired with 2 post speaker connections (replacing original 4,8 & 16ohm taps) all I have is a multimeter and a soldering iron so go slow! I am assuming I would use the 8ohm wires???? Thanks for your help!!
Essentially, you pick the tap you want. The common remains the same.
As you move up the taps from 4 to 16 ohms, distortion reduces somewhat, damping goes up, somewhat, and power is reduced somewhat, all other things being equal. HOW TO:
a) Obtain two new output boards in the configuration you wish with the connectors you want - and make sure they will fit.
b) Label all connections to the existing outputs - carefully.
c) Remove existing outputs. To the extent possible, attempt to unsolder (not cut) the wires from the tabs. A solder-sucker might be your best friend for this endeavor.
d) Decide which tap you want as you permanent fixed-level output. Were it up to me, I would go immediately to the 16-ohm tap as the loss in actual power is all but meaningless at the levels under discussion. And, the advantages realized are helpful.
e) Fold, back, isolate and cap either with heat-shrink and/or a small wire-nut+tape the unused leads. Tuck them out-of-the-way under the chassis (DO NOT CUT THEM). You might also wish to secure them to something convenient with a small zip-tie.
f) Double-check everything - visually and mechanically.
DONE!
Now, if you want egg in your beer, you might want to connect a small double-pole, multi-position rotary switch where the mono-stereo switch is right now (unless you wish to retain that feature). Which will allow you to change taps by clicking the switch.
https://www.mouser.com/ds/2/128/c4_m-559662.pdf
eickmewg- Posts : 103
Join date : 2014-08-29
Roy at tubes4hifi can sell you triple binding posts for $25/pair. That way you can have both 4 and 8 ohm options readily available. You only use these two as the 16 ohm OT taps ordinarily go to the feedback connections on the driver board.