Can't seem to get this to work. I see no mai, address when I click on your picture.
Put me down for two stereo sets including risers, please.
Hi Jacco noticed picture of Selectronic R core
How it mesure up?
The similar one I had few months ago (50 VA and 30VA) where way off spec.
one secondary a few volts above other...
No worse than the older series with the metal sub-frame, sheet happens.
Both bobbins of an R-core are wound simultaneously at the same rotational rate/speed of the bobbins, fully automated.
All that the girl in India has to do is cut the wire and stick a piece of tape over it.
It's the rotating bobbin that pulls the copper wire around it, sole function of the feed is to keep the tension on the wire constant.
If the contact edges of the plastic bobbin halves are less than perfect, the bobbin may slip a little during the winding.
(e.g. mishap during the injection molding, plastic mold opening a little early, or a dirty mold)
And the finishing touch is by hand, soldering the ends of the left + right windings to a pad : Monday, bloody monday !
Larger chance of mishaps with the balanced winding setup of an R-core, plus odds are higher for lower voltage secondaries.
Makes no difference for me, I live at two hours drive from the Selectronic store in Ronchin, drop by every couple of months, but I rewire these things anyway (L/R balancing of primaries and secondaries, screen exchange).
Even with a diy manual bobbin roller jig plus core clamp, still much easier for the little ones with single winding secondaries, than with a 4-parallel secondary 500VA. (just as I handpick every part, still some fools here who complain that they can't read resistor band colors)
Very old news from the messiah drunk (with his willy hanging out) => http://www.diyaudio.com/forums/anal...rch-preamplifier-part-ii-734.html#post3409723
For the small R-cores, just balancing voltages of both secondaries is easy to do yourself.
Both bobbins of an R-core are wound simultaneously at the same rotational rate/speed of the bobbins, fully automated.
All that the girl in India has to do is cut the wire and stick a piece of tape over it.
It's the rotating bobbin that pulls the copper wire around it, sole function of the feed is to keep the tension on the wire constant.
If the contact edges of the plastic bobbin halves are less than perfect, the bobbin may slip a little during the winding.
(e.g. mishap during the injection molding, plastic mold opening a little early, or a dirty mold)
And the finishing touch is by hand, soldering the ends of the left + right windings to a pad : Monday, bloody monday !
Larger chance of mishaps with the balanced winding setup of an R-core, plus odds are higher for lower voltage secondaries.
Makes no difference for me, I live at two hours drive from the Selectronic store in Ronchin, drop by every couple of months, but I rewire these things anyway (L/R balancing of primaries and secondaries, screen exchange).
Even with a diy manual bobbin roller jig plus core clamp, still much easier for the little ones with single winding secondaries, than with a 4-parallel secondary 500VA. (just as I handpick every part, still some fools here who complain that they can't read resistor band colors)
Very old news from the messiah drunk (with his willy hanging out) => http://www.diyaudio.com/forums/anal...rch-preamplifier-part-ii-734.html#post3409723
For the small R-cores, just balancing voltages of both secondaries is easy to do yourself.
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Yes did that, is not big deal to take a few turns out of offending winding but less experienced may find this a bit dounting.and forghet any under warranty claim....
Also they are much easyer to wind up than other transformers and where 26V DC is the best compromise between thermal load and regulator operation it may be a bonus.
For the price they cost a DIY session is free and part of the fun, still is not a quality part.
Lou Reed Goodnight Ladies
Now it's time....
Boards are on order.
Tonight everybody will have an invoice....
Now it's time....
Boards are on order.
Tonight everybody will have an invoice....
Says who, the Al...O guy in the cell-ar who just beta-measured a few thousand cheapos ?
What am I, the sales rep. ?
It also occurs with toroidals, happened to me more than once, and the standard toroids here for the last 3 decades are manufactured in UnKi.
At this forum, several examples even of large size toroidals with secondaries offset larger than a volt.
Back in the EI days, I could buy each part of a transformer separately around the corner.
Now, the choice is limited to an EI transformer kit with the primary already on the bobbin, minus a reel of wire for the secondary, at 4 times the cost of an all-completed off the rack.
I'd rather have just the R-cores+bobbins, but having to order a number of the, let's say R10-R260 range, by the dozens is even for me a bit over the looney top.
Number of years ago, I bought up THL's (Tang Hill in Taiwan) entire remaining stock of NOS R-cores.
(R160, came out of Proton AM-S3 integrated amps, the Taiwan company was about the 1st to use R-cores in serial manufactured gear in the mid '80s)
Far worse winding & finish quality than the Shilchar's, but I'm only interested in the cores and bobbins.
They cost peanuts thanks to THL willing to make an exception for me to send the hefty load over by ship (took 3 months to arrive)
=> http://www.diyaudio.com/forums/pass-labs/129604-lookie-lookie-ono-oh-yes-6.html#post1649634
Japan manufacture R-cores cost me more +2 decades ago than Selectronic charges now, I'd be scared to hear what the price label for original Japanese reads at the moment.
Afair on this forum, the quotes of US R-core manufacturers was scary enough.
(folks with limited mileage, and avid fashion magazine readers, may be better off sticking to the standard BOM and flatblocks. No ?)
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