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In Reply to: RE: Sorry IF I have asked this before, as well as all that, what about an NTC on the HT/B+ secondary posted by Timbo in Oz on June 07, 2012 at 16:29:01
I have never found the in rush limiter to reduce voltage on turn on,only current if you were to measure it. It does prevent arcing of tubes and reduces the chance of damage to filter caps ..Mcintosh used them for years in the Mc240,Mc275,Mc225,and the monos with a SS power supply.
They do work well tho.
When problems become increasingly difficult,we can always rely on our collective knowledge and seek relief.
Follow Ups:
So, a second one on the HT/B+ wouldn't hurt.
There's a snubbed full-wave SS rectifier set-up using way overrated SoftRecovery diodes in each amp, the tech added an NTC on the primary in each.
Since the early 90s I don't do HT work, promised TMFW&F! But I could always solder one in when they've been off a couple of days, no? ;-)!
Note that a post in response is preferred.
Warmest
Timothy Bailey
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
So, a second one on the HT/B+ wouldn't hurt.
Its actually preferred.
When problems become increasingly difficult,we can always rely on our collective knowledge and seek relief.
Likely to be rebuilding two TL12 Plus soon. The mono versions with an EF86 input tube. Both small signal tubes will become a 6DJ8 twin-triode one triode only, and a 6CG7 and a FET CCS.
For two bass channels up to 150 - 400 hz 3rd order filter, possibly a knee'd type, a PLL* 1st then cascaded by a 2nd order active low-pass.
20wpc in UL or ?watts in pentode, we'll see!
I'll probably add AC balance pots and a LED to each op't stage in all 6 channels.
*One more question, with Passive Line Level filters, a bandpass filter is possible? Yes?
IE a 1st-order 'matching' high-pass in the bass and a 1st low-pass at 6kHz?
Note that I'll be using the sealed sphere's own 2nd order slope as well. The driver is a WR 5 inch and should be okay power-wise with a 1stord. and the enclosure's own roll-off. I'll need to reduce the Vb with some roof-tilers epoxy/sand mixture.
Three spheres stacked using cut-down basketball hoops and and adjustable height column-stand per side.
Columns? Remember when DOS type computers and their noisy dot-matrix printers needed a 3 shelf thing on 4 rollers? That's where the two columns will come from. Two triangular bases and 2 more matching rollers.
You'll soon have mail.
Note that a post in response is preferred.
Warmest
Timothy Bailey
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
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