Horio Posted October 27, 2011 Report Posted October 27, 2011 (edited) You definitely need the thicker Aluminum Oxide Pads that Wink posted. Though they aren't very cheap, the PEEK screws are really what you want for mounting the semi's to the sinks as well. No sense "skimping" on a build of this nature and cost. Edited October 27, 2011 by Horio
Milosz Posted October 27, 2011 Report Posted October 27, 2011 (edited) Yep, use the PEEK screws, you don't want to have a metal screw.... 900v can pretty readily arc through one of those insulating shoulder washers you'd normally use at lower voltages to insulate the mounting screw from the TO-220's tab. PEEK is polyetheretherketone, a fairly high-strength plastic. You can't tighten PEEK screws to the same torque you'd use with a steel screw, but PEEK is tougher than other plastic screws- nylon, derlin, etc. and you can get them pretty tight before they fail. Max torque for the PEEK screws is about 21 oz-in or about 1.5 kg-cm. Edited October 27, 2011 by Milosz
wink Posted October 27, 2011 Report Posted October 27, 2011 PEEK screws are a pain to get here in the antipodes. $57+ for 100 m3 x 12mm screws and almost $90 for shipping........... Nuts & washers, ditto.. I'm feeling more like Birgir every day......
Horio Posted October 27, 2011 Report Posted October 27, 2011 PEEK screws are a pain to get here in the antipodes. $57+ for 100 m3 x 12mm screws and almost $90 for shipping........... Nuts & washers, ditto.. I'm feeling more like Birgir every day...... I bought the M3 PEEK screws, but I am planning to use a metal "heavy hex" nut and nylon washer from McMaster-Carr. The heavy hex nut has more depth than the PEEK nut, so you should be engaging even more threads on the screw. In theory, this should actually make it more difficult to strip. Nylon washers are dirt cheap too, and I don't really see the need to spend $50 on PEEK washers. You should already have plenty of isolation from the PEEK screw alone.
wink Posted October 28, 2011 Report Posted October 28, 2011 That's what I figured. Nylon washers and perhaps Stainless steel nuts.
justin Posted October 28, 2011 Report Posted October 28, 2011 I bought the M3 PEEK screws, but I am planning to use a metal "heavy hex" nut and nylon washer from McMaster-Carr. The heavy hex nut has more depth than the PEEK nut, so you should be engaging even more threads on the screw. In theory, this should actually make it more difficult to strip. Nylon washers are dirt cheap too, and I don't really see the need to spend $50 on PEEK washers. You should already have plenty of isolation from the PEEK screw alone. why not use a metal washer? i assume you're talking about the washer under the screw head.
wink Posted October 28, 2011 Report Posted October 28, 2011 I was thinking about the washer and nut on the heatsink side. Screw , washer, transistor, thermalloy, heatsink, washer, spring washer, nut.
Horio Posted October 28, 2011 Report Posted October 28, 2011 I was thinking about the washer and nut on the heatsink side. Screw , washer, transistor, thermalloy, heatsink, washer, spring washer, nut. Those were my plans exactly.
justin Posted October 28, 2011 Report Posted October 28, 2011 I was thinking about the washer and nut on the heatsink side. Screw , washer, transistor, thermalloy, heatsink, washer, spring washer, nut. ok.. im switching to the PEEK screws for the BHSE. but those are all tapped holes, no nut. so likely just screw + spring washer + flat washer + transistor + insulator -> heatsink surface
swt61 Posted October 28, 2011 Report Posted October 28, 2011 Then you do the hokey pokey and you turn yourself around...
wink Posted October 28, 2011 Report Posted October 28, 2011 That's what it's all about..........................
spritzer Posted October 28, 2011 Author Report Posted October 28, 2011 Yay, my parts are finally on the way here from Bangladesh!! Mouser does get props for great customer service and they even dug up the phone number for the bakery and called me when my email wasn't working. ok.. im switching to the PEEK screws for the BHSE. but those are all tapped holes, no nut. so likely just screw + spring washer + flat washer + transistor + insulator -> heatsink surface Wait... what!!??!! I demand parts to upgrade my unit to the newest spec!! On a second thought the non-PEEK units might be rare and collectable... Which version soundz bettah??
Voltron Posted October 28, 2011 Report Posted October 28, 2011 Those PEEK screws won't sound their best until +/- 500 hours of burn in.
Fitz Posted October 28, 2011 Report Posted October 28, 2011 Where can I get one with -500 hours of burn-in?
guzziguy Posted October 28, 2011 Report Posted October 28, 2011 Just play black noise into a new one for 500 hours. Since black noise is the opposite of white noise, you'll have -500 hours of burn-in.
wink Posted October 29, 2011 Report Posted October 29, 2011 How about you change the colour of the "ON" light? That's gotta be worth at least 30% of subjective sound difference. RED = sounds more lively Orange/Yellow - more mellow Green - more relaxing. Blue - more cool/analytical. White - more detail. If you put in one that keeps changing colour you get the best of it all.
spritzer Posted October 29, 2011 Author Report Posted October 29, 2011 While waiting for my parts to arrive it was time to clear the batteries and do some more damage to the chassis... I'm growing ever more annoyed by the rear mounted power switches on my gear and a power indicator is a good thing for somebody like me who hasn't slept a good nights sleep for over a year now. I figured I'd kill two birds with one stone and here it is: Matches nicely with the titanium volume knob. I also replaced most of the caps in the PSU after the whole transformer episode plus put in some slightly smaller EPCOS units.
Horio Posted October 29, 2011 Report Posted October 29, 2011 I like it spritzer. I think I'll do something similar, as rear mounted power switches are a pain to access in my rack.
pedefede Posted October 31, 2011 Report Posted October 31, 2011 Both Channels are working, and playing music. There is still no more sign of oscillation. I do have noise in left channel (very same sympoms as Kerry, Bubliss), and 1 battery there is adjustable, but voltage is drifting a lot - so keeps having to being re-adjusted. - So i will try lift my resistors - and if that doesnt change, ill replace. What resistors are reported as "noise-curing" as of now? - Gilmore: Xicon - Inu: Takman - chinsettawong = 1% Royal resistors (Thai brand)
Milosz Posted October 31, 2011 Report Posted October 31, 2011 Does anyone have a file (drawing- CAD or otherwise) that shows dimensions / location for the tube holes in the amplifier chassis top panel?
kevin gilmore Posted October 31, 2011 Report Posted October 31, 2011 nothing usable but here are the numbers from the circuit board which is 11.950 x 16.00 There is .1 inch between the front of the circuit board and the inside of the chassis. From the front center of the circuit board, in inches +1.900,+2.575 +5.465,+2.575 +12.150,+2.500 +13.950,+2.500 +1.900,-2.575 +5.465,-2.575 +12.150,-2.500 +13.950,-2.500
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