metal112524
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^Punnisher, I made that same assumption. Tomb, thanks for the info, I doubt ill be getting a matched pair, what are the negatives of having a unmatched pair.
Originally Posted by CaptHowie /img/forum/go_quote.gif Hey Everyone, I'm having a bit of trouble obtaining these parts: R16/17 50K, 1/4W Resistor I used Jaycars - RR0614 51K 1% metal film 1/2watt RLED 2.4K, 2W Metal Oxide Resistor Jaycars - RR2784 2.7K 1 watt works fine in mine 3MMAJ Neutrik [NMJ6HCD2] 3.5MM, Stereo Audio Jack Jaycars - PS0195 SNDOF 20MM M3x0.5, Male-Female Aluminium Hex didn't use stand offs TO220 TO-220 Heatsink Kit didn't use insulated the heat sink from the case HEATS TO-220 Heatsink, Unspecified (Which one?) Jaycars - HH8526 Heavy Duty TO-3P Heatsink (ML97 Type) PWRS Cisco [PSA-18U] 120/240V Input, 48VDC@0.38A Reg. Pwr. Supply eBay I need to find these parts in Australia. Any help would be greatly appreciated. Sorry i'm talking like a lunatic, but i'm in a rush -CaptHowie |
Originally Posted by CaptHowie /img/forum/go_quote.gif Thanks heaps for that Fred. I've changed a few things in my design like removing the LEDs so that will remove those hard to find resistors. I'm using the Jaycar 3.5mm Stereo Chassis jack as you mentioned above as well. With the standoffs and the heatsink and kit, why didn't you need the standoffs and the kit, and how do you insulate the MOSFETS using the case? I'm trying to minimize the price (i'm a student...) and cutting those things off the list would reduce the price, as would using Jaycar's heatsinks (2x$3.00 something for the Jaycar vs. 2x$12.10 for the Farnell one). Removing the heatsink kit would also save some money as the minimum order quantity on Farnell is 10. Any further tips would be greatly appreciated. Thanks, -CaptHowie |
Originally Posted by metal112524 /img/forum/go_quote.gif ^Punnisher, I made that same assumption. Tomb, thanks for the info, I doubt ill be getting a matched pair, what are the negatives of having a unmatched pair. |
Originally Posted by Fred_fred2004 /img/forum/go_quote.gif I was using a Jaycars ABS box (HB5970) so the heat sinks were insulated from the circuit, the switch has abuilt in LED ( SP0704) which makes life simple, the home made pcb is sitting flat on the case's base, So I didn't need to stand it clear of any metal. The Mosfets have clear heatshrink on them but its hard to see (because its clear). The amp is great well worth building cheers Fred |
Originally Posted by kuroguy /img/forum/go_quote.gif Anybody know the voltage gain of a starving student with 12sr7 or 12sw7 versus the 19j6 tube? |
Originally Posted by TimJo /img/forum/go_quote.gif Looks good Fred, the only thing I noticed was WRT the FET's. If my memory is correct, I thought Pete said at one point that it was important to attach the 2k resistors connected to the gate of the mosfet as close as possible to prevent oscillation in the buffers. I may be mixing this up with another design, so folks, please correct me if I'm wrong here. Anyway, looking at the photos, it looks like you have a wire going from the gate to the board, with the 2k on the board. Again, it's hard to tell from the photos, but that may be a minor change worth making. But on the other hand, if it's working, maybe it's not worth messing with... |
Originally Posted by Logistic /img/forum/go_quote.gif The gain with the 12sr7 and 12sw7 is around 6. |