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kevin gilmore

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What voltage rating should the 1uF and 0.1uF capacitors be?  (On the right side of the amp board.)  I didn't see them marked on the silkscreen.  

The 1uf cap has to be 25V+ so anything with 15mm lead spacing will work.  I use 250V Panasonic caps which fit perfectly into the footprint.  Kevin posted the part number either here or in the KGSSHV thread.

 

The 100nf caps should be rated to handle the B+/B- plus a bit of headroom.  We've normally used 1000V caps here but 630V also works.

 

So I didn't notice there were two types of 0.1uF caps on the amp PCB. :palm:  I meant to ask about the 0.1uF capacitors by the servo.  The BOM says 50V will be sufficient.  Is this still true?

Edited by chiguy
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They are just DIP jumpers and can be found everywhere.  The ones I used I got off ebay some years ago but Mouser should have something like that. 

 

It could be years or it could be tomorrow when we see some action there but the aftermath can be pretty bad when the flash flood comes from under the glacier.  That particular volcano last went active in 1996 and I visited the result of the flash flood to the south side of the island.  Icebergs the size of houses scattered around a huge region with most of the infrastructure washed away.  Nobody lives there though and all the roads, bridges and power lines are designed to break away and be replaced quickly. 

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My wife's grandson lives in Reykjavik, so we follow the news there.

About the DIP jumpers. Perhaps I have to try harder, but I found this 571-826646-2 and this one 517-9691020000DA in the Mouser catalogue. Will this do? I can't see in the picture of your boards weather they are open or closed.

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I think there is an error in the BOOM of this thread, in the "KGST-New" label the 3K5 resistor should be 1K5?

The KGST is an evolving work in progress, so there is no one single BOM. Use the value printed on the PCB (1K5). That is correct for the revision the board was made to.

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Indeed and this also changes with the actual tubes used.  1k5 with a 1K pot should work for most tubes but at +/-400V you might need to go lower.  1k37 is what I use in my amps. 

 

My wife's grandson lives in Reykjavik, so we follow the news there.

About the DIP jumpers. Perhaps I have to try harder, but I found this 571-826646-2 and this one 517-9691020000DA in the Mouser catalogue. Will this do? I can't see in the picture of your boards weather they are open or closed.

 

Those jumpers will work just fine and we are far away from an volcanic activity so it will be fine. 

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PCBs received.  Thanks for an awesome group buy!

 

So I have been requesting quotes from different vendors for transformers using the specs posted earlier in this thread. 

 

I'm still waiting on a few vendors but so far SumR wants $94 and Toroidy quoted:

Audio grade transformers with mounting pads:
TS 150VA PRI: 2x 117V SEC:
> 2x 280V @0.18A
> 15 - 0 - 15V @0.5A
> 2x [email protected]
cost: 75,80 EUR/pc
 

Audio Supreme version:
TS 150VA PRI: 2x 117V SEC:
> 2x 280V @0.18A
> 15 - 0 - 15V @0.5A
> 2x [email protected]
cost: 112,70 EUR/pc
 

In audio grade, noiseless transformer price You'll get transformer wound on high inductive, selected and measured core. 
Core and all the windings will be impregnated. Transformer will also has electric and electromagnetic shields, epoxy 
filled interior and mounting pads in price.

Audio SUPREME version is fully epoxy resinged in stainless steel box:
http://www.toroidy.pl/s783/57ad94c01a056094fc22ba3ecded9a40.jpg

Will using 150VA as quoted be okay or should I stick to 120VA?  Also, is the Audio SUPREME version worth it?

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Avel Lindberg quotes me as follows.  Any thoughts?

This  request for an extremely high end Audio Transformer and  as “mechanically silent”, heavier wire gauges”, Static Shield”, 
Magnetic Shield” are standard requests that will always improve a transformers operational quality. However the offered dimensions 
of 100mm Dia x 50mm Ht are restrictive to the design relating to performance. In addition the rating of this transformer is nearer 
135VA than the 120VA stated in the request which also affects the design parameters. The is the best 135VA possible that we can 
offer within the 100mm Dia x 50mm Ht dimensions given.

Description         Toroidal Transformer.
Primary               117v + 117v   50/60Hz
Secondary 1        280v @ 0.18A rms.
Secondary 2        280v @ 0.18A rms.
Secondary 3       15v-0-15v @ 0.5A rms.
Secondary 4        6.3v @ 1.5A rms.
Secondary 5       6.3v @ 1.5A rms.
Total Rating        135va approx.   
Int. Shielding      Pri-Sec Static Shield.
Ext. Shielding     External GOSS “Magnetic” Band Fitted
Mounting            Dish Mounting kit supplied.
Finish                     Polyester Tape
Leadouts              300mm Flexible Style.
Size                        100mm O.D x 50mm Ht approx.
Weight                 1.54Kg approx.
HIPOT 4000VDC PRI-SEC

$209.75
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Yes that's the one. (edit; of course that doesn't mean that everyone should be fitting that value, just note you might have to adjust this)

 

Public thank-you to Kevin and Birgir for the design and pcb layout for this very nice project.

 

Birgir's and Kerry's comments encouraged  me to build it and I'm pleased I did.  The SQ is excellent.

 

Mine is on a piece of plywood at the mo.

 

To encourage those who have just got their pcbs;

pqABUCW.jpg

Edited by headinclouds
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