Three questions about 1Watt - 2Watts or 3Watt resistors?
Posted: Thu Dec 29, 2011 9:39 pm
I'm putting together a BOM for a JTM45 build.
I have a couple of schems and layouts to work from and i have come across a couple of irregularities.
So..
Question one;
On the main board there are two large resistors.
1 X 10K next to the 16uF cap in the middle of the board.
1 X 8.2K up near the 10uF caps.
On the schem i have from the metro instructions it shows these to be 1 Watt.
But i also have another schem and a couple of layouts, including the one from ceriatone, that show these to be 2 watt for the one closest to the 10uF can's, and 3 watt for the one next to the 16uF can.
I have another layout that shows both as 3 watt.
So, whats the deal here?
I'm planning on using valve storm to get most of my parts and they have both of these resistors down as 1 watt, and Georges picture of his GPM45 seems to show this also, so if its all good with George.. its all good with me. I'm just curious why there might be a difference. What would be the reasoning behind this choice?
Question 2
I have seen some gut shots of JTM45's that seem to have a 1K resistor running from the 8.2K resistor and choke on the board to pin 6 of V4, the first KT66 after the 12AX7's.
This is in the schem, but not on Georges GPM45.
What is this doing?
Question 3
On the ceriatone layout, as with most of the layouts that Nik produces, there are 1R 1Watt resistors tying pins 1 and 8 on the KT66's together and then going to ground. There are also two 5k6 1Watt's running from pins 5 on the KT66's to the two 220K bias resistors on the board between the two 0.1uF caps..( at least, i think these are the bias resistors,,i'm still learning this stuff..).
What are these there for?
Cheers for any help in this regard.
Its all about learning my way through this.
OH!.. and happy New Year!!
I have a couple of schems and layouts to work from and i have come across a couple of irregularities.
So..
Question one;
On the main board there are two large resistors.
1 X 10K next to the 16uF cap in the middle of the board.
1 X 8.2K up near the 10uF caps.
On the schem i have from the metro instructions it shows these to be 1 Watt.
But i also have another schem and a couple of layouts, including the one from ceriatone, that show these to be 2 watt for the one closest to the 10uF can's, and 3 watt for the one next to the 16uF can.
I have another layout that shows both as 3 watt.
So, whats the deal here?
I'm planning on using valve storm to get most of my parts and they have both of these resistors down as 1 watt, and Georges picture of his GPM45 seems to show this also, so if its all good with George.. its all good with me. I'm just curious why there might be a difference. What would be the reasoning behind this choice?
Question 2
I have seen some gut shots of JTM45's that seem to have a 1K resistor running from the 8.2K resistor and choke on the board to pin 6 of V4, the first KT66 after the 12AX7's.
This is in the schem, but not on Georges GPM45.
What is this doing?
Question 3
On the ceriatone layout, as with most of the layouts that Nik produces, there are 1R 1Watt resistors tying pins 1 and 8 on the KT66's together and then going to ground. There are also two 5k6 1Watt's running from pins 5 on the KT66's to the two 220K bias resistors on the board between the two 0.1uF caps..( at least, i think these are the bias resistors,,i'm still learning this stuff..).
What are these there for?
Cheers for any help in this regard.
Its all about learning my way through this.
OH!.. and happy New Year!!