2203 V1?
Moderator: VelvetGeorge
-
- Senior Member
- Posts: 511
- Joined: Thu Jul 28, 2011 1:37 am
- Just the numbers in order: 7
2203 V1?
Looking at a lay out I have for a 2203 downloaded from the forum and looking at 2203 gut shots I see the shielded cable from the input jack socket has the 68K resistor on the other end connected to pin 7 of V1.
The other shielded cable connects to pin 2 of V1 and is routed to the preamp pot.
When following the down loaded kit instructions the connections of these two wires at V1 are reversed. Is this ok?
The other shielded cable connects to pin 2 of V1 and is routed to the preamp pot.
When following the down loaded kit instructions the connections of these two wires at V1 are reversed. Is this ok?
-
- Senior Member
- Posts: 1099
- Joined: Tue Sep 10, 2013 9:09 pm
- Just the numbers in order: 13492
Re: 2203 V1?
IIRC, the first way that you described is how Marshall originally ran the wiring to V1. The second way is suppose to be slightly quieter I believe. I have always followed the original layout so I can't say if there is any actual benefit to changing it.
- neikeel
- Senior Member
- Posts: 7231
- Joined: Tue Dec 06, 2005 8:31 am
- Location: Suffolk, England
Re: 2203 V1?
Normally V1b is the preferred first stage so the grid from the inputs should go to pin 7 and the 0.68uF/2k7 cathode to 8
the 10k cathode is pin 3 and grid is pin 2. Normally only ground the pot/input jack end unless 'hot shield'.
the 10k cathode is pin 3 and grid is pin 2. Normally only ground the pot/input jack end unless 'hot shield'.
Neil
-
- Senior Member
- Posts: 511
- Joined: Thu Jul 28, 2011 1:37 am
- Just the numbers in order: 7
Re: 2203 V1?
Thanks for the replys fellas.
I do wish the instructions had mentioned it was a deviation before I soldered that nice nos imported resistor in there.
I guess the noise factor comes from crossing the shielded wire but if it was done at 90' and being shielded I can't imagine there would be cause for concern?
I was going with a star ground scheme so grounding of the input jack and pot would be to separate points (not a pot bus). The shielding of each wire is only grounded at one end ie the respective jack and pot, the other end is heat shrunk.
Is this OK?
I do wish the instructions had mentioned it was a deviation before I soldered that nice nos imported resistor in there.
I guess the noise factor comes from crossing the shielded wire but if it was done at 90' and being shielded I can't imagine there would be cause for concern?
I was going with a star ground scheme so grounding of the input jack and pot would be to separate points (not a pot bus). The shielding of each wire is only grounded at one end ie the respective jack and pot, the other end is heat shrunk.
Is this OK?
-
- Senior Member
- Posts: 511
- Joined: Thu Jul 28, 2011 1:37 am
- Just the numbers in order: 7
Re: 2203 V1?
Has any one got experience with both methods? What's the preference and why?
-
- New Member
- Posts: 31
- Joined: Tue Nov 08, 2011 3:28 am
- Just the numbers in order: 7
Re: 2203 V1?
I doubt there is any significant difference between using V1a or V1b as the first stage. Replacing that NOS resistor with a modern metal film resistor would probably be much more signifcant (in terms of reduced noise).
- neikeel
- Senior Member
- Posts: 7231
- Joined: Tue Dec 06, 2005 8:31 am
- Location: Suffolk, England
Re: 2203 V1?
Depends if it is a NOS Piher CF or a cc. The Pihers are probably the best all round resistors I use, but I generally avoid carbon carbon comps.
Neil
-
- Senior Member
- Posts: 511
- Joined: Thu Jul 28, 2011 1:37 am
- Just the numbers in order: 7
Re: 2203 V1?
I'm using all piher for this one.
I've started a kind of build journal with pics over in the 100w master vol section now I've finally sussed out the picture thing.
I have a bit to do on the board but should have some more bits to up load by the end of the week.
As it is I've re ordered all the parts to redo it so I have the option. But im just trying to figure which is the best method, as in why V1b is preferred?
I've started a kind of build journal with pics over in the 100w master vol section now I've finally sussed out the picture thing.
I have a bit to do on the board but should have some more bits to up load by the end of the week.
As it is I've re ordered all the parts to redo it so I have the option. But im just trying to figure which is the best method, as in why V1b is preferred?
- neikeel
- Senior Member
- Posts: 7231
- Joined: Tue Dec 06, 2005 8:31 am
- Location: Suffolk, England
-
- Senior Member
- Posts: 511
- Joined: Thu Jul 28, 2011 1:37 am
- Just the numbers in order: 7
Re: 2203 V1?
Not a big deal really but I feel because the 68k resistor lead is trimmed so short that the resistor must have seen a lot of heat.
Also not sure I have enough shielded cable to 're do it. There's enough length on the resistor lead but probably not quite enough for the other lead.
Just a little frustrating as I felt I had done a nice job of it then clocked the differences when I looked at the other lay out. Also collecting all the parts has taken patience and time... You know how it is.
Also not sure I have enough shielded cable to 're do it. There's enough length on the resistor lead but probably not quite enough for the other lead.
Just a little frustrating as I felt I had done a nice job of it then clocked the differences when I looked at the other lay out. Also collecting all the parts has taken patience and time... You know how it is.