Son Of Boogie input 2 volume ?

[MK IIB]

Hi guys.
Should there be a big difference in volume between channel 1 and 2 on an SOB 60 watt combo?
input 2 is the "clean" channel but it's a lot quiter too.
Input 2 skips the first half of V1 but there is quite a significant difference in volume in the 2 channels.
Input 1 uses both volumes 1 and 2 and input 2 uses only volume 2 but with volume 2 up full I have to run the master up around 4-5 to get a half decent level when giiging but using input 1 with the master at 2 gets me around the same volume?
I'm having to crank the master up to get a decent volume in a band situation with a drummer(Albeit a loud drummer)but this could just be down to tubes as I don't know how old the current tubes actually are!I'm just wondering if it is normal to have to run the master so high with volume 2 up full?
Here's a couple of pics showing how the inputs are wired.

Thanks in advance folks.

 

[MK IIB]

I pulled this image of another SOB from the web.Mine seems to have an extra resistor added?Has mine been modded at all?
Are there any SOB owners that could compare theirs.It doesn't seem right to me that there should be such a difference in volume between the two inputs/channels even with the extra gain stage in channel 1?

Any help would be much appreciated.
Thanks folks.

 

[lovetoboogie]

Most if not all of the SOB's have a volume difference between the two(2) inputs... the inputs and tube stages are wired like a Mark I albeit there are some subtle variations...

I see yours has a 470k series resistors tied to input 2...that could be padding it down a bit. Mark I's had a 220k there...

What's the other resistor tied to the "make contact" lug on the input 1 jack? It's kind of out of view. That should be a 1Meg in a standard Mark I but have seen some SOB's with as little as 330k there...

The SOB is kind of a one-trick pony but it does that trick exceedingly well...

 

[MK IIB]

I'm not sure what that other resistor is?I'd need to open it up and take a better angled picture.
Looking at that other SOB picture though notice that there is only the one resistor between both inputs.I'm wondering if this "extra" resistor on mine was a mod or if it was made like this?
Obviously there is gonna be a difference in volume with input one having that extra gain stage but I feel it's quite a substantial difference.
Using input 2 cranked with an overdrive pedal with this amp sounds amazing though I just feel I'm having to crank the master up a fair bit.
Aren't these meant to be REALLY loud?
Thanks a lot.

 

[lovetoboogie]

There are 2 resistors on your input jacks...the 470k is original, that's a period correct mesa resistor. I can see the lead of the other one going down under the input 1 jack, and can just make out the nub of it...but cannot see the color bands...

on the other picture you provided of another SOB there are clearly 2 resistors as well...a carbon film type just behind the shielded cable, and a metal film Dale resistor coming off of input 1 to ground...

again, there will be a difference between the 2 inputs as far as drive and output goes...i wouldn't lose any sleep over it unless the amp is showing other symptoms of being sick...

 

[MK IIB]

There are 2 resistors on your input jacks...the 470k is original, that's a period correct mesa resistor. I can see the lead of the other one going down under the input 1 jack, and can just make out the nub of it...but cannot see the color bands...

on the other picture you provided of another SOB there are clearly 2 resistors as well...a carbon film type just behind the shielded cable, and a metal film Dale resistor coming off of input 1 to ground...

again, there will be a difference between the 2 inputs as far as drive and output goes...i wouldn't lose any sleep over it unless the amp is showing other symptoms of being sick...

No other problems as such.It's just that I'm mainly using channel 2 and it just seems a bit on the quiet side even with volume 2 up full.
Oh well if that's the nature of the amp then that's fine.I was just keen to find out from other SOB users if this was the norm?
Maybe a new set of output tubes will improve things as I don't know how old the ones that are in there now are.
Thanks a lot.

 

[MrWhoever]

I played a SOB for 8 years.. since the 2nd channel cascades into the first, it is always going to be louder, but master on 4/5? your channel 1 is not loud enough, could easily be a bad tube in v1/2, or maybe a low gain tube; i used a 12at7 in v2 and that kinda mellows out things a little bit, some use it also in v1 that would explain it. My SOB was deafening at 2.5 master with 7.8 and 8 channel volumes, gig volume with a very loud drummer was 2.1 max usually. It was a 60watter, awesome amp that got stolen..