Mark 2B issues and Transformer

[denrad]

Hi all,

I bought a Mark 2B head. The head sounds fuzzy and not as focused as (and nothing like) my Mark 2C+ and Mark 3, in the lead channel. The cleans in the clean channel on the other hand are nice.

It's not easy to find a Boogie qualified tech here, but would anyone know what may be causing this issue? I tried transferring the 12AX7's and 6L6's from one of my other Boogies, but it didn't make a difference to the sound.

The Mark 2B is from 1980, so it probably needs a service, but I'd like to know if anyone would know what exactly could be behind this (if it's obvious).

One other question I have is, I have another Simulclass Mark 2C+ in need of a 240 volt transformer. The (100/60 watt non simul) Mark 2B I bought happens to have the exact same tranny model number as my other Mark 2C+ (X101-162318).

If I were to take out the tranny from the (100/60 watt non simul) Mark 2B and have it installed in the Mark 2C+, will this enable "Simulclass" operation of my Mark2C+?

Thanks in advance...

 

[Blueracer]

I also have both a IIB and IIC+ and find that the lead channel on the IIB is more fuzzy than the IIC+. I think this is just the nature of the individual beasts if you will. I believe there is some sort of effects loop mod that Mesa used to do and may still be doing that opens the amp up. Try doing a search of the forum or maybe someone more knowledgable on the topic will jump in. It also may be cap time to get the best performance out of your amp. BTW I also like the clean channel on my IIB and is the reason I picked the amp up.

As far as swapping the transformers goes what you have identified is the power transformer and it is not the component that determines simulclass/non-simulclass operation. It is the output transformer that determines this. The period correct simulclass output transformer is the SC-152019B which is no longer made. There are other that can be substituted but usually the consences is to leave it alone rather than trying to do this modification. Transfering the power transformer will give you international power capability if you include a power selection switch. This would allow you to use 100, 120, 200, 230 and 240 volts from the line. The x101 transformer also develops a lower plate voltage which results in a smoother lead channel voicing or at least this is what I have seen posted in the past. Hope this is helpful.

 

[denrad]

Thanks for your response Blueracer.

The Mark 2C+ I was referring to does indeed have the SC-152019B output tranny (EIA606-425).

So just to confirm, based on the info above, installing the X101-162318 tranny into the Mark 2C+ would enable me to have Simulclass operation of my Mark 2C+ with worldwide voltage selection? I'd be including the power selection switch from the Mark 2B.

 

[Blueracer]

Hi denrad. I misread your first post. Yes installing the x101 transformer into the iic+ will give you world wide voltage selection capability. Further the x101 transformer is considered by many the best power transformer for the iic+. As I did indicate before the plate voltage developed by the x101 is somewhat lower than the 105 transformer, which is typically found in the iic+, and is supposed to give it a smoother lead voicing. Simulclass is really a function of the SC-152019B output transformer so you are good to go on the simulclass issue. Hope this helpful.