Welcome Rayce, I noticed you said you are getting a reading of 38mvDC at the "bias port". I assume you are using an inline bias probe on 1 tube and not the test points on the amp? The 2 onboard test points on a MA100h measure each of the 2 pairs of tubes so that is why the reading is double, ie 76mv...

Hi Washburn, I don't know how it works out on the 50 watt presumably where you have 1 trim pot/per valve versus 1 trim pot /per 2 valves on the 100 watt. Though I'm kinda wishing myself I had stuck with a 50 watt version for all the conveniences it brings only having 2 power valves but the 100 watt ...

A couple more tips for those wanting to bias their MA100H. As SteveD mentioned you must remove the chassis from the cabinet and then turn it upside down to access the bias test points and trim pots. I found the putting the empty cabinet face down on a padded surface and then putting the amp chassis ...

Thank you for the reply guys. My reason for thinking about it was that I wondering if it would let me drive the amp a little harder with the volume knob while getting a little less overall loudness from the amp without having to buy an attenuator. To me the MA100 sounds best (less fizzy, more girth)...

Question for SteveD or anybody who has tried it, I'm curious about how pulling 2 of the EL-34's will affect the MA100h. Can it be done safely without causing any additional wear or strain on the amp's components? I've read in other amp manuals about doing this and they usually indicate the specific ...

I definitely concur with you jagermike, at low volumes (1 to about 3-4), the gain channel is all preamp fizz but once you get the amp up to proper gig volume (5+) it sounds wonderfully Marshall-y. I've tried a TS-7 and LPB-1 to boost the front end but personally think it sounds great without anythin...

If you are looking for a volume boost I would suggest trying the pedal in the effects loop (post preamp) and see how it sounds. I think what you are experiencing with not begin able to get much of a volume boost on the gain channel is par for the course on any amp with both gain and volume controls ...

Sorry ask again if this was already covered in another post but what is the preamp tube layout of the MA100H? I presume the one next to the EL34's is the PI but not sure on the other 2. SteveD, any chance you could also divulge what factory/manufacturer the Marshall branded preamps are from? Oddly e...

Thank you again Steve. So in my case where the desire is to use the Crunch Balance first and foremost as a volume/solo boost at gigging levels would the original voicing be better suited for that as compared to the new voicing?

SteveD thank you very much for taking the time to respond. That's perfect, exactly what I needed to know. I'd like to ask too if perhaps you could elaborate a little more on what the revoicing means in comparison to the original version. I don't know if you are at liberty to give some technical deta...

How to determine manufacture date of MA Series? Just bought a MA100h but didn't think to check when it was manufactured to see if it was a revoiced model. The serial number tag shows 2009 so obviously this is not revoiced model but I'm wondering if I return it and buy another how I can be sure I'm g...