Just took delivery of a Mesa Mark IV A/B - ie: one of the transitional amps that Mesa built between the Mark IV A and the Mark IV B. The serial number is solidly in the mid 58XXs.
There are a few amps I’d love to add to my shelf (KSR Gemini, Rev F Rectifier, Alta 100, Hellion) but a Mesa Mark wasn’t on the radar.
That said, I spotted this one for sale and did some digging and the idea of grabbing something a little out of the ordinary appealed to me. As I understand it, only a couple hundred of the transitional models were made and I guess not too many of those made it to the UK / Europe.
As I understand it I’m only the third owner and I know that servicing work (including the cap replacements and board clean up) was undertaken by a well known and respected amp tech. It used to be in a rack unit, but Zilla are building me up a headshell.
In case of interest, there’s a gut shot below and it has the 561137 and 562004R transformers. It also has the IV B fx loop.
I am very, very far from being any sort of expert, but from pictures I have seen I can see a fair few similarities to the Mark IV B circuit, a couple of similarities to the Mark IV A circuit and maybe a couple of places where this circuit doesn’t seem to be like either.
I’d be interested to hear from those with more knowledge about where the similarities and differences between this and the IV A and IV B circuits lie and if there are places where this circuit looks like something else (I heard of one A/B amp that had Mark IIC+ features).
It would also be interesting to hear from other A/B transitional amp owners as to whether this circuit is the same as the one in their amp, or whether they have further variations.
The amp sounds great, so all of the above is purely out of curiosity!
Cheers,
Jimty
There are a few amps I’d love to add to my shelf (KSR Gemini, Rev F Rectifier, Alta 100, Hellion) but a Mesa Mark wasn’t on the radar.
That said, I spotted this one for sale and did some digging and the idea of grabbing something a little out of the ordinary appealed to me. As I understand it, only a couple hundred of the transitional models were made and I guess not too many of those made it to the UK / Europe.
As I understand it I’m only the third owner and I know that servicing work (including the cap replacements and board clean up) was undertaken by a well known and respected amp tech. It used to be in a rack unit, but Zilla are building me up a headshell.
In case of interest, there’s a gut shot below and it has the 561137 and 562004R transformers. It also has the IV B fx loop.
I am very, very far from being any sort of expert, but from pictures I have seen I can see a fair few similarities to the Mark IV B circuit, a couple of similarities to the Mark IV A circuit and maybe a couple of places where this circuit doesn’t seem to be like either.
I’d be interested to hear from those with more knowledge about where the similarities and differences between this and the IV A and IV B circuits lie and if there are places where this circuit looks like something else (I heard of one A/B amp that had Mark IIC+ features).
It would also be interesting to hear from other A/B transitional amp owners as to whether this circuit is the same as the one in their amp, or whether they have further variations.
The amp sounds great, so all of the above is purely out of curiosity!
Cheers,
Jimty
