In the market for a used Mark IV, but which Mark IV: A or B?

[enigma]

I'm in the market for a used Mark IV short head. Which one is preferred? A or B? I've heard that A has the IIC+ lead tone. Besides this and other small feature differences (attached cord, no switch for reverb/efx loop) what other differences are there that I should consider? Thanks for your inputs.

 

[GD_NC]

I've owned both. My observations...

The lead CH & Channel 2 are a bit more aggressive on the B. In all fairness there was a 3 year gap between selling my IVA and purchasing the IVB. I never had the opportunity to use them side by side. Tube and Speaker choices likely have a as much impact on the tone.

Unless you are trying to set up a stereo rig (IVb), they are both great it's hard to go wrong.

Oh yea, I'm not gonna touch the "IIC+ lead tone" question on this board. That's pretty much asking for slapdown. :lol:

 

[enigma]

Oh yea, I'm not gonna touch the "IIC+ lead tone" question on this board. That's pretty much asking for slapdown. :lol:

A member on birdsandmoons forum got his IV modified to get a IIC+ tone and apparently made a difference.

For me, the question is whether A or B is sought out more, or whether for Mark IV model it doesn't matter as it does with the Mark II models.

 

[Rob Lockwood]

As far as I have seen scanning ebay and other ads there is no noticeable difference in the used price of Mark IV a and b amps. That suggests to me that neither one is particularly more sought after than the other at the moment. IVa's would be rarer which might make a difference for collectors in future but for now I can't see it.

I think that there is a noticeable difference in sound though. My reference for classic Boogie lead tone was a guy I used to see in the early 90's who played a MarkIIb cranked very hard and driven a bit further by a little Korg A5 pedal. There was a really unique vocal 'yowl' to the sound that has really stuck in my head, its difficult to describe but I know it when I hear it. I tried a MkIV in the early 90s that had that sound - but I could afford one at that time. I had a MkIII for many years but couldn't quite find it there (At least not while keeping a good clean sound). Later on over the years I tried several iv's in shops which would have been b's (at that time I didnt know that there were different versions) and was always frustrated because I couldn't quite get back to the sound of that first one I had tried. Finally tried a nice used IVa and there it was.

I can't comment on the IIC+ thing because I've never heard/seen one live in a room but in my experience the IVa lead may be a bit closer to the older Mark II sound and possibly a bit more versatile for pop/blues/rock styles and the b is a bit higher gain and may have been voiced a bit more towards the heavier rock/metal people who started to use them. Its probably a quite subtle difference in reality, so as always I think any preference between them comes down to the reference sound in your head that you are trying to work towards. They are both great amps!!

 

[enigma]

As far as I have seen scanning ebay and other ads there is no noticeable difference in the used price of Mark IV a and b amps. That suggests to me that neither one is particularly more sought after than the other at the moment. IVa's would be rarer which might make a difference for collectors in future but for now I can't see it.

I think that there is a noticeable difference in sound though. My reference for classic Boogie lead tone was a guy I used to see in the early 90's who played a MarkIIb cranked very hard and driven a bit further by a little Korg A5 pedal. There was a really unique vocal 'yowl' to the sound that has really stuck in my head, its difficult to describe but I know it when I hear it. I tried a MkIV in the early 90s that had that sound - but I could afford one at that time. I had a MkIII for many years but couldn't quite find it there (At least not while keeping a good clean sound). Later on over the years I tried several iv's in shops which would have been b's (at that time I didnt know that there were different versions) and was always frustrated because I couldn't quite get back to the sound of that first one I had tried. Finally tried a nice used IVa and there it was.

I can't comment on the IIC+ thing because I've never heard/seen one live in a room but in my experience the IVa lead may be a bit closer to the older Mark II sound and possibly a bit more versatile for pop/blues/rock styles and the b is a bit higher gain and may have been voiced a bit more towards the heavier rock/metal people who started to use them. Its probably a quite subtle difference in reality, so as always I think any preference between them comes down to the reference sound in your head that you are trying to work towards. They are both great amps!!

Thanks for that. Enjoyed reading it. It's always good to get that "extra" information!

 

[Hellraiser6502]

Here's a stupid question: How can you tell the difference between the A & B??

I mean do you go by serial# or other visual features?

I've got a IV but not sure which one it is. I am curious to know.

Any help is appreciated.

 

[Rob Lockwood]

The effects loop arrangements are different:- The IVa has a pair of send and return sockets, one for the switchable loop and one for the normal loop (on all the time). So there are 4 effects loop sockets arranged in a square pattern. The IVb has the 'stereo' loop. This has one send and two returns, so there are three effects loop sockets arranged in a triangular pattern. There are a few other differences, the IVa has no footswitch socket for reverb. If you look at a few pictures on google images this will be more clear.

 

[Hellraiser6502]

Thanks very much for your time Rob, it's very clear now.

I have an Mark IVB.