Carol-Ann British Series 67-50H Plexi Head
The Carol-Ann British Series 67-50H Plexi Head is now in stock!
A while back we went to Alan Phillips to see if he would be interested in us commissioning him to build two different vintage Marshall style amplifiers for us. We were looking for an 18 Watt Plexi, and a tube rectified JTM50 head. Being extremely well versed in vintage Marshall amps, Alan loved the idea of the JTM50 (he owns a great sounding one) but he wasn't so keen at first on the 18 watt head. First of all, there were never any 18 Watt Plexi heads, just combos, but even those were very hit and miss. Some sounded great but others not so much. If he were to do this for us, Alan wanted to make absolutely sure they sounded phenomenal. Needless to say, he hit the nail on the head! There's a lot more info on the 18 watt by following this link, but we'll focus on the 50 watt here.
As an owner of an original '67 JTM50 for many years, Alan was intimately familiar with its tone and feel and having built himself several versions of this amp over the years, it stood to reason it would be done right! Given the wide array of awesome British amps from the late 60's, Alan thought it would be a lot of fun and a change of pace to build the British Series and so chose the '67 JTM50 head with EL34's and GZ34 rectifier as the 50 watt plexi of choice.
Many people attempt to visually clone these style of amplifiers, and will source original vintage parts, but with electronics certain components don't age well just sitting on shelf. For instance an electrolytic capacitor only has a shelf life of 10 years. Sure, you end up with a visual clone but not very often a tonal clone.
To tonally clone an amp requires a different mindset. You start with the basic circuit and work from there, not being feared to change values of components of material types if the end result is to get as close as possible to the individual target amplifier. Certain changes were also made to improve the noise floor, grounding and modern safety standards.
So, going back to 1967, even when new every one of these classic amplifiers sounded different. For one, components values have a tolerance range. Two identically rated resisters or caps will have different actual values. As well, Marshall was known for running out of certain values of electrical components and making running substitutions just to fill the orders. Because of this process, no two of these amplifiers are absolutely identical from an electronic standpoint. When Alan builds amps, he makes component changes as necessary to achieve the tonal goal for each one. All too often there is a fear of straying the path. As an actual Electronics engineer, that's not how he thinks. The end tonal goal is what us players truly care about.
So, back to the 67-50H. From a technical angle, Alan found that dropping the plate voltage to around 385V achieved the closest replication, even though the original runs at 420V. An example of type of changes and the open mindset necessary. He sourced signal capacitors that physically and electronically were as close as possible to the original Philips Mustards used in these amplifiers. Ironically, the capacitors used were not typical of those sold as Mustard clones. He tried many different types and settled on one from CDE. There is a little more power supply regulation than on the original in order to better cope with modern wall supply, there are also sensible changes made to help reduce external interference from cell phones etc.
Alan says he's actually very ecstatic about just how close he managed to very accurately replicate his original, and in truth, he thinks these sound even better because of their improved noise floor and response. He also says he would put it up against any 50W Plexi, original or not! Yes... We love his enthusiasm.
Visually, it is a very close replica of the original. Vintage style tolex and a new gold logo were used.
Like every Plexi, this model features dual channels and is a non-master volume model. The channels are very balanced just like the original, there isn't a crazy bright and crazy bassy channel like the later Plexi model. channel 1 is a tad brighter than channel 2 and Channel 2 has a little more low end than channel 1. Both are very useable on their own without jumpering.
1 x GZ34 Rectifier Tube
2 x EL34 Power Tubes
3 x 12AX7 Preamp Tubes
Hi and Lo input on each channel
Volume 1 - Channel 1 Volume
Volume 2 - Channel 2 Volume
Treble - Master Treble Control
Middle - Master Middle control
Bass - Master Bass Control
Presence: Global Presence Control
120V AC - Dual 120/240V Available Special Order