Preamp tubes: three ECC83 (12AX7 equivalents)
Output tubes: two KT88
Controls: Volume II, Volume I, Treble, Middle, Bass, Brightness
Output: approximately 75 watts RMS
We might not expect anyone to give much of a hoot for an amplifier with “Park” on its badge – a brand that has also graced budget-grade solidstate amps from Asia for the past couple of decades – except for the fact that any player or amp collector in the know is hip to the fact that a Park from around 1965 to around 1980 really is just a Marshall by another name, and often one with a nifty twist.
This situation has set up the unusual circumstance that the sub-brand Park amps from the golden years, the point-to-point amps made from the mid ’60s until around 1974, often fetch a little more on the vintage market than their Marshall counterparts. That probably fewer than 800 or so such Parks were ever built doesn’t hurt their desirability, and the pervasive rumor that Jim Marshall made many Park models “a little hotter” than similar Marshalls coming out of the factory alongside them adds further cache to the name.
The original Park amplifier line represents a clever and rather devious piece of marketing brinksmanship on the part of Jim Marshall. In the early years of Marshall, the Jones and Crossland music store in Birmingham served as a distributor of sorts for the north of England, but was cut out of directly handling Marshall business when the company penned a bigger and broader distribution deal with U.K. music-industry biggie Rose-Morris in 1965. Store owner Johnny Jones had long been a pal of Jim Marshall’s, however, and the amp maker seemed keen to accommodate his friend one way or the other. Meanwhile, Jones and Crossland was already handling a “house brand” line of guitars and other musical instruments, apparently dubbed in honor of Jones’ wife’s maiden name, Park. Marshall and Jones devised the ploy of giving a few minor twists to Marshall-built circuits to sidestep any exclusivity issues, along with some visual alterations and the rectangular Park logo… and Bob’s your uncle; Marshall keeps on supplying its sought-after tube amps to Jones and Crossland for Birmingham and Northern England.
For the first several years of production, most Park amps followed Marshall designs very closely, and the larger heads are therefore comparable to the evolution in Marshall JTM45, plexi, and metal-panel heads from the mid ’60s to the early ’70s. Often they had black or silver control panels rather than the Marshalls’ gold, some came in taller or differently shaped head boxes, and earlier examples displayed other cosmetic tweaks such as chickenhead knobs and different control layouts and labeling. By the mid/late ’70s, Park amps had even more of their own thing going on, such as the more “basic” looking front-mounted metal control panel of the Lead 50 combo, which was also quite different internally from any other amp wearing the Marshall name at the time. Like their more populous siblings, these Parks were built with printed circuit boards post-’74, but are still great amps with loads of sonic character.
This 1972 Park 75 is of an era when the northern alternative was looking rather more Marshallesque, though it is distinctive for its silver metal control panel. It also retains the split channel volumes different from the Marshall setup with the two channel input pairs side by side, and the Volume controls following. It’s purely an alteration of layout, which doesn’t change the way the channels function, but must have provided Jim Marshall yet another way of saying, “Why, no, Mr. Rose, Mr. Morris, this is not a Marshall amp at all – it’s a Park 75!”
One of the biggest technical differences between this Park 75 and a 50-watt Marshall Model 1987 of the same era was its use of KT88 output tubes rather than EL34s (note that this example, however, has been modded by a later owner to use EL34s). Marshall used four mammoth KT88s in the Major to pump out a whopping 200 watts, and a pair of them keeps the Park 75 pretty clean and bold up to a higher point on the dial; most owners report these amps don’t start to break up until the Volume control hits 7 or 8, by which time they are moving a lot of air through a 4×12. At the same time, there’s talk of Park amps having slightly lower-value resistors feeding the preamp tubes in the first gain stage than those used by Marshall in similar circuits, resulting in higher plate voltages and, in turn, more sizzle from the amp’s front end; this might be another distinction of sorts, but in truth, some Marshall amps of the era display similar variations. One further interesting difference here is the “lie down” power transformer configuration, something seen in earlier Marshall plexis, but changed to the stand-up transformer configuration in 50-watt Marshall heads of the early ’70s.
Beyond the input stage, the Park 75 is pretty much classic Marshall all the way out – which is to say, perhaps, that it still follows the basic circuit template laid out by Leo Fender in the 5F6-A Bassman of the late ’50s. A cathode-follower tone stack offers Treble, Middle, and Bass controls, and a long-tailed-pair phase inverter delivers its load to two KT88s in fixed bias, with a negative feedback loop that is tapped to yield a Presence control (called “Brightness” here) just to further differentiate things (and again, not by much). Otherwise, from the fat “mustard caps” to the British carbon-comp and carbon-film resistors and several other distinctive components, it really is solid Marshall stock through and through – and a great alternative means of getting your Brit-rock on.
This article originally appeared in VG July 2013 issue. All copyrights are by the author and Vintage Guitar magazine. Unauthorized replication or use is strictly prohibited.