Wednesday, April 27, 2011

The Mission Chicago 32-20 harp amp: Cheap?


The new theme now emanating from one of the competing amp makers is that the Mission Chicago amps are cheaply made, using inferior parts. I encountered one blowhard online who was particularly insistent about this, so I put him on the dime and asked him to be specific: Exactly what is cheap about the Mission amp? He replied that it was the circuit board, and he said he had pictures to prove it. In fact, he promised to send me the pictures the next day. Of course, they never arrived, even after I repeatedly requested them.

Here are the facts about the circuit board in the Mission harp amp: The eyelet board upon which the circuit is mounted is hand-fabricated from a fiber-reinforced polymer sheet. Vintage tube amps used a composite eyelet board that buckled when exposed to moisture. Anybody who has spent time with old tube amps has seen these buckled circuit boards, and the problems they cause such as noisy cracked solders. In fact, some makers of expensive amps use un-dyed versions of the same old composite boards, another invitation to future problems. The circuit boards in the Mission Chicago amps are impervious to moisture and heat.

The circuit board (pictured above in low resolution to preserve trade secrets) looks like a work of art. It is hand crafted, one board at a time by a master amp tech, not assembled in a factory like some other “custom” harp amps.

The components on the board were all chosen using only two criteria: tone and reliability. It did not matter if the component was the most or least expensive. For example, we spent many hours trying tone capacitors and listening to the differences. The NOS military-grade K40Y-9 paper-in-oil caps were by far the best, imparting a subtle human vocal quality to the tone. Most caps (including those used in some expensive custom harp amps) made no impact on the voice of the amp. None.

The transformers used in the Mission amps are custom wound in Chicago to Bruce Collins’specs. The chassis upon which all the electronics are mounted is made of thick chrome, fabricated and bent to Mission’s specs by a vendor here in Denver. The tweed cab is from Mojo Musical Supply, the same cab used by the two biggest custom harp amp sellers.

The speaker is an Eminence Cannabis Rex, chosen for its smoky tone and punchy character. Its 102db sensitivity rating gives the amp great efficiency and volume, with a gorgeous crunch and rip. This is a premium speaker, not a no-name rebranded compromise acquired from the lowest bidder. The Mission Chicago harp amp is sweet enough for recording and loud enough for a raucous blues jam.

For more than two decades Mission Amps have been known worldwide as serious tools for working players: Superb tone, beautiful build quality, and exceptional value. The competitors are evidently getting very nervous indeed.

============================

Disclaimer: I helped design and develop the first Mission Chicago 32-20 harp amp, which I own and use as my primary gig rig. I have no other relationship or interest with the company, other than Bruce Collins is a friend and occasional band mate.

2 comments:

strawwoodclaw said...
This comment has been removed by the author.
Rick Davis said...

I don't think Bruce is planning to disconinue the 32-20 amp, but I know he is planning to add other configurations, including a 2x10.

Hey, it is a great-sounding custom hand-made amp for a reasonable price. Demand is high. At least it's not like the B-Radical harmonicas, with two-year waits. If you are interested in the amp keep trying. And I'll try to pass your message along to Bruce.