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.

Monday, April 25, 2011

Ziggies Famous Sunday Blues Jam - April 24, 2011

This was one of the best moments of the jam, I think. Jasco killin it with the beer bottle slide. Dan Treanor blazing on harp. Steve Mignano just rippin' it up on the Les Paul, getting epic tone with zero pedals. I was a smilin' jam host at this point.

Dan is playing the Mystery Amp.

Friday, April 22, 2011

Mystery Amp: Modded Bassman RI in Sonny Jr Cab

A buddy of mine bought this amp on eBay: It is a modified Fender Bassman chassis circa 2003 in a Sonny Jr 410 cabinet. The eBay seller did not misrepresent the amp at all, and my friend got the amp for only $750, which is a smokin’ good deal.

The seller said the chassis had been modified by Gary “Sonny Jr” Onofrio himself. I contacted Onofrio and sent along photos for his comment. He said he had no specific memory of working on this amp, and had no idea how it ended up in an SJ 410 cab. He said he may have modded the amp back in the timeframe when he was transitioning from the 410 model to the Super Sonny amp. He took on custom work during that time of low amp sales.

When examining the Bassman chassis it is easy to see the mods. They are the standard tweaks that are typically used whenever adapting a guitar amp for use with blues harp: Convert to tube rectifier, larger than normal coupling caps, and lower idle plate current in the power tubes. There is nothing secret or magical in the tweaks here. Pretty standard stuff.

When bench tested the amp produced 32 watts just as it began to distort on the scope, and 39 watts at peak output.

One thing did stand out. Bassman RI owners often use low-gain 12AU7 tubes to calm the amp down and reduce feedback, and this amp was no exception. They get bad advice from yokels on the Internet who claim the AU7 tube is the magic bullet for the amp. In fact, the 12AU7 tube is incompatible in circuits designed for the 12AX7, such as the Bassman RI. The 12AU7 tube draws more current than the 12AX7, so the cheapo ¼- watt carbon film resistors found in many PCB amps get stressed, sometimes burning open and causing a nasty hum and damaging downstream components. In this case the tech changed the plate load resistors to a higher value. Good call.

This amp had a nasty sizzling noise that usually indicates a bad preamp tube or a bad solder joint. After resoldering several connections the noise went away.

The amp is loaded with four Alnico Blue speakers, which I believe are rebranded Eminence 1028s. We tried several different preamp tubes and finally settled on this combination: 5751 in the preamp socket, 12AX7 in the secondary gain stage, and 5751 in the phase inverter.

How did the amp sound? Good! Very good, in fact. It has less of that reedy edginess typical of the stock Bassman RI. It has a bit more wamth, with good note definition but not much crunch, which is normal with 4x10 harp amps. Nice big sound. I need to borrow the amp and play it in a performance setting to wring it out more, but I am initially impressed. (I'll be using this amp at the Sunday Blues Jam my band hosts at Ziggies Saloon in Denver this Sunday night.)

I am so impressed I plan to buy a used stock Bassman RI for a project amp. I’d like to see just how much tone can be wrung out of this amp. I suspect the amp can rival the expensive custom 410 amps for a lot less money.

NOTE: Many thanks to Bruce Collins at Mission Amps in Denver for helping with this article.

Sunday, April 17, 2011

Harmonica Amplifier Poll



In my consulting company one of our biggest lines of business is public opinion polling. I plan to conduct a poll of harmonica players regarding the amplifier they use most frequently in a variety of settings. To participate simply reply to with the answers to the questions below. Sorry, poll responses that are posted in the comments section of this blog will not be tabulated.

Your responses and email addresses will be kept strictly confidential and never used by anyone to contact you. The ONLY exception is if we need clarification for any of your poll responses. When the poll is finished I will publish the aggregate results only. The poll will close on June 1, 2011.

These questions apply to amplifiers you OWN. I know most harp players own multiple amps but please pick the one that most applies to each question.

Thank you very much for being a part of this poll. The questions begin here:


-What amplifier do you use most frequently in a performance setting, either Jam or Gig?

-What amplifier do you use most frequently for recording?

-What amplifier do you use most frequently for practice?

-How many amplifiers do you own that you use for harmonica?

-Thinking of the amplifier you named in Question 1, did you buy it new or used?

-Do you earn more than 25% of your income directly from playing harmonica?


-What is your age?

-What is your gender?

-In what state do you live?



Friday, April 15, 2011

Shameless Self Promotion

Please visit The Blues Allstars page on Reverbnation and click on "Become a Fan."


Tuesday, April 12, 2011

The Cruncher Amps

I’ve played and heard others play the Sonny Junior Cruncher and Super Cruncher many times, and I am only mildly impressed every time. A friend who is a good young player brought his Super Cruncher into my jam at Ziggies last week. Let me try to explain as clearly as I can what I dislike about the sound of these amps.

I hear it every time a Cruncher amp is played: First, a trebly nasal quality to the tone. Second, a serious lack of bottom end. Third, not much crunch, despite the name!

Those 8-inch tweeters in the Cruncher amp can be shrill. I am of the opinion that 8-inch speakers sound good ONLY in small class-A amps such as vintage Champs. Those circuits get their distortion in an entirely different way than a big fixed bias amp like the Cruncher, where the small speakers just kind of rattle as they break up.

Sonny Junior claims the 8-inch speakers help the amp “throw” the sound to the back of the room. That is true… They are beamy and project the treble tones well, but the low end rolls off about 10 feet in front of the amp, as if the speakers are out of phase.

Whenever anyone offers criticism of the Cruncher amps, its supporters point to the list of endorsers. What they don’t mention is the list of great harp players who chose not to play the Cruncher. Kim Wilson is arguably the best blues harp player in the world. Dave Barrett arguably has the best technique and tone. When you listen to either of them play it becomes evident why they choose other amps: Both of them like a deep warm sound. In this video Barrett is explicit about why he prefers a different amp: Deeper tone.

I feel the same way. A deep warm lush tone is a must in a good gigging harp amp. The Cruncher amps do have a bold sound, but there are other amps with better tone. The Cruncher’s nasal quality make it annoying after a while. Sure, when Charlie Musselwhite plays his Cruncher I can appreciate his amazing virtuosity and command of the instrument, but the whole time I’m wishing he were playing a better amp.

The Cruncher amps are popular because they have a bold sound some players love. And amp tone is of course entirely subjective and personal. I and others prefer a warmer, more natural amped tone.

UPDATE: Listen to an audio comparison - Cruncher amp vs. Mission Chicago 32-20 amp

MORE: I’ve heard from several Cruncher owners and former owners, some of whom agree with me and others who don’t, just as you would expect. One of them reminded me of something I should have made clearer in the original post.

If you stand in front of the amp and play it, it does indeed sound great. But that is not what your audience is hearing if you actually play in large rooms in front of people. When you stand in front of your amp the bass sounds huge and the highs are pointed at your knees. Highs are much more directional than lows.

If you use a wireless rig as I do you can walk around the club as you play and hear exactly how your amp sounds. Try walking out 30 feet from your amp and see what I mean. I frequently walk all the way to the back of the club to listen to my amp as I play.

When you play at home in your living room the Cruncher sounds nice and full. When you stand in front of it on stage you hear all the bass and little of the highs, so it sounds good to you. It’s a different story out front, and that is what I am talking about in this article.

Saturday, April 9, 2011

Why Blues Jams are Important

Blues music is kind of like baseball: It is often passed from father to son, from sister to brother. Without that generational link it will wither. Blues is oral history… It is three chords and the truth.

Blues jams have been an important tradition nearly since the beginning of the form, with raucous head-cutting sessions among jazz and blues players in New York City, and jams from Delta juke joints to Chicago night clubs. The blues Jam I host on Sundays at Ziggies Saloon in Denver is at the end of a long, long train of blues relationships, and I expect it will eventually help pull more boxcars that hook up along the way. Blues jams are about keeping that train rolling.

One of the things I like best about hosting the jam is encouraging new players. Playing in front of a crowd can be terrifying, especially the first time. The newbies who come to the jam and bust out their chops on stage for the first time are my heroes. Every blues jam has a debt – an obligation – to nurture the music. That means attracting, helping and inspiring new blues players.

I’ve seen new and intermediate players blossom over the year and a half I have hosted the jam at Ziggies. Playing on stage every week with musicians of all levels, some of them develop a real talent for the music and the show. A few have moved on to working bands.

Accomplished players frequent the jams to see friends, to try out new chops or gear, or to just share the joy of playing the music with others. Blues is a performance art. Practice is just waiting.

One of my goals for every jam is to put together at least one killer feature set; a set that includes some of the best working pros who drop in, perhaps backed by members of my band. My main duty as a jam host is to put on a good show, and that killer set can bring people back to the jam and help inspire the new players. At jams, aspiring performers pick up riffs and showmanship and attitude from the more seasoned players. They hear great tunes to add to their repertoire. It’s about paying it forward. The blues will abide.

Blues jams are about doing a simple thing very well. They are about a shared understanding – a visceral instinctive joy – for the sound of the Delta, and Memphis, and Chicago, and West Coast Jump, and all the regional dialects of the blues language.

A big shout out to my brothers and sisters who host blues jams. It doesn’t pay much, it is often chaotic, and you have to deal occasionally with drunk and/or egotistical jerks. But it is service to the blues tradition. It is helping to keep the blues alive.

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UPDATE: People from all over the country have contacted me asking for permission to reprint this article. I am flattered. Anyone may reprint this verbatim with attribution. Please include a link back to here if possible. Thanks!

Thursday, April 7, 2011

Denver's Best Blues Jam: And the winner is...

Westword magazine -- the definitive voice on Denver’s music scene -- has named The Sunday Blues Jam we host at Ziggies Saloon as Denver's Best Blues Jam - 2011.