Marvel Amp Update

I dropped by Bruce Collin’s Mission Amps shop yesterday for a little work on the newly acquired Marvel vintage tube amp. This was the first time I’d had the chassis all the way out of the amp. The circuit is sparse and primitive, reminding me of a 1947 Gibson amp I once owned. It has a half wave rectifier, just a tiny diode. Weird.

Mostly I wanted Bruce to install a grounded power cord and test the caps, because I really like the tone of the ratty little amp as it is. Here is what we ended up doing:

-Install grounded power cord
-Remove the “Death Cap”
-Install cathode bypass cap on the power tube. This gave the amp a bit more punch.
-Test all tone caps for leakage. 
-Test all circuit voltages.
-De-oxidize the tube sockets
-Install speaker jack

We then tried five different preamp tubes: 

-The vintage RCA gray plate 12AX7 I had in the amp
-a 5751 from JJ Tesla
-a 12AY7 from EH
-an NOS 12AZ7
-an NOS RCA 5965

Of those tubes I liked the 12AZ7 best, so I have it in the amp for now. We did not change the power tube. The original 7591 tube is a gem; a Sylvania rebranded as Multivox.

We found some date codes on the chassis and filter cap. It looks like it was made late in 1963.

The amp tested at 7 watts just as it began to clip. It still has the same old-school raspy sound but slightly browner. Sounds good! It’s a keeper.

Vintage Kay Amp

My friend Timothy Patrick O'Reilly from the DC area sent photos of his cool vintage Kay amp.

All the tubes are original and Tim says it sounds great.  That is a 6L6 power tube on the left and a tube rectifier on the right.  A 12AX7 preamp tube is hidden in the far left.  With that 6L6 I bet this little amp kicks butt.  I'd like to hear it next to my little Marvel amp.

Test - Amp volume vs Mic volume

This video compares two scenarios:  In the first segment the volume on the amp is all the way up and the volume on the harp microphone is barely cracked.  In the second segment the amp volume is on 4 and the microphone volume is all the way up.

My phone is in the foreground running the RTA app to show the relative loudness. The amp is a Mission Chicago 32-20 and the mic is a 1959 Shure 440SL with 99B86 CM element.

The two segments sound similar.  To my ear the segment with the amp all the way up was less lively and not as full sounding.  The amp tipped into screaming feedback if I turned the mic up the slightest bit, so this is about as loud as I could get in this scenario.  That was my benchmark volume for the comparison.

In the second scenario the amp is on 4 with lots of room for more volume, and a greater range of tonal inflections.

I'd heard about the "amp all the way up" thing over the years and decided to test it after hearing a jammer do it at Ziggies the other night.  I think there is a good reason it is not very common.  The traditional way sounds better.

Please pardon my noodly playing....

Bad News Blues

Vintage Boss DM-2 For Sale

You know what this is: Boss DM-2. The best sounding analog delay pedal ever made. They sold from 1981 to 1984, and today they fetch around $350 on eBay. Very highly coveted by blues guitarists and harp players. A pro harp buddy of mine has one for sale, and I know he's asking less that that. Let me know if you are interested.

Wezo Megatone ME-18 Amp

The Wezo Megatone ME-18 blues harp amp is all that, and then some.  It is faithful to the vintage Masco tone it is designed to emulate, with a glorious crunch.  It is feedback resistant (at least it was in Ziggies) and at a rated 35 watts it has plenty of volume before feedback for strong gig levels.  The amp is a keeper.

It is a keeper if you are looking for a distorted sound, and many blues players are in search of this tone.  It sounds very much like the 50’s vintage tube amps used by the famous blues harp players of the era, only louder.

Until a few weeks ago I owned a 1953 Masco ME-18 amp for about 5 years, so I am familiar with the kind of sound Mike Wesolowski was looking for in this amp.  It nails the flavor of the vintage tone, if not the exact recipe.  It does not compress the sound as much as the original and it has a brighter tone that does not quite sing as much.  These differences may be intentional in the design; compromises along the way to the great tone it does deliver.  It made me smile as soon as I heard it.

This was not a comprehensive and thorough test…  It is just playing impressions from a blues jam.  Gary Yates, the owner of the amp, has had it for only a couple of weeks and may not have it dialed in just yet.  We played it without much adjustment, and the amp has LOTS of flexibility in its adjustments.  It would take more time and focus than I could provide at a busy blues jam to really explore all the limits of the amp.

But I was very impressed.  It has a big, forward sound that gets attention and is immediately recognizable as “Chicago Blues Harp” even by people not really familiar with the genre.  It sounds old and gritty, and I mean that in a very good way.  If that is the sound to which you aspire, this is the amp for you.

I played both my Bassman and the Megatone a couple of times during the jam.  The Bassman sounds bigger and warmer, as you might imagine.  It is impossible for me to say which was “better” since they both rock in different ways.

The Megatone amp seemed very heavy for its size, almost as heavy as my Bassman which weighs in at 63 pounds.  That is a load, and something to consider.  And they ain’t cheap, ranging in price from $2000 to $2160.  That is something to consider, too.

Still, the Wezo Megatone ME-18 amp gets the Blues Harp Amps Blog seal of approval.  That crunch is sick.

In this video Dan Treanor is playing the Megatone ME-18 amp and using my 1959 Shure 440SL bullet microphone.

NOTE:  The owner of the amp (Gary Yates) tells me that both "Pull Boost" switches were in the down position when this recording was made, meaning the amp was in it's cleanest mode.

Ultimate 545 w/Bulletizer into Mission 32-20 amp

Ultimate 545 mic with Bulletizer from Greg Heumann, played into a 1x12 Mission Chicago 32-20 amp.  No delay or effects on the amp.  (Al blows some high notes into the PA first...)

Comparison: Masco ME-18 vs Sonny Jr 410

At Ziggies last night Dan compared two amps:  My 1953 Masco ME-18 and his Sonny Junior 410 amp.  It is an interesting study in contrasting tones.

The SJ amp sounds like a lot of Bassman-type amps:  Smooth and strong; not a lot of crunch.  The Masco, because of it's more primitive cathode biased circuit, crunches happily along.  At 20 watts it does not get the big thump of the 410 but it sure gets more color.

For you guys who love tube amp distortion (like I do) this is about as good as it gets.

UPDATE:  Dan decided he liked the Masco so much be bought if from me.  Now it is his.

I didn't need the money, and I loved the amp, so why did I sell it?  I almost never played it any more because it plays in the same power and tone category as my Mission Chicago 32-20 amp, whose milder crunch I actually prefer.  I was thinking it was time to find a good home for the Masco.  Dan is a great local player who is devoted to vintage tone, so I know the amp will get played and appreciated a lot.  I bought my Bassman from Dan and he gave me a great deal, so I sort of owed him one.  Mostly I sold it to Dan because he is a friend and a true bluesman.

Now I have three harp amps:  The hot-rodded 1971 Fender Champ, the Mission Chicago 32-20 1x12, and the beastly Fender Bassman RI.  I'm good with that for a while.

Irrational Amp Tinkering

This Champ is ridiculous. No sane person would ever spend so much time and money on such an inexpensive small amp, would they? It is irrational.

I got the amp in Sacramento in 2005 from the estate of a woman who bought it new in 1971 along with her new electronic organ. The amp sat in her living room, occasionally singing church music, for 35 years. The picture above was taken the day I brought it home.

It was the coolest little amp I had ever heard for harp, but I just could not leave it alone. First I tried several new input tubes, and that is when I learned that the 12AT7 tube is a terrible tone generator and the 5751 is great. The Champ is a good test bed for things like that because its circuit is so simple.

Next I replaced the speaker with a Jensen reissue P8R. Hated it. Then I altered the baffle so it would accept a 10-inch speaker and tried a Jensen P10R. Hated it. I tried several other various speakers and finally settled on the Weber 10A-1250 with H dustcap. Now we were getting somewhere. The Champ settled into that configuration for several years. 

Then one day I lost my mind and decided to trick the amp out more. (Read: spend more money on it.) 

First I installed a pot in the negative feedback circuit so I could adjust it to find the optimal mix for crunchy tone. I discovered the optimal mix was ZERO, so I removed the NFB circuit and the pot (which was mounted on the back part of the chassis) and used the hole where the pot had been to mount a line out jack.

More tube swaps followed, finally ending with the 5751 in the input section, a vintage black plate GE 6V6 in the power section, and an NOS “Coke Bottle” Sylvania 5V4G rectifier. Again, the Champ settled into this configuration for some time. It was sounding GOOD.

But not good enough. So I asked Bruce Collins at Mission Amps to voice the tone stack for harp using NOS Soviet K40Y paper in oil tone caps. Big improvement, but I wasn’t finished quite yet. A few months later Bruce installed a Hammond 15-watt output transformer and a choke. There! The amp was finished. A sleeper amp, with big punch and crunch in a small package.

Which brings us to today. Before guitar player Steve Mignano headed off to tour with Cassie Taylor and the Soul Cavalry he gave me a Warehouse Veteran 10-inch speaker and said, “It crunches like a motherf---er.” Hmmmmm, this I had to hear.

I looked around for a 10-inch cabinet and finding none I decided to swap it into my Champ, removing the nice Weber alnico speaker. The Weber speaker made the Champ darker and warmer, and Steve was right: The Veteran speaker crunches like a mutha with a brighter, raspier tone. It’s fun. Ratty!

I really don’t know how much I have invested in the Champ now, but it is a ridiculous amount – certainly more than the value of the amp. I have learned more about harp amp tone from the Champ than from any other amp. It is now the amp I have owned longest. Purists might sneer at me for altering a classic but it has been a blast. And the amp is a little beast.

Choke and 15-watt transformer

Silver bullet-shaped Soviet military PIO caps

Rectifier and power tube, and Veteran speaker

The Champ at work

Jam Amps

Players often leave their amps at home when heading to my jam since they know there will be at least one good harp rig they can use.  But a recent thread in Adam Gussow's blues harp forum got me thinking about all the different amps that have been honked on the stage at Ziggies over the last three years.  (At least the amps I can recall right now, in no particular order)

-Original 1959 Fender Bassman

-Fender '59 Bassman Reissue

-Mission Chicago 32-20 1x12 and 3x10

-Harpgear HG50 410

-Harpgear HG30 and 35

-Harpgear HG2

-Sonny Jr 410 and Super Sonny

-Sonny Jr Cruncher and Super Cruncher
-Fender BF Super Reverb

-Fender silverface Princeton

-Fender silverface Champ
-Fender Champion 600

-Fender Blues Jr.

-Fender Pro Jr.

-Fender’65 Princeton Reverb RI

-Peavey Delta Blues 210

-Kendrick Texas Crude

-Kalamazoo Model 1 from Greg Heumann

-Pignose 7-100 and HOG30

-VHT Special 6 Combo

-Weber 5F2H custom

-Masco ME-18

-Edward ED amp
-Fat Dog 2A and 4A