VHT Special 6 Amp - Modified for Blues Harp

This is an amazing little amp to start with, and these mods make it even better.

Bruce Collins at Mission Amps modified the voicing and tone stack as described in the previous blog post. The changes were actually very small: a few components on the eyelet circuit board. Anybody who can solder could do it.

I installed an Eminence Lil' Buddy speaker, mostly because it has a hemp cone similar to the Cannabis Rex speaker I use in my Mission Chicago 32-20 amp.

The amp has a JJ Tesla 6V6 S power tube in it in this video, but the stock power tube sounds the same.

The delay pedal -- with a small amount of delay -- is ON when the video starts. The delay is OFF after you see me hit the button.

Here are the differences I hear in the modified amp:

-It is louder than the stock amp. The Eminence speaker is more efficient.

-It is warmer/darker than the stock amp. Bruce voiced it lower, and the Eminence speaker is less bright. IMPORTANT NOTE: The amp is sitting on a pedestal in this video, up off the floor and away from the walls and corners. That gives it a truer sound, with less exaggeration of the bass tones. If you put the amp on the floor or against the wall the bass with be more apparent.

-The sound is bigger and less boxy.

-The break-up is more organic. The stock amp had a slight crackly, reedy quality to the tone.

-The amp tips over into nice distortion when you push it a little bit. You can hear that in the second part of this video when I play the blues riff a second time a little harder. This is because of the circuit mods.

-The amps seems more dynamic and musical. I gotta tell ya... it is a blast to play!

I played this amp at a loud blues jam at Ziggies Saloon in Denver on Sunday and it did well. I got lots of nice comments on my tone. It is not as robust and powerful as my normal gig rig, so I had trouble hearing myself in the loudest moments. The next mod will be a line out, so I can put a bit of the amp through the monitors. That will be perfect. In all but the loudest situations I think the amp will do just fine by itself.

So, I paid $200 to Amazon.com for the amp. It arrived in five days, no shipping charge. The speaker sells for $75. There is no real need to change the stock tubes unless you are an inveterate tinkerer (like me). The tubes sound fine. For $275 you can own a killer little harp amp that beats the pants off the EL84 amps like Kalamazoo, Epiphone, and Fender Pro Jr.

With the circuit mods the amp steps up to a whole new level and becomes a true harp amp. It has the tone and feel you crave... It's a boutique harp amp for a fraction of the cost.

I am thinking of offering a kit for the circuit mods. If there is interest in this, let me know. I will produce detailed instructions including a video, and include all parts and wires. I may also offer complete conversions. If I get some demand for this I'll come up with some prices and publish them here. The price of the mod kit would be quite modest, for sure.

VHT Special 6 Harp Amp Project – Step One

Today the Special 6 project amp spent some time at Mission Amps in Denver for testing and first-step harp mods. Here is what I can tell you:

-The amp produces its rated power of 6 watts with about 5 percent distortion at two o'clock on the volume control (it is not numbered). Feedback is well controlled. The amp is very well made, with a hand-crafted circuit similar in design to a blackface Fender Champ from the mid-60’s era.

-Changing to a 6L6 power tube in the amp does nothing to increase the power or improve the tone. It sounds and performs better with a 6V6. Also, the magnet on the stock ceramic speaker makes many 6L6 tubes a very tight fit.

Right out of the box this is a very good harp amp. It is among the most harp-friendly guitar amps I’ve seen. A harp player could buy this amp and do nothing to it, and get great tone from it.

But the amp does have a few compromises that can be improved upon to make it more suitable for outstanding blues harp tone:

-The slope of the tone stack is too trebly. It needs to be shifted downward.

-There is a slight reedy quality to the tone that detracts from its warmth.

So, we decided to make a few simple modifications to the tone stack, making it more like the circuit in a tweed Bassman amp. Each of these mods was tested by playing the amp to ensure the tone was improved in the way we expected. We sometimes had to try several different component values to get the tone just right.

We changed the tone stack slope resistor, the bright cap, and the cathode bypass cap, and changed the plate voltage on the preamp tube.

The result is a smoother, warmer tone without the reedy quality. The voice of the amp has been shifted downward, and its tonal girth has been enhanced. It retains the nice crunch and grit. It is a very fine sounding blues harp amp.

Remember, at this point the amp still has its original tubes and speaker, and I am in no hurry to change them. I suspect the speaker will break in well, and the stock tubes sound great. I’ll try other tubes later, after I’ve played it more and made certain the circuit mods are as they should be.

UPDATE 11/26/11: The amp is substantially louder now. Same room, amp settings, mic, and harp. I suspect the speaker got broken in during all the hard playing at Mission Amps while we were proto-typing the mods. The tweaks to the tone stack also focus more of the amps energy on the harp spectrum.

Jump to review of this amp with mods

VHT Special 6 Amp - First Impressions

My new VHT Special 6 amp arrived a couple of hours ago and I've already given it a hard workout. My first impressions? I'm impressed! Very impressed. This little amp sounds great right out of the box.

The VHT Special 6 is a point-to-point wired tube amp that sells for $200.00. The power tube is a 6V6, the same tube that powered vintage Fender and Gibson amps and has such wonderful natural harp tone.

Here are a couple of videos I made within minutes of the UPS guy dropping it off. In the first vid I am playing a bullet mic with a Shure CM element, very similar to a vintage Green Bullet mic. In the second video I'm playing a Front & Center mic with a crystal element.





The Shure mic is plugged into the "Lo" input and the F&C mic is plugged into the "Hi" input. Otherwise, the controls were the same for both.

This little 6-watt (nominal) amp has caused me to rethink my favorite starter amps. Already, this VHT seems to have more volume and much better tone than the low-priced EL84 amps such as the Epiphone Valve Junior. It's 10-inch speaker blows away the Fender Champion 600, and it just runs rings around the old Kalamazoo amps. The amp has a natural warmth and crunchiness and it responds well to the pressure you put on the microphone. It is essentially a blackface Fender Champ with 10-inch speaker for $200. Amazing.

The VHT Special 6 amp begs for mods with its intelligent open design, eyelet board, and point-to-point wiring. The next step will be to take this little gem to Mission Amps in Denver for bench testing and upgrades. As I said, stay tuned...

Jump to Step One Mods

VHT Special 6 Amp

Yesterday I ordered the VHT Special 6 amp from Amazon.com. This will be a new harp project amp, with great potential. Stay tuned on this one....

Update: Mission Chicago Amp

Bruce Collins has posted a few interesting details to his Mission Harp Amps website. He has changed the name slightly to the Mission Chicago 32-20 amp. As far as I know there are no changes in the design or features or sound.

One detail he added concerned the output transformers used in the amp: "Custom made, oversized windings and vintage style open frame, paper bobbin." These are the same killer OTs he's used since the amp was first offered for sale.

Bruce recently shipped a Chicago amp with 5881 power tubes that produced 41 watts in fixed bias mode. Crikey! It retained all the warm tonal qualities of the 6L6 amps, but with more bark and punch. What a beast...

Update: My bad... The tubes Bruce used in the 32-20 amp to get 41 watts were 6L6WXT+ tubes. You can order the Chicago 32-20 amp with these tubes, no extra cost.

Smackdown! – Harpgear HG35 vs. Mission Chicago 32-20

Let me say right up front that I think Brian Purdy at Harpgear makes excellent harp amps. For years I have recommended to my students and others that they buy the Harpgear HG2, a 5-watt tweed Champ clone with outstanding tone and build quality.

I’d heard and played the HG35 amp on several occasions, and at a blues jam last night I had the opportunity to play both it and my Mission Chicago amp and do a close comparison.

The two amps are similar: The HG35 claims 35 watts of power, while the Mission amp claims 32. They are both built in tweed cabinets of roughly the same size, with the Harpgear amp using two 10-inch speakers and the Mission amp using a single 12-inch speaker.

The basic circuits are similar, with twin 6L6 tubes providing the power in each amp. These tubes are cathode biased in the Harpgear amp, and that presents one of the biggest contrasts between the two: The Mission amp is switchable from cathode bias to fixed bias, and I prefer to play it in the fixed bias mode.

I have been curious about the Harpgear HG35 for this reason: Claiming 35 watts from a cathode biased 2x6L6 amp is unusual. Using the standard method of measuring output wattage, it is tough to get more than about 25 watts from this configuration in a harp amp.

This difference was evident last night when I played the two amps on stage at a blues jam. The 32-watt Mission amp is substantially louder than the 35-watt Harpgear HG35. In fact, the Mission amp has a remarkably fuller tone at half volume than the Harpgear has at three quarters volume.

Both amps produce good tone, but the Mission amp produces a bigger tone with noticeably more crunch and bottom end. I switched back to the Mission amp because I was concerned I would not be heard in the loud jam setting.

The Harpgear amp has a cleaner sound, and I am sure that is a feature that Brian designed into the amp. His amps are known for this. The amp sounded brighter and more directional. It was a bit more prone to feedback.

When I switched the Mission amp to cathode biased mode its volume dropped to a level similar to the Harpgear amp, but the tone retained more of a vintage-style warmth. Overall, the Mission amp breaks up more readily than the Harpgear amp.

For those who prefer a cleaner tone and always play in situations with low-to-moderate stage volume, the Harpgear HG35 could be a good choice. For players looking for a bigger crunchier tone, the Mission Chicago 32-20 amp might be a better choice.

Interview at Ziggies

We were interviewed during the Sunday Blues Jam that we host at Ziggies in Denver. Charles Billiris (guitar player/singer) and I are standing out on the sidewalk in front of the club while the jam goes on.

The Truth About Gear

It is an arcane debate that rages forever on music forums and elsewhere: How important is gear to your tone?

The Curmudgeons in this argument insist tone comes only from the player, and too much attention is paid to gear. The Gear Heads lust after one piece of gear after another, dreaming that some combination of hardware will give them that perfect blues harp tone.

I’ve been in both camps at various times. Here is the truth about gear:

-No matter what gear you use, you will still sound like you. People who are familiar with your playing will still immediately recognize it and most of those people won’t notice much difference no matter what gear you are playing.

-Players spend an enormous amount of time and money on custom gadgets that do not improve their tone, and in fact may make it worse. This includes vintage or custom mics, pedals, amps, harps, etc.

For good blues harp tone you need an amp and a mic, period. Let’s start there. After you are satisfied with your tone it is fair to experiment. But when I read (rather frequently) about new players spending big bucks on a custom harp amp and then throwing a bunch of pedals in front of it I cringe.

A custom harp amp will not improve your tone, technique, or playing, except to the extent it inspires you to practice more. And a good-sounding amp will certainly raise your level of excitement and commitment to the craft. The value of a custom harp amp is this: It allows you to focus on your tone. It will be less likely to have screaming feedback, and it will have the potential to reward good playing. It can make you a better player if you work at it.

You don’t need an exotic vintage or custom microphone. You most certainly don’t need a “HOT HOT HOT!” element, as advertised on eBay and elsewhere. That high output will kill your tone, and the flame paintjob will be indifferent to your tooting and honking. Much money is wasted on expensive mics that do nothing to improve your tone.
If you have a good harp amp (see above) you don’t need any pedals except for perhaps a simple delay pedal. A complex pedal chain is a waste of your money and an impediment in your quest for good tone. And, the arguments over which delay pedal is best are often absurd. There is nothing about blues harmonica that demands a certain circuit in a delay pedal. As long as the pedal sounds good to you it is perfect. The pedal I use costs $60 and sounds great.

If you aspire toward good blues harp tone you don’t need $200 custom harps or demon tweaks from high-priced amp Gurus. You need a good basic rig: a harp amp and mic, and maybe a delay pedal. You need these working tools, and that’s it. Other players don’t sound better than you because they have exotic or expensive gear. They sound better because they practice more or are simply more gifted.

Bugera V5 Amp

Yesterday I was over at Gary Yates' house to practice harp and go over some points from Ronnie Shellist's harp workshop last week. Gary had a little Bugera V5 amp set up and I played it for a few minutes. It was fun!

The tones from the amp are good, and feedback was not a problem. Gary had a small tube preamp hooked up but I preferred the sound when I plugged straight into the amp.

It's a little 5-watt bugger with a 12AX7 preamp, an EL84 power tube, and a solid state rectifier. Controls are gain, tone, volume, and reverb. Fiddling with the gain and volume I was able to get some pleasing harp tone. The digital reverb is usable but a bit too watery.

It also has a power attenuator on the back panel, but this will be a lot more useful for guitar heroes than for harp players. It has settings for full power, 1 watt, or a tenth of a watt.

Interesting feature: It has a headphone out connection; a 1/4 inch jack that would work fine for a line out into a PA system.

The Bugera V5 sells for about $150. It is certainly worthy of consideration if you're looking for a small harp amp and your budget is modest.