©2010 Bruce Clement, BC Audio, San Francisco

Other copyrights and trademarks are the property of their respective owners.

Frequently Asked Questions

 

What is the difference between the 15w and 25w versions of Amplifier No. 7?

Is 15 watts loud enough?

Is 25 watts loud enough?

Does Amplifier No. 7 have enough gain?

Is No. 7 geared more toward humbucker guitars or single coil guitars?

What speakers should I plug it into?  Open- or closed-back?  Ohms?  Brands?

Does it get hot?  Why doesn't it have ventilation holes?  Or a fan?

Why is everything on the front panel?  Why not put the power and speaker jacks on the back, like every other guitar amp on the face of the earth?

Why those funny octal preamp tubes?  Why doesn't No. 7 use 12AX7s, like every other guitar amp on the face of the earth?

Why not EL84s?  You know, like every other 10-36w guitar amp on the face of the earth?

Why the ammo can?  Why not put it in a normal head box, like every other guitar amp on the face of the... oh, never mind.

Will it run on European 220VAC power?

Do I need to set the bias when I replace the tubes?

Can I buy Amplifier No. 7 with NOS tubes?

Can I buy Amplifier No. 7 with both types of tubes you offer?

Can I install tubes types other than those you specify?

Is it quiet, you know, when I'm not playing?

How did you come up with the ammo can idea?

 

 

What is the difference between the 15w and 25w versions of Amplifier No. 7?

 

Nothing. They are the same amp, it’s jut a matter of which power and rectifier tubes are installed.

 

 

Is 15 watts loud enough?

 

Probably. Depends on your situation. In its 15w configuration, Amplifier No. 7 will certainly hold its own playing rock in a club, even if it's vocals-only-in-the-PA. If you need lots of clean headroom, or your bass player or drummer are just too damn loud, go for 25w.

 

Remember, you don’t have to decide now. The amp itself is the same in 15w and 25w configurations - it’s just the tubes that are different. You can always change them later.

 

 

Is 25 watts loud enough?

 

Yes. Any louder and you should probably me micing up the amps anyway. Keep in mind that most 50 watt or larger amps built these days are multi-channel or Master Volume designs, where you really never tap the full power of the amp; you never experience the glory of power tube overdrive, where the whole amp is cookin'- not just one channel or just the preamp section.

 

 

Does Amplifier No. 7 have enough gain?

 

Probably. Again, it depends on your situation. It has about the same amount of gain as most classic non-Master Volume amps. If you need more than that...cool! No .7 loves pedals. Pushing the front end with a dirt pedal or clean boost works quite well for leads or high-gain rhythm. I put some tips in the Owner's Manual (download it on the Specs page) about using pedals with No. 7 or any non-Master Volume amp.

 

Pro Tip:  If you use a wireless, you can use it to increase the gain of any amp.  Simply turn the wireless receiver’s output control up beyond unity gain - it’s the ultimate clean boost!  Use your guitar’s volume controls to dial back the gain for rhythm, roll it up for leads.

 

 

Is No. 7 geared more toward humbucker guitars or single coil guitars?

 

It's not! I'll readily admit that I am a Gibson guy. But I also play single coil guitars including Strats and my lovely 1956 Les Paul Junior, and guitars with mixed pickups and coil taps. No. 7 has a purity of tone that clearly brings out the character of whatever guitar you plug into it.

 

A little story: I was showing Amplifier No. 7 at a guitar show. I actually had more than one guy come back to my booth to test out a guitar they were considering buying from another vendor, because they knew they would get a true and accurate impression of the guitar by playing it through a No. 7.

 

 

What speakers should I plug it into? Open- or closed-back? Ohms? Brands?

 

Speakers are a very subjective subject. No. 7 will happily drive any 8 or 16 ohm cabinet, open or closed back, with whatever speakers you like. No. 7 is NOT an amp that needs to be paired with a particular speaker. Its pure tone brings out the character of whatever speaker you plug it into - just like it does with whatever guitar you plug into it.

 

You really must at least try No. 7 thru a good 4x12. You'll be amazed how big this amp can sound, how much clean bottom end it has.

 

Here's what you should do. Take your shiny new No. 7 down to your local (cough) center for guitars (cough, cough) on a Saturday afternoon - you're sure to draw a crowd - and give those kids a lesson in tone while you try out some different cabs.

 

 

Does it get hot? Why doesn't it have ventilation holes? Or a fan?

 

A fan? Are you kidding me? Sure, it gets hot. All tube amps do. But it never gets too hot to put out perfect, beautiful tone for hours on end.

 

During the amp's development, I put it through brutal stress and heat testing. It never broke a sweat. No burned parts, no melted iron, no weird noises, no fading. Just unchanging flawless operation under severe conditions for extended periods of time. And every single No. 7 goes through a burn-in as part of a rigorous QC procedure.

 

Besides, consider the typical tube amp head. It is closed on the top, bottom, sides and front. On the back it may be somewhat open, or it may be covered with a perforated metal panel. Amplifier No. 7 has more free air movement than that!

 

As it says on the sticker inside the lid, "Case will get hot. Don't worry about it."

 

As for ventilation holes, two reasons it doesn't have 'em:

- It doesn't need 'em (see above).

- RUST! If you cut holes in the metal, you expose raw, unpainted steel to the elements. Unless you re-paint the can - and thereby loose that beautiful patina of the original olive drab - rust will undoubtedly develop over time. It may take a couple years, but there's no way I'm gonna have amps out there that will start rusting away a few years from now. You should fully expect your Amplifier No. 7 to last every bit as long as so many beloved 1960s workhorse amps have to this day.

 

Speaking of rust, the steel chassis is galvanized and powder coated, the aluminum front panel is powder coated, and all nuts, screws, washers and the like are stainless steel.  So rust will not be an issue.

 

 

Why is everything on the front panel? Why not put the power and speaker jacks on the back, like every other guitar amp on the face of the earth?

 

Several reasons:

- Flexibility. You can't set up your rig with the can sitting on its bottom (not the amp chassis bottom, but the ammo can bottom) if there are jacks there.

- Reliability. When the lid is on and you're carrying the thing around, do you really want to set it down on the floor/ground/parking lot with exposed jacks on the bottom? Sure, rubber feet blah blah blah. No thanks. Makes me nervous about damage and exposure to crud. Again, I built these things to be here a long, long time.

- Rust. See previous question about ventilation holes, above.

- Integrity. I want to maintain the physical and visual integrity of the original ammo can as much as possible.

 

 

Why those funny octal preamp tubes? Why doesn't No. 7 use 12AX7s, like every other guitar amp on the face of the earth?

 

I think you just answered your own question.

 

I'm certainly not knocking 12AX7s. 12AX7s and other "miniature" or "peanut" tubes as they were called back in the day when they were new, have been used with great success in so many great amps, you can't argue with 'em. But I discovered that 6SL7s have a great sound. In a good circuit, they yield a rich, power-tube-like tone that even the best NOS 12AX7s cannot match.

 

 

Why not EL84s? You know, like every other 10-36w guitar amp on the face of the earth?

 

Who is writing these questions? Anyway, in my humble opinion, 6V6s kill EL84s. Eat 'em for lunch. Blow their doors off. Take 'em to the woodshed and... I think you get the idea. And 5881s even more so.

 

Now, 6V6s have a reputation for having a flubby bottom. So does my sister. (I don't have a sister.) But, as you have read in the magazine reviews, this amp does not have that problem. It has lots of good, strong low end, and the tone is thick thick thick. But it never "farts out" or gets week in the knees.

 

 

Why the ammo can? Why not put it in a normal head box, like every other guitar amp on the face of the... oh, never mind.

 

 

Will it run on European 220/240VAC power?

 

No. Amplifier No. 7 operates on 120VAC exclusively. If you want to take one overseas, you will need a suitable step-down transformer.

 

 

Do I need to set the bias when I replace the tubes?

 

No. Amplifier No. 7 is cathode biased, and designed to operate properly with a wide range of hot- or cold-leaning power tubes. And of course the preamp tubes never need biasing or matching. Yes, you should buy matched pairs of power tubes.

 

 

Can I buy Amplifier No. 7 with NOS tubes?

 

Aside from the NOS (new old stock) 5Y3 that I supply with the 15w configuration, if you really want NOS, and you don't already have your own stash, I can furnish you with them. But, it really would be more economical - and more enlightening for you - to buy them yourself from one of the known sellers, all of whom can be found on the web. If you need advice as to which NOS tubes to buy, my best suggestion is to do a little research. Get a variety of opinions. Talk to NOS tube sellers, ask on the forums, read tube shootouts. Everyone's idea of what is best will vary, and no one knows what is best for you except you. Which is why I don't offer an option to buy with NOS tubes by default. But, again, I can work with you on this - give me a call.

 

 

Can I buy Amplifier No. 7 with both types of tubes you offer?

 

Yes, for a small additional charge you can have both 6V6 and 5881 power tubes, along with 5Y3 and GZ34 rectifiers. Contact me for details.

 

 

Can I install tubes types other than those you specify?

 

Yes for the preamp tubes, and generally speaking, no for the power tubes.

 

Hey, I love KT66s as much as anyone, but aside from the fact that they don't fit inside the ammo can, they - and 6550s, EL34s, KT88s and the like - draw too much heater current. There are some smaller 6L6s that will fit, so you can try those if you like.

 

Now, in the preamp, feel free to substitute a 6SN7 for the 6SL7 in either or both positions. This will lower the overall gain of the amp, much like substituting a 12AY7 for a 12AX7 lowers gain in amps that use those.

 

Pay extra for low-noise tested tubes. I do.

 

 

Is it quiet, you know, when I'm not playing?

 

Yes. I hate noise. Hiss, hum, crackling - I hate it all! You will not hear bacon frying when you fire up Amplifier No. 7. Even in a quiet room, you have to really crank it up before you'll hear any hiss.

 

 

How did you come up with the ammo can idea?

 

The idea first came to me when I was a teenager, back in the late 1970s. I was already building gear for myself and my friends. I was in an Army/Navy surplus store and spotted a couple of the now familiar olive drab metal boxes. I thought, “Wouldn’t it be cool to build some kind of guitar gizmo in one of those things?” I didn’t even know what I wanted to put in there - amp, fuzz box, who knows.

 

Some years passed before I acted on that thought. In the mid-1990s I built a couple of prototype preamps in .50 caliber ammo cans. Later, to tame my big Marshalls, I built some attenuators in .30 cal ammo cans.

 

I was working on an idea for my next ammo can tube preamp when it hit me. I didn't want a preamp, I wanted what my Marshalls and other amps were giving me - power tube overdrive. So, in early 2004, I began work on what you now see on this web site: Amplifier No. 7.

 

So, you could say Amplifier No. 7 was five years in the making. But it really is more than that. It is the realization of a vague but compelling idea sparked over 30 years ago.