Building a pair of valve combo-practice-amps

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For learning, I expect it to be mostly clean.
If you can find a Vox Pathfinder 15R cheaply, grab it.

It's got some of the best clean tones you'll find at a budget price point. With tremolo and an OK spring reverb thrown in.

Yes, your valve amp will sound better. But if you're anything like the rest of us it'll be constantly on the bench being "improved" :p

Check out Gilmourish.com
+1 gilmourish.com is a damn good read even if you're not interested in Mr Gilmour.
 
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No, I can't go buying an amp now, I'd never finish the darn thing I've started ! besides, I have a Traynor on loan from a buddy.

Now the sides are glued on. The box is one solid piece of glued up wood. Well, it's hollow. Nice chunky pine and a pair of boxes 17.5" x 16" x 8.75". I think that's a good size.

Thanks for the encouragement Gnobuddy and the link to Gilmourish is great ! much for me to mine from there although I don't think my Tele is the best starting point necessarily but who knows what might be possible :)
 

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I don't think my Tele is the best starting point necessarily but who knows what might be possible :)
On DVD, I've seen Gilmour play half a dozen different electric guitars during a single show. If you're not looking, you may not hear a change of guitars at all. Gilmour with an electric guitar in his hands always sounds like Gilmour.

I bet if you gave David Gilmour a tennis racket for a guitar, and a fifty-cent coin for a guitar pick, he would still manage to produce sounds so beautiful they make our noisy minds go quiet for a second.

It's only us lesser mortals that feel we need to have exactly the right equipment to get anywhere!

That said, IMO, the most useful guitar pedal you can own is a graphic EQ. It's astonishing how much you can change the sound of a guitar (or an amp, or an FX pedal) with one.

It looks like your amp is coming along fast, nice work!

-Gnobuddy
 
I bet if you gave David Gilmour a tennis racket for a guitar, and a fifty-cent coin for a guitar pick, he would still manage to produce sounds so beautiful they make our noisy minds go quiet for a second.
There's a nice video of DG playing a solo on an acoustic guitar on Seymour Duncan's
How to sound like David Gilmour page.

Yes, he still sounds like him. (He does crack out a pedal for the solo)
 
I need to pick a power transformer. As my sister is in the UK it means one that works with both Canadian and UK supply voltage & frequency. Locally I can get Hammond iron. There seems to be two choices

a) 260A ($60) 200-0-200 @40mA and 6.3 @1A
b) 369EX ($65) 190-0-190 @75mA and 6.3 @2.5A

The first one is lighter in weight (I think) which is a benefit. Nothing to choose based on price difference. But I fear the first one doesn't have the VA for the job as I'll be using all of it's current capacity and plus I plan to use a capacitor input filter after the rectifier so the transformer really should be rated at more current. My experience with Hammond power transformers is that they run really hot if pushed. So I'm seeing the 369EX as the only option here. Unless you know otherwise ? (Edcor say, in not so many words on their website that most of their transformers are build to order so they have long lead times and I'm not that patient).
 
So I'm seeing the 369EX as the only option here.
The schematic you posted uses a 250-0-250 transformer secondary, and a full-wave rectifier. I can't for the life of me think of a good reason to do that, when you can use a single 250V secondary and a diode bridge to get the same DC voltage.

If you're willing to provide the heater power from a cheap switch-mode DC power supply, use a bridge rectifier, and settle for 230V AC (rather than 250), this might be an option, at half the price of the Hammond: A41-43-230 Bel Signal Transformer | Mouser Canada

The datasheet is here: https://www.mouser.com/ds/2/643/A41-1131073.pdf

In the USA, wire both primaries in parallel and both secondaries in series to get a nominal 230V AC. In the UK, wire both primaries in series, and also both secondaries in series, so you have a 1:1 ratio, 230V:230V transformer.

There is a beefier (80VA) version as well, but the price difference from the Hammond vanishes: A41-80-230L Bel Signal Transformer | Mouser Canada

I would expect somewhere between around 330 - 350V DC using a bridge rectifier and capacitor with a 230V secondary. That seems about right for a 6V6, at least in my world (not Leo's.)

Something like this ( TRG1506-A-11E02-Level-VI Cincon | Mouser Canada ) should happily supply the heater power you need for an EF86, a 12AX7, and an EL84 or 6V6.

With DC heater power, you no longer need black magic to get hum-free performance. In 1930 you had no choice, but here in 2018, DC heater power from a switch-mode power supply makes so much more sense than the ancient alternative.

You may be able to tweak the nominal 6V DC up to 6.3V DC - there is often a trimpot inside these switching power supplies.

Alternatively, you can use a supply that puts out more than 6.3V, and drop the excess voltage in a power resistor. I use a Sony 8.4V switching power supply in one of my amps, with a series resistor to drop the voltage down to 6.3V at the heaters.

-Gnobuddy
 
Hi Guys,

some interesting options !

I must admit I'm wasn't feeling comfortable with the SMPS option simply because I wanted to build with parts I can see and touch and repair rather than use modules that are essentially a black box - it's not so much a rational issue as an emotional issue !!!

Cost is not a prime driver, but I like the 'challenge' of using up parts and materials I have at hand and then buy the minimum to achieve the goal. It's a perverse pleasure really since I could easily buy an amp and have done with it but I like to make things.

I could go with the Bell transformer you recommended and add a Hammond 266JB6 heater transformer for a traditional supply. The total weight is about the same as a single 369EX and the cost a bit less but not enough to worry about. The advantage of the separate heater supply is no rectifier pulses from the HT supply leaking into the heater circuit. The advantage of the 369EX is that it's encased and therefore a much safer option for anybody sticking their hand up inside the box when the power is on.

Gnobuddy - good catch on the schematic as I hadn't notice the supply voltage. Most of the other AC4 circuits seem to aim around 250V but the one I posted is closer to 300V (allowing for the 50V drop across the power supply 1k series resistor). I guess anywhere in this range is going to do the job.


My guitar teacher has asked me to practice with a metronome. It has been a most irritating experience, like being micromanaged or something - I bet Gilmour didn't have to do it.
 
My guitar teacher has asked me to practice with a metronome. It has been a most irritating experience, like being micromanaged or something - I bet Gilmour didn't have to do it.

I'll bet he did...;)

Regardless, practicing to a metronome is something you'll thank yourself for persevering with in the long term.
I'd been 'playing' for well over a decade before I knuckled down and learned to play in time. Boy, were those bad habits hard to break!

Do yourself a favour and do it right from the off. Trust your guitar teacher, they know best :).

Matt.
 

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....My guitar teacher has asked me to practice with a metronome. It has been a most irritating experience, like being micromanaged or something - I bet Gilmour didn't have to do it.

I've known some very serious (and musical) musicians who did all their practice with a metronome. One advantage to me was: when I asked how long their (composer scored) performance would be (to know my tape need), their answer was *reliable*. (Add some for walk-out and applause, of course.)
 
Let me add my voice to the chorus. Every good musician works with a metronome, period. Those who don't have sloppy timing - maybe good enough for drunken rock 'n roll, but not good enough for anything more.

Victor Wooten, musician, composer, singer, martial arts exponent, and bass guitar virtuoso, wrote "Never lose the groove to find a note" in his book "The Music Lesson". His point is that the foundation of all music is the groove - and it is more important than anything else. Without a good groove, you cannot create good music.

Musicians must have an accurate internal clock, and it must remain accurate in the background even while your brain is simultaneously occupied with many other music-related tasks - operating your left hand, operating your right hand, operating your vocal folds (if you sing), listening to the sounds you're making, listening to the sounds your bandmates are making (if you're playing with others), listening to your guitar to make sure it's in tune, searching for possible harmony notes to sing, et cetera, et cetera.

For most (all?) of us, this automatic, accurate, background internal clock doesn't come easy. When you are learning to play guitar, you will almost inevitably slow down or speed up erratically, as your fingers and brain struggle with difficult passages, or zoom through easy ones. You won't notice this, because your brain is on overload with the struggle to coax sounds out of your instrument. But your listeners will!

The metronome is your lie-detector, letting you know when your internal sense of time is scrambled. Work with the metronome long enough, and you start to develop that accurate internal sense of timing.

I had nobody to give me this good advice when I started teaching myself to play guitar. Years later, I started recording my own playing, and it was only when listening to the playback that I realized how sloppy my timing was. Like Matt, I then had a long uphill slog to correct bad habits and develop better timing.

Bad timing is a problem that doesn't fix itself. I attend jams with two senior citizens who have been playing guitar for a long time. One is in his eighties, and has been playing guitar since he was ten. The other is in his seventies, and has been playing guitar since he was in his late teens. Both have atrocious timing - one sounds like a sack of potatoes falling down a staircase, the other changes chords randomly on beat 1, 2, 3, 4, or maybe 3 1/2, speeds up, slows down, forgets how many bars he's played, et cetera.

The metronome is maddening at first because it points out all your failings in the timing department. But, believe me, it is your greatest friend in the long run!

-Gnobuddy
 
I bet Gilmour didn't have to do it.
I almost forgot - Gilmour, in his sixties, learned to play the saxophone alongside one of his sons, even hiring the kids school music teacher to give him (Gilmour) lessons.

Gilmour says he couldn't read music when he started (which is typical for most self-taught guitarists), so he had to work quite hard to match his young son, and the competition kept them both motivated.

Here is Gilmour playing the saxophone in the Royal Albert Hall, in front of a huge audience: YouTube

-Gnobuddy
 
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Let me add my voice to the chorus. Every good musician works with a metronome, period. Those who don't have sloppy timing - maybe good enough for drunken rock 'n roll, but not good enough for anything more.

Victor Wooten, musician, composer, singer, martial arts exponent, and bass guitar virtuoso, wrote "Never lose the groove to find a note" in his book "The Music Lesson". His point is that the foundation of all music is the groove - and it is more important than anything else. Without a good groove, you cannot create good music.

Musicians must have an accurate internal clock, and it must remain accurate in the background even while your brain is simultaneously occupied with many other music-related tasks - operating your left hand, operating your right hand, operating your vocal folds (if you sing), listening to the sounds you're making, listening to the sounds your bandmates are making (if you're playing with others), listening to your guitar to make sure it's in tune, searching for possible harmony notes to sing, et cetera, et cetera.

For most (all?) of us, this automatic, accurate, background internal clock doesn't come easy. When you are learning to play guitar, you will almost inevitably slow down or speed up erratically, as your fingers and brain struggle with difficult passages, or zoom through easy ones. You won't notice this, because your brain is on overload with the struggle to coax sounds out of your instrument. But your listeners will!

The metronome is your lie-detector, letting you know when your internal sense of time is scrambled. Work with the metronome long enough, and you start to develop that accurate internal sense of timing.

I had nobody to give me this good advice when I started teaching myself to play guitar. Years later, I started recording my own playing, and it was only when listening to the playback that I realized how sloppy my timing was. Like Matt, I then had a long uphill slog to correct bad habits and develop better timing.

Bad timing is a problem that doesn't fix itself. I attend jams with two senior citizens who have been playing guitar for a long time. One is in his eighties, and has been playing guitar since he was ten. The other is in his seventies, and has been playing guitar since he was in his late teens. Both have atrocious timing - one sounds like a sack of potatoes falling down a staircase, the other changes chords randomly on beat 1, 2, 3, 4, or maybe 3 1/2, speeds up, slows down, forgets how many bars he's played, et cetera.

The metronome is maddening at first because it points out all your failings in the timing department. But, believe me, it is your greatest friend in the long run!

-Gnobuddy
100% agreed!:)
 
I will persevere with the metronome then !

I've been trying to use it with a simple scale, learning to interpolate between 'clicks' of the metronome, i.e. playing a down pick on the 'click' and then an up pick in the gap before the next 'click'. My teacher wants me to learn how to subdivide in my head !
 
My teacher wants me to learn how to subdivide in my head !
And one day, when you're playing more complex things, or making up your own guitar rhythms or solos, you'll be able to mix and match whole notes, half notes, quarter notes, eighth notes, and sixteenth notes. And you will sound much more interesting than the unfortunate guitarists who only know how to play long unbroken streams of eighth notes!

It sounds like you have a good teacher! :)

-Gnobuddy
 
I wanted to build with parts I can see and touch and repair rather than use modules that are essentially a black box - it's not so much a rational issue as an emotional issue !!!
I understand. My early electronics experience was with discrete transistors. I remember having exactly this reaction when op-amps, and then other audio chips, arrived: dismay that I didn't know exactly what was going on inside that enigmatic little blob of black plastic, combined with elation at the incredible number of new possibilities that these chips opened up.

Okay, I might not know what every transistor did, but I still had the ambition to at least understand what was happening inside consumer electronics at the block level. As the years went by, that ambition also fell by the wayside. By the time I got my first CD player, I realized I was never going to fully understand how the dratted thing worked (for instance, the details of the incredibly precise optical servo subsystems that keep the laser accurately focused and precisely tracking that microscopic string of pits in the disc.)

I think the personal PC was the final nail in the coffin for me. Even relatively early CPUs were too complex for any one person to fully understand (and Intel wasn't exactly publishing the full internal schematic for the 8088 anyway.)

Now we have several billion MOSFETs in each CPU, far beyond the capability of the human brain to keep track of. Each new generation of CPUs is designed by the previous generation of CPUs, because it is beyond the ability of humans to do this manually.

I think this is part of the reason why people keep building Champs and 5E3 Tweed Deluxes and Fuzz-Faces. Those circuits are almost stone-simple, and with a little effort, just about anyone can understand how they work.

-Gnobuddy
 
You could say I'm not so much building a guitar amp as indulging in a bit of industrial archeology :D

I'm not adverse to the modern stuff. My best amplifier by a long mile uses a mix of through hole and surface mount components. So, I have no fear of surface mount. But for some reason, the same fat fingers that can solder a small SMS resistor find it hard to press guitar strings into place without occasionally interfering with a neighbouring string !
 
...occasionally interfering with a neighbouring string!
It's certainly possible that this could be nothing more than inexperience, because your hands are still figuring out what to do.

But if you have bigger than average hands, and / or strong fingers, you may be dealing with a very real problem - electric guitar necks are too narrow!

In Europe, the nylon-string guitar - which was considered a boudoir instrument for women at the time - evolved over centuries to have a 2-inch / 50 mm nut width, and petite European women with petite hands had no trouble playing these. (I know a few petite American women who also have no trouble playing these.)

By the time Leonidas developed his steel-string electric guitars in the USA, guitar necks got much narrower. I don't know whether Leo was indulging in his usual penny-pinching by using less wood, or whether crude cowboy playing techniques of unschooled guitarists of the time (guitar neck held too low, thumb wrapped over the top edge of the fretboard) drove a preference for narrower necks.

Whatever the origin of the problem, you now have Fender and Squire electric guitars with nut widths as low as 1 5/8" (41 mm, 9 mm narrower than a classical nylon-string guitar.)

These really only suit small hands and slim fingers. I can barely play these at all, and then only using the most basic playing techniques (cowboy chords and a guitar pick.)

Aside from difficulty with string spacing, these spindly necks look and feel like holding a pencil in my hands - they are awkwardly much too small to fill up my left hand, making it harder to find a stable left-hand position.

Very slightly wider nut widths of 1 11/16" (43 mm) are available on some guitars in the Fender stable now. This is still very narrow for many men with normal-sized hands - and more than a quarter of an inch (7 mm) narrower than those nylon string guitars originally developed for petite European women!

These guitars are also limiting for me to play - I cannot play fingerstyle on them, for example, because the strings are too closely spaced for my fingers to be able to get in between them without buzzing.

After many buzz-filled years, I eventually found a brand that carried some 1 3/4" (44.5 mm) nut width electric guitars, and it was a revelation how much easier these were for me to play. Most of the electric guitars I own now have this nut width. If I am careful and precise with my technique, I can play fingerstyle guitar on these, as well as using a pick.

Finally, after a lot of hunting, I found a Takamine electro-acoustic guitar with a 1 7/8" nut width (47.6 mm), and it is the only steel-string acoustic guitar I have on which I can comfortably play finger-style guitar without buzzes. I also installed a 1 7/8" wide Warmoth neck on a Squier Standard Stratocaster (which has the same neck and body dimensions as Mexican and American 'Strats.)

Finally, I have an off-brand 'Strat copy that came with a 1 7/8" neck (but the quality of the instrument is so poor I do not recommend this particular brand to anyone.)

I have the same problem with Leo's 4-string Jazz Bass - the spindly neck feels awkward in my left hand. I solved that problem by getting a 5-string Squier Deluxe Jazz Bass Active V.

By all means wait until you have more playing time under your belt. But, depending on the physical size and shape of your hands and fingers, keep in mind the possibility that a spindly-necked 'Tele might just be the wrong-sized guitar for you.

Before anyone tells me that I'm imagining the whole thing and it's all down to my bad playing technique - my fingers stick between the black keys on a piano, and I wear size 13 shoes. It's very likely your feet won't fit my shoes, and it's very likely that my hands won't fit your guitar!

It's actually rather absurd - clothing manufacturers don't expect everyone to wear the same size clothing or shoes, so why on earth do guitar manufacturers expect everyone to play the same-width guitar neck?

-Gnobuddy
 
I can't claim size 13 shoes - we'll have to stick with the 'novice' explanation for now !

Router and Jigsaw resulted in some holes being cut into the wooden boxes. I checked and yes, the speaker does fit nicely behind the circular cut-out and yes, I can get the darn thing in through the back of the cabinet (not removable). Their still looking really rough :D
 

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