Kicking a dead pig - upgrading low-end practice amps

[Gnobuddy]

...have you seen the price of low-wattage valve guitar combos these days?

The prices of those little valve amps are a great DIY motivator, aren't they?

Here in Canada, the "cheap" end of the valve guitar amp market seems to start at around $500, and leap immediately to $1000 and more. Let's not even mention the "boutique" ones that sometimes cost several thousands.

Electric guitars in music are dying slowly, and valve guitar amps are probably dying off a little faster yet. Those trends are not going to help valve guitar amp prices any, particularly when you add inflation and the ongoing slow downward spiral of global economics, at least as it translates to the typical person's purchasing power.

Electric guitars in popular music have had a 60 - 70 year run, which is more than some other instruments ever had. I wonder, how long did the great American Mandolin craze that launched the Gibson corporation's fortunes last?

-Gnobuddy

 

[MrLucky]

The prices of those little valve amps are a great DIY motivator, aren't they?

I'll say they are! Although I recently scared up a wonderful trio of Haydens, two High 5s and an ahem "Mighty Mofo" - all 5w, but the MF has an extra gain stage and a 12" instead of 8" speaker - used on ebay, for under £380. In a wet/dry/wet config they are lovely.

Here in Canada, the "cheap" end of the valve guitar amp market seems to start at around $500, and leap immediately to $1000 and more. Let's not even mention the "boutique" ones that sometimes cost several thousands.

Gack! Ridiculous, stupid greed...

Electric guitars in music are dying slowly, and valve guitar amps are probably dying off a little faster yet. Those trends are not going to help valve guitar amp prices any, particularly when you add inflation and the ongoing slow downward spiral of global economics, at least as it translates to the typical person's purchasing power.

Electric guitars in popular music have had a 60 - 70 year run, which is more than some other instruments ever had...

If popular music is indeed leaving the electric guitar behind, it probably has a lot to do with the sheer adolescent sociopathy of much electric guitar 'culture', ie guys competing for the fastest widdle, nastiest tone and most aggressive stance, and it's well deserved...

But beauty is its own reward. The highest compliment I can pay those Haydens is that they can make a straight electric guitar sound as beautiful as a good acoustic [in a different way, of course].

For the present at least, valve amps are getting smaller and quieter; and more efficient modern PA systems have made big stacks and maybe even big combos redundant, except for posing and wrecking your ears...I think humane volume levels with loads of tone and 'presence' is the way forward, if there is one.

Several small valve amps now also incorporate output attenuation right down to 100mw for home use...

 

[PRR]

the day's hit sensation, a wave of Italian mandolinists travelled ...in the United States by the mid-1880s, ... popularity continued to increase during the 1890s ....After the First World War, the instrument's popularity again fell, though gradually.

https://en.wikipedia.org/wiki/Mandolin#Second_wave.2C_the_Golden_Age_of_mandolins

Say 30+ years.

If electric gitar took-off in 1950 and ran the same 30 years, it would be history by the 1980s.

As in fact synths became VERY popular in the 1980s, it did seem guitars were waning. But not the way mandolin faded-out.
_________________

> big stacks and maybe even big combos redundant, except for posing and wrecking your ears...

And BACKS.

Some of my persistent pain is from 120W-350W amps and their speakers in the 1970s.

 

[chris661]

FWIW, my all-valve (apart from the rectifier) practice amp is the Vox Lil' Night Train. 2w push-pull from a 12AU7 on the output stage. If you do the cap mod and give it a good 12" speaker, it sounds nice and goes loud enough until you've got a big drummer hitting hard.
It was pretty cheap when I got it, and I'd be willing to bet they can be had 2nd hand at some very low prices.

Chris

 

[MrLucky]

Great name! - and sounds [& looks] like a very nice thing to have a couple of around the house.

Sadly, even used they still seem to command £150+, minimum...there's probably a reason for that.

 

[Gnobuddy]

Gack! Ridiculous, stupid greed...

Certainly for those multi-thousand-dollar boutique amps. But maybe not for the $500 ones - an electronic product has to be manufactured for no more than 25% - 35% of its final selling price to make a profit, because of all the added costs and middle-men between factory and buyer.

There was a "hundred buck amp challenge" on this forum circa 2011, and reading through it is quite interesting. Even with free labour and surplus-store parts, it wasn't easy to meet the $100 price point.

If popular music is indeed leaving the electric guitar behind, it probably has a lot to do with the sheer adolescent sociopathy of much electric guitar 'culture', ie guys competing for the fastest widdle, nastiest tone and most aggressive stance, and it's well deserved...

I'm sure that has been part of the story. If shred and metal and their descendants were the only forms of guitar music, I wouldn't have gone anywhere near the instrument myself.

Supporting your thesis, acoustic guitars now outsell electric guitars, something that was probably last true only in the era when vacuum tubes were still prohibitively expensive, and young men couldn't afford the electric guitars they longed for.

Taylor Swift has had a lot to do with it too - she may not be able to get within half a semitone of a target note without Autotune, but she's managed to inspire thousands of girls to take up acoustic guitar. Every minimally talented cosmetic-surgery-enhanced cloud has a silver lining, apparently!

But beauty is its own reward. The highest compliment I can pay those Haydens is that they can make a straight electric guitar sound as beautiful as a good acoustic [in a different way, of course].

There is an interesting student research paper on guitar pickups floating around somewhere on the 'Net. It points out that the magnetic field around a pickup pole varies in a very nonlinear way with distance from the pole piece, causing nonlinear distortion and harmonic generation in the signal that the pickup itself generates. (The electrical signal is a distorted copy of the actual guitar string motion.)

In other words, the very thing that made the electric guitar possible - the magnetic pickup - also took away much of the beautiful sound of the acoustic guitar, and gave us a nastier and dirtier tone instead.

Which is probably why we need a good valve amp to generate it's own harmonics, and re-introduce some beauty into the sound!

I think humane volume levels with loads of tone and 'presence' is the way forward, if there is one.

Agreed, but, as you hint in that last clause, people do get tired of the familiar, and the sound of the guitar has now been familiar for decades. Maybe terminal guitar-ennui has set in for many?

Several small valve amps now also incorporate output attenuation right down to 100mw for home use...

That's certainly in the right ballpark, and can in fact be too loud for some types of home use.

For me, one of the joys of DIY valve guitar amp building, has been the discovery that there are quite a few very low-power NOS output pentodes out there, still to be had very cheap, because the original applications are long gone, and are no longer "cool", and there never were 2-watt "classic" guitar amps that achieved huge fame.

So, for now, we can still build inexpensive and low-powered valve amps around some of those unloved little NOS radio and TV audio output tubes of a bygone era.

-Gnobuddy

 

[Gnobuddy]

But not the way mandolin faded-out.

Remember when the sound of the saxophone was liberally sprinkled all over pop music?

There were even people who made huge solo careers playing the saxophone. Remember the talented and beauteous Candy Dulfur?

Where did all those sax players go, I wonder? Are there now thousands of middle-aged former saxophonists who occasionally open up the closet and take a look at their old saxophone, stashed away there since 1990, and heave a deep sigh when they remember the good old days?

-Gnobuddy

 

[MrLucky]

Please forgive the re-post, it's because a] I didn't mention that the Fender Frontman 15Gs also use a TDA2050 power-amp chip, b] MAYBE a chance to un-clump the formatting, and c] someone else may have one of these kicking around, and be interested in the schematic [uh, when I can make an attachment, that is].

Iiiinnteresting; I recently hurt a pair of cheap and fairly nasty Fender 15g practice amps, with a J-Station high-gain patch I wasn't expecting; they were previously OK [well, bearable] set clean, just to make the J audible, but now they both have nasty buzz. I guess I've fried something in the input stages by double-preamping, silly of me; they have a CD input [presumably straight to the power amp?], which would almost certainly have been a better idea than overloading something that's expecting a tiny guitar signal... anyway, I have an old record-player box with a tiny and very simple ECC83 valve amp in it; I used to hang it off an old mono PA/mixer's Send, connect its secondary out to a big ol' 15-inch bass cab, and run all kinds of stuff through it, and it sounded great, at house volume too. So I'm thinking seriously about duplicating the little wide-band gramophone amp [maybe even twice, considering the age of the original] and installing them in the Fender carcasses...or even better, paying someone who doesn't have my dangerously little knowledge to do it properly. It may sound a silly project to some, but have you seen the price of low-wattage valve guitar combos these days? I suspect, nay contend, that it will pay for itself in quality, as well as expense [if you already have the boxes, which were £20 each].

2x Drivers, TFs, valves & bits, that could get expensive quick!...scrapyard car speakers, maybe...adapt the front ends for 'hybrid' use with nice valves...work the existing TF less hard, aim for 5w output instead of 15?

 

[Tubelab_com]

Remember the talented and beauteous Candy Dulfur?......Where did all those sax players go, I wonder?

She is still hot, and doing shows in Europe, often with a shredder backing her up on guitar.....the lead guitar is near the end.....good too!

https://www.youtube.com/watch?v=4iG78guV3f0

I recently acquired a Squire SP-10 Chinese Fender amp for $5 in working condition. It doesn't sound as bad as the Frontman that I gave away, especially O.D. button pushed. It didn't sell at two recent hamfests for $10, so it becomes a cabinet donor along with the Crate.

I'm sure the speaker in the sealed cabinet sucks, so i'll find something better.

I made some cabinets with a pair of Parts Express 6 inch "full range" speakers ported and tuned for 75Hz. I made them for "test speakers" since they eat lotsawatts and aren't very efficient (91db). I was very pleasantly surprised when I powered them up with a Lepai 2020 and fed that with a Roland JV1000 running off an inverter. We had an electric piano in the park for about 7 hours powered by a boat battery. Maybe one of those speakers would work in the Fender box with about 4 watts of tube amp from said Hundred Buck Amp Challenge.

https://www.parts-express.com/dayton-audio-pa165-8-6-pa-driver-speaker--295-015

 

[Gnobuddy]

She is still hot, and doing shows in Europe, often with a shredder backing her up on guitar.....the lead guitar is near the end.....good too!

https://www.youtube.com/watch?v=4iG78guV3f0

Thanks for the link! Dulfur is still beautiful, still has all her saxophone chops, and still has a great band around her. That was really enjoyable to listen to.

And it also reminds me that a lot of the history of electric guitar has been driven by "saxophone envy". All those overdriven amps, fuzz pedals, distortion boxes, in the quest to make a guitar solo sustain and sing with the power and beauty of a saxophone. And yet no one has quite managed it, though Gilmour and Eric Johnson certainly came close.

At least we guitar players can console ourselves with the thought that we can play multiple simultaneous notes, even if they sound thin, feeble, and short-lived compared to a sax!

We had an electric piano in the park for about 7 hours powered by a boat battery.

The parks here in southern BC are absolutely gorgeous at this time of year, and I've been wanting to arrange an outdoor guitar jam at one. The catch is that I have to put together some sort of battery-powered amp, at least for vocals. And the budget is close to zero.

I have managed to scrape together a borrowed cordless tool lithium-ion battery pack (nominally 20V, 5Ah), a surplus store ceiling-speaker find (8", post-mounted coaxial tweeter, real crossover network mounted on the back of the woofer), a Lepai amp, and a slightly more powerful class-D amp module.

I just remembered I also have an old ART USB Dual Pre, which can handle microphone preamp duties, and which can run off an internal 9V flat battery in a pinch.

The big question is whether that ceiling speaker will have enough sensitivity to be loud enough for outdoor use with a few acoustic guitars.

I guess I better get busy cutting up pine planks before Fall arrives and kills the fun!

Maybe one of those speakers would work in the Fender box with about 4 watts of tube amp from said Hundred Buck Amp Challenge.

I too have been looking for cheap guitar amp speakers, with kinda-sorta success.

I've never tried those little P.A. speakers, but the GRS 8FR-8 works acceptably with my little 2-watt amp. It doesn't have much character to it, but sounds decent: https://www.parts-express.com/grs-8fr-8-full-range-8-speaker-pioneer-type-b20fu20-51fw--292-430

I also tried another 8" dual-cone full range, intended for ceiling-mount paging and background music. This one has a very high (135 Hz) fundamental resonance, and is drastically lacking in bass. But it's quite efficient, and with a little treble boost from 1 kHz to 5 kHz, it can produce a very vocal sounding guitar tone, with some of the quality of an expensive archtop jazz guitar: https://www.parts-express.com/8-ceiling-speaker-for-background-music-and-paging--300-010

I'm in the process of building a pine 2x8 cab so I can try combining the sounds of both these 8" drivers, hoping to get the better bass of the 8FR-8, and the more colourful midrange and treble of the other one.

-Gnobuddy

 

[Tubelab_com]

I've never tried those little P.A. speakers

I bought 4 of them when they were under $20 each. I didn't feel comfortable connecting my 20 year old Yamaha NS-10M Studio Monitors up to big powered amps so I built some "expendable" test speakers. The cabinet is 1.2 Cu Ft made with 1/2 inch plywood. They contain a pair of the 6 inch Daytons and some sort of cheap car audio tweeter from Parts Express.

We slapped them silly for an afternoon by feeding them with a 125 WPC version of Pete Millett's big red board which was fed by a mixing board with everything but the bass guitar. They survived, and sounded reasonably decent, but super cranked guitars weren't part of the program.....there was a banjo, a DIY electric / acoustic guitar, a mandolin, a violin, and a few different vocalists. The power level was loud, but not enough to clip the amp often. It did cause some of the coating to rattle off of the cabinets though.

Part of one can be seen here along with a proto 4 watt guitar amp chassis. Each cabinet cost me under $75, the plywood was free (scrap from the dumpster at the wood shop classroom). I should have used thicker wood.

The guitar amp with all the mods added since the HBAC ended is still under $70 including chassis, but not the wood cabinet. Since that picture was taken everything was mounted into a $10 Hammond chassis which would fit the original wood case that was made from scrap wood.