Building the Tiny Giant amp

[PRR]

> more than 4A? I have an extra laptop supply that can do 3.4A.

http://www.diystompboxes.com/smfforum/index.php?topic=89687.msg764759#msg764759

[PRR]

We are veering off-topic.

I stick to my suggestion: if Tiny Giant is to play LOUD with reasonable total-rig size, use a large (8"-12") light-cone speaker in some form of baffle/box. In today's speaker market, suitable speakers are almost all "guitar speakers" (a few PA speakers work, at higher price and less flavor).


> Perhaps you meant this as more of a semantic argument

Well, I mean that driverless cabinet efficiency is dead zero.

> for example, a horn loaded cabinet increases coupling efficiency?

OK, granted, quite true.

How many horn-loaded GUITAR amps are there?

"Coupling efficiency" is the crux. There are no good speakers. The compromise chosen for home hi-fi, TVs, car-audio speakers is smooth modest output with cheap chips to brute-force bad coupling.

Horns have their own problems. They must be big. They beam. They will not cover a large frequency range with high efficiency and useful beamwidth, so must be 2-way or 3-way, which is not a Good Thing even when necessary. Splitting the band seems to be more obvious on a single widerange instrument than on a complex full-band signal. Most practical horns have further problems.

Horns are efficient and also LARGE for their bass limit. Does it make sense to use your 20W Tiny Giant amp with a 15% efficient 150 pound 3-foot horn? No more than it would to carry a 0.1% efficient shoebox speaker and a 3,000W amp. If anybody still needs 3 acoustic watts, 1.2%+300W to 5%+75W rigs work well.

The direct radiator has a goal efficiency which it will cover over a certain bandwidth, and a fairly constant sensitivity for a few octaves more. The cabinet affects only the lowest octave of that range.

> standard guitar cabs have intense beaming and terrible off-axis

So do non-electric instruments. Trumpet is wickedly beamy. Violin/viola (or acoustic guitar!) pattern is like a mutant sunflower. Woodwinds radiate dipole different every note. Piano is wack. Nobody has a problem with that. (Except the sax-players.)

OTOH, a mis-spent youth did too much work with pure synths and hi-fi speakers. Little of it worked as "music"; it was a job. By choice, I would rather be in a dive with a Twin.

> That could be improved easily and with no drawbacks.

In music, "flawless" is boring. Writers write about "improved" and some products are available: BOSE's 'stick' stage-speakers are technically fascinating, but have not caught-on. Nobody redesigns guitars or pianos for "constant directivity". (Price and traditions are objects, but even so....)

[p_wats]

Finally boxed mine up tonight! I added a pilot light, on-off toggle and BMP tone knob. Sounds great so far! I'm just waiting to decide what to draw on the top of the box, then I'll post pics!

[StarGeezers]

   Got mine finally assembled , did my continuity checks and fired it up ....   Now not really being a fan of SS amps , I must confess this one sounds pretty darn GOOD !!!    The Clean Tone is very Musical , and even the distorted Tone sounds pretty smooth !!!   And it does get LOUD !!!!  No hum I can tell ... and I have a very usable full range on the V pot (much like any other SS amp)  ...    Very COOL little amp , easy project .... I'd recommend this one  to everybody !!!!  

I'm using the IBM 16V 4.5A PS...  with the mute switch ...   Perfect !!!!  

  The only problem I'm having is keeping the tiny enclosure in one place, so I put some some Velcro on the bottom to secure it to the pedalboard... Problem solved !!!

[Taylor]

Thanks for the build report! Never thought this little guy would please tube amp fans with its tone, so that's very nice to hear.

I use mine every day for both guitar and bass and still really like it. I keep thinking about adding some EQ and clipping and all that, but honestly I like it a lot without any of that.

[StarGeezers]

  Taylor BIG THANKS !!!!   I Love this little amp ....     Perfect just like it is !!!!   

[p_wats]

I'm loving this little guy! Throuth a 12" speaker it really wails. So Happy I might have to get another one (for my bandmate to use with her keys).

Here are a couple pics of my Tiny Happy Giant---I added a pilot light, BMP tone control and on/off switch (disconnects power):

[oldschoolanalog]

Finally got to test my TG amp after sorting through a load of post divorce "pack it & run" boxes. It was the last thing I built before getting ousted.
Using an old Altec 418B (15" 8 ohm) in a "nothing special" homemade open back pine cab it sounds simply fantastic! Way more volume than my new neighbors can tolerate. Nice & clean too.
Time to build another and go stereo.
Thanks Taylor!!!

[Taylor]

Awesome build Paul! The color and graphic are perfect. Does the BMP tone control work well with the amp?

Thanks for the report, Dave, glad you're liking it. I, too, was surprised the first time I fired it up at the volume and clean tone. I've never gotten it loud enough to distort like Star Geezers - need to get some practice space so I can hear what it sounds like clipping. I figured it would be horrible, since we usually hear that clipping a SS amp is to be avoided. But maybe not?

[oldschoolanalog]

I figured it would be horrible, since we usually hear that clipping a SS amp is to be avoided. But maybe not?

Only one way to find out, eh? 

[p_wats]

Awesome build Paul! The color and graphic are perfect. Does the BMP tone control work well with the amp?

Thanks for the report, Dave, glad you're liking it. I, too, was surprised the first time I fired it up at the volume and clean tone. I've never gotten it loud enough to distort like Star Geezers - need to get some practice space so I can hear what it sounds like clipping. I figured it would be horrible, since we usually hear that clipping a SS amp is to be avoided. But maybe not?

Thanks Taylor! I'm going to be recommending this circuit to anyone I come across...very happy with it!

I find the BMP tone control to be very effective. I had to use an audio taper pot, as that's all I had, but it still dials in (or out) a great deal of treble.

I was playing my Tiny Giant through a 12" in a homemade cabinet (used to be a reel-to-reel suitcase) with a Jay Turser mini-Les Paul and it sounded amazing!

[StarGeezers]

   I too expected the usual SS distortion , but was most pleasantly surprised ...   So Happy , I went all out and decorated it ...

  And even made a short  clip ...  http://www.wattkins.com/node/17710

[space_ryerson]

I made one for both bass and synth use (2 inputs) in a 1590B, and added a power off switch via a pot with a switch built in. Here's what it came out looking like:



We tried it out last night at rehearsal through a 1x15" bass cab, which isn't ideal for synths. It sounds pretty good! My wife (who's using the amp) uses a bass eq pedal for tone shaping, which helped dial out some of the inherent problems with the cab. The only problem I ran into is when both the synth and the bass are plugged in at the same time, there is an immediate volume drop for both. Would adding buffers to both inputs cure this?

[Taylor]

Would adding buffers to both inputs cure this?

Yes, but you might also just try adding putting a resistor in series with each input:

bass in - 10k resistor - "node a"
synth in - 10k resistor - "noda a"
"node a" goes to TG input

[space_ryerson]

Would adding buffers to both inputs cure this?

Yes, but you might also just try adding putting a resistor in series with each input:

bass in - 10k resistor - "node a"
synth in - 10k resistor - "noda a"
"node a" goes to TG input

Interesting, I'll give it a shot, and let you know how it goes. Easy enough to try the resistors before bothering putting the buffers in. Thanks!

It's a fun project, by the way!

[Taylor]

Cool, glad you're liking it. 

The resistors will do the mixing better than just connecting them directly to each other, however I suspect you'll have some volume issues, since synths are line level and passive basses are instrument level. You probably want an actual active mixer.

[space_ryerson]

I suspect you're right as well. For what it's worth, it's an active bass, and the last pedal in the chain is a buffered bypass (DOD Bass EQ). I'll give the resistors a shot tonight and see how it goes, and take it from there.

[ckyvick]

Forgot to post this here when I finished it, I might add some sort of tone control to it but its nice and loud so far

Did a side by side with a .22 caliber and they both had about the same amount of clean headroom with the cab I was using.

[Taylor]

I was wondering how long it would take for us to see a "Tiny Green Giant"! Awesome.

Did a side by side with a .22 caliber and they both had about the same amount of clean headroom with the cab I was using.

Ooh... take that, EHX. 

[PRR]

Bass direct from the axe? That's a rather different signal than the already-amplified output from a synth or other Line-level source.

Pre-amp the axe with the preamp Taylor gave you; sneak (mix) the synth in after the preamp and before the power amp.

plan (13KB GIF image): http://i.imgur.com/Uill1.gif

If the synth has Volume control, the added pot may be omitted (you still need two 10K or 15K resistors). The mix network breaks-into the return from original pot wiper.