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bluering

Trad climber
Santa Clara, CA
Topic Author's Original Post - Aug 28, 2016 - 12:15pm PT
I gonna give this a go. Woodcrafted cabinets and old-school tubes.

These WILL NOT be meeting any current CE/TUV emissions regulations.

I'm thinking of starting with a custom Fender Twin Reverb design. It'll be 'hot-rodded' of course. Already have the spring reverb can.


For my bass I'm going to re-create the Ampeg bass amp!!!!
bluering

Trad climber
Santa Clara, CA
Topic Author's Reply - Aug 28, 2016 - 12:34pm PT
What kind of hardwoods (I assume hardwoods are used) would be choice for a cabinet?

For a combo like a Twin Reverb-style cabinet, acoustics of the wood is very relevant. The 'cabinet' is a resonance chamber. The wood type and craftsmanship adds/detracts to the sound.

For heads they are acoustically insignificant. They are just a vessel for the electronics.

Red oak?
zBrown

Ice climber
Aug 28, 2016 - 12:47pm PT
Barracuda analog flanger



http://www.teneffects.com/Barracuda.html
bluering

Trad climber
Santa Clara, CA
Topic Author's Reply - Aug 28, 2016 - 12:50pm PT

This will be the model. Great stage amp for gigs. I'm going to limit the inputs to 2. The original amp was over-engineered a bit to suit too many different needs.

That's beauty over customizing one!!! These things are selling for like $800 still. The originals. The problem is that they can't sell them like that new anymore. Regulations.

But you can still build them like that privately. Even sell them. Just not commercially. Maybe in the US, but not in Europe and Asia.

Next dilemma. Speaker configuration. 1x12", or 2x10"? 2 12's like the twin Reverb is overkill IMO for my purposes. That's the next phase anyway, building an awesome head to drive a cabinet of speakers.

I think a 2x10" is ideal. Maybe a 1x12", just because it's easier. Usually, radical is not easy though. I'm leaning 2x something, prolly 10"s
bluering

Trad climber
Santa Clara, CA
Topic Author's Reply - Aug 28, 2016 - 01:12pm PT
Actually, I'll have to meld the Twin Reverb and the Deluxe. I may have to go with twin 12" speakers. I want AT LEAST 60 watts. Prolly 100.

12ax7 pre-amp tubes with 6A6 power output tubes to 2 speakers. And you gotta use good Celestin/EV speakers, or something equiv. Perfect!

Now, the design....

Zbrown, I grew interested in electronics, and my current career, from building my own guitar effects. Mostly distortion pedals. Got me my second job in the field, and my current job for the past 18 years.

Fun stuff!!!
zBrown

Ice climber
Aug 28, 2016 - 01:38pm PT
You and my nephew. He sold some to the Rolling Stones.

On the other hand he wrecked my Animal Traks surfboard.

bluering

Trad climber
Santa Clara, CA
Topic Author's Reply - Aug 28, 2016 - 03:15pm PT
Bluering, what is the difference in current regulations VS what was allowed in the past ?


Lead restrictions are first (RoHS). I don't really care about lead in solder or my IC's.

Most of the CE/TUV regs are aimed at controlling and damping emissions, or interference. The want minimal emissions from your product. These are usually high-frequency emissions.

These regulations really stifle great products. I have seen it first-hand. We met their standards, and ended up costing us a lot of money as a result. And we have worse problems now.

E.g. we had power-supplies in a sub-chassis that fit into a larger chassis with fans. Even though our vented power-supply was in an enclosure we still had to seal it up so kids/people can't stick things in there.

Now our sealed power supplies that are kid=-safe blow up at 4 times the rate they did before.

These are violent failures too. Sparks shooting out, smoke, etc...

They worked fine for years before that.

EDIT:
the Quilter Aviator I like most is an open- backed 2 x 10


Fo sho! Open backed 2x 10's is solid. I'll prolly end up there.

#Prolly100
WBraun

climber
Aug 28, 2016 - 03:23pm PT
Now our sealed power supplies that are kid=-safe


Are these switch mode supplies or standard transformer supplies?

Switch mode power supplies when not designed well put out a lot of dirty harmonics onto the rails.

What ARE you using for a power supply for audio frequencies?

I used to build 12ax7 preamps and power amps from 6a6 tubes in the late 60's.

Anyways .... are you custom building the amps on metal chassis or printed circuit boards?

hooblie

climber
from out where the anecdotes roam
Aug 28, 2016 - 04:19pm PT
i'm drinking the koolaid over here[Click to View YouTube Video]sonic farm ... maybe a beamer? http://sonicfarm.com/ yay canada!

i'd be very interested in following your progress on this bluering.
i'm up to my gills on verbal description of sound qualities though, it's a little frustrating.

but silence? i've got access to enough silence to die for
Srbphoto

climber
Kennewick wa
Aug 28, 2016 - 04:59pm PT
the volume knob should have one notch above ten...



"yur gonna die"
NutAgain!

Trad climber
South Pasadena, CA
Aug 28, 2016 - 06:30pm PT
Last year I bought a Fractal Audio AxeFX IIXL. It models in extreme detail (enough to give wet dreams to even the most ardent of electrical engineers) all of the internal components of 249 amplifiers and has a framework for importing captured impulse responses for cabinets, interactions between amp and speaker, etc.). Of course it also has a bazillion effect blocks that you can chain together in a bazillion ways. It is not quite as flexible as audio software development like C-Sound where you can route as many audio and control signals as you want, perform math operations on collections of control signals to use as a general purpose additive or subtractive synth. It has a weak spot in that the input is buffered so you can't have a Fuzz pedal emulation that reacts to the unique load of the guitar. And if you use a computer-based post-processing workstation you can use reverb plugins or other IRs with longer tails and make use of more CPU power. So this thing isn't infinitely flexible and perfect, but it is amazingly good at emulating the characteristics of the vast majority of amps and cabinets/speakers out there, and it is good enough for many many life-long tube amp addicts to sell of their collection of decades and stick with just this product.


So if you want to build your own amp and cab as a hobby and aren't really that picky about how it sounds in the end, or you know exactly how the circuit diagram you are following sounds, go for it! But if you are going after a specific sound and want to search around a bit to make a more informed choice, I highly recommend investing in a modeler, and seeing how deep the rabbit hole can go as you start digging into all the possibilities, and are able to hear in real-time how different design decisions affect the sound. Then armed with this knowledge you can roll your own and hope to make it sound exactly like you want.

For example, are you aware of how it sounds differently if the pre-amp section uses 12AX7A vs 12AX7B tubes, or EF86?

Going for Fender amp sounds, have you heard how the different circuit designs sound, e.g. using schematics for 5F1, 5F8, 6G4, 6G12, AB165, AA964, etc.? If you get a chance to play with a modeler that has already implemented all of these and many more, then you can get an idea for what you like and focus on that model. Given that you are building it in hardware and not emulation, probably the most important factor would be how loud you have to turn up the master volume before triggering the signature distortion tones.

I'm sure no matter what path you take, you will have a bunch of fun and learn a lot and help those of us interested learn something too. I'd like to see more "trip reports" for this adventure :)

This should give you an idea of how deep you can go to experimenting with sound in a modeler before you commit to a hardware design:
http://wiki.fractalaudio.com/axefx2/index.php?title=AMP_block_parameters

http://olongjohnson.xp3.biz/_assets/Amp_&_Cab_Quick_Reference.pdf

http://wiki.fractalaudio.com/axefx2/index.php?title=Amp:_all_models

http://wiki.fractalaudio.com/axefx2/index.php?title=Cab:_all_models
bluering

Trad climber
Santa Clara, CA
Topic Author's Reply - Aug 28, 2016 - 08:27pm PT
NutAgain, yeah. I know all about the differences in tube biasing and their tones. Actually I'm still learning about biasing them, but as a guitarist I know all about guitar tonality, and why tubes are rad.

Werner inquired:
Are these switch mode supplies or standard transformer supplies?

Cheap Chinese supplies that are switching psus. They are rated a certain way, but then installed into our custom chassis enclosure.

Switch mode power supplies when not designed well put out a lot of dirty harmonics onto the rails.

Indeed. That can be shielded though. If it's properly vented. Seal in the emissions, but vent the heat. Huge, but generally simple problem.

What ARE you using for a power supply for audio frequencies?

See above.

I used to build 12ax7 preamps and power amps from 6a6 tubes in the late 60's.

Anyways .... are you custom building the amps on metal chassis or printed circuit boards?

The beauty of the electric guitar and vacuum tubes is their tone. Software engineers have tried to recreate it. Tried to 'model it'.

Nothing is the same. It's pure current flow and tone. You'll know it when you hear it, but most people settle for less. Mediocrity.

Werner, I'll keep you updated. My old band-mate, co-worker, and good friend dabbles in this too. Along with making some of the best micro-brew around.

Anyway, the dude writes DSP software for us. He basically tells DSP's how to handle up to 460 channels of audio with upwards of an additional 24 Mix Buses, 24 Group busses, and 24 Aux busses. All SIMULTANEOUSLY!!!

He's kind of an audio genius. But very cool. And he a f*#king liberal, but that's okay. He's also a rational person.

Oh! I'll probably try to make my own PCB's. I may even try to hard-wire everything. Nothing is better than a hard connection with that kind of current.

I also have friends in the business who may help me out if I get a solid design I'd want to re-create. They'll make the boards.

EDIT: 12AX7's vs EF86's? Isn't there an EL86. I remember some old amps that sound real f=goog using those. Very 'warm' pre-amp tube.

I need to do some more research.
Dr.Sprock

Boulder climber
I'm James Brown, Bi-atch!
Aug 29, 2016 - 01:05am PT
your thinking of EL84's aka 6BQ5, (VOX, Trainwreck, Peavey)

don't use oak, too heavy, you want something light, Fender used yellow pine,
all of which has been harvested down south, regular pine is ok,

bolt the baffle board on the sides only, this is called a floating baffle board, you want the baffle board to vibrate,

don't use rubber feet, you want the amp to transmit vibrations into the stage floor.

Sevetlana EL34's sound better than 6L6GC, Amperex 12AX7's sound better than JJ's,

guitar amps modulate the power supply, so the supply is very important, so is the output transformer,

keep your plate voltages down, people are running 500 volts+ nowadays which is crazy, 440 sounds best, plus you can use a tube rectifier for more sag,

use carbon comp plate resistors, 1 watt, not 1/2 watt like old blackface amps,

i wind 1959 Triad output transformers for a guy who builds the Tweed DeLuxe amps, unusual gapped core which lowers primary inductance but stabilizes permeability, made for a pair of push-pull 6V6 tubes, which sound better than 6L6 IMHO,
http://www.tweeddeluxe.com/about-us.cfm

my 6V6GT output transformers are 45 bucks each if you want one.
here is a demo>
https://youtu.be/reY61-EhHQQ

this guy also had Weber build a custom Jensen AlNiCo speaker since the re-issues don't have the mojo, uses a 410 Nomex former,

http://www.tweeddeluxe.com/speed-shop-a12q-custom-alnico-speaker.cfm



here is a link to back issues of Vacuum Tube Valley, done by my friends Chales Kittleson and Eric Barbour,

https://web.archive.org/web/20130604042043/http://www.jumpjet.info/Pioneering-Wireless/eMagazines/VTV/vtv.htm

need good tubes and don't want an evilbay ripoff?

KCA

http://www.kcanostubes.com/

Pick up Gerald Weber's books if you want to learn about tube amps,

here is a good one>

https://www.amazon.com/Tube-Amp-Talk-Guitarist-Tech/dp/0964106019

Aspen Pitman's book is also a must>

https://www.amazon.com/Tube-Amp-Book-Aspen-Pittman/dp/B000KXK6A6

Look into the Kustom 72 Coupe amp by James Brown, who designed the 5150 for Eddie VanHalen if you want to pick up on tone tweaks

http://www.amptweaker.com/page/About-James-1.aspx







ionlyski

Trad climber
Kalispell, Montana
Aug 29, 2016 - 02:56am PT
A lot of cool interest in this thread. Hey I'll buy one from you Bluey if they sound good.

Upthread, what exactly is "regular pine" out of curiosity? Yellow, or Ponderosa I suppose is kind of regular. Anyway, what about Ash?

Blue what are your opinions of the SL6 console by the way?

Arne
NutAgain!

Trad climber
South Pasadena, CA
Aug 29, 2016 - 09:50am PT
EF86 is used to increase output in the preamp stage...
http://www.thegearpage.net/board/index.php?threads/ef86-vs-12ax7.230244/

You can hear the difference of changing this out when using the AxeFX modeler. Some VOX models use it, Matchless DC-30, Dr Z, etc.

EL84 tubes are typically used as an option on the power amp stage.
NutAgain!

Trad climber
South Pasadena, CA
Aug 29, 2016 - 10:21am PT
Quite a lot of people have done A/B comparisons of mic'd classic tube amps and the direct outs of Fractal AxeFX, and can't tell the difference.

If you use the amp simulator to a real cab, can't tell the difference standing in front of the cab (some amp models are probably better than others).

Technology is catching up. This is getting reminiscent of the "Vinyl is better, CD's are sterile" argument.

That said, I can't fault folks who want to stay with tubes. They sound great, and are the de facto reference and some people do have the ability to hear the difference. The vast majority of people can't if it is tuned well. For me at least, the emulation is NOT the weak link in my sound. My playing is!

Edit (added after Locker comment): One really cool thing, is that there are world-class players/tone hounds who are still niggling away at identifying what is not quite right, and the CEO of this company is incredibly receptive and driven to make this thing better and better. Pretty frequent software updates have the fan base gushing with statements like "I didn't think you could make it any better but somehow you did!"

Here's an example of where it was about a year ago, with several major improvements in the modeling since then:

[Click to View YouTube Video]

I guess it's all still new enough that the user experience to adjust tones is not that refined. You have to have an engineering mindset to manipulate the controls. Probably in 5 years it will be dumbed down like an Apple product with minimal controls... but having access to all the controls underneath makes it almost a new hobby in itself. I get easily distracted chasing tones and don't actually practice playing technique or learning songs as much :)
bluering

Trad climber
Santa Clara, CA
Topic Author's Reply - Aug 31, 2016 - 09:14pm PT
My software engineer buddy who makes amps gave me some tips. He's a 'softie', more attuned to writing algorithms to manipulate digital audio. A DSP engineer.

I only mention that because I should have better luck than he in customizing the circuits for my needs. He sticks by the schematics. I want to explore, after I see the schematics.

I also need to read up on tube-biasing. It's essentially a transistor, just a lot more voltage and current. But I've worked around transformers and tubes bigger than that.

He's saying I should go with a Marshall 18W model as a stand-alone 'head' than can be toggled to mate with 2, 4, 8. 12 Ohm speaker loads. Basically anything you'd want.

This is brilliant actually. I can use it as a portable 18W amp to plug into ANY cabinet. And it's low enough wattage I can get it to clip very nicely as a house/garage practice amp. Gotta drive the tubes medium-hard to get them just right sounding.

Should be fun. He wisely also pointed out that my top dollar expenditure should be for a high quality OUTPUT transformer, not the AC transformer. Makes sense. Keeps the noise off the outputs.

EDIT: Funny too, without me mentioning it, he also explained the downside of many Fender designs is they also had 2 discrete channels, for clean and 'reverb'. These ran through additional circuits and different tubes.

He agreed this was a waste and could be 'fixed', or modified by a skilled tech. It depends on what you want. Bluey's Kustom Shop.

I'm gonna get going on the Marshall 18-20W unit. It'll prolly use EL-84 power tubes. The nice, warm ones....
Dr.Sprock

Boulder climber
I'm James Brown, Bi-atch!
Aug 31, 2016 - 10:37pm PT
go to Banjo Center on stevens creek and try out all the amps then copy the one you like, Peavey makes a good el84 amp, some of the marshall valvestates sound nice but they use chip preamps (hybrid) or just copy the old vox ac 15 circuit,

output transformer does not keep noise out, they determine the frequency response and distortion characteristics, they are non linear devices (look into B-H curves)and when combined with tubes they form an eliptical loadline.

here is an amp forum with lots of info>

http://vintageamps.com/plexiboard/viewforum.php?f=28
Ksolem

Trad climber
Monrovia, California
Aug 31, 2016 - 11:43pm PT
This is getting reminiscent of the "Vinyl is better, CD's are sterile" argument.

I think this cuts to the heart of the digital simulation vs. analog debate.

Playing a vinyl record is about procedures you don't have to deal with playing a cd. The turntable is essential, and setting it up properly is a never ending process. Phono pre-amplifiers are fickle at best. Then there is the suspense of handling the record. He's sliding it out of its paper sleeve, will he touch the surface by mistake, or drop it?? OMG. Drop a CD who cares? For me, all other things being about equal, the whole experience of playing vinyl is more rewarding than playing CD's. And often the sound is better too.

I don't make guitar amps, but I understand the thought process which would eschew the digital modeling - no matter how precise - versus the satisfaction of dealing with the endless variables of the analog world. If I'm right, the tube-heads are into the fact that each time they power up their rig and play it there will be something different going on.
bluering

Trad climber
Santa Clara, CA
Topic Author's Reply - Sep 1, 2016 - 06:19pm PT
The doctor is in! Thanks for the beta, Sprock. I know you have a wealth of info in this regard.

Thanks, brah!

Kris. Yeah, you got most of it right. The sound is very dynamic.

While most human ears, in theory, cannot detect the minutia of digital conversion and processing. The overall sound is distinct enough. Of digital audio versus un-converted analog audio.

Most people think EQ'ing and Dynamics/Filters enhancing audio. They may be to your own ears, but you have usually altered the pure signal to something much different than the source.

If the source is pure, you shouldn't need conversion and processing. Purity! This is what tube amps are, and yet more. Tubes tend to add a 'warmth' that is considered pleasant to most, as opposed to the sharp, compressed, mediocrity of digital audio.

Our old CS3000 consoles were the best of both worlds. Digitally controlled, pure analog signal path. Through the use of DCA's (digitally controlled amplifiers), one can have digital accuracy of a pure analog, un-converted signal.

This is considered old-school 80's/90's technology now. But it is still very sweet. I'm an analog purist is you haven't noticed. But I still use digital crap. It's easier.
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