Flat profile guitar amp and cabinet design

Hello guys,

I have a task to build a flat profile guitar amp and cabinet that would be driven by transistors instead of tubes. I have searched the forum but was unable to find proper information due to large amounts of posts that come up after every search..

What I am after is a closed cabinet design with 2 or 4 drivers.

The dimensions of the cabinet would be around 450x150-200x600 (LxWxH) in milimeters.

Prefferably a digital type module that would have the possibility to run the signal through several digital effects like reverb, delay, chorus and so on.

The device would also have a jack for audio line input to play audio and a microphone in to be able to actually play the guitar and sing at the same time.

I am new to speaker designs although I have proper qualifications in engineering and acoustics. I really want to do a DYI build and get more familiar with the ins and outs of speaker and guitar amp design.

If you could forward me to some forum threads that are worth reading - I would love that. Any reference to books I should also read would be greatly appreaciated. Also, any advice or questions are welcome.

First questions:
1. What speaker cabinet volume should be optimal for such a design?
2. I am investigating low profile drivers to do the cabinet as flat as possible. Is it a good idea of should I aim for a certain width for sound quality and loudness?
3. The focus is not to only play the guitar, but sometimes use it as a line or microphone playback device. Therefore, would it be wise to use different types of drivers to cover as much of frequency range as possible?

P.S. The idea is to fix the cabinet to a hinge system (like a door etc.), thats why the profile has to be flat.

I know the thread will look weird, but I think its a very unique design idea.. I couldnt find much to be read in detail about something like this..

Thank you and have a nice day,
AM
 
We can certainly help you with the design. May I play devil's advocate and ask how you came up with your unconventional design? I ask because for a first DIY project something basic and conventional is typically preferred, and selecting something unconventional without having experience to back it up can lead to disappointment.
 
We can certainly help you with the design. May I play devil's advocate and ask how you came up with your unconventional design? I ask because for a first DIY project something basic and conventional is typically preferred, and selecting something unconventional without having experience to back it up can lead to disappointment.

I am totally on board with you here, brother. I understand the path to where we are going might be hard and disappointing, but I am ready to do it.

I already went through a daunting process of designing and building a recording studio so this one shouldnt be as hard, i think.. I do have quite a bit of knowledge about sound related engineering, but I think speaker design is a completely different world in itself.

The idea came as a request and maybe a sort of a weed induced joke to build a guitar amp/speaker system/player that would be fixed to a hinge system (a door in this case). Since its a door - we need it to occupy as little space as possible and have the most effect.

I might be a noob, thats why i asked about a closed type system. I thought since it would be fixed to a flat surface i thought it should also be closed. Maybe an open design wourks as well? I know plenty of materials to dampen the vibrations, but does it make sense to have an open end design if it would be permanently fixed to a door?

And thanks for the love guys :) Just registered and already getting help :) Gotta love the internet :)

Cheers!
 
Solid state guitar amp designs are easy to find by the thousands. Look at some Peavey "Transtube" series designs. Those sound nice and the circuits are not challenging.

An amp/speaker that sounds good for both guitar and vocals is a compromise at best. Acoustic guitar maybe, but electric guitar, not so much. For vocals or acoustic guitar we have basically a small PA system. Like any PA or hifi, the goal is to faithfully reproduce the input signal and send it out the speakers. The speakers want to be fairly flat for true fidelity.

But a guitar amp is the opposite. It is not made or designed to REproduce sound, it is intended as a primary creator of sound. It is not supposed to sound flat or neutral. it is intended to have a sound of its own. That is why players prefer Fenders or MArshalls, or whatever brand. They like the particular sound of those brands. Plug an electric guitar into a PA system, and it sounds very ordinary. Like an unseasoned steak.

GUitar speakers tend to be more efficient that hifi speakers, and they are anything but flat. In fact the speaker is the single most effective way to change the sound of the amp.
 
GUitar speakers tend to be more efficient that hifi speakers, and they are anything but flat. In fact the speaker is the single most effective way to change the sound of the amp.

I understand that. Thats is why I was thinking about a 4 driver system. What about a cabinet, that consists of 2 guitar drivers and 2 flat drivers that are connected as separate circuits. When you plug in a guitar - the guitar drivers and the circuit is engaged and the drivers pump out that sweet electric guitar goodness, but if you plug a microphone or a line - the other two speakers start playing the fairly flat sounds of their circuit.

I am not sure about how combining these speakers would work, but I think it should be possible..

BTW - thanks for the directions!
 

PRR

Member
Paid Member
2003-06-12 7:04 pm
Maine USA
www.diyaudio.com
> 450x150-200x600 (LxWxH) in milimeters.

So in antique units, 18" 7" 24".

Many upright two-Ten cabinets are about this size.

I do not understand hinged like a door. Can you draw a picture? Even a cardboard model?

You could also look at existing "Modeling Amps". They ARE different from a conventional guitar amp. It sure would be easier to buy a pre-made amp and change the cabinet to your design, just keep the same box volume and any venting.
 
Seems overly complex to me.
I understand this. But I dont think there is another way to approach this.. Or else compromising on sound between the two inputs..

I think modelling amps would work, but they are full of DSP and such, and since this is a DIY project, I suspect that is beyond the scope of the project. Just an opinion.
Hmm.. DO you think it would be too expensive or too complex? I have money to fund this project and I am ready, if I need to, to make 3 or 5 pieces until I make a good one that I like :) So the determination is there..
 
Hello guys,

I have a task to build a flat profile guitar amp and cabinet that would be driven by transistors instead of tubes.
Tubes would hugely complicate your already complex project.

What I am after is a closed cabinet design with 2 or 4 drivers.

The dimensions of the cabinet would be around 450x150-200x600 (LxWxH) in milimeters.
So you are talking 2 x 10" speakers or at best 4 x 8" in a zig zag pattern.

Prefferably a digital type module that would have the possibility to run the signal through several digital effects like reverb, delay, chorus and so on.
Irrelevant. Digital effects can be played by any kind of amplifiers.
Besides I guess you call "Digital" what are actually Class D amps.
The device would also have a jack for audio line input to play audio and a microphone in to be able to actually play the guitar and sing at the same time.
Then you want an Acoustic Guitar amplifier.

First questions:
1. What speaker cabinet volume should be optimal for such a design?
You already defined it, so why ask?
2. I am investigating low profile drivers to do the cabinet as flat as possible. Is it a good idea of should I aim for a certain width for sound quality and loudness?

3. The focus is not to only play the guitar, but sometimes use it as a line or microphone playback device. Therefore, would it be wise to use different types of drivers to cover as much of frequency range as possible?
Copy commercial Acoustic Guitar amps which do all that.
P.S. The idea is to fix the cabinet to a hinge system (like a door etc.), thats why the profile has to be flat.
What will the hinge be fixed to?
Describe the full setup better.
 
Well, you asked for technical advice, not psychoanalysis, so I'll go ahead and describe how I would build it.

I would start with one of the Chinese NE5532 preamp kits, the one with tone controls. I would use FET opamps instead of 5532s, maybe adjust input resistors as well to get a high input impedance. I would build 1 of the channels as is, dry, and for the other 1 I would add 2 LEDs to the feedback loops, 1 on each stage.

For power I would just use a chipamp, you can choose whatever power level and class you want.

Driver is a tougher choice, basically you have to decide how important hifi performance is as compared to guitar performance. If good hifi performance is very important, maybe something like an Eminence Alpha 6A? Never used one so I'm not sure whether closed or ported is best, but a few minutes playing with WinISD will tell you that.

EDIT: I should clarify that I ignored some of your specs that are nonsensical. I mean, why are you specifying driver size, quantity, and enclosure type and dimensions when you haven't said what it's supposed to DO. You should stop claiming you have a strong technical background, frankly.
 
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So you are talking 2 x 10" speakers or at best 4 x 8" in a zig zag pattern.
Yes, i was thinkg about 10" ones. But loudness is not the key thing here, so maybe I dont really need that many speakers.. What is key is to be able to play electric guitar and plug in a mic or a line jack at the same time.

Besides I guess you call "Digital" what are actually Class D amps.
Ok boss, got it.

Then you want an Acoustic Guitar amplifier.
But wouldnt an acoustic amp sound a bit dry? What about like I said - combine 2 amps in one box?

Describe the full setup better.
The setup is simple - I want to make a guitar amp that i could fix to a small door. The door is used in a friends room where he keeps his goodies and fun stuff, lets put it that way :) I want to make the door to that little place a guitar amp so that he can also plug it in and riff while having fun :) He taught me to play the guitar so I want to do something nice for him ;)
 
I would start with one of the Chinese NE5532 preamp kits, the one with tone controls. I would use FET opamps instead of 5532s, maybe adjust input resistors as well to get a high input impedance. I would build 1 of the channels as is, dry, and for the other 1 I would add 2 LEDs to the feedback loops, 1 on each stage.
Uuuu, technical! So if I understand correctly, then the dry channel would be the line and the feedback channel would be the guitar?

For power I would just use a chipamp, you can choose whatever power level and class you want.
I havent really gone that far as to choosing power supplies, but since were talking about them - how important is the power supply type for a transistor preamp? I was thinking about a simple, small impulse supply.

Driver is a tougher choice, basically you have to decide how important hifi performance is as compared to guitar performance.
Is it possible to have both? The main thing though is guitar performance. Hifi is just there to maybe plug in a mic and be silly, or play a song from a phone or a player. Guitar performance is the key here :)

I mean, why are you specifying driver size, quantity, and enclosure type and dimensions when you haven't said what it's supposed to DO. You should stop claiming you have a strong technical background, frankly.
Ok boss, all I am doing here is trying to purify the idea into something doable :) I have a good background in high voltage electrical engineering systems and acoustics, but speaker and amp designs and PCBS and PNP or NPN transistors and diodes arent my thing :) Thats why im here :)

Basically it will just be a guitar amp that will be fixed to a cool door, that opens a nice, small compartment of my friends home :) All it has to do is to have a nice guitar sound and to be able to plug in a mic and a jack ;) And i will have to make it look nice, like a real guitar amp :))
 

Printer2

Member
2010-04-02 6:34 pm
This is easy. A 8" paging type speaker, wizzer if you got one. can do vocals and guitar reasonably well. talking about speakers that were designed in the 50-60's and have not changed much since. I have put these in Champ type amps with good success. they used to use these type of speakers in a column.


u33rrop9aw7azaaxz2ao.jpg





But to get silly, shame I tossed this one, could fit on a door.


754048d1530859607-yamaha-ja5002-speaker-elephant-ear-anyone-got-experience-3.jpg



But to get serious again (within reason),


Bogen_Communications_S810T725_S810T725_8_Cone_Loudspeaker_1233162923_541179.jpg



Just saw the loudness is not the key thing, which is good, makes it easier. You could always have two channels, one going to a guitar speaker and one to a full range system to do vocals, music.
 
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Printer2

Member
2010-04-02 6:34 pm
Google did not play nice when I gave that to chew on. On the Yamaha, some people thought it was ok for organ, I did not like it for guitar. No attack from what I can remember.



If you don't mind, could you maybe put into words what you want given some of the feedback you have received? Do you want just one signal path or will two do given that you want vocals and guitar together. You have enough room in the box to have a small amp for guitar and one channel for vocals. Then a real 8" guitar speaker and a woofer and tweeter for vocals would work. How big a room do you have and do you play any amps in it now that you can compare how loud you want it to be?
 
You have enough room in the box to have a small amp for guitar and one channel for vocals. Then a real 8" guitar speaker and a woofer and tweeter for vocals would work. How big a room do you have and do you play any amps in it now that you can compare how loud you want it to be?

Okay, so mainly it should be a guitar amp. A good sounding guitar amp with some effects. The mic and line are just an addition. If, given the size of the box, we can fit in a decent sound system to play line and mic - it would be even greater.

As for the room - its 8x5x3 in meters (26x16x10 ft). There are guitar amps in the room and they are played as well. But I am not aiming for loudness here.

One thing I forgot to mention is that the idea to build this came from listening to Rolands Microcube. Being su ch a small size and actually sounding so nice was what I came here with. And since its a closed design - I went with it here. Also because it will be fixed to a door anyway. Achieving something like the Microcube would be great.