PDA

View Full Version : Discussion on developing Build Your Own Amplifier Cab



adam
17-09-2016, 07:22 PM
Discussion, ideas, plans, examples, list of parts...

Dedman
17-09-2016, 07:28 PM
13930
Rather large for a 1 x12 but sounds great
http://www.buildyourownguitar.com.au/forum/showthread.php?t=6178

stan
17-09-2016, 07:29 PM
that's a ripper Dedman!!

some hints from Celestion:
http://celestion.com/speakerworld/guitartech/3/7/Build_Your_Own_Guitar_Cab/

DrNomis_44
17-09-2016, 07:30 PM
I'm going to see if I can do a basic hand-drawn design for a 2 X 12 DIY Speaker cab, based on the dimensions of my Marshall MA100C amp, will scan it into my computer and then see if I can convert it to a PDF so that those interested can download a copy, stay tuned.

WeirdBits
17-09-2016, 08:02 PM
The AX84 Cabinets section (http://www.ax84.com/corecabinets.html) may help with the 1 x 12.

DrNomis_44
17-09-2016, 09:32 PM
Here's a link so you can download the PDF of the basic 2 X 12 Speaker Cab design I came up with, based on the dimensions I got from my Marshall MA100C amp, hope this proves to be useful to you guys:


https://dl.dropboxusercontent.com/u/7787692/Basic%202%20X%2012%20Speaker%20Cab%20Design.pdf


I can't see why this couldn't be made as an open-back Cab, even though my MA100C amp is a semi-open-back design, I'm going to use this basic design to build a 2 X 12 Cab for my Peavey Renown amp because the width of the cab seems to match it pretty well.

FrankenWashie
18-09-2016, 04:44 PM
Hmmm may need to advance the plans for my XF212 cab.

DrNomis_44
18-09-2016, 06:10 PM
Here's a tip:


To make it easier to transport your new Speaker Cab short distances, consider installing a set of Casters on the bottom of it, and a couple of carrying handles on the sides, saves hurting your back, which is not a fun thing to do, believe me, you can buy Casters from your local Big Green Shed (i.e. Bunnings), I tend to use the grey coloured ones that have an integral braking-lever system, works a treat.


These are similar to the ones I installed on my Marshall amp, you need four of them:

https://www.bunnings.com.au/ambassador-75mm-90kg-blue-rubber-swivel-brake-castor_p3940241


While at your local Big Green Shed, also buy a pack of 8G X 20mm Timber screws, these are perfect for attaching your new Casters to your Speaker Cab, they work a treat.

fender3x
19-09-2016, 10:03 AM
My favorite place for cab plans is the Bill Fitzmaurice Loudspeaker Design website:

http://www.billfitzmaurice.com/

Designs go from fairly simple (Simplex cabs) to fairly difficult (DR cabs).

It was actually the help that I got from the forum associated with that site that lead me here. When I decided to try to build a kit guitar, I wanted the same sort of help that I got from that site. The help there is phenomenal, and it does not hurt that the owner is a bonafide audio engineer.

My main cab for Bass is one of his DR250's. It's one of the hardest to build, but it's a fantastic cab. It's as loud as an average 4x10, but weights 20 lbs less than a G&K Neo.

When I play outside and want extra oomph I pair it with one of his Titan 39 subwoofers. That gives me similar output to an Ampeg 8x10. The difference is that I can carry both cabs. With my back I'd need a forklift for the Ampeg cab.

Still questing for the lightest gig-able bass cabs...I have plans and plywood to build a couple of his Jack 12-Light cabs. These use thin plywood and aircraft bracing for stiffness. They should be louder than most 112 cabs, and weigh in at 20 lbs.

I have been really impressed by these cabs. I started building them because I wanted light and loud, and figured I could EQ to get the sound I wanted... But the reality is that I really like the way they sound.

Simon Barden
05-11-2016, 11:01 PM
My favorite place for cab plans is the Bill Fitzmaurice Loudspeaker Design website:

http://www.billfitzmaurice.com/

Still questing for the lightest gig-able bass cabs...I have plans and plywood to build a couple of his Jack 12-Light cabs. These use thin plywood and aircraft bracing for stiffness. They should be louder than most 112 cabs, and weigh in at 20 lbs.


I've got a Jack 210 home-made cab that I bought, sight unseen, from a friend. My experience of 2x10" cabs was that they are fairly compact but this is a big beast. It's got a piezo tweeter in, which helps even out the sound as it is quite heavy in the mids. Couple of 300W Eminences in it, so it's capable of handling loads of output. I'm thinking of cutting it down to a 1x10", to save weight and storage space (I only bought it so the bass player in the band had something to play through if we held a 'working out songs' rehearsal at my place. I think it was rather over-engineered on the woodwork side, with thick plastic corner/edge protectors from an H&H cab. Though over-enginering can sometimes pay sonic dividends. A friend of mine had a 4x10" cab made from 25mm ply, with lots of internal bracing to stop any resonances and it sounds awesome, if almost impossible to move.

fender3x
06-11-2016, 12:06 AM
I plan to make two Jacks although the plans show you how to make it a 210 or in my case a 212. For bass there is no real advantage between 2 110s and a 210, but the former is more flexible.

It's big because it's a semi-horn loaded design. So the box is a big part of maximizing SPL. Even in a normal reflex cab, adding volume to the box can improve the low end SPL dramatically.

My next project after finishing my ESB-4 will is to do two Jack 12 Lites. They're still relatively big for 112s, but they use thin plywood with aircraft bracing to make them light. I plan to make them swith able so that they can be used either for bass or PA....and so that I have the lightest possible cab that can still keep up with a drummer ;-)

Sent from my SAMSUNG-SM-N900A using Tapatalk

Simon Barden
06-11-2016, 12:14 AM
I wish you the best of luck with your build.

fender3x
06-11-2016, 12:19 AM
I wish you the best of luck with your build.
Thanks! I had about half the jigs made, the plywood,drivers and tweeters bought...and then I got distracted with a bass kit...

Sent from my SAMSUNG-SM-N900A using Tapatalk

Simon Barden
06-11-2016, 12:22 AM
Better than being distracted by fluffy kitten videos.

ihasmario
26-11-2016, 06:46 PM
Ive got a fEarful bass/fullrange cab here :)

UpperCaseH
30-11-2016, 05:42 PM
I'm gonna try to build a small cab to go with my DIY 1 watt amp. I'm also building a different tiny amp, so I kinda need a cab to test them because hooking alligator clips to the speaker in my horrible old no-name practice amp is getting real old.

I've decided to go with a Celestion Eight15, mostly because it was the nicest speaker I could find that wasn't overly expensive. This is more of a test run than anything else. If I enjoy the process and it comes up OK, I'll look into doing it better with a bigger speaker (or speakers).

Going to build an open-back cab for it out of 12mm ply, with pine battens. It will be screwed together and also glued. I'm probably overbuilding, but this is a test run for an eventual 1x12 or 2x12. Plans for finishing are simple: fill screw holes, sand, spray black, clearcoat. I'll get some rubber feet and plastic corners, a grille of some kind, and maybe a handle for the top. Possibly, if the new DIY amp sounds OK, I'll recess a plate into the top and turn it into a combo.

Over the last couple of days I've been trying to learn to use Sketchup to produce plans. There's no indication of where the jack plate will go, but it's gonna be the center of the top part of the back. I've never used a program like this before and I'm sure it shows, but here's what I've come up with:

http://i.imgur.com/3IJw53T.png

http://i.imgur.com/SV9vNHd.png

http://i.imgur.com/U5HtjHW.png

Simon Barden
30-11-2016, 06:47 PM
Looks like a decent design. A bit over-engineered as you say, but you certainly won't get any cabinet resonance!

Have you considered making a spare panel, that either screws or velcros into the rear gap, so you can convert it into what would effectively be a closed-back cab?

Is there any reason, apart from the lower cost, that you've picked an 8" speaker? Unless there's a special reason for choosing an 8" speaker, I'd have picked a 10" speaker myself, even for use with a small amp. 10" is about the smallest size speaker IMO, that you get any decent bass-end from. Looking at the frequency performance graphs on the Celestion website, there's about a 5-6dB difference in output at 80Hz (roughly the fundamental frequency of bottom E on a guitar) between the Eight 15 and the Ten 30. That's almost twice as much output at that frequency. Their outputs are similar once they get to around 150Hz, but that's almost a whole octave where the 8" speaker has quite a lot less bass-end output than the 10".

UpperCaseH
30-11-2016, 08:14 PM
Good point on the 8" vs 10+" stuff. That's in line with what I've read over the last couple of weeks. I'll see if I can figure out a better way to cut the ply and if I can get an extra panel then I'll try both open and closed backs.

My eventual goal is to build a tube amp and a 2x12 to go with it, but that's a long way past my current skill set and tool collection. I learn best by doing, but I make a lot of mistakes as I go so I like to try to learn on something that won't break the bank if I mess it all up.

Also this is intended to be a testing speaker for home made amps. I'm sure I'm going to damage it at some point, even with the 0.5-2 watt stuff I'm learning on at the moment. Don't want to waste an expensive speaker on something like that!

Simon Barden
30-11-2016, 08:44 PM
When testing out your home-made amps, it may be wise to construct a simple resistor load bank to test the amp's outputs on first, before connecting up to a speaker, especially as you are only dealing with small wattage amps. You can get 5W and 10W rated wire-wound power resistors that come in a range or low value resistances. Some come with a heat sink, others need an external heatsink.

So you could make up a switchable load bank of 4, 8 and 16 ohm resistive loads (or as close to those values as you can get with the resistance values available by using a mixture of series and parallel connections) so that you can test the amp's outputs on at all the available output transformer tappings, and measure the volt drop across the resistor bank to calculate the output wattage being produced, before connecting up to a speaker. Slightly lower DC resistance values than the standard speaker ratings are OK, and most speakers' AC impedance values are lower than the DC resistance value at most frequencies (except around the speaker's resonant peak).

For testing purposes, it would be worth getting a test-signal generator with a variable output level as well, as it's a lot easier than trying to play a guitar whilst measuring voltages! It's also very useful if fault finding signal paths in the amp. And an oscilloscope would then probably be your next purchase. It never ends!

Simon Barden
30-11-2016, 08:49 PM
If you were recording with an 8" speaker, you could use the high bass-proximity effect of a ribbon mic positioned right by the speaker to increase the amount of low end in your signal. You can do the same with other sized speakers as well, but you may have to back the mic off a bit as the speaker size goes up, in order to not end up with too bass-heavy a signal.

Hobastard
08-01-2017, 08:22 AM
Here's a tip:


To make it easier to transport your new Speaker Cab short distances, consider installing a set of Casters on the bottom of it, and a couple of carrying handles on the sides, saves hurting your back, which is not a fun thing to do, believe me, you can buy Casters from your local Big Green Shed (i.e. Bunnings), I tend to use the grey coloured ones that have an integral braking-lever system, works a treat.


These are similar to the ones I installed on my Marshall amp, you need four of them:

https://www.bunnings.com.au/ambassador-75mm-90kg-blue-rubber-swivel-brake-castor_p3940241


While at your local Big Green Shed, also buy a pack of 8G X 20mm Timber screws, these are perfect for attaching your new Casters to your Speaker Cab, they work a treat.

I always put Castors on the Sides of my Bigger Bass Cabs, That way, you don't need Brakes, Just stand it up and you're on solid ground....

DrNomis_44
07-06-2017, 04:15 PM
I always put Castors on the Sides of my Bigger Bass Cabs, That way, you don't need Brakes, Just stand it up and you're on solid ground....


That's fair enough, my whole mindset is that it's better to have something and not need it, than to not have it and need it a lot.


I recently popped into my local cashies shop to see what they had in stock, and saw that they had a Marshall Quad Box going for about $250.00, I'm going to have another close look at it tomorrow while I stop off at Jaycar Electronics (it's right next door to cashies) to buy some new rubber stick-on feet for my Korg FK-1 VCF pedal, I want to find out the impedance and power-rating of the Marshall cab that's at cashies cause I could use it with either my Peavey Renown amp or my Fender Super Twin amp.

Marcel
08-06-2017, 05:02 PM
I used this web based calculator to build my 2x12 cabinet.

https://www.diyaudioandvideo.com/Calculator/SpeakerBoxVolume/

Some of the dimensions I knew I wanted, but others needed to be calculated out. Calculators for things like driver displacement and resonant frequency and the like are all available.
The programs only allow for 1 speaker so I simply doubled the cubic volume for two speakers. My cabinet is also ported which is my compromise to having neither a sealed or open back cabinet.

I used 19mm form ply from the big green shed at $12 per 600x1200mm sheet. 3 sheets for under $40 was the cheapest way I could figure to get a durable black finish and reasonable build material in one hit...

Cabinet is now loaded with two 16 ohm Celestions in parallel to give me a 8 ohms load... 1 x V30 and 1 x Creamback G12H75