*** The DIY Audio Thread ***

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About time this place deserved a permanent place for us bonkers DIY'ers to talk about new designs, new builds, completed builds, and SHOW THEM OFF.

Il start with my Millett MAX amp. No internal pics yet as it is a ***** to take apart, but a few outside pics from my state of the art 4Mp camera:

KING OF THE CASTLE (in borat voice)

The bum shot

Nichicon KZ caps in the PSU section, its got an AMB e12 muting circuit, some toshiba BJTs I can't remember what model they are, black gate NX capacitors at the critical output positions, and old school VIT-Q paper in oil caps in bypass positions.

It's setup for Grado's and sounds very very sweet indeed. The black gate burn in was interesting as it sounded great after a while, then weird for a bit, then great, etc repeat, but now with a few 100 hours on it, it sounds very very nice indeed.

All you need to know over at http://www.diyforums.org/MAX/MAXoverview.php

 

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My 99.9999999999999991% silver stereo interconnect build. Got some 0.5mm silver wire from pete (Zanash), teflon tubing, pvc tubing to wrap around the teflon in a sprial configuration, and yarbo silver plated plugs. All covered in cotton. Build is here:

http://www.head-fi.org/forums/f6/how-make-interconnect-step-step-pics-50729/index61.html

and here are some pics:

Cable sounds great, but haven't had the time to compare to the mark grant LV61S it replaces. Cost was about £80-90 and is enough to make 5.5m of single cable, so for stereo peirs Im making x2 sets 0.8m cables, 0.5m pair, and a small 20-30cm pair to use as bi-amp jumpers or to connect the millett max to the new equipment switchbox I still need to build.

 

[adamau5]

The Soha Headphone Amp, soon to be accompanied by a twin but with the E12 and the JISBOS discrete output modules.

The USB Dac (alien Dac). Great sound from something the size of a credit card.

The Class T Amp ran from a valve preamp.

Pure silver interconnects.

 

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Sweet, totally forgot the LD acts as a pre-amp. Good sound ?

O and loving the silver IC, same chris venhaus double helix design as I used, and cotton it seems

Im putting blackgates in my cd-player next and am sorting out something special and very unusual for speaker cable. Just need to source the bits from all over the globe

 

[AbsenceJam]

Nice stuff, my only DIY piece is a super-duper-power amp with 10 bi-amped tripath based channels and a lots of heatsinkery, no camera sadly.
I've been thinking about doing the same but with valves, possibly a little mad?

 

[Kanifee]

, some nice sexy work here guys. Loving the interconnects, ive got plans for mine but loads other stuff to do first and all on top of buying my first car aswell (which i cant afford either but hey what the hell!)

You have all seen mine but ill post again just for the sake of it and to bulk the new thread out


LM3886 Stereo build

Sorting out the pre-amp build aswell, this kit has took my fancy. Diy quality is supposed to be greatly increased with the replacemant of some of the stock parts with higher quality audio grade parts.

Specs:
This circuit will drive most power amps.

Power Supply: 15V DC supply or 12V DC battery. 50 mA min.

Maximum output: > 3 V RMS

Maximum input: > 300 mV, G = 20 dB 3V RMS, G = 0dB

Input Z > 10 k ohm

Output Z < 300 ohm

Frequency response: < 10 Hz to > 50 kHz!

+ / - 1 dB THD at 1kHz : < 0.1 % at 1V output

Signal to Noise ratio: > 80 dB, G = 0 dB

Bass boost/cut ~ 15 dB at 50 Hz

Treble boost/cut ~ 15 dB at 15 kHz


It has treble/bass and volume control along with balance aswell, instead of analogue pot's controling the functions its all done by voltage so it makes things a lot easier.
should be good and only comes in at aroun £16 with shipping, power supply will be moved inside the case with the guts of it all, and the pots will be taken off the board and fastend in new spacings on the fornt in a matching case to the power amp section just thinner. Should be mighty sexy

these come in at around £26 inc, each not bad eh!

Edit** i must ask this as i allways wounderd, what benefits does tube amplification have over chip amps? better sound quality, i know its much prettyer but what else?

 

[adamau5]

different sound, the top end is....sweeter. Less abrasive, more timbre.

Just different i would say. Some tracks sound better through tubes, some dont.

 

[Grimley]

I might be wrong but are the speakers JBL control 1's

 

[dave-lew99]

It's not pretty but i'm using my own designs: (it's no where near finished)

Basic aim: 4 stereo pairs in, 4 out in a variety of formats.

2x pairs of balanced inputs
1x pair of unbalanced inputs
1x internal pair to be linked to old usb soundcard

1x pair of balance and 1x pair of unbalnced outputs via main volume control
1x stereo headphone amp out
1x pair balanced outputs @ line level (possibly via switchable low pass filter)
1x pair of internal outputs to usb soundcard

Volume control will be motorised from IR remote and PIC control
Any input can be routed to any output by way of a matrix switcher which is PIC controlled allowing for IR and USB control as well as the direct button pressing

To achieve all that there's a variety of differential amplifiers, unity gain followers etc as well as the psu and control circuitry. (not all in the pic)

 

[adamau5]

I might be wrong but are the speakers JBL control 1's

they are indeed. any issues with them or just a question?

 

[Grimley]

Just a question. Here's another one.

Have you tried the amp with other/better speakers?

 

[adamau5]

yep, tried it with my kef q5's. Very good but not enough vol for loud listening in a big room.

That setup is just my bedroom / shower listening rig.

I'll take some pics of the rear later, its got very nice yarbo speaker posts.

 

[Kanifee]

To achieve all that there's a variety of differential amplifiers, unity gain followers etc as well as the psu and control circuitry. (not all in the pic)

very impressive work, have you worked on many other projects?

 

[dave-lew99]

The odd thing here and there, but this is the most major project, it's taken 3 years to get this far, i've just about completed the audio circuits now and i'm starting on the controls.

Cost wise, it's probably hit around £150 so far.

I'm mostly a software dev these days, i do my own projects but i'm one of 5 developers for the company who produces www.irisradar.com

 

[Dr.EM]

Some very neat projects here! Always love looking through them over at DIY Audio, nice to have another thread to check out.

Don't post much unfinished stuff but whatever. These are 2 of 3 amps for an eventual tri-amplified active crossover speaker system. All cases are made the same, from a pair of heatsinks (0.4c/w each) and 4mm aluminium panels. Holes drilled and tapped to assemble them with allen head bolts. Both designs use a speaker protection circuit, the treble one (in production) probably won't as it'll need to be capacitively coupled anyhow.

Heres the amp designated for bass, created from this design:
http://sound.westhost.com/project101.htm



And the newer amp designated for midrange based on this design:
http://www.lf-pro.net/mbittner/Sym5_Webpage/symasym5_3.html



And them sat on my desk. Front panels are being decided on, probably will be some kind of wood.

 

[Kanifee]

OOOOOOH!!! i like the cases, how much did they cost to construct and did you get the panels cut for you?
Looks like an impressive setup, should sound pretty sweet, where did you get your transformers form, im looking to get mine so id be intrested in a location and price?

 

[oli collett]

Interesting stuff!

Any idea how a DIY amp would compare to an off the shelf one? I was thinking about building something along the lines of this:
http://sound.westhost.com/project3a.htm

But i'm a bit wary without having any idea what it'll sound like!

 

[Kanifee]

Well, ive never heard one myself so i cant really comment... but i have been told i will be pleasantly surprised by the results.
When i have asked the same question i was told not to be put off by the fact its D.I.Y, a simple chip amp costing £50-60 to construct can sound as good as £200+ off the shelf amps. Same with any thing else i guess, you get out what you put in, more work/tweaks you put in the better the result. hopefully someone else can give you a more definate answer as it really is a cool world to get into is D.I.Y audio!

 

[Dr.EM]

Cases work out about £50 in parts each. Buying 6 heatsinks got a nice price break dropping them to about £16 each. The panels for all 3 were about £60, they were cut for me by a local company (saved delivery cost). Still need fronts mind, but don't expect them to be that expensive. A bench drill is essential for construction though

http://export.farnell.com/1211720/semiconductor-accessories-prototyping-antistatic/product.us0?sku=FISCHER-ELEKTRONIK-SK-56-100-SA
http://www.metalfast.co.uk/

For transformers, I bought them here:

http://export.farnell.com/toroidal

Now, the one in the bass amp is fine, but the one in the midrange amp is buzzing, which is very annoying, so i'm hesitant to reccomend that. Any of suitable voltage and current rating should be fine; I must have got unlucky with that one of mine, still not sure what to do with it (it buzzes with nothing connected too).

A DIY amp can easily better a commercial one of even 4 or 5 times the cost when constructed properly. Both mine sound far better than my Rotel RA-01 amp. The midrange amp apparently "cannot be touched by any commercial amp under £1000", as told by the many people who have built it and compared it against many commercial offerings. If you build that P3A amp oli using the PCB it should be great and not too difficult to do. As damian666 mentioned you can tweak it too and I know there are a few for that design

 

[Kanifee]

Yeah i plan to spend a small fortune on cases, the base case is coming from modushop.biz but then i plane to have custom panels for the face sent form over seas from either france or germany, not quite sure of its location at the moment.
Looks like a great company and does some real nice work from what i have seen, you download there free tool, desighn your face panel in a variety of coulerd anodsed aluminum or perspex, it gives you an estimate fo rthe work then you order.

Here is the plate im designing for my preamp

I have a matching piece or perspex set up with 6mm holes in direct center to the larger holes on that piece, i have set the larger holes 2mm larger than the volume knobs i plan to use. The perspex will be sanded finly to give it a frosted look, then placed directly behind the aluminium face, with a blue light inside the chasis bright enough i should get a very sexy thin blue ring around the input/bass/volume and balance knobs, also a nice glow of blue at either end of the amp on the edge of the perspex, ill be covering the top some how so that is black like the rest of the top and no light is seen there.

Give the software a try you might decide its worth a go, certainly opens up a lot of creativity in the project with the complicated cuts and engraving made possible by them doing it!

Website linky