Guidance for a 'beginner'

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Hi All

This is my first post :) For the past year I have been working on a project. A small part of this was the amplifier. In this case it was a TDA2003 which preforms perfectly for the design it is a part of. I am now working on a bridged version, well more like thats finished :D, Which has proved more of a challenge. One circuit design I used off the net didn't work but I got there in the end and have 8W at the disposal for the original circuit. So as I went through all this I found this site and a lot of stuff going on based on the 'gainclone' amplifiers. Right I am getting to the point now :D . I am a builder of electronics not a designer and there is much I don't understand and probably never will. I just like soldering things up and trouble shooting if they don't work, thankfully, so far so good! But I have always fancied making my own audio amp (for music) and speakers. I am now in a position where I can, albeit slowly, achieve this teenage dream (I'm now 40 :( ) So I've looked around at all the clever stuff you chaps have done and I would like to build something. Can you point me in the direction I need? I can etch my own PCB's so something with a freely available pattern would be good.
I am looking to go stereo (2 mono circuits) and build the PSU for it. Power Output? well I guess this will be governed by the spec of speaker cones I get. So a bit of guidance would be good especially as I would like to make my own enclosures. I guess 'simplicity, quality of sound, not super expensive' is the governing directive. I will be using MP3 players, CD, and turntable as the primary inputs.......the latter will need an RIAA pre amp. I know that bit because I built one from a velleman kit way back in the 80's when I was in digs so I could listen to my vinyl collection :D I know there is a huge dearth of options and ways of doing this which has got my interest but I have no Idea what to choose from all the available info. So I will rely on your experience if I may.

regards

Fooboo
 
Fooboo, welcome to the wonderful world of chip-amping. As you can see, you can find just about all the help that you need right here on this forum.

But may I humbly suggest that you start off with some homework by visiting the Gainclone pages at Decibel Dungeon.

To make things as easy on yourself as possible, aim to build a power amp, and a separate pre amp with the necessary inputs and RIAA stage etc. You will find that infinitely less confusing that trying to put it all in one box IMHO.

If you are yet to choose speakers, do yourself another huge favour and get something as efficient as possible. Your chip amp will love you for that and reward you with even better sounds. ;)

I nearly forgot. Start off with a basic chip amp. Don't worry about all the different versions, different power supplies etc. If you start with a basic as a reference, you will be able to change things later and hear what you actually doing.
 
Thanks Nuuk :)

Currently spending lots of time over at DD :) I was thinking along the lines of separate Pre amps, power amps and PSU! Speaker wise I am remembering a pair of Mission 761i's I heard a long time ago. ARcam CD and Amp feeding them........Actually it was like there were no speakers and the band were present! Right back to DD for more education!

regards

Fooboo
 
fooboo

Don't let him seduce you with his smooth typing ways, turn back now while you have chance. You are entering addiction country.

I was once like you, a casual Decibel Dungeon visitor. Since then, I'm now on with my fourth chipamp, with most of the bits laid by for a fifth. I only have eight rooms in my house but if I build an extension I could have one in there as well..........

Keep us posted with your progress.

John
 
It's to laaaaaaaaaate!!!!!!!!!!!!!!!!! I can't turn back! His writing is so eloquent :D
Seriously though it's all interesting reading. I'm currently at the stage of 'I've read
far to much and it's hurting'. Now P2P or PCB, it's all so much fun! Right then back
to DD for a fix!

regards

Fooboo
 
Hi Nuuk.

I will wait in eager anticipation for bottom kicking developments, hot iron in hand! I assume there will be an announcement when you have it sorted.

What are you up to? I had thought that all permutations of the chipamp were covered but maybe I'm wrong on that as well. As the bloke I was apprenticed to was fond of saying "It's not often you're right but you're wrong again" He was the one drinking tea that had been stirred in a most unconventional manner mindst.

As for the Riff Raff coment I prefer to think of it as "Earthy Rustic Charm" with a hint of beasts of the field about it.

John
 
Hi Gentlemen

Well I have looked at sourcing the primary Items, Toroidal transformers 2 off and a pair of LM3785's. both from Farnell. Luckily that takes me over the minimum order limit :D . I can also get a pair of LM3886's from Cricklewood electronics. After that it's just sourcing the discrete's, I have an account with Rapid online :) . I am getting both chip types because I am unsure which to attempt first but all being well both will get built :D . I am a bit nervous of the P2P setup but I think it's bloody clever. I have found a couple of PCB patterns that I could print of as well but on the whole DD is soothing my tattered nerves :D . I think the nerves stem from having built most of my circuits on vero board and a year ago I made my first home made PCB successfully first time so I am a bit tied by habit to fitting things to a PCB of one sort or another. I have done a bit of 'cludging' (I think that's the term) when I needed to fix a design problem. A case in point being the bridged TDA2003 amplifier I have just finished. It failed on first trials but I added 2 poly caps and an electrolytic radial, on the track side, very neatly with a few deft bends of the wires. After that it worked and I redid the PCB with provision for these bits to be fitted topside on the final design. Is there a PCB pattern for either of the GC's on the DD site? I know I could design my own but although I understand that I/O's and power planes need good separation I really suck at self designing PCB's. I can adapt and modify existing patterns but thats usually just to suit components that may be larger or smaller than the original design. My current PCB for an existing circuit has shrunk by 10mm on the length and width as I have fiddled with parts orientation resistor wire lengths. basically the PCB traces are unchanged just a little more compact. That's my limit :( Still I'll stop waffling now and go read some more. :)

Just been through the Rapid site 'by hand' and I can get the LM3876.....any good?
and the toroidal coils

regards

Fooboo
 
fooboo

Make sure you know if you have the T or TF chips. I ordered LM3875Ts (uninsulated) and then found out the price of silpads, it cost twice as much for the insulating pads than the cost of the chips.

Using a pcb and known good design makes perfect sense for a first build, theres great happiness value in it working first time. You can get exotic with the next one and start comparing how one type compares to another until you find the sound for you.

Have you seen this site? http://www.madaboutsound.com/

He (Vikash) has PCBs for the LM3886 in stock, and a good range of speaker drivers, heatsinks, connectors etc to boot. Add to that he's a moderator on here, a good bloke to do business with and you are onto a winner in my opinion.

John
 
Oh yes been there! very nice they are to and already added to my bookmarks! :)
I think I may go with the PCB first then Go on to a DD GC. Half the fun is going to be making a nice enclosure for the unit(s). Two other items that I will need to address are.......My 'HiFi' is still in it's box since I moved 2 years ago as there is nowhere for it to go as yet. On top of that it's a modular Akai with a rubbish turntable and it can't be split to use the 3cd changer on it's own as it has a proprietary connection system. Apart from that it would probably not do justice to the Amplifier I intend to build. So without having to sell an arm and a leg what would be a good introductory CD player, Tuner, turntable, and possibly tape player in that order. Also I doubt the speakers that came with it are good enough either so I want to build my own pair. What is a good beginners design to self build and what would be a reasonably priced pair of drivers to use as the basis for picking the cabinet design. I fancy floor standing, small footprint, and 4-5' tall ? I know it's a lot of questions and I have read bucket loads on here and at DD but I still lack a clear direction I fear.

These look very nice, good price and full range to boot. 2 x CSS FR125SR & Firm Hold Fasteners

regards

Fooboo (who asks to many questions)
 
I'm using the FR125s in ported small boxes with stereo LM3875s and the Uno active pre from DD. I love the setup. If you want internal organ damaging bass in a barn sized room they're not for you, but for smaller rooms they are great.

How far "Up North" are you? If you fancy a journey to the Wirral you can come have a listen before you commit any money. There are a multitude of speaker designs out there, it depends on your room size and height, required sound pressure, material listened to etc etc.

This is a good place to start http://www.frugal-horn.com/spawn-plans.html I love the Harvey design but my room isn't really big enough for them. I've heard a pair of the Sachicos and they are belting speakers but 6 feet high!

Enclosures are a subject on their own, they can take way longer than the electrickery to sort out. I used old metal video recorder cases using steel front and back panels. They are rather industrial looking but that appeals to me, as did the economy factor. The P2P 3875 project will be in an old cassette deck chassis.

If you are looking for a budget CD player that gives you an excuse to break out the soldering iron take a look at the "playstation as cd player" thread in digital. You can have a listen to one of them as well if you come over. All I have to compare it against is a 10 year old Denon that was about £200 when bought but I cant remember the model number off hand. The Playstation is more enjoyable and much more detailed to listen to and all the mods needed are here.....

http://dogbreath.de/PS1/index.html

Even more reading and more parts to price up!

John
 
I will wait in eager anticipation for bottom kicking developments, hot iron in hand! I assume there will be an announcement when you have it sorted.

John, I hope to make an announcement very soon now. Everything is in place, just a question of waiting for the right time.

Fooboo, if you feel more comfortable working with PCB's by all means start with them. Apart from the ones offered by Vikash, I saw some on Ebay the other day. Also checkout Ebay for the chips.

As regards suggestions for other equipment, I think the most important thing to do is decide on a budget and let us know what that it so we may be able to make specific recommendations.

Perhaps a kit speaker would suit you, or a search around the loudspeaker forum for a tried and tested design. Like I said go for something with high efficiency. A lot depends on what types of music you listen to a lot.

CDP, tuner, tape player and turntable could all be bought S/H to get more for your pounds. Personally, I won't go back to a CDP now I am streaming music from the PC. Yes, another option for you! ;)
 
Hi There

Yep found frugal about half an hour ago. Gorgeous designs and done in one of my favorite programs (google sketchup). The calhoun looks great. My music is pretty varied from classical to rock and just about everything in between. Room size is 8'High x 21'wide x 13'Deep overall. The fire breast is center and 15" into the room. I'm in W. Yorkshire so not that far away but currently carless.
I had seen a bit of the PS mod and PC CD modding I think the PS may be less complex to do I shall have a look at the link you have posted.........More reading matter! :D

regards

Fooboo
 
Hi There

Budget, budget! Bugger there is that. £100-£200??? That's spread out over how ever long it takes I guess. Does that give me a reasonable base to full fill my dream of 'audio heaven'
The majority of my CD collection is on my PC where I listen to it. I can also stream my music to my Xbox 1 which is soft modded to be able to do this (and more ;) ) I have some vinyl which I still, would, like to listen to, I had the first CD player in my street so my vinyl beginnings were killed early :D . I love the feel and sound of vinyl though.

regards

Fooboo
 
Should I leave now? :D Hit me with the minimum average I can expect to
get a good beginners set up with. Shall we the cost of the electronics and the drivers
only to start with.........I've strapped myself down and am prepared for the
worst............ :(

regards

Fooboo (soon to be very broke???)
 
It really is very hard to nail down a cost for these things.

Speakers I would expect to spend at least £100 on anything decent, and then it would have to be simple although that is no bad thing.

You could do the PS1 thingy for under £50.

Turntable, tuner and tape deck? Well how long is a piece of string? If you take your time and keep your eyes open on Ebay, you could get some decent examples for pocket money.

It's when you get the upgrade itch that it starts getting more expensive.

Poor John is soon to be tempted once again but that's another story for another day! ;)
 
Hi All

I guess I was a little adrift :D Turned brain on and I can see it will have a bit of a 'cost' to it.
But still cheaper than buying a quality mass market item that doesn't do the job as well with the minimum of electronic fuss and it wont be the same as using something built yourself. I'm game, and patience i can do :D . So PCB's, the chips, the rest of the components, then the speakers... Running throughout I can look at PS modding and or a CD player and there after as and when the additional peripherals. Up grading. :D theres more!!! Well that may consist of adding a subwoofer so presumably That will involve extra circuits to split the source output (probably a simplistic view) :) I can go with that!

regards

Fooboo
 
fooboo
I'm from t'West Riding mysen, born in Dewsbury when it were in black and white.

One of the advantages of diy is that you can do things a step at a time rather than laying cash out for something all in one go. The pricey bits are the transformer, heatsinks and enclosures so scavenging around for dead or obsolete stuff to gut for usable bits becomes a cash saver. You soon wont be able to pass a skip without a crafty peep to see what's in there.

You could start with an unregulated psu with a suitable passive pre for cheapness, using your pc as source and small single driver speakers.

Once the upgrade budget allows you could try a buffer or active pre maybe, or a regulated supply, which ever way you fancy going with it. A good DAC for the computer would be a big improvement also.

You can try different speakers if you choose drivers that will suit a few box designs. Start with a small box as a cheaper entry point and develop as money, tools and skills allow.

Nuuk
Tempt away, you haven't been wrong so far! Does it use the 3875? I've got a pair sat waiting for something to do with them.

John
 
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