DIY audio.......

[SeventyNine]

heres my gainclone - never really got round to finishing the case ;D great if someone catches there hand on the toroids (power switch was at the rear too ;D )


circuitary is a copy of the 47 labs gaincard - about 3200 nicker in any shop lucky enough to find one in, mine built for the princely sum of £80, same sound quality, slightly ghetto'er looks






next plan is to build some speakers worthy of the amp, something like this:

www.hifi-bg.com/projects/arthorn/001450746-big.jpg

[grizz]

Not quite up to the skill level you are at.

However, Bought a pair of Monitor Audio RS6 Silvers a few weeks ago, to replace my ageing Accustic Research Pi2's that I have had a long time and enjoyed very much.

The drivers in the AR Pi2's are dying, not bad after 15 years. However, being the womble that I am, I put them back in the box, and into the loft.
Did not have anyone to offer them to, did give Jabbo a call, in case he wanted them for his bus. The boxes are obviously, still great, and if you were to refit decent drivers, you would have a set of shelf speakers for little outlay (potentially)

If you want them, let me know.

I am in Rochester, Kent.

[SeventyNine]

ive got a set of decent shelf speakers at the moment, some B+W drivers and some unknown tweeters in some old cases i had.

eventually want some of these:



build them in some rediculously oversized boxes, and hey presto, exeptionally good sound for the price of an aiwa hifi ;D

[herald948]

OK, you have me intrigued. I see toroidal mains transformers, bridge rectifier boards, and the amp boards themselves. All is in order... except where are the power supply smoothing capacitors? Not the little electrolytics on the amp boards, surely!

100Hz hum a go-go!

[VW]

Ill get some pics up later but i built all my hi fi, mostly kit though.

I built a WAD kel84 valve amp, push pull el84, sound lovely.
I also built there aperiodic (sp) speaker kits.

I built my own turntable based on a lenco idler deck but cut up, re plinthed etc. I then made a tengential air bearing tonearm.

All together its pretty good, beats a guy i knows MEGA buck naim set up ;D

So, are we all vinyl lovers or fans of the silver disc?

[VW]

amp kit of parts


speakers once built


Heavily modified quad set up I had for a bit


Feeding these babies


Turntable as it sits now although its currently broken. Arm floats on air and moves tangentialy (sp), much better than a pivoted arm.


previous incarnation of the same deck with a rega arm


The air arm cost £30 to make and will beat most tone arms upto the £2000 sort of price range!

I was using a shure v15vxmr, probably the best MM cart ever made but now the decks broke I think ill sell the cart.

Oh, and heres a pic of initial lash up testing of the arm, can see the finished amp here too

[herald948]

I built a stereo valve amp when I was an electronic engineering student.

I had no money to speak of so I used what I had. I stole the circuit from an old ITT TV set, a class A design using a single PCL86 triode pentode per channel. Initially I used output transformers from old TVs but they gave really poor quality sound so I swapped them for the output transformer for small valve amps that RS still had in their catalogue at the time. Power was only a few watts per channel but since it was a true class A design I could use most of that power. I had to add a negative feedback loop to flatten off the frequency response and that rather screwed up the impulse response so it never had real "punch", but since I was the only EE student of my acquaintance with a home made valve amp I didn't care because I had bragging rights.

I still have it, though it needs a new power supply. It runs from 150v, in the TV set this came direct from the 240v AC via a valve rectifier and a dropper resistor, When I tried the same circuit with an isolation transformer and a silicon diode rectifier it wasn't successful because unlike the valve rectifier my circuit gave the PCL86 full volts straight away before it had heated up - pretty purple glow. So like a fool instead of using a valve rectifier I built a regulated 150v supply and that's what's died.

I really ought to dig it out and fix it.

[SeventyNine]

herald948 said:

OK, you have me intrigued. I see toroidal mains transformers, bridge rectifier boards, and the amp boards themselves. All is in order... except where are the power supply smoothing capacitors? Not the little electrolytics on the amp boards, surely!

100Hz hum a go-go!

yes those are the smoothing caps! no hum! the circuitry is tiny therefore less chance of picking any intereferance.

the design is copied from this:
www.sakurasystems.com/products/47amp.html

seems to work for them, if they can charge $3200 for a few caps and resistors then it was only a matter of time before some nerd stole the design and boshed it out for a few quid ;D

[Deleted]

Anyone know where to get valve power supply transformers? Mine blew years ago in my home made amp and Maplin don't do them any more. Needs to be able to supply 500V at about 150ma and 170W overall. I figured I'd just have to steal one from a Gibson guitar am or something?

[VW]

this site, english
wduk.worldomain.net/forum/index.php

and this site, international
www.diyaudio.com/

will tell you all you need to know.
Loads of VERY talented people and loads of links to suppliers etc. Info on buying another transformer will be found on the first one.

diyaudio.com has all sorts of sections.

How about making your own projector TV for £50? ;D

[stealthstylz]

I wish I could do electrics lol. My flat was filled with stereo could hear it 5 floors up lol

Matt

[SeventyNine]

recased it:







its started getting a bit hotter than usual, i think i messed up the boards desoldering them and re soldering them, its ok as long as i don't wang the volume up for extended periods of time, but i live in student accommodation (where i also work) so can't really go mental anyway as its a bit hypercritical when i have to go round and tell other people to be quiet ;D ;D

I've started to design a new one in Catia that should be a bit better, shorter signal path, better heat sinks, and generally looking very very pretty, I'll post up some of the designs once I've got something worth looking at

[SeventyNine]

Aug 23, 2007 17:42:21 GMT VW said:

this site, english
wduk.worldomain.net/forum/index.php

and this site, international
www.diyaudio.com/

will tell you all you need to know.
Loads of VERY talented people and loads of links to suppliers etc. Info on buying another transformer will be found on the first one.

diyaudio.com has all sorts of sections.

How about making your own projector TV for £50? ;D

i'm intrigued on your DIY turntable, thats the next on the list as i've collected a lot of records of late but have nothingn to play on them!

[qwerty]

Well thats some impressive work! Just wish I knew what most of the words mean.

[mclellanmac]

That is fantastic!

[jrevillug]

Excellent work there.

Personally, I have a sort-of working DIY tonearm on a Thorens TD150 running into a cheap amp and speakers.

I do however, have some projects waiting for me to find a little tme - a DD TT (re-plinthed cheap Technics) with a similar tangential tonearm, a SE EL84 Valve amp and a pair of horn-loaded full-range speakers.

I have most of the bits (excluding the drivers), it's just a case of getting a Round Tuit.

james

[VW]

Nov 9, 2008 13:56:30 GMT SeventyNine said:

Aug 23, 2007 17:42:21 GMT VW said:

this site, english
wduk.worldomain.net/forum/index.php

and this site, international
www.diyaudio.com/

will tell you all you need to know.
Loads of VERY talented people and loads of links to suppliers etc. Info on buying another transformer will be found on the first one.

diyaudio.com has all sorts of sections.

How about making your own projector TV for £50? ;D

i'm intrigued on your DIY turntable, thats the next on the list as i've collected a lot of records of late but have nothingn to play on them!

My arm design has changed a little and the TT plinth is now 4" of slate. Sounding very good indead.

Done loads of mods to the amp too and have nearly finished building a valve phono stage.

Any q's about TT's fire away.