An Amplifier For The Computer

For the three and more legged things
simon
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Post by simon » Thu Nov 29, 2012 10:08 pm

I reckon it must be a south east thing...

Hadn't forgotten thanks Phil ;-)

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Mike H
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Post by Mike H » Fri Nov 30, 2012 3:11 pm

simon wrote:I'm sure you're right Dave. I'm in two minds to either get a wallwart of unknown provenance, or use a trafo and put it all in one box and use the rectification and filtration on the board. I don't know what a good PS for SS looks like
Depends what you mean by 'good'. You could go nuts and have a full-blown regulated capable of 'X' Amps continuous :D

For your more simple purposes, spookily similar to a bog cap-input PSU for valves, transformer, silicon bridge rectifier, reservoir cap. The cap problee about 4,700uF would do.

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ed
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Post by ed » Fri Nov 30, 2012 4:39 pm

Hi Simon

the cheap wallwarts from maplins/ebay etc are good for most things. I've been using the basic telephone charger versions for avr microcomputer power supplies and they all seem to work flawlessly.

They all seem to have periodic spikes between 6 khz and 1 mhz but it's not pervasive. If you use one and it's a bit touchy then just add some cap filtering. I've found it simpler than building from scratch but YMMV.

I have one on the Pass B1 and that works fine with a bit of extra filtering, and I also have one on the CLIO(speaker measurement) outboard reference amp and that works fine without extra filtering.
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simon
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Post by simon » Fri Nov 30, 2012 4:58 pm

Thanks chaps. I bought the amp late last night and got the simple LM317 reg they have too. Under £5 which is a lot for a 317 and a few passive components, but to paraphrase the car insurance ad with Iggy Pop I'm buying time! We shall see.

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Dave the bass
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Post by Dave the bass » Fri Nov 30, 2012 5:10 pm

I'll try and measure current at say 19V and 24V DC 'HT' Simon. I've got a 0-30V DC Bench PSU on loan for the weekend that'll do up to 3A.

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simon
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Post by simon » Fri Nov 30, 2012 10:20 pm

Cheers Dave, I appreciate the effort in the interest of hi fi excellence!

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Dave the bass
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Post by Dave the bass » Sat Dec 01, 2012 5:50 pm

Bat-Face has been evicted, I have the project room back.

Right I've replicated a worse case scenario, 4R dummy load on each channel of the amp, driven by a 1kHz sine wave from the sig gen to just before clipping (observed on the scope) at the max DC rail voltage of 24V DC... max current pull for both channels driven is 1.37A.

Howsat.

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shane
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Post by shane » Sat Dec 01, 2012 7:50 pm

Just out of interest, what does she call you?
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simon
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Post by simon » Sat Dec 01, 2012 11:21 pm

Thanks Dave, you're a gentleman and scholar. A 317 would just about do but I might just stick a 338 in instead.

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Dave the bass
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Post by Dave the bass » Sun Dec 02, 2012 11:05 am

shane wrote:Just out of interest, what does she call you?
Fatty.
Ugly.
Minger.
Evil Step-Father.

You want the full list? This could take sometime y'know, we've both had over 18 years of practise at name calling :-) She was only just 7 when JTS and me 1st met. At 25 she's got very good at retorts!

But... when she wants summat doing or she wants help I suddenly become...

Slim.
Gorgeous
Mummys yummy fella.
The best step-dad in the whole world ever.

Strange eh! :-) Both kids have an ace sense of humour.

No prob's our-Simon,let me know if you need anymore info.

DTB
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Nick
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Post by Nick » Sun Dec 02, 2012 12:40 pm

Simple to try both and use the best sounding, but you may find a simple CRC supply like Pass uses for his amps works out better than a regulated supply, I dont think the device will worry if the voltage is 1v higher or so off load. Use the money saved on the reg on better/more caps.
Resistance isn't futile it's V / I.

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Mike H
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Post by Mike H » Sun Dec 02, 2012 2:04 pm

Yes I wouldn't have thought of a reg for a TDA2050, they're pretty non-fussed about supply variations, going by what I remember from the datasheet
 
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