Using your hi-fi for PC desktop sound.

[raleighnut]

although aesthetically pleasing, and quad are a recognised good make, I do recall an article in wireless world some 35 years ago where they tried to get to the bottom of whether valves where better for hi-fi, and in fact even if there was such a thing as "valve sound". They did blind listening tests under very carefully controlled conditions, with matched levels etc, and tested two quad amps against each other, I think the 405 transistor amp, and whatever the valve alternative was at the time. After a lot of statistical tests, they concluded that listeners couldn't actually tell the difference, never mind have a preference. . They got similar scores for a preference A versus B as A versus A or B versus B. Both sounded the same. Admittedly both the same make, and hence built to similar aims, but was interesting.

I think QUAD did that several times with various variations of their transistor amps from the 303 (Triode) to the 405 (Current Dumping) against the QUAD11 (valve) and no-one was able to tell the difference.
My own preference is 2 303 poweramps each fed a single channel (from the pre- amp) that is 'commoned' across the inputs powering a pair of speakers that have separate terminals for the bass and tweeter. This gets around the problem of intermodulation/crosstalk within the poweramps that is present in all stereo amplifiers with a single powersupply, (quoted at better than 60db for the 303) by effectively using them as 2 channel monoblocks.
Not as 'pretty' as valve amps though.

amps

• raleighnut
• 21 Jan 2016
• 3

Sound nice though.

 

[slowmotion]

Yebbut isn't it the case that valves are more resistant to EMP weapons?

Good point. As an extra precaution I got my small army of North Korean mercenaries to line my crater with 12mm of lead. It makes listening to Radio Luxembourg a little difficult but I'm prepared to make sacrifices for my cause.

 

[jonesy]

I think you are supposed to match the internal resistance of the headphone socket to the internal resistance of the amplifier. If this is wrong, the power transfer (signal transfer) may be poor, and you will need to turn the volume up a long way on the PC or Amplifier (maybe has implications for signal to noise ratio).

http://electronicdesign.com/communications/back-basics-impedance-matching-part-1

Maybe someone such as @jonesy or @swansonj can explain better?

...

Missed this, sorry.

It's been a while since I did this sort of thing, however my understanding is that impedance matching matters where you need to maximise power transfer, e.g. to a loudspeaker (the article you cite also discussions RF amplifiers driving an aerial); but when you are feeding an audio signal into another amplifier then it isn't power that you need to maximise, but rather signal level (ie. voltage). Voltage transfer is maximised by having input impedence higher than output impedence.

That said, many years ago I was trying to connect the output from a 'Walkman' style personal stereo (yes, that long ago) to another amplifier and found that, to avoid distortion, I was having to turn the personal stereo volume down very low. This lead to a noisy output from the second amplifier, because I had to turn its volume control up high, and it was amplifying the noise from the personal stereo's output stages. So I got some 100 Ohm (I think) preset potentiometers which I connected across the stereo's output, and fed the second amplifier with the signal from the wiper, thereby allowing me to run the personal stereo at a much higher volume level, swamping the noise in the output stages, attenuating the output so that the second amplifier could be fed without distortion.

 

[MontyVeda]

Forget all the techy stuff... just put a lead between the headphone-out on the PC and aux-in on the hi-fi.

All the mixer volumes on my PC are at 100% and the output on my hi-fi is pretty much the same level as my radio, turntable, tape-deck, minidisc and cd/dvd. I also have a monitor lead coming back from the hi-fi to the PCs mic-in* so i can rip anything coming through the hi-fi to a digital format. All it takes is a couple of phono to headphone leads

* mute the mic-in in the pc audio mixer settings when not ripping

 

[Poacher]

Thanks to this thread, I've just bought one of these 5 metre leads from Maplin - just £2.99 - and wish I'd done this ages ago. Seems decent quality too, in fact very decent for the price. Started off as advised with low levels on both laptop and amp, ended up with 100% on laptop and a surprisingly high setting on the amp (an Arcam Alpha 7R). Must try @MontyVeda 's ripping advice at some point!

 

[MontyVeda]

Thanks to this thread, I've just bought one of these 5 metre leads from Maplin - just £2.99 - and wish I'd done this ages ago. Seems decent quality too, in fact very decent for the price. Started off as advised with low levels on both laptop and amp, ended up with 100% on laptop and a surprisingly high setting on the amp (an Arcam Alpha 7R). Must try @MontyVeda 's ripping advice at some point!

I use the tape monitor on my amp for the in/out feeds, and a freebie bit of software called Audacity. I think that's what all those 'usb' turntables come bundled with.