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I use mainly digital source from a CD player.
Is there any reason why I should need an expensive pre-amp between the CD player and Power Amp. I have never understood why this is necessary in a simple set up. Why not a decent volume pot wired into the Analogue input.
I understand that some Integrated amps e.g Pioneer a400 effectively used such a simple solution to great effect ?
You can do that no prob (Passive Pre amp)..Some will argue that sounds better with an active stage..Keep your interconnect short if your doing the passive route & be carefull what Quality & value pot you use even the internal wire, as all have a marked effect on the overall sound.Quote:
Originally Posted by Dogruff
Or.... buy my passive! :)
Some agree they are wonderful, others don't. Some say they affect drive, others don't. I used to use a passive and the result was bloody marvellous; so free and natural and clean.
However there can occasionally be impedance matching issues, but with modern CD players / DACs having a low impedance output it's normally not a problem.
What player and power amp are you using? You're welcome to borrow mine to try it out if you'd like. :)
Once again it is all about LCR and interface.Quote:
Originally Posted by Dogruff
An active has a fixed LCR (or should have, more or less) and gain, a passive has variable LCR and no gain. A pot or resistor based passive has mostly variable R, a TVC or transformer based passive has mostly variable L.
A cable (interconnect) has LCR and if litz construction or leaky dielectric and close spacing or is twisted then has high C.
A power amplifier if it has been designed for an active pre-amp input has low R but quite high C and low L to comp RF at the input. A power amplifier specifically designed for a passive has high R and low C and the extra gain built in to compensate for that lost in a passive.
So to cut a long story short if you wish to get the full benefits of a passive you must have low C interconnects otherwise turning the VC acts as a simple tone control, and you must have a power amp designed for variable LCR input without going unstable.
If you get this right then a passive will outperform any active made and cost much less in comparison. Reason - getting blockage out of the signal path. ANY active or passive component in the signal path corrupts what comes in IT CANNOT IMPROVE IT by the laws of physics.
Now there are variations in passives sound. Pot passive depend on the sound of the pot. Stepped attenuator passive depend on the resistors in the ladder. A TVC depends on the winding quality and size of the transformer, cheap frame ones ring and cause higher R. Get a good large toroid (expensive) and we might be getting somewhere with these.
Dogruff: Just build yourself a cheap stereo in/stereo out passive with short interconnects & see what you think or your never gonna get anywhere, if your happy you can build one with specialist parts with specialist tecniques ie Lin Pot/LFR..Use say 10K Log pot.
I wouldn't advise Litz interconnects.
http://i275.photobucket.com/albums/j...AN/Passive.gif
My Hi Fi is now PC based, a 100K Ohm log pot is between the PC sound card (soundblaster) and the power amp. I have not heard such good sounds in my previous systems using preamps.
It works well with all my power amps, including valve Radford STA25, Quad II, Transistor Quad 303, 405-2, Radford SPA50.
It will cost virtually nothing, worth a try.
If anyone is struggling.
LCR = inductance, capacitance, resistance
TVC = transformer volume control
pot = variable resistor track volume control
SA = stepped attenuator, fixed resistor ladder volume control
litz = thin insulated wire woven in a braid when the positive and negative legs are woven together to bring all the wire in close proximity.
RF = radio frequency
frame = a transformer wound on a square plate core
torroid = a transformer wound on a doughnut shaped plate core.
It is then self explanetary. There is no yes and no answer to his question, if he has some ability to ask question about his power amplifier and cable he will find if it will work, if not try it and see, and if it doesn't then the reason why is in my post.
To be honest, why don't you listen and see which you prefer? Then post your findings on here.
Theory is all well and good, but nothing can beat an actual test.
You're welcome to borrow my passive and have a go Dogruff, it's TVC based, might be your cup of tea. What CD and power amp are you using?
Paul although you choose to completely ignore my e-mails fore some reason, jut because i blocked it for reasons nothing to do with you!!! (Why is beyond me??)i can 100% guarentee you your PC soundcard is of shite quality. Look at another option please!Quote:
Originally Posted by spendorman
Dogruff asked about eliminating the pre amp from his music reproduction equipment. Perhaps we have not yet given him the answer he wants even though Vinyl Grinder's clear sketch of how to connect a volume control is good.
It may still look daunting to anyone that is not an engineer and just interested in music. There is a simple way to do this of course. That is to connect the source direct to the power amplifier.
Obviously a volume control is needed somewhere. It could be on the source, some have this, CD players, cassette decks (if anyone still uses them) etc. or power amplifiers sometimes have them.
If either power amp or source has a volume control, he can just try connecting directly up. If the CD has a remote, volume may be on that.
Failing the above, perhaps Maplin or some other supplier have a cheap simple audio attenuator (volume control) with phono connectors that could be experimented with.
As for Creative sound cards being of "shite quality", everyone is entitled to their own views of course, but several years ago I did fairly careful tests putting high quality audio into this type of soundcard and comparing the output with the original. Good quality ancillary equipment was used (speakers and amplifiers etc.) Neither I nor several golden eared friends (including musicians and audio enthusiasts, one a BBC Sound Engineer) could hear any difference. It is unlikely that they were all wrong in their conclusions or that the equipment was poor/faulty.
Furthermore, I have built many PCs using this same soundcard, and a lot of them are integrated into Hi Fi systems (mainly containing excellent equipment like Quad ESL63s, Radford amplifiers etc. etc.) of discerning friends and they very satisfied with the audio quality.
Just for the record, I have not blocked any of Vinyl Grinder's e mails. Only just checked my PMs (Private Messages on this forum) and there is one from Vinyl Grinder dated 22 Feb. which I have now replied to. I do not seem to get an ordinary e mail to inform me when a PM is to be read. This does happen with other forums that I am on. Perhaps someone can advise on this.
Regarding your latter request, Paul - done! :)
Marco.
Thanks Marco
That should be good now.
Should it be by default to receive an e mail to indicate that a PM is waiting to be read?
You can control it from your 'User CP' menu, Paul. I have enabled the option for you, but you can change it if you wish at any time.
Marco.
Why did I not think to look!! Must be my age!. On some other forums this is default setting, so I've never needed to worry.
LOL. Remember also that under 'Welcome, spendorman' at the top right-hand of your screen you have 'Private Messages'. If it says 'Unread 1' then you have one to read ;)
Ahem... :lolsign:
Marco.
Point taken, perhaps I need new glasses!! This is probably true as well. Some years ago I wondered why the writing on fuses was getting less distinct. I then realised the truth of the matter and had to get glasses. I find that repairing faults on printed circuit boards more difficult these days, possible they are getting smaller!! Even the older ones!!!
The e mail notification of PMs is useful, especially if one does not enter the Forum frequently.
Might be the greatest sound card in the world but your using the PC power supply to power it, this to me is the problem (there noisy & of poor quality), there never seems to enough output from these cards anyway, setting this to higher output through your PC settings just induces more noise...I have one of the best 'M' audio soundcards, i can detect a minute amount of power supply noise, hardly worth moaning about but still there.I think i'd rather just use the PC to control the files only, everything outboard even the hard drive containing.Quote:
Originally Posted by spendorman
Yes I agree with the PC power supply being a weak link. Also motherboards vary a lot in noise, not always the most expensive being good. I have to admit that I have only a standard quality power supply in my PC. I may think about getting a better quality one.
No problem with limited output though, drives all the amps I have tried. I was surprised that it worked well the the Quad II power amps because they need quite a lot of input.
One obvious tip for anyone using PC sound cards for fairly serious audio quality, make sure the inputs that are not in use are muted, so as to keep noise down. eg. If the Microphone slider is up and mute box not ticked , this may add noise to the output. I have been guilty of doing this after using Skype.
Oh yes, the 3.5mm sockets on soundcards are a pain, perhaps I should mod mine to bypass them. I know some cards do have phonos.
Still, we are likely to see improvements in PCs in the future that will be good for audio.