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Pre-amp bypass

Posted: Sat Aug 25, 2012 2:06 pm
by markof
Anybody here feed their line-in direct to the power amp, bypassing the preamp and controlling the volume directly from the source?

I gave it a try this morning and the results are dramatic. Much clearer upper mid to treble and bass is more solid and punchy. Improved the separation also. I guess the improvements are due to a shorter, more direct signal path.

I'm controlling the volume from the dac using audirvana plus which also has a volume limiter built in to it's preferences.

Needless to say some care is required to remember the volume.

Mark.

Re: Pre-amp bypass

Posted: Sat Aug 25, 2012 3:06 pm
by Fran
Points fairly clearly that something in the chain isn't suiting either the power amp or source - pre might not be the best match or something?


Fran

Re: Pre-amp bypass

Posted: Sat Aug 25, 2012 3:54 pm
by markof
The amp is a relatively inexpensive integrated valve amp and I guess they spent more on the power amp components than on the preamp side. Also, I'm guessing that the quality of output from the JKDac32 is superior to the preamp output.
I'm firmly in the "less is more" camp and in this case reducing the amount of circuitry that the electrons have to flow through has definitely paid off.
Searching on the net, I notice that others have found a similar benefit with more expensive gear too.
I would like to hear from others in the forum who have conducted a similar test and what their conclusions are.

There is an inherent danger in the setup as a computer or application crash may unleash a hell of a kick to the speakers.

Mark

Re: Pre-amp bypass

Posted: Sat Aug 25, 2012 8:11 pm
by jaybee
I know there are Wadia owners here using the source as pre-amp

Re: Pre-amp bypass

Posted: Mon Aug 27, 2012 12:05 pm
by markof
One other question related to my attempts to improve the sound without blowing up my beautiful speakers.

Has anybody here tried a passive pre-amp (essentially a volume control with or without switching) on their system?
If so, any recommendations or comments?

Re: Pre-amp bypass

Posted: Mon Aug 27, 2012 12:41 pm
by Diapason
Another forum member used to use a Placette in his system, and he was happy with it. One day we compared his Placette with a Bryston BP25 in a not-very-scientific test. The Placette was leaner and cleaner but maybe a bit "flat", the Bryston sounded ballsier and bassier, but maybe not as accurate. Like everything it's going to be system-specific.

FWIW I run a Wadia directly into power amps without a pre, and I use the digital volume control on the player. I occasionally wonder would it improve things to use a pre of some sort, but it's cheaper for me not to find out.

Incidentally, Darek mentioned plans for a passive pre coming down the line when I spoke to him, so you could offer to be a guinea pig! I don't know if he's actually made it yet.

Re: Pre-amp bypass

Posted: Mon Aug 27, 2012 12:59 pm
by Claus
My only experience is Ken's Music First passive pre running into a Gamut amp. That is still one of the best systems I have heard to date... I use Audirvana digital volume myself for head phone use (straight out of JKDAC) and it sounds great to me....

Re: Pre-amp bypass

Posted: Mon Aug 27, 2012 1:57 pm
by Derek
The Music First is a crackin' passive pre-amp the best I've come across, although I've not been in the company of many Passive Pre-amps.

Re: Pre-amp bypass

Posted: Mon Aug 27, 2012 3:04 pm
by Ken Moreland
I bought the Music First Preamp from a Gentleman on this forum, I had already purchased the Gamut and was running it directly from a Benchmark Dac1 using the dac volume control. I tried the preamp and liked the sound, bought it and continue to enjoy it. It doesn't impart any sonic signature to the music and feels like it's airy and transparent. It has no power input and is entirely transformer based.
If you're using software to control volume sound quality will be affected depending on the capability of your dac. Here's Jplay's input.
"Bitperfect Volume [-6dB,-12dB,-18dB,-24dB,-30dB]. Digital volume control for CD format is available only if DAC supports more than 16 bits. People with no pre-amp, i.e. no ability to control volume, have been asking for this for a long time. Note: only ~6dB steps are allowed in order to preserve ‘bit-perfect’ output. Also note that if you apply volume to HiRez tracks, they won’t be bit-perfect anymore (unless your DAC can process 32 bits) – in theory that’s not ideal but in practice it may not matter due to huge dynamic range of 24-bit material – we thought it is best to leave it up to you, to listen and decide for yourself. "
KM

Re: Pre-amp bypass

Posted: Mon Aug 27, 2012 3:23 pm
by Rocker
I use a Resolution Audio Opus 21 straight [using balanced cables] into a pair of monoblocks, the analogue volume control on the Opus 21 controls the replay volume. I am lucky in that the Opus 21 has a digital input so it accepts the digital output from my Squeezebox.

I did try a Croft pre-amp [using SE cables] but was not convinced that the valves added anything to the sound. The cables used were cheapies so I was not comparing like with like. After about a month I reverted to the balanced cables and have used these ever since.

Such a system is limiting if you have more than two sources. For me it is not a problem as I only have CD and Squeezebox. And there is less clutter [??????] in the music room.