Why Use A Dedicated Preamp When My Computer Is The Only Source?

[alcarp]

The Swiss Solution 720 preamplifier retails for over $40,000. The Audio Research Reference 5 preamplifier for about $12,000. Why would anyone spend this amount of money if these preamplifiers just enabled volume control and the ability to connect multiple components?

[dallasjustice]

You can integrate subs nicely without a preamp. If you are you going to do it right, you will need something like a lynx aes16 to multipe aes. You can then use jriver's awesomeness to dial in crossover, mono signals to each sub and correct delay for main left and right. I am designing a configuration like this right now with multipe totaldacs.

 

If the dac has a good output stage and properly implemented digital volume control, a preamp will only degrade the sound. For example, ive tried some very highly acclaimed pre amps after my totaldac and they always add something or take something else away.

 

The final frontier in computer audio is judicious use of DRC and I hope you use your computer to implement the sub. That's my next project. It will be exciting when I am done.

[Gary.D.Olson]

If your Velodyne is like mine, you could connect the DAC to the line-in of the sub and then connect the line-out of the sub to the amp and let the sub's high pass filter do the work, but that means you have added a layer of circuitry to the path and to some extent negated the advantage of eliminating the pre-amp. I have fiddled with these various combinations with my system, using the volume control in JRiver to replace the pre-amp, which allegedly causes negligible signal degradation, but in the end, I am terrified that one day I will inadvertently leave or set the software volume on max. and blow my speakers to pieces (my DAC has no volume control).

 

It's like you're in my mind. Everything you said is identical to my own beliefs and fears. I'd already decided not to use Mr. Velodyne's "preamp" using the same logic as yours, plus I'll lose sleep at the thought of not having real hardware to keep my power amp from inadvertently cooking my Canton's. I think Bluesman's passive volume solution is the hot ticket. Even the $400 passive knob would be a small investment in the grand scheme.

 

Thanks.

[Gary.D.Olson]

It just occurred to me that finding a power amp with a single volume knob might be the best solution for clean attenuation. Hmm.

[sandyk]

It just occurred to me that finding a power amp with a single volume knob might be the best solution for clean attenuation. Hmm.

 

The trend these days is for power amplifiers to have quite low input impedance in order to maximise signal to noise ratio.

Neither can longer interconnects be driven directly from the output of many DACs into a lower impedance without degradation.

A good preamplifier may also be capable of driving a 75 ohm coaxial cable with a low value input resistor in the amplifier in order to reduce HF roll off. If the power amplifier has a volume control, then the chances are that it also has an integrated preamplifier section.

Regards

Alex

[Gary.D.Olson]

The trend these days is for power amplifiers to have quite low input impedance in order to maximise signal to noise ratio.

Neither can longer interconnects be driven directly from the output of many DACs into a lower impedance without degradation.

A good preamplifier may also be capable of driving a 75 ohm coaxial cable with a low value input resistor in the amplifier in order to reduce HF roll off. If the power amplifier has a volume control, then the chances are that it also has an integrated preamplifier section.

Regards

Alex

 

I'm sorry. Would you kindly translate that into laymen's terms? Are you saying it might be "good" or "bad" having a dedicated pre - in the context of my rig (computer/dac/poweramp/speakers)? Please pardon my ignorance.

 

Thanks.

[Gary.D.Olson]

It just occurred to me that finding a power amp with a single volume knob might be the best solution for clean attenuation. Hmm.

 

 

Easier said... It seems most modern power amps these days have a dedicated "VOLUME" knob but not the older models.

[Melvin]

It just occurred to me that finding a power amp with a single volume knob might be the best solution for clean attenuation. Hmm.

 

For the ultimate in simplicity .. great sound too (and no I'm not affiliated, I just own one).

 

Odyssey Audio: Cyclops integrated amplifiers. Call us (317) 299 5578. IN, USA.

[Panelhead]

[quote=dallasjustice;

 

 

The final frontier in computer audio is judicious use of DRC and I hope you use your computer to implement the sub. That's my next project. It will be exciting when I am done.

 

This is very true. Once you use a little DRC to help with room nodes and phasing it would be very hard to go back.

I expect the number of options will continue to grow. I like the Lyngdorff method. But that may be very outdated. That is four - five year old technology. The technology has to be advancing rapidly.

[sandyk]

Gary

why don't you just try what you have first, as mav52 suggested ? If you go for a power amplifier with a volume control you may be virtually duplicating what you already have, but in that case the preamp will be external, not in the power amplifier itself

There are pluses and minuses to both methods.

Regards

Alex

[Gary.D.Olson]

Gary

why don't you just try what you have first, as mav52 suggested ? If you go for a power amplifier with a volume control you may be virtually duplicating what you already have, but in that case the preamp will be external, not in the power amplifier itself

There are pluses and minuses to both methods.

Regards

Alex

 

That would be the thing to do, but I haven't purchased the Yamaha gear yet. I'm scheduled to meet with the seller this Saturday. "To buy or not to buy" is now in question and I'd like to give the seller respectable notice if I'm going to cancel. He seems like a helluva guy.

 

That said, barring any new information to the contrary, I still intend to get the Yammies and try the preamp out for myself. AND the tuner. (I'm actually getting excited at the prospect of using a real honest-to-goodness dedicated tuner, and I've read good things about this one on the interweb, so it must be true.)

 

Thanks for the sound advice.

[mitch751]

I am not an expert, but I believe pre-amp is more than just a volume knob, otherwise, every pre-amp should sound the same.

 

25 years ago when I replaced by Accuphase pre-amp with ARC SP9, the improvement was very significant.

 

Till now, I can live without a pre-amp, even my dac has a very nice volume knob.

 

Further more, I must connect my Cello Audiophile palette MIV in between my pre-amp and power amp, even I set the SQ settings are at flat, again the sound quality is much better with it.

[Brian A]

My pre-amp needed repair earlier this year, so played my rig with and without pre-amp for many months.

 

My subjective experience was that I much prefered having the pre-amp in the signal path.

 

One major benefit to my system was that the pre-amp could raise the volume level much higher than the DAC could alone. My DAC could not provide the signal gain that my power amp needed.

 

Another major benefit was sound quality. This is the stuff of audio voodoo and the stuff of major debate on this website, so won't try to justify my preference. I just liked the sound with the pre-amp better.

 

I suggest trying to find a way to audition pre-amps to determine your preference.

[Gary.D.Olson]

My pre-amp needed repair earlier this year, so played my rig with and without pre-amp for many months.

 

My subjective experience was that I much prefered having the pre-amp in the signal path.

 

One major benefit to my system was that the pre-amp could raise the volume level much higher than the DAC could alone. My DAC could not provide the signal gain that my power amp needed.

 

Another major benefit was sound quality. This is the stuff of audio voodoo and the stuff of major debate on this website, so won't try to justify my preference. I just liked the sound with the pre-amp better.

 

I suggest trying to find a way to audition pre-amps to determine your preference.

 

 

Back in my days as a professional recording musician, I remember hearing an owner of a studio say "It's all about the preamp". They were VERY expensive, btw. That remark stuck in my mind. I've owned lots of semi-pro recording equipment at various points in time, and I have a memory of conducting an experiment. I took a high-quality "active" microphone, unplugged it from the mixing console, and plugged it directly in to the 1/4" input jack on the front of my Teac half-track reel-to-reel. I then trimmed accordingly. Guess what happened to the sound quality. It stunk up the place, that's what. Talk about dynamics, it was completely out of control. "P's" popped; "S's" distorted (Ever heard of a "de-esser"? Every recording studio has them). I tried other non-active mics with much the same results. That's why I used the word "stabilize" in the op.

 

Since then I assumed preamps weren't an option. Then I found this forum and the question "to pre or not to pre" has returned. Part of my mind remembers the experiment and says "No preamp = stinky quality" but another part of my mind says "Listen to the audiophile wackos - the microphones used to record your favorite music have already been processed through appropriate preamps. Any further processing can only take you further away from the purity of the studio's creation and how it was intended to be heard. Just crank it up, dude!"

 

I think the issue could be answered scientifically, but I sure as hell don't have the test equipment. Until then, I'll do what everyone else does: listen and decide for myself.

[bluesman]

I am not an expert, but I believe pre-amp is more than just a volume knob

 

And it is - a preamp is a voltage amplifier whose job is to boost source signals to a level sufficient to drive the output stage ("power" or "basic" amplifier) to its rated spec. If you look at the full spec table for a power amp, it tells you the input voltage required to achieve the rated output in watts at the rated specs (distortion, S/N ratio etc). And power (i.e. current) amplifier stages are low impedance, which means the input signal must be of low enough impedance to drive it - high impedance source signals cannot push electrons into a low impedance load as hard and as fast as low impedance sources at the same voltage.

 

Whether or not you truly need a voltage gain stage (an actual preamplifier) is simple to determine. If the source signal voltage from phono, DAC, tuner, CD player, tape player etc is too low to drive your power stage to rated output, you need voltage gain. Sources with sufficient output voltage to drive the power amp do not need any voltage amplification. That's it.

 

But most preamps also include or serve as a buffer stage, converting the signal to lower impedance to better drive the power amplification stage. If the source signal impedance is too high and it requires a buffer stage to bring it down so it can drive the power amp optimally, bypassing the buffer is clearly audible. But this has nothing to do with amplification - it's a separate function in a separate circuit that has zero gain. The better "passive preamps" / volume controls are also buffer stages - that's why they're so much more expensive than a simple volume pot.

 

Most preamps also incorporate frequency response modifiers (tone controls, "equalizers", filters) plus multiple inputs and outputs that can be selected by switches for flexibility in playback, recording etc. But each of these things can be done by stand alone devices - they're additional functions incorporated into the same chassis with the voltage amplification circuit for convenience, cost effectiveness, ease of set-up & use, and control over the signal paths among the various circuits to minimize noise.

 

Bottom line - electronically, a preamp is simply a voltage gain stage. But what the industry calls a preamp is a voltage gain stage plus one or more ancillary functions that include impedance matching, frequency response modification, switching, remote control, etc. To optimize your sound quality, use what you need - but only what you need.

[Jud]

bluesman, that was nicely done.

[Gary.D.Olson]

I met with the seller who seemed truly perplexed as I uncovered a bad left channel on his preamp. His ad was $300 for the "fully functional" trio. We had agreed over the phone on $250. I told him the cost to repair the preamp would be no less than $60 and offered him $190. He agreed.

 

This was my first purchase of anything audio in a coon's age. In fact, that coon had to have kick-ass health insurance. Franky, I have a lot of mixed feelings about the whole thing. However, I plugged my vintage Sony CD player directly into the power amp. The CD player has variable output control. The sound was fantastic. Look mom. No pre!

[sandyk]

Gary

A CD player of that vintage would be using analogue volume control, so in effect you would be doing similar to a preamp.

I presume that your Sony player has both fixed level output sockets and variable level output sockets ?

All you need to do now is try a few tweaks in the CD player such as vibration dampening, to further improve it, although some of the earlier Sony players are above average in that respect.

Regards

Alex

[Gary.D.Olson]

Gary

A CD player of that vintage would be using analogue volume control, so in effect you would be doing similar to a preamp.

I presume that your Sony player has both fixed level output sockets and variable level output sockets ?

All you need to do now is try a few tweaks in the CD player such as vibration dampening, to further improve it, although some of the earlier Sony players are above average in that respect.

Regards

Alex

 

 

Alex,

 

I bought this CD player in the mid 1980's and it just occurred to me it's the only one I've ever owned. It's been a real champ but the volume pot cries out for Deoxit. It does have separate "fixed" & "variable" sockets and very rarely skips, so I don't think any dampening is necessary. I've been wondering how much it might benefit from a modern DAC. Having not heard any other CD player through my system leaves me with limited frame of reference.

 

The Yamaha power amp has a few bad VU meter lights but otherwise seems fine to me. Someone at another forum suggested I drop the amp and preamp off at Northridge Electronics and get them back better than new.

 

Thanks.

 

 

Gary

[sandyk]

Hi Gary

If you have carpet on the floor, try sitting it on the carpet to see if the sound changes. That should give you an idea whether additional sound deadening is worth while. or not A good modern DAC from coax SPDIF Out of the Sony, is likely to be considerably better.Most recent DVD/CD players use Switch Mode PSUs which degrade the signal to noise ratio when used with older amplifiers which are normally using 3 pin mains plugs. If you go to a new DAC in line with the Sony player, you may then need to use a preamp for best results.

 

Kind Regards

Alex

[Gary.D.Olson]

The preamp is now working properly!!!! A big blast from my garage air compressor and a can of Deoxit and Deoxit Gold was all it took.

 

A kind gentleman at another forum specializing in vintage audio gear suggested a dirty "Balance" pot was the likely culprit. After reading his post I turned on my air compressor and left to get some Deoxit. When I got home, I blasted it with air. Clearly The Munster's once owned this component because it belched out an epic amount of dust. After the dust cloud moved on to the next city, I cleaned all the pots & switches, plugged it into a makeshift bench audio rig (aforementioned vintage Sony CDP-970 CD player, The Munster's preamp, vintage Denon DRA-1025r receiver [slaving its amplifier], and a pair of vintage JBL L20T's. It seems fully functional and sounds perfectly fine after preliminary listening.

 

In summary, I bought Yamaha's TOTL-in-1984 power amp, preamp, & tuner for a total investment of $205.00 ($190.00 to the seller and $15.00 to Radio Shack). I can live with that. Now it's time to see if I can live with how it sounds in my main system.

 

Thanks for all the comments.

 

Gary

[bluesman]

I bought this CD player in the mid 1980's and it...very rarely skips, so I don't think any dampening is necessary.

 

I don't think that's why damping was suggested, Gary - if a home CD player skips, it's almost certainly not from otherwise undetectable mechanical shock. Complete isolation of your CD player (which is also a mechanical device, with a moving optical head tracking a data stream encoded on a rotating disc) may improve your sound by removing one source of variance in stability of the platform on which the disc spins and the head tracks. I've never played with this, so I have no opinion - all my electronics are on rack ears or sitting on the feet they walked in on.

 

I find it hard to believe that undetectable background vibration affects pure electronics enough to change sound quality if everything inside is screwed / soldered / mounted firmly. Although I've not observed it myself, many believe that they can hear the effect(s) of changes in mechanical coupling between electronic components and their supporting surfaces. If they're correct, you might also experience improvement with a damped mount for your CD player. Of course, Eric Johnson thinks he can hear differences among brands of battery in his effects pedals too - so who knows what's real?

 

It's time to enjoy your new stuff - listen now, fiddle later!

 

David

[Booster MPS]

The preamp is now working properly!!!! A big blast from my garage air compressor and a can of Deoxit and Deoxit Gold was all it took.

 

A kind gentleman at another forum specializing in vintage audio gear suggested a dirty "Balance" pot was the likely culprit. After reading his post I turned on my air compressor and left to get some Deoxit. When I got home, I blasted it with air. Clearly The Munster's once owned this component because it belched out an epic amount of dust. After the dust cloud moved on to the next city, I cleaned all the pots & switches, plugged it into a makeshift bench audio rig (aforementioned vintage Sony CDP-970 CD player, The Munster's preamp, vintage Denon DRA-1025r receiver [slaving its amplifier], and a pair of vintage JBL L20T's. It seems fully functional and sounds perfectly fine after preliminary listening.

 

In summary, I bought Yamaha's TOTL-in-1984 power amp, preamp, & tuner for a total investment of $205.00 ($190.00 to the seller and $15.00 to Radio Shack). I can live with that. Now it's time to see if I can live with how it sounds in my main system.

 

Thanks for all the comments.

 

Gary

 

Glad that you were successful in getting the component working. I did want to point out to you and those in the community that using compressed air from a compressor designed for air tools is probably not ideal. All of those compressors have some degree of oil carry over into the compressed air and what you are getting is not dry, hospital grade air. It is indeed wet with some level of oil in aerosol form.

[phusis]

Hobby (short for "The Audiophile Hobby") keeps telling me the stereo system I once considered "great sounding" is actually pathetic and in dire need of upgrades. True or false? HA! Irrelevant, of course. Hobby NEVER lets up on the snobbish whispering. "OKAY, OKAY!" I say. "I'll upgrade already! NOW will you shut up?" Satisfied with himself, Hobby ignores me and comfortably settles in to the "wait-and-see" position. The torment continues.

 

In defense of Hobby (could he exist if we didn't defend him?), my rig has been powered by the same component for a quarter of a century. What's worse is that it's a stereo receiver. ANATHEMA! So I've been searching the various secondary markets for a replacement to the aforementioned unholy component and believe I may have found it, but I have to buy three components to get it.

 

This weekend I'll be replacing my late 1980's TOTL Denon 125wpc Class-A receiver with a vintage Yamaha M-70 200wpc power amplifier bundled with the matching C-70 preamplifier and T-70 tuner - all for a paltry $250.00.

 

(Here's where my question comes in) Should I use the preamp, or should I plug my Schiit Modi DAC directly into the power amp?

 

As the title indicates, I have no turntable and won't be using the bundled tuner, my computer AND the power amplifier can provide volume control, and I never use tone controls or loudness buttons. And yet I can't shake the thought that a good preamp does something more... to stabilize or even improve sound quality. If not, it would seem those who spend multiple thousands on high-end preamps are being duped. Is Hobby that evil?

 

In my setup(see signature) I've gone from using the digitally controlled, analogue volume control in my DAC, which by the way is conncted directly to the poweramp, to using the internal (dithered) digital volume control in my JRiver MC18 mediaplayer - with notable sonic improvements not only to my ears. Digital volume controls may not be the same in their different software iterations, for algorithm-reasons I won't dare get into, but in general I'd say using them with 24-bit output DAC => poweramp gets you a long way over(read: past) the use of a hardware preamp. From what I've read the Foobar digital volume control is fine, but I'd urge you to try out JRiver's latest MC18 build and its internal volume control via their 30-day free trial and see whether it makes a worthwhile difference(I have no affiliation with JRiver; this is mere user-recommendation). Truncation or not, I believe the high-bit digital volume controls in-effect have advantages over analogue dittos; why would the latter be such a reference when all is counted in with the addition of hardware + cables?

[edorr]

The Swiss Solution 720 preamplifier retails for over $40,000. The Audio Research Reference 5 preamplifier for about $12,000. Why would anyone spend this amount of money if these preamplifiers just enabled volume control and the ability to connect multiple components?

 

Simple answer. Because they improve sound quality. I have tried it all. Digital volume control on DAC (trinnov and ps audio), analog VC on dac (msb), solid state preamp (pass labs, emm), tube preamp (modwright)? I thought I had it figured out and ditched the preamp. Someone urged me to try the ARC ref5se and I reluctantly did. Guess what? Better sound - plain and simple....Pleasant distortion? May be. I don't care one bit. More musical is more musical to me.