Opinions on the role of the preamp in a modern single source system

[garylkoh]

I realize now that I should have started my own thread, should have asked a much narrower question about the technical requirements for properly driving an amplifier. That question was answered here, but a lot of others were raised by the way I went about my inquiry, pushing so hard on the how and why, and not just accepting people's experiences on face value. I'm helping a friend put together a single-source system. It will be different - bigger - than my own, and I wanted to know if, once the source has sufficient output and a quality volume control, there is any substantive advantage to adding a preamp.

The answer, it seems, is "Yes. If you hear one." Unless you have the money to buy a roomful of quality pres to switch in and out of a system until you're satisfied that you've answered that question and sold off all, or all but one, or unless you're willing to displace at least a part of your love of music with a passion for years and thousands of dollars in the pursuit of system synergy, it's not an answer. It's another whole series of questions. I guess I was really looking for "your output x needs to be between A and B if your amplifier z is between C and D." Can it be that simple? Perhaps not, but I think it's a lot closer to that simple than it is to this complicated. YMMV.

When I got subjective evaluations of emotional experiences instead of my answer, I pushed for data. That got interpreted as me not excepting people's experiences. The truth is I probably asked the wrong question in the first place. Sorry.

Tim

PS: Looking back through, I see that my question was answered, pretty definitively, by page 5. Had I bowed out at that point instead of challenging people to provide some substantive explanations for subjective experiences, this whole thing would probably have ended better. My apologies.

Tim,
Thank you. That is very gracious of you. I thought that you just wanted to draw this back down into what can me measured.

I have the same problem - I thought that if you got a source component with a low enough output impedance, and a power amp with a high enough input impedance, the preamp and the interconnect would not matter. The generally accepted ratio is 10 times. But I've gone to 20x and even more, but it still does, and I don't know why - I suspect it has to do with the power supply of the source component, but then how do you measure this? You build a better power supply for the source component of choice.

My Weiss DAC2 (Minerva) with volume control has a power supply for the analog output that is over 5 times more than the original. All who have done a direct comparison with the DAC202 here have said that it sounds better even though the DAC202 sounds quite a bit better than the standard DAC2.

However, with a superlative preamp, it still sounds better using a preaamp.

The three best DACs with volume control I have heard (and did extensive testing in my own room while I was deciding on the DAC to bring to CES this year) were the BADA, MSB, and my own Weiss. In all three cases, inserting the SMc Audio VRE-1C improved the sound TO MY EARS (and also to my sister's ears and those PNWAS members that visited to help me decide).

Why? I don't know. The power amp has an input impedance of 75k ohms balanced, so any of those DACs would have a low-enough output impedance to beat the ratio. Interestingly, the VRE-1C has an output impedance that is HIGHER than the BADA.

Another example, on Thursday night, Todd Garfinkle was in town with his highly modified Korg MR-2000S. He brought his high-rez recordings (5.6 MHz DSD) and we were setting up the system prior to the meeting. He was using the stock power cord supplied by Korg. And the music was good, and palpable.

On a whim, we suggested using one of the audiophile power cords we had. The shock on his face was palpable. You could see it in his eyes that he thought his recordings would be improved if he had that power cord. His comment was that it seemed that the musicians had more energy. He said that it was the biggest improvement any cable had ever given him.

We took the cable off and went back to the cable he started with, and it went back to as before. Putting the cable back in, we got the same improvement. Needless to say, he left for home with the power cable in his bag.

Why did that happen? A power cable?? I don't know either. But it made a difference - and this was to the recording engineer who was there during the musical performance.

 

[andromedaaudio]

Well i might have been a bit overenthousiastic about the CAT pre in the system ,direct sounds also very transparent and natural, i think i have to get used to the new sound , its not so easy, i dont know what the vol control consists of in the 7000.
Monday i ll buy 2 female /female cinch connectors for cable extension and plug the SME in direct.

These 300Bs make cd s definetively more listenable , is it coloration ??? i dont know i sounds pretty real

 

[AudioExplorations]

Something that has not yet been discussed is the implementation of the analogue output stage, measurements aside. Output stages can be seen as mini amplifiers and have many possible implementations:

- Operating mode: class A across all loads? class AB? class D?
- Operational amplifiers: cheap off the shelf IC's or discrete custom designed?
- Open loop, no feedback design vs. closed loop?
- Power supply: powerful and non-switching? Sensitive voltages with their own regulators separated between left and right channels?
- Output circuitry: servoless, DC coupled?

It may very well be possible that a more robust analogue output stage in a preamp is better at driving complex power amp loads and hence would provide a sonic improvement over a less robust, more cost conscious implementation in a source component.

 

[garylkoh]

True - I've seen output impedance plots vs frequency for tube amps, but I've never seen one for a source component, nor an input impedance vs frequency for a power amp.....

However, when we did impedance vs frequency plots for cables, there are many members who said that such tiny variance cannot be audible and hence all cables sound the same.

 

[JackD201]

Something that has not yet been discussed is the implementation of the analogue output stage, measurements aside. Output stages can be seen as mini amplifiers and have many possible implementations:

- Operating mode: class A across all loads? class AB? class D?
- Operational amplifiers: cheap off the shelf IC's or discrete custom designed?
- Open loop, no feedback design vs. closed loop?
- Power supply: powerful and non-switching? Sensitive voltages with their own regulators separated between left and right channels?
- Output circuitry: servoless, DC coupled?

It may very well be possible that a more robust analogue output stage in a preamp is better at driving complex power amp loads and hence would provide a sonic improvement over a less robust, more cost conscious implementation in a source component.

You really didn't read my posts did you?

Tim,

Love ya' man.

 

[AudioExplorations]

You really didn't read my posts did you?

I did, maybe some was lost in translation. I remember you writing about the importance of the power supply, maybe I missed something. I don't recall any talk regarding most of the other design choices in the list, particularly discrete vs IC opamps.

 

[Phelonious Ponk]

Alrighty then. Next up? How about recommendations for bone-simple (there's really no point in complicating a single-source system, now is there?) solid state pres that can be found on the used market...so they can hopefully be re-sold at little or no loss if it doesn't work out.

What was that vintage Yammy Mark had before the Krells and the Arcs?

Tim

 

[mep]

The C2a.

 

[garylkoh]

Alrighty then. Next up? How about recommendations for bone-simple (there's really no point in complicating a single-source system, now is there?) solid state pres that can be found on the used market...so they can hopefully be re-sold at little or no loss if it doesn't work out.

What was that vintage Yammy Mark had before the Krells and the Arcs?

Tim

The cheapest preamp that I have that measures up is the Adcom GFP-750. However, at this age (over 10 years) if you do pick one up second hand, you might need to change the coupling and power supply caps. I bought one for less than $500 on eBay.

 

[JackD201]

I did, maybe some was lost in translation. I remember you writing about the importance of the power supply, maybe I missed something. I don't recall any talk regarding most of the other design choices in the list, particularly discrete vs IC opamps.

I meant the part about output stages being little amps like you said. I've got practically all you mentioned in my DAC/Player elephant graveyard from NOS to J-fet to 3 pairs of interleaved discretes in one unit. No tube DACs or players though.

 

[JackD201]

Alrighty then. Next up? How about recommendations for bone-simple (there's really no point in complicating a single-source system, now is there?) solid state pres that can be found on the used market...so they can hopefully be re-sold at little or no loss if it doesn't work out.

What was that vintage Yammy Mark had before the Krells and the Arcs?

Tim

How about an integrated amp? They seem to be enjoying a renaissance of sorts from cheap and cheerful to big bruisers that can drive anything.

 

[egidius]

Alrighty then. Next up? How about recommendations for bone-simple (there's really no point in complicating a single-source system, now is there?) solid state pres that can be found on the used market...so they can hopefully be re-sold at little or no loss if it doesn't work out.

What was that vintage Yammy Mark had before the Krells and the Arcs?

Tim

For my digital System i use a wadia s7i going into an Audio Consulting silver rock, tva...fabulously expensive, fabulous sound.
Sh for about 1500$. Doesn't loose value.
Egidius

 

[Phelonious Ponk]

How about an integrated amp? They seem to be enjoying a renaissance of sorts from cheap and cheerful to big bruisers that can drive anything.

No amp. We'll be going from dac to pre to active speakers.

Tim

 

[Mike Lavigne]

No amp. We'll be going from dac to pre to active speakers.

Tim

i think it's hard to beat the Placette RVC for reasonable cost, 30 day money back return policey, simplicity, ease of use, and total transparency. you could maybe find a used one for a little less (they are only sold direct) but then you could not return it.

http://www.placetteaudio.com/remote_control.htm

i used this for 4 to 5 years in my system. i know Myles had some comments that it was this and that but passives are always system dependant; and his reference is Conrad Johnson, not exactly the ultimate in transparency.

the Placette will not add anything to the signal path in any way if that is what you want. it replaced and easily bettered the (at the time) $15k ML #32 in my system and i never looked back.

i did try the Silver Rock which was slightly better for lots more money but no remote volume....maybe the Silver Rock now has remote volume, it did not back when i did the comparison.

 

[MylesBAstor]

i think it's hard to beat the Placette RVC for reasonable cost, 30 day money back return policey, simplicity, ease of use, and total transparency. you could maybe find a used one for a little less (they are only sold direct) but then you could not return it.

http://www.placetteaudio.com/remote_control.htm

i used this for 4 to 5 years in my system. i know Myles had some comments that it was this and that but passives are always system dependant; and his reference is Conrad Johnson, not exactly the ultimate in transparency.

the Placette will not add anything to the signal path in any way if that is what you want. it replaced and easily bettered the (at the time) $15k ML #32 in my system and i never looked back.

i did try the Silver Rock which was slightly better for lots more money but no remote volume....maybe the Silver Rock now has remote volume, it did not back when i did the comparison.

Ummmm.... Guess haven't heard the new cj n the right system Perhaps the older gear. In fact, the new cj gear is stunning, especially with the new Atlas and Transparent ref. MM2 or tape. I was listening to Everybody Digs Bill Evans last night and the drums were laid out in bold relief. You could literally hear and see every hair in the brushes pass over the skin

But alas wasn't just in my system Mike

YMMV as they say.

 

[Mike Lavigne]

Ummmm.... Guess haven't heard the new cj n the right system Perhaps the older gear. In fact, the new cj gear is stunning, especially with the new Atlas and Transparent ref. MM2 or tape. I was listening to Everybody Digs Bill Evans last night and the drums were laid out in bold relief. You could literally hear and see every hair in the brushes pass over the skin

But alas wasn't just in my system Mike

YMMV as they say.

same for me. when i used the Placette i had Tenor 75 watt OTL amps and Kharma Exquisite speakers back in the day and it had dynamics and body and was very natural and open sounding. and others used it too and enjoyed it too.

agree on the YMMV.

i did have the CJ M140LP's recently in my system and i did enjoy them (and agree they don't have the same 'golden' CJ house sound of years past); but it was not quite transparent to my ears compared to my darTZeel or even my 2a3 monoblocks. but we all have a slightly different sonic compass.

my only point was that many like the tonal balance of the Placette.

 

[Gregadd]

Of course noise can affect separation. You know of a case of analog noise being used to improve separation?

Tim

I can't ever recall hearing anyone talk about a noise inherent in, or deliberately added to analog components to increase their fidelity.

Emphasis added.

Tim just poking a little fun at you.

 

[Phelonious Ponk]

Emphasis added.

Tim just poking a little fun at you.

I don't get it.

Tim

 

[rbbert]

I doubt the Placette will work well with interconnects longer than 6 ft or so.

 

[microstrip]

(...)

i did have the CJ M140LP's recently in my system and i did enjoy them (and agree they don't have the same 'golden' CJ house sound of years past); but it was not quite transparent to my ears compared to my darTZeel or even my 2a3 monoblocks. but we all have a slightly different sonic compass.

I think that the tittle of this thread is particularly true with cj amplifiers - you will never get the best of them unless you pair them with a cj preamplifier. I still own the MV125 (ancestor of the 140, somewhat more golden sounding) and unless I use a PV9 or a premier 14 it sounds vulgar.