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Do tube preamps add or take away dynamics

68.231.156.10
Posted on June 8, 2017 at 14:31:42
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 I did try posting this elsewhere but the topic only took off in various directions.

I was toying with the idea of building a DIY impedance buffer/passive type preamp. Just a fun project and nothing serious to replace gear - just fun.

https://www.passdiy.com/project/preamplifiers/b1-buffer-preamp

So here's two questions for the engineer types and those that know FAR more than I do.

I understand the source is the limiting factor. But I'm a tad fuzzy on the potential of preamps gain vs. just a straight signal from the source.

If your source goes through a tubed preamp can the signal in any way have added dynamics. Not only the added gain and buffering of a normal preamp. More actual punch, dynamics, detail, etc.... Can a preamp with gain bring more out, or just loose a tiny bit in the gain process?

With today's sources is a tubed preamp really even needed? Or can it just be replaced with a buffer going basically "passive" directly into a tubed amp?

 

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RE: Do tube preamps add or take away dynamics, posted on June 8, 2017 at 19:31:36
hahax@verizon.net
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Posts: 4306
Location: New Jersey
Joined: March 22, 2006
 Good tubes are very linear devices. In a good circuit they will be very dynamic, albeit not more dynamic than the input.

 

RE: Do tube preamps add or take away dynamics, posted on June 8, 2017 at 19:49:07
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 Thank you.

I think what I'm also asking does gain basically give those transient peaks a bit more "push" as it were.

I understand the source is the limiting factor, but with these high output devices is the gain just getting in the way - or helping?

 

RE: Do tube preamps add or take away dynamics, posted on June 8, 2017 at 22:24:56
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 Think in terms of avoiding info. loss.

Passive control centers exhibit inherently high O/P impedance and poor drive capability. LOW capacitance (read short and unshielded) cabling to the power amp(s) is essential. Notice the lack of flexibility. Also, a pentode voltage gain block at the power amp(s) I/P(s) is helpful, as it allows a high I/P impedance, without adverse CMiller interaction.

An active control center, with or without voltage gain, typically has a lowish to low O/P impedance and decent or better drive capability. Flexibility is present, but "colorations", bandwidth limitations ... may be negatives.

All legitimate options are compromises. Each 'phile decides which way to "jump". We are dealing with yet another perfection is the enemy of the very good situation. A "perfect" solution simply doesn't exist.


Eli D.

 

RE: Do tube preamps add or take away dynamics, posted on June 9, 2017 at 05:34:38
waterfall
Audiophile

Posts: 189
Joined: May 28, 2000
 There is signal degeneration with every device a signal needs to pass through. A poor analogy would be water passing though a hose. You sill get your water, but some is left behind in the hose. Or mixing the batter for a cake, you can never get all the batter out of the bowl. In cable TV/ satellite TV terms. The signal degrades every time it passes through a splitter, or a surround system receiver ( caps, resistors ) etc. Sorry, can't think of a better analogy at the moment.

I remember Cal Audio Labs manufactured a cd player with volume controls. It completely eliminated the need for a preamp. With all the A/B demos I did, no preamp sounded as good with the Cal, as the Cal did simply hooked up to the amp.

 

That had a tube output stage, didn't it?, posted on June 9, 2017 at 08:18:33
Rick W
 What was the volume control?

 

RE: That had a tube output stage, didn't it?, posted on June 9, 2017 at 11:48:50
waterfall
Audiophile

Posts: 189
Joined: May 28, 2000
 It's been so long I don't recall everything about the Cal. However I saved the link to the Sterophile audition if you want to read up on it.

https://www.stereophile.com/cdplayers/1198cal/index.html

 

Cary 303/300, posted on June 9, 2017 at 12:12:37
Uncle Mike
 I've had one for quite some time. it uses an 12au7.

 

Seems I was wrong. No tubes. Thanks for the link. nt, posted on June 9, 2017 at 12:58:32
Rick W
 nt

 

RE: Do tube preamps add or take away dynamics, posted on June 9, 2017 at 13:44:12
2con
Audiophile

Posts: 77
Location: lombardia
Joined: February 12, 2003
Listen a 400cx 2 Fisher preamp in your set -up :if you think

that a passive one is better ,forget about pre-amps.

I own several old and up to date pre-amps :when i hoked up

400 cx first time i saw the light and understood what a

serious preamp can do.

Always imho

 

RE: Do tube preamps add or take away dynamics, posted on June 9, 2017 at 17:23:25
Thermionic27609
Audiophile

Posts: 411
Joined: March 29, 2009
 With Eli's comments in mind, there are lots of different approaches to preamp design. Some preamps do the bare minimum to avoid the downsides of purely passive controls, while vintage preamps frequently had lots of switching options in the signal path (tape monitor controls, etc...), each of which became a point at which the signal could be degraded. Tone controls and their implementation are places where things can go wrong, but it's a judgment call.

I recently dealt with a McIntosh integrated amp, and its preamp section had lots of features that it would never occur to me to use.

 

Well, Eli ... that is 'the best' answer... for me {smile}~nT, posted on June 10, 2017 at 01:47:07
Cleantimestream
Audiophile

Posts: 7550
Location: Kentucky
Joined: June 30, 2005
 ~!
The Mind has No Firewall~ U.S. Army War College.

 

RE: Do tube preamps add or take away dynamics, posted on June 10, 2017 at 01:50:01
Cleantimestream
Audiophile

Posts: 7550
Location: Kentucky
Joined: June 30, 2005
 For me, the Audio Research Reference 1 was the turning point {after market Mundorf caps}...up till then... I thought simplicity would always trounce complexity.

I was wrong.


The Mind has No Firewall~ U.S. Army War College.

 

Systems - These things are parts of systems, posted on June 10, 2017 at 06:19:35
Chip647
Audiophile

Posts: 2649
Location: The South
Joined: December 24, 2012
 Talking about a component in isolation is like discussing if upgrading Usain Bolt's Pancreas will increase his speed. Maybe, depending on....

Fewer parts, fewer gain stages, fewer attenuation stages make for a simpler system. Impedance and gain. An amp that goes full power with 0.5V input does not play well with a preamp with gain (or a CD player for that matter).

Look at the system from diamond to cone/dome as a living entity.

 

Thank you, posted on June 10, 2017 at 07:27:47
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 That was perhaps the best explanation of passives vs buffer vs traditional preamp usage I've read. Simple (for the non engineer) and non bias.

I like my CJ preamp very much. It doesn't seem to limit the bandwidth or add coloration to the sound. That is one transparent preamp.

However I was always fond of fooling around with passives. Never had much luck with them and I always came back to the more traditional preamp. Now at least I know why.

Maybe one day when I get REAL bored I'll build that Pass DIY buffer. Again it was only a fun project and not intended to replace anything.

 

RE: Do tube preamps add or take away dynamics, posted on June 10, 2017 at 22:45:23
DannyR
Audiophile

Posts: 611
Joined: January 21, 2001
 look into the akido diy stuff. I've always read that they seem to really add dynamics and sound fantastic. I really have to make myself one someday.

 

Taking away dynamics???????, posted on June 11, 2017 at 02:28:33
Timbo in Oz
Audiophile

Posts: 23221
Location: Canberra - in the ACT - SE Australia
Joined: January 30, 2002
 When they can swing 10-40 VOLTs!!!!!

And, have far more storage in their PSUs than most SS pres?




Warmest

Tim Bailey

Skeptical Measurer & Audio Scrounger


 

RE: Do tube preamps add or take away dynamics, posted on June 11, 2017 at 09:01:52
Mechans
Audiophile

Posts: 1804
Location: East Coast
Joined: May 23, 2004
 In my humble opinion tube pre amps do no not diminish slam or otherwise limit any sonic.
The only way for you to be certain/decide is to listen for yourself and not worry about whether your listening is backed up by the electronic theory.

 

Nelson's DIY projects are all worthy, but, posted on June 11, 2017 at 20:27:31
E-Stat
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Posts: 37605
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Contributor
  Since: April 5, 2002
 you might consider what he considers a no-compromise solution.

XS Preamp

He gave Wayne a blank check for this design.

I was a passive fan until I heard a really good active in my system. :)

 

LOL - "the Xs series has drawn a line in the sand", posted on June 11, 2017 at 23:29:34
Triode_Kingdom
Audiophile

Posts: 10045
Location: Central Texas
Joined: September 24, 2006
 No compromise? It's the biggest compromise of all - loaded with silicon!

 

With a digital source, why preamps at all?, posted on June 11, 2017 at 23:51:35
andy evans
Audiophile

Posts: 4378
Joined: October 20, 2000
 I sold all my LPs and my CD player and put all my music on my Mac's hard disk, plus I can stream music from various sources. That's pretty typical of younger people these days, though I'm a lot older than that.

The volume control is digital, in the computer. So no need to think about that. No need for a selector since it's all in the computer. Then after that all we need is amplification. Ideally 2 stages, if not 3 stages. So as long as the driver can dynamically drive the outputs, why burden the system with any additional stages that will simply compromise the transparency?

 

RE: With a digital source, why preamps at all?, posted on June 12, 2017 at 00:29:08
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 I can't say if your sound card works the way some older CDPs with digital volume controls did, but those things lost info., when attenuating.

I strongly favor listening level control in the analog domain. The issue of bits being thrown into "oblivion" is not present. Perhaps you should try SY's "heretical unity gain" setup. A very knowledgeable man went to enormous lengths to achieve transparency.

FWIW, I have a pretty darned good digital playback setup that's "dropped jaws" on several occasions. I then pulled out a LP with the late Sir Neville Marriner conducting a Haydn symphony and "reality" set in. Really good digital is fine, but it is not quite up to really good "vinyl". Of course, large numbers of people are getting better sound out of digital than they did with phonographs. That's a reflection of how poor their LP playback chains were. Hands down, digital offers more "bang for the buck", but good (unfortunately VERY expensive) analog playback chains are superior. I'm lucky I bought in peak revenue times. I certainly can't afford the "up scale" analog stuff now.


Eli D.

 

RE: With a digital source, why preamps at all?, posted on June 12, 2017 at 01:04:44
91derlust
Audiophile

Posts: 1101
Joined: December 25, 2014
 You can't credibly make those claims re: digital versus turntable without posting system details... or at least giving us an idea of what sources were compared.

:)

Cheers,
91.

"Confusion of goals and perfection of means seems to characterise our age." Albert Einstein

 

RE: With a digital source, why preamps at all?, posted on June 12, 2017 at 04:13:50
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 Some details follow.

Digital: a Rotel CDP as the bitstream source into an anti-jitter filter and on to an AVA FET-Valve DAC.

Phono: SOTA Sapphire TT/SME Series V arm/AT OC9 LOMC.

FWIW, a dealer I did business with called the digital chain "reference". To be fair, this was several years ago and digital definitely continues to improve. JMO, digital still has a way to go, before it catches up with 1st class analog.

BTW, that LP has been and remains my CD "killer". Again, fairness requires me to state that recording quality frequently is more important than any particular technology. A well done CD beats a crappy LP and L_RD knows plenty of crappy LPs were pressed. ASMoF/Marriner and a very competent recording crew did a SUPERB job on "The Queen". "Maria Theresa" on the flip side is excellent too.


Eli D.

 

RE: With a digital source, why preamps at all?, posted on June 12, 2017 at 07:25:35
andy evans
Audiophile

Posts: 4378
Joined: October 20, 2000
 LPs are always worth a listen - I'm a musician and I had thousands. But I just don't have room for them, I'm not about to fork out hundreds of pounds on styli, I'm not going to get up every 20m and change the side and on and on and on. I listen to music while I work on other things, and I want my mouse to do the walking.

The thing about digital volume controls is to design your system so that your listening volume is close to the maximum on your computer. So typically you attenuate very little. That's certainly how I've configured it. Just 2 amplification stages. Just enough.

 

RE: With a digital source, why preamps at all?, posted on June 12, 2017 at 07:53:28
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 Thanks Eli

My situation is that I like easy classical listening and had to transition over to digital streaming for the following reasons.

1- When I was in NJ FM died. Now I'm living in Arizona it's a little different. Reception is the issue but my antenna days are over with this house.

2- I was in college for about 10 years and had to travel REAL light. So my stereo (Dynaco SCA-35 and A-25 speakers) and records all disappeared with the help of my brother-in-law. As well as having those years NOT building and tweaking out a system.

3- Through the late 80's and 90's I was SO excited when ebay started that I was trading stereos once a month and I didn't focus on what was really important in audio.

4- Now I use a Marantz NA7004 network streamer. It's pretty good and I do like the variety of classical music. I do realize that it all comes down to a good engineered recording. Without that it doesn't matter what you're using.

5- I'm trying to max my system to what I have and what I use it for. Not a fantasy of a system I don't have - or need.

Systems:
Summer
Sherwood S-5000 integrated amp - love that little thing

Winter/Spring/fall
CJ pre and Latino ST-70 - my favorite
CJ pre and Marantz 250M fully restored and upgraded - Wow!
CJ pre and NAD C275BEE just to break things up.

Source
Marantz NA7004 network streamer

Speakers
DIY Zaph Audio SR-71 with stereo subs

Room
Bedroom 12x12

 

Surely it is well known, posted on June 12, 2017 at 10:33:24
E-Stat
Audiophile

Posts: 37605
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Contributor
  Since: April 5, 2002
 that NP is a SS designer. Both the B-1 buffer that Airtime talks about and the best efforts of Pass Labs both use FETs.

As for me, I prefer Audio Research and VTL tubes. :)

 

That's exactly what I thought years ago, posted on June 12, 2017 at 10:38:52
E-Stat
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Posts: 37605
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Contributor
  Since: April 5, 2002
 and debated that very question here with Charles Hansen. It's true that is really isn't a question of gain as most digital sources provide more than enough.

And yet, active preamps flourish. Why? I now finally understand the full measure of delivering low level and micro dynamics - which really is the domain of good actives.

 

RE: Do tube preamps add or take away dynamics, posted on June 12, 2017 at 17:53:34
PakProtector
Audiophile

Posts: 12363
Joined: May 14, 2002
 Since I like a single point volume control, and the stuff I build is waaaaay too heavy to put onto a stereo chassis, the pre is a useful thing. Gain is a good thing, and since I tri-amp with an active cross over, I like to have one with balanced outputs. It is a matter of of how this is done that can make or break a system.

I tend towards low output Z designs with enough drive to let me ignore silly cables. Just in case it has not been contemplated, the EL84 is a fine signal tube...:)

Cheers,
Douglas

Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

 

Follow-Up Question, posted on June 13, 2017 at 13:30:54
Jim Hodgson
Audiophile

Posts: 399
Location: New York City
Joined: March 9, 2006
 Eli ... is this the Haydn LP that you're calling your "CD killer"? (Link below.) If so, I'd like to locate a copy. (It shouldn't be difficult as there are four on eBay at the moment.)

I also wanted to "+1" the following, which you stated in an earlier post:

[R]ecording quality frequently is more important than any particular technology. A well done CD beats a crappy LP and L_RD knows plenty of crappy LPs were pressed.

Although I might change "frequently" to "always"? This is why (IMO) we need both great analog and great digital sources in 2017, and why we shouldn't have a predisposition toward either.

Living in a neighborhood that's considered the hipster capital of the world, I have a girlfriend, numerous friends, and lots of acquaintances who are absolutely convinced of vinyl's superiority. I've demonstrated for many the fact that this is hardly an across-the-board fact. The truth is, given the freedom to select the recording, I can easily prove that Tidal streamed from an iPhone to my DragonFly is far superior to my analog rig.

 

RE: Do tube preamps add or take away dynamics, posted on June 13, 2017 at 15:37:06
Mechans
Audiophile

Posts: 1804
Location: East Coast
Joined: May 23, 2004
 I certainly think so.
I hate to be so utterly simplistic in my answers, but tubes seem to help give dimension to music. After putting together an all tube system with tube mono blocs, I was astonished at the three dimensional nature of my sound. My tube pre amp a humble AE-3, with it's two 6SN7s had added a lot of magic already. A good audio pal said that he thought that indeed, tube's greatest addition, was producing the incredible sonic picture we were so thrilled to hear, the moment I finished my complete tube set up.
(The mono blocs also fairly humble Cyber 800s by Opera Consonance, 78w from 4 fat bottle EH6CA7s ea. amp)

 

RE: Follow-Up Question, posted on June 13, 2017 at 15:46:29
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 It might well be the same master tape, but my LP is London Speakers Corner. If that pressing is readily available, go for it.

Quality of recording is definitely a very critical factor. "You can't turn shit into gold."


Eli D.

 

RE: Follow-Up Question, posted on June 14, 2017 at 08:55:11
Tubegroover
Audiophile

Posts: 246
Joined: May 18, 2000
 No you can't turn shit into gold as they say but in the right set of circumstance make it a bit more palatable and that is a positive.

 

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