Tube Buffer

[jcmusic]

OK who can tell me about tube buffers? I would like some info.

[Erik Mandaville]

Most likely a circuit, such as a low output impedance cathode follower, which will sometimes help impedance matching between a driving source and its load. There should be suitable impedance relationships between different stages in both individual components (such as input/driver and output stage of amplifiers) and between such components as preamps and amplifiers. A vacuum tube buffer will often not present gain, just the benefit of good impedance matching, which is important.

I hope that ferrite I and some others mentioned for noise helps, Canyon. I have family members who are expert class radio operators, and swear that there isn't much better for fighting RF junk than ferrite. Sorry I didn't have the link to the Radio Shack product, but someone else provided that. It might work really well for you.

In addition to trying the small value cap on the output of the amplifier, you may get equally good or better RF suppression by installing it (as long as you know what you're doing -- don't attempt electronic work inside a component unless you are familiar with it) on the input. Historically, those small value capacitors were used to fight RF in very high frequency radio circuits, and even on interconnect cables, themselves.

Erik

just an FYI: small ceramic capacitors across ICs is a form of bypassing -- and can also be used in conjuction with an RFC (radio frequency choke). The chokes can be easily hand wound, BTW, but again, I don't suggest doing this work without knowledge or experience (which you may have, but something for me is an obligation to mention).

[greg928gts]

I thought it was what you're called when you take a soft rag and lightly rub the glass to make it shine. []

Greg

[Mark Hardy]

I always thought that this was an intriguing little product :-)

PAIA "Tubehead" tube "preamp":

http://www.paia.com/tubestuf.htm

[nicholtl]

The Musical Fidelity Tube Stage Buffer is one of the most popular products in that niche of the marketplace.

http://www.musicalfidelity.com/mf/en/Products/SmallX

[Daddy Dee]

I think what Erik has said is right. The tube buffer serves as a utility type thing to better match impedance and such. Doing that, I do not think it would offer much to give the signal "that tube sound".

[BiggerIsBetter]

If you are refering to the musical fidelity, I would not recommend using it uless you have an inexpensive CD player and SS preamp and needs to tubes in the chain. If you have a good CD output stage and/or a tube preamp it is redundant and unecessary and will likey detract more than it would add.

[Erik Mandaville]

Canyonman:

Not sure if you're still checking this thread, but here's another example of what I referred to above. It is a very straightforward design, and as can be seen from the supplied schematic, is simply a cathode follower output (for low output impedance), and uses 1/2 of a 6N1P per channel.

I would say that whether it detracts or is an improvement would be largely subjective. Dee: As with any device a signal travels through, there is the chance for possibly some alteration or coloration from how the sound was formerly perceived. Like we have both said so many times here, whether that coloration is an improvement depends on who is listening and what he/she likes or doesn't like to hear. My Lexicon processor can 'color' the original recording in a very significant way, and I like some of those changes in some cases and less so in others. I also can see how this kind of begs the question: "But, if the sound is being changed so much from the original, is it possible to consider the change a valid representation of the intent of the artist?"

It's a good question but (1) I wasn't present at the recording session, so I don't know what the original really sounded like; 2) All equipment will color and change that original signal in some way -- some of those ways possibly being more subtle than others. For example: IMO, the same thing happens with EQ, but we will use that tool (if you will) as a way of coloring the sound further yet to best suit our own preferences and tastes -- just as one might throw an extra dash or two of salt on a steak, freshly sputtering- hot off the grill. In my mind, there is very little difference between the two. It's a matter of taste. And (3) I may have no idea what the original intent of the artist was -- unless the artist/composer/performer made that information available. In that case, I could compare the explanation with the product or work, and decide if to my way of thinking, seeing, or hearing those two elements are related.

Here's the link: http://www.decware.com/linestage/zp1.htm

Erik

[jcmusic]

Erik, what do you think about this product, personaly.

[Erik Mandaville]

Canyonman:

"Erik, what do you think about this product, personaly."

I have no experience with the Decware component, itself, but have used the same tube in other designs and have built cathode followers before.

I was just thinking that, since you have somewhat of a complex system right now and seem to be experiencing some RF noise issues, I agree that reducing it to something more simple and basic might be a good first step in troubleshooting the problems with interference and noise. If you can get by with just a CDP (or whatever your main source is), a preamp, and an amplifier (or just CD and integrated amp, as the case may be), you may find that noise is reduced and the overall sound possibly improved.

If you are interested in tube electronics, IMO it might be appropriate to look around for a tube linestage with gain to use with your CDP and amp. As another forum member mentioned, this would present both a high input impedance for your source (a good thing) and a low output impedance into the amplifier.

There are lots of good tube linestages out there.

Erik

[jcmusic]

Erik, would you give me a few names to take a look at, thanks.

Jay

[Daddy Dee]

Erik,

Well said, my friend.

[Erik Mandaville]

Dee:

I think what you said about sound quality and buffer stages was correct in that I think in the past they were often used between stages for improved coupling, just as an audio transformer is used for the same thing. It's why output transformers have very high impedances on the primary winding (for the output stage tubes) and far lower impedancs secondary windings for proper impedance matching/power transfer to loudspeakers -- as in 2,4,8, 16, etc., ohms. I think in an ideal world (for which I think we all continue to enjoy searching!), it would be nice if OPTs could supply their different audio and power functions without imparting anything of their own personalities, so to speak. I think that's one of the reasons some designers have spent as much time as they have trying to improve or create anew amplifiers that do not rely on transformer coupling (as in OTL designs) between the amplifier and the speaker load it's driving.

I know my saying this is redundant as heck, but it's again just a matter of someone finding the component/s that subjectively 'color' the sound in the way that looks and sounds best to that person.

I will say that where passive preamps are concerned, I am more inclined toward designs that strive for the best possible impedance matching for both input and output stages. For me, that requirement would most likely involve a passive design that used either transformer coupling between the input and output, or, as we have discussed above, an impedance matching tube buffering stage. The potential problem I see with those, though, (tube buffers) is that although they may or may not provide some sort of voltage gain, they are nevertheless 'active' in the sense that power supplies are needed for the necessary working voltages. And that fact, unlike a completely passive transformer-based design, allows for the possibility of what might be one very important reason for using a passive device -- the wish to reduce power supply related noise.

"Erik, would you give me a few names to take a look at, thanks."

Sure, I could mention some I have tried and liked, but the two-channel forum would be a good place to ask for advice, too. Cost always figures into the this, but there are tube preamps used by forum members that offer super good performance at a very reasonable cost. Some preamps out there are insanely priced, and may very well not necessarily be much better at all than a few of those products that have become favorites here.

Erik

[djk]

I always thought that this was an intriguing little product :-)

PAIA "Tubehead" tube "preamp":

I have one. A good idea in need of better execution.

[jbsl]

I have a Ground Grid tube preamp and tried a Merlin tube preamp that I returned and feel tube preamps are not for me. I have been happier using a X-10v3 tube buffer than tube preamps between my NAD C542 Cd player and my Luxman preamp.

With that being said I really like my Cayin TA 30 tube amp and just bought a pair of SET Welborne Moondogs 2A3 tube amps at 3.5 watts which I am going to try with the Ground Grid tube preamp.

My X-10v3 does not make a drastic change but it smooths things out a little. With speakers at 104 db a little can make more of a difference than some people realize.

At first I ran left and right analog chanels from my Denon 2900 to the buffer and then to my Luxman preamp with good results. Not a huge difference but it gave the sound a smoother presentation.

Tried it between my Luxman preamp and Cayin TA 30 tube amp but did not like it. finaly put it between cd player and preamp. I cannot hear any loss of detail or anything when I compare just the cd player and the cd player and X-10v3. As I said it smooths things out just a little. If the recording is bad or bright it does not help. Well recorded cds are just a bit smoother.i On those bad, bright, etc cds I play on my Denon 2900 and they sound better on it.

It also could be the placebo effect and my brain is making me believe it improves the sound even a little. I have been using it for 4 months now so I will take it out and put it back in and do a review on the sound.

[Erik Mandaville]

JBSL:

"With that being said I really like my Cayin TA 30 tube amp and just bought a pair of SET Welborne Moondogs 2A3 tube amps at 3.5 watts which I am going to try with the Ground Grid tube preamp. "

I've used Grounded Grid preamps with 2A3 SET amps, and think the match is excellent. The GG is different from many tube preamps, and I think there is a good chance you will like it with the Moondogs.

Erik

[aviserated]

To sum up the Stereophile Recommended Components review:

The X-10 is intended to remove any mismatch between sourcedevice and amplification stage, the X-10 shows your CD player, DAC, or other source a high input impedence while offering your power amp, integrated, or preamp a low output impedence. Adding more depth and dimensionality to the sound, with more body and weight, the X-10 "brought the X-Ray's performance up to that of a world class CD player," said ST.Offers no gain, however, and has no control functions. "Stereophile rates it "Class A for what it is!" he sums it up.

For what it is? Huh

[jcmusic]

What about the Zbox vs. the x10?

[jbsl]

I have not had some really good tube amps to try with my Ground Grid tube preamp. So now that I'm geting the Moondogs it should give me a better idea of what tube preamps can do.

When I tried the GG with a pair of Monarchy Audio SM 70 pros it was a very good example of a nice match with a tube preamp and solid state amp.

Is the GG tubes 12AX7s?

[Erik Mandaville]

James:

"When I tried the GG with a pair of Monarchy Audio SM 70 pros it was a very good example of a nice match with a tube preamp and solid state amp."

It's an example of the subjectivity associated with this hobby. I am familiar with both of these components, and have used both in our system -- but not together. I think the Monarchy SM 70 is a good amp, although for me it tended a little toward the 'dry' side with the Klipschorns. Doesn't mean it's not a good amp, but I think you outlined the importance of finding components that work well together in terms of the owner's (rather than those of someone else) personal tastes and preferences.

The Transcendent GG uses 12AU7s

Erik