[lostrockets]

In your experience, can you still get the tube sound with just a preamp?

 

[Dogmatrix]

In your experience, can you still get the tube sound with just a preamp?

Yep

Even a buffer will impart tube flavour

 

[lostrockets]

Yep

Even a buffer will impart tube flavour

Ok cool, any recs? Pros cons vs buffer?

 

[Dogmatrix]

Ok cool, any recs? Pros cons vs buffer?

Depends on set up , what do want from the rig ?

Basically a buffer is the cheapest option but you don't get any control

 

[ProtegeManiac]

In your experience, can you still get the tube sound with just a preamp?

Depends on what you expect to be "tube sound."

Can it be a bit warmer? Sure, with the right tube. But then again you can get most of that with the right SS circuits.

Can it feel "effortless" like an OTL amp on a high sensitivity, high impedance headphone to use with a low impedance headphone? Yes, except the tube amp produces the warmer tone but the amp output stage is what will make the sound seem "effortless" when reproducing dynamics etc. Also slapping on a high impedance headphone to this amp may not have the same midrange boost that pushes the vocals forward making it seem to have more air between the instruments since that's mostly the high impedance of the OTL amp interacting with the high impedance headphone.

What it does though is that in most chassis it's easier to pull off whatever 12ax7 or 6dj8 was in there and replace it with a vintage Mullard for example and it's gonna be a bit like using a tube pre with the same tubes (don't expect the sound to be exactly identical because the circuits matter too, kind of like how the same CPU or GPU would not be their best if the power delivery and cooling on another board/chassis aren't good).

One example: I had some Wharfedale floorstanders before and a NAD 304, tried a Technics Class A dual mono (70wpc Class A IIRC; up to 100w but 70w was the switchover point to Class B) with the NAD's preamp and the tone was brighter although you can really tell the low end was more effortlessly delivering bass drum hits. Added some cheap no name tube preamp (it was kind of infamous at the time for being surprisingly good) - solid caps were low noise, but didn't much sound too warm overall. Replaced the caps with Mundorfs and it was a bit warmer, while the low end sounded deeper (mostly because the noisefloor was even lower, as heard when standing next to the speakers; so yeah, "no noise when music is playing/at listening chair" doesn't mean "noise isn't interfering"). Put in some Amperex tubes and it got even warmer but I got a little bit more noise over the Shuguangs so I put those back in. Note though this did not necessarily replicate the sound of, say, SET monoblocs driving 90dB/1W at 1m or higher speakers, because 1) I'm not using the same speakers and 2) the output stage is still the Technics dual mono (not that it was bad but don't expect them to be identical). It was however closer to, if not better, than some Class A/B push pull pure tube amp.

Note that on headphone amps when I say "the tube pre can help so sure maybe try it" I don't mean add a tube preamp, I mean "get a hybrid amp." Because if you just add a tube preamp to a headphone amp that already has its own preamp (which is 99.9% of headphone amps) using them in series can up the voltage too much and as a consequence, any noise generated by the first (ie the tube pre).

 

[lostrockets]

Depends on what you expect to be "tube sound."

Can it be a bit warmer? Sure, with the right tube. But then again you can get most of that with the right SS circuits.

Can it feel "effortless" like an OTL amp on a high sensitivity, high impedance headphone to use with a low impedance headphone? Yes, except the tube amp produces the warmer tone but the amp output stage is what will make the sound seem "effortless" when reproducing dynamics etc. Also slapping on a high impedance headphone to this amp may not have the same midrange boost that pushes the vocals forward making it seem to have more air between the instruments since that's mostly the high impedance of the OTL amp interacting with the high impedance headphone.

What it does though is that in most chassis it's easier to pull off whatever 12ax7 or 6dj8 was in there and replace it with a vintage Mullard for example and it's gonna be a bit like using a tube pre with the same tubes (don't expect the sound to be exactly identical because the circuits matter too, kind of like how the same CPU or GPU would not be their best if the power delivery and cooling on another board/chassis aren't good).

One example: I had some Wharfedale floorstanders before and a NAD 304, tried a Technics Class A dual mono (70wpc Class A IIRC; up to 100w but 70w was the switchover point to Class B) with the NAD's preamp and the tone was brighter although you can really tell the low end was more effortlessly delivering bass drum hits. Added some cheap no name tube preamp (it was kind of infamous at the time for being surprisingly good) - solid caps were low noise, but didn't much sound too warm overall. Replaced the caps with Mundorfs and it was a bit warmer, while the low end sounded deeper (mostly because the noisefloor was even lower, as heard when standing next to the speakers; so yeah, "no noise when music is playing/at listening chair" doesn't mean "noise isn't interfering"). Put in some Amperex tubes and it got even warmer but I got a little bit more noise over the Shuguangs so I put those back in. Note though this did not necessarily replicate the sound of, say, SET monoblocs driving 90dB/1W at 1m or higher speakers, because 1) I'm not using the same speakers and 2) the output stage is still the Technics dual mono (not that it was bad but don't expect them to be identical). It was however closer to, if not better, than some Class A/B push pull pure tube amp.

Note that on headphone amps when I say "the tube pre can help so sure maybe try it" I don't mean add a tube preamp, I mean "get a hybrid amp." Because if you just add a tube preamp to a headphone amp that already has its own preamp (which is 99.9% of headphone amps) using them in series can up the voltage too much and as a consequence, any noise generated by the first (ie the tube pre).

Thank you for this! What about tube pre into regular amp? And why hybrid pre instead of tube pre?(eg was looking at schiit lyr)

 

[ProtegeManiac]

What about tube pre into regular amp?

You mean a tube preamp feeding a headphone amp? I covered that briefly...that puts two preamps in the chain which can be problematic.

To elaborate, you'll then end up with two active preamps upping the voltage. All active preamps will add noise. Keeping the first preamp (the tube preamp) at a lower level may minimize the noise upstream, but then that might also minimize the tube effect you're looking for, making it all useless for what you want to achieve. If you minimize the setting on the second preamp, it's still upping the voltage on a prior signal, so any noise is going to get preamped, making for a louder noise making it to and getting amplified by the output stage.

At the same time even if you get around noise (since it's entirely possible that cars with a preamp on the receiver/processor and gain control on the amps do not actually have audible noise, as opposed to the noise not being audible because you have air on the spinning tyres and the body plus the engine) additional voltage does not actually help. Just having a preamp that can apply a truckload of voltage to a signal doesn't just infinitely make it louder because the amp's power might not be able to translate the high voltage signal into a proportionally high dB output sound. Going back to a car's system, they're actually tuned not just for avoiding noise, but also clipping and distortion. Two preamps in a chain doesn't work like fictional weapons where a Gundam like the ZGMF-X19A Strike Freedom can put two beam rifles in series and shoot a beam that can bust all the way through a warship and also damage whatever is behind it.

That said, there is kind of a way to do this, but it's gonna be a custom job: one of the preamps has to be a passive preamp. The usual way this is used is for the passive preamp to serve as a switcher. Since it's passive and only attenuates the signal, it won't up the signal voltage and add noise. The problem is since this is normally used as a switcher then this is a separate box, meaning any headphone amp you use with it will still have its own preamp and you're not even at getting a tube pre in there so why not just get a hybrid headphone amp ie a tube preamp mated to a SS amp stage. Or just get a full tube headphone amp.

And why hybrid pre instead of tube pre?(eg was looking at schiit lyr)

I wasn't talking about a hybrid preamp; I'm not aware of such a thing, other than Schiit preamps (that can work as a tube preamp, or has an alternate route for the signal to run through opamps so it works as an SS preamp, or unplug it and flick the switch and now it's a passive preamp). I'm talking about a hybrid headphone amp, like the Lyr.

Are you considering all these from a speaker audio perspective? Because headphone amps are more analogous to integrated amps for speaker audio, ie, the preamp and amplifier stages are in the same box. It isn't like the usual preamp unit in a speaker system with a separate amplifier because most of these have just a driver chip and some signal caps on a board just behind the headphone socket. It's nothing like a real headphone amp where you have a power supply circuit that has a transformer and fat (for what it's for) power caps servicing a circuit with discrete or tube components that take a line signal, run it through its own preamp that can boost to a much stronger signal, and then spit out power that's either around 15V or 2000mW (2watts) per channel (depending on what the manufacturer uses to rate the amp, but the latter is more common now) if not more (like...60V peak to peak on Violectric amps, and 6watts on the Lyr/9watts on the Lyr2/16 watts on the Lyr3) that obviously isn't just a chip with caps taking a tiny amount of power. heck not even integrated amps all run like headphone amps, some just have that tiny board that isn't even converting power from the amp output stage.

 

[DuncanDirkDick]

Depends on what you're after. If you want distortion, a buffer is the way to go, because it won't mess with output impedance. If you're going for elevated bass and rolled-off treble plus distortion, something OTL will suit your needs better. That's primarily for dynamic driver headphones.