Tube preamp recommandations

[Zblarg]

Hi,
I hope this thread is posted into the right category. If not, please accept my apologies.

I'm looking for a replacement of my tube preamp FX Audio Tube-03 which has served me well over years but has some flaws (only one output, no remote, too light so the cables make it move).
I've thought you guys would have good advices for not-so-expensive tube preamps which have good measurements. I really would like to have two outputs, by the way, because I'm feeding several amplifiers and systems with a single preamp. I'm quite fond to the "tube bloom" or "syrupy sound" of tubes, which is probably distortion or third harmonics so it's certainly a flaw from some point of view, but I like this. I don't need a headphone output, I have headphone amps.

By the way, I have another bonus question which is not related to tube preamps: I use a toslink (optical) cable to connect my source (a PC) to my dac. Would I get some audible difference if I bought an interface to connect my PC to the dac using usb or aes/ebu or spdif or, well, any other more modern kind of digital connexion? I know toslink is quite old and limited but if you don't look at the numbers, is there an audible difference with the others? I can't make the comparison by myself and I think if I can have a reliable answer somewhere, it's here.

Thanks in advance for the help and comments.

 

[DVDdoug]

I'm quite fond to the "tube bloom" or "syrupy sound" of tubes, which is probably distortion or third harmonics so it's certainly a flaw from some point of view, but I like this

That's a problem... IF a tube amp has a tube sound it's going to sound different from any other tube or solid state amp and you'll just have to listen for yourself to decide if you like it.

Of course, a good preamp (or power amp) won't have any sound of its own. You are more likely to get "tube characteristics" from a power amp because the transformer makes it harder and more expensive to get low distortion and flat frequency response. But still, a MacIntosh tube power amp is simply going to amplify cleanly.

I really would like to have two outputs, by the way, because I'm feeding several amplifiers and systems with a single preamp.

A pair of Y-splitters will also work.

By the way, I have another bonus question which is not related to tube preamps: I use a toslink (optical) cable to connect my source (a PC) to my dac. Would I get some audible difference if I bought an interface to connect my PC to the dac using usb or aes/ebu or spdif or, well, any other more modern kind of digital connexion?

No. The digital audio data is the same. Unless you have a ground loop that's causing hum or other noise. (And that's noise getting into the analog electronics.) Since optical has no common ground you can't get a ground loop (from that connection). If you don't have that problem there will be no difference.

These S/SPDIF connections/variations don't support Blu-Ray formats. For those you need HDMI.

USB is "more universal" because the drivers will make any necessary conversions to make the DAC work. But since you can get conversions and it doesn't tell you, it's can be trickier to get "bit perfect" audio.

P.S.
Usually if you want to change or improve the sound, start with tone controls/EQ because it's cheap and often free, especially if your audio source is a computer. Then different speakers (or headphones). Different speakers/headphones always sound different (better or worse). Speakers (or headphones) are by-far the most important component (and enough amplifier power to go as loud as desired). Beyond that you can use room correction EQ and/or acoustic treatment.

 

[whataboutmusic]

This is a rather interesting topic,

Is there a way to add "tube sound" to your playback with EQ? I have tried some plugins but they where never close to a real tube amplifier.

I personally like the idea to have a neutral source, a neutral speaker (headphones) and play around with tube amps for different sound.

I find colored headphones too much for me combined with a neutral source.

 

[somebodyelse]

Is there a way to add "tube sound" to your playback with EQ? I have tried some plugins but they where never close to a real tube amplifier.

That's tricky since there isn't an accepted definition of what "tube sound" really is, and different amps have different levels of different distortions. PKHarmonic will let you enter whatever harmonic profile you want, but that wouldn't cover some of the other distortion mechanisms. One of the modelling effects or amps might do a bit more, but they're usually aimed at guitarists not hifi.

 

[whataboutmusic]

That's tricky since there isn't an accepted definition of what "tube sound" really is, and different amps have different levels of different distortions. PKHarmonic will let you enter whatever harmonic profile you want, but that wouldn't cover some of the other distortion mechanisms. One of the modelling effects or amps might do a bit more, but they're usually aimed at guitarists not hifi.

Thanks for the info I was not aware of that thread.

I have used a plugin called "tube saturator" it worked well with foobar though was consuming a lot of cpu. It did change the sound profile but not for the best...or to be more accurate only the subtle changes sounded pleasant...if you added lots of distortion it was very bad.

Yes I agree it does not come close to the ''tube sound" whatever that is...not to my ears anyway. I have tried 2-3 budget (under 1K) tube amplifiers and I was not disappointed in the end.

 

[somebodyelse]

I have used a plugin called "tube saturator" it worked well with foobar though was consuming a lot of cpu. It did change the sound profile but not for the best...or to be more accurate only the subtle changes sounded pleasant...if you added lots of distortion it was very bad.

This one? It's a modelling plugin for one particular circuit, and the high distortion levels are meant to be like what you'd get from a guitar input stage with the gain turned up and volume down. I doubt anyone would use a hifi preamp with that configuration - they usually aim somewhat lower on the gain, trying to stay more or less linear, so just a bit of distortion which you may not be able to hear.

You may be looking for an effect more like the high output impedance of some tube power amps, changing the frequency response in line with the speaker's changing impedance. If that's the case you should look at changing the EQ not the distortion, as hoping you find a 'good' combination of amp and speaker could get very expensive. Erin did a video on this interaction recently.

 

[whataboutmusic]

This one? It's a modelling plugin for one particular circuit, and the high distortion levels are meant to be like what you'd get from a guitar input stage with the gain turned up and volume down. I doubt anyone would use a hifi preamp with that configuration - they usually aim somewhat lower on the gain, trying to stay more or less linear, so just a bit of distortion which you may not be able to hear.

You may be looking for an effect more like the high output impedance of some tube power amps, changing the frequency response in line with the speaker's changing impedance. If that's the case you should look at changing the EQ not the distortion, as hoping you find a 'good' combination of amp and speaker could get very expensive. Erin did a video on this interaction recently.

Yes that was the one...vst plugin loaded into foobar...it was nice to experiment but never had a good result that could be part of my daily listening.

As for the changing the FR tube amps tend to be a good combination for my hd650's so yes I would say that this is true...at least with those I have tried.

The ndh30's not so much...but it did add a nice spice...not unusable like the plugin....and more pleasant than any changes I have tried on the EQ on my rme dac.

 

[somebodyelse]

As for the changing the FR tube amps tend to be a good combination for my hd650's so yes I would say that this is true...at least with those I have tried.

The HD650 has an impedance peak around 100Hz which will give a boost to FR with a high output impedance headphone amp, or if you put a resistor in series with the headphones. That's about the point the response drops away from target for the HD650, so it could improve things. Most EQ suggestions use a low shelf boost a bit lower though, like the 75Hz one suggested in the review. The lesser boost approaching 20kHz is in the region that depends on individual anatomy and hearing, so could work either way.

 

[whataboutmusic]

The HD650 has an impedance peak around 100Hz which will give a boost to FR with a high output impedance headphone amp, or if you put a resistor in series with the headphones. That's about the point the response drops away from target for the HD650, so it could improve things. Most EQ suggestions use a low shelf boost a bit lower though, like the 75Hz one suggested in the review. The lesser boost approaching 20kHz is in the region that depends on individual anatomy and hearing, so could work either way.

For me the problem with the 650's was always a boost in uper bass that blends into the midrange...and making treble sounding kinda soft and dull...

I have found the perfect replacement in the ndh 30's with almost every plus of the 650's including the lifelike midrange...but not so soft sounding and way more clear.

Today I just got a new toy it is a fosi audio tube amp (GR70) that costs around 230 euros and it can be used also as a pre amp. Its very ''tubey'' sounding and at that price I think its a good starting point for someone who wants to add some tubes in to his system without spending too much.