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Tortuga TPB.V1 Tube Preamp Buffer Review

testp

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No, I am not going to recommend the Tortuga TPB.V1 Balanced Tube Preamp Buffer.

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But...but.... These are Tubeesss!
 

Bruce Morgen

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Aren't tube enthusiasts just old peeps trying to recreate that 80s sound?

Tubes were already passe in the 1980s. The last time they were performance-competitive with decent solid-state equivalents was in the mid-1970s.
 

Robin L

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Tubes were already passe in the 1980s. The last time they were performance-competitive with decent solid-state equivalents was in the mid-1970s.
Tube gear experienced the start of their resurgence in the 1980s as the CD first appeared. For reasons already mentioned, the extended high frequency response of digital playback sounded harsh on most systems tweaked for LPs. So the reappearance of tubes, from manufactures such as McIntosh, Conrad Johnson and Audio Research began. However, 1980s "sound" for pop music production leaned hard into intense treble. Lots of synths, drum machines and sequencers in the early 1980s, resulting in lots of treble heavy productions, esp. for dance/pop and "new wave":

 

sarumbear

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My recorder is all vacuum tube so it adds back some even order distortion along with the saturation effects.
I wonder if that "even order distortion" is real or mythical. As we have seen in this review it is the latter...
 

MakeMineVinyl

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I wonder if that "even order distortion" is real or mythical. As we have seen in this review it is the latter...
To be honest, when a make a copy of a digital file to this recorder the sound is a bit more 'grainy' and a tiny bit less focused. The digital original file is cleaner. The difference is not by any means night and day, and 99.999% of people wouldn't notice it at all unless observation bias came into play.

Now if this is the type of 'good distortion' which attracts audiophiles, I can't say. If I had a choice to do an important recording either on the Ampex or to digital, I'd take digital any day.

However, as you can see from the picture of this tape machine, it looks totally, completely and utterly cool. A digital box, not so much. :p
 

Robin L

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I've done that a couple times too. My recorder is all vacuum tube so it adds back some even order distortion along with the saturation effects.

View attachment 140702
Ampex 354.jpg


What's the model #?
[Look at file info, sez 354, so it looks like a # selected between 300 & 400]
 

MakeMineVinyl

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What's the model #?
Its a later production Ampex 354. It was their last vacuum tube machine (the MR-70 came a bit later and used Nuvistors). It was in unusually good shape when I purchased it from its only original owner, and then I spent a lot of time refurbishing everything, even having the stainless steel front panels re-grained at a machine shop.
 

sarumbear

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My comment was on your "even order distortion" comment. We have seen in this review that the predominant distortion is odd order. Naturally, we cannot generalise with this unit on test, however, we also do not have any objective proof that the distortion that everyone talks about is indeed even order.

That was my point.
 

RichB

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The tube "warm" sound has got to be the ultimate example of "expectation bias".... They certainly do an excellent job of heating up a room though.

Why not just power the tubes and take them out of the circuit?
Or better, yet use DSPs to get the sound of choice, at least you know what it is doing.

- Rich
 

don'ttrustauthority

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There seems to be a market for people who think these add to the sound of their system, but don't want to go through the trouble of at least getting a properly designed tube amplifer. What I don't get is the high price; presumably part of the rationale is that one box of two tubes is cheaper than a tube system for that tube sound? I don't find that adding tube distortion for the sake of distortion is very satisfying for very long.
 

617

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What I don't get is the lack of control. For less money you could buy two highly controllable distortion devices (maybe configure them differently to get the channel imbalance you like).

Even at the silly-expensive, boutique end of the market, e.g. Origin Effects RevivalDrive with 15 control knobs per channel to allow you to shape the sound, the total cost would be less than this thing.

View attachment 140684
Part of me felt that the price was reasonable but then I remembered that the most complex tube driven guitar pedals with twenty knobs cost way less.

Ironically in the guitar space, vst based amp emulation is finally becoming popular. For the price of this unit you can buy this:
Screenshot_20210712-174451.png

A 600W amp head which can listen to your signal chain and emulate it, has space for 200 downloadable emulations, a million bands of eq, tons of hardware controls, and accurately emulates the dynamics and sag that guitar players love tube amps for.
 

MakeMineVinyl

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My comment was on your "even order distortion" comment. We have seen in this review that the predominant distortion is odd order. Naturally, we cannot generalise with this unit on test, however, we also do not have any objective proof that the distortion that everyone talks about is indeed even order.

That was my point.
Even order distortion is consonant with musical pitch - it is simply x2, x4 etc of the original frequencies present in music. In high enough quantities, it will simply add 'brilliance' to the sound since its only adding higher octave intervals to the music. Odd order distortion has a much more complex relationship to the original music. The 3rd harmonic is an octave and a 5th above the fundamental pitch. The complexity of odd order distortion against the original frequencies of the music gets dramatically higher the higher order odd order distortion you go. It takes a lot less of it to start to sound objectionable.

Some people like these added harmonics. I hear them as simply distortion since I've been hearing distortion for decades. There's nothing here which demands 'proof'. How we hear these added harmonics is entirely a subjective thing with each listener.
 

tomchr

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The beat frequencies of 940 Hz and 1060 Hz are IMD products of the 1 kHz test signal and the mains hum induced by the tube heaters. That's very common in tube amps with AC heaters and/or high ripple voltage on the B+.

Tom
 

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Maxicut

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Not in my experience. The bad was the transport, and the willingness of these transports to eat the tiny tapes. If the transport needed repair, all you could do was replace the transport. That cost as much as the DAT recorder all by itself. The next bad thing was the built-in ADCs. But I got good sonic results using an outboard ADC, mid-nineties. Modern hand-held recorders with storage on a tiny chip makes so much more sense.
Well I don't know what early digital recorders you used back then, because all the ones I used were fully-bricked...
 

MakeMineVinyl

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tomchr

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But is it audibly distinguishable in a blind test?
Even the ultimate tube nut, George Anderson of Tubelab, finds the 60 Hz IMD products objectionable in his subjective tests. So, yeah... It's audible. Have a look at his reasoning for using DC heaters in the Tubelab SE: http://tubelab.com/designs/tubelab-se/theory/ It's in the section about the output stage.

There's plenty of research on the audibility of harmonic distortion. Belcher did a bunch of such research for the BBC in the 1970s. The levels measured here would certainly be audible.

Tom
 

Maxicut

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Tube gear experienced the start of their resurgence in the 1980s as the CD first appeared. For reasons already mentioned, the extended high frequency response of digital playback sounded harsh on most systems tweaked for LPs. So the reappearance of tubes, from manufactures such as McIntosh, Conrad Johnson and Audio Research began. However, 1980s "sound" for pop music production leaned hard into intense treble. Lots of synths, drum machines and sequencers in the early 1980s, resulting in lots of treble heavy productions, esp. for dance/pop and "new wave":

I think you are pretending to be someone you are not, as that is not correct. 100% of All early digital recordings had to be run through either a tube stage &/or transferred to analogue tape... because early converters & filters back then were just plain horrid, which has nothing to do with the higher resolution of digital.
 
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