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Tortuga TPB.V1 Tube Preamp Buffer Review

dougi

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This does seem overpriced for what it is. If you want a linear tube buffer the iFi iTube isn't bad. I measured the first version in this thread.

If you want tube sound at a better price, I also measured the LittleDot D300 pre in this thread.
 

ywhy

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To the owner of the buffer: have you noticed differences in sound - for better or worse - when the buffer is plugged into your system?
Amir, have you tried the buffer in your system?
 

MakeMineVinyl

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I have a question; why would anybody need a buffer, whether tube or transistor? I can see their use in distribution boxes where one input is routed to multiple outputs and each of those outputs must be isolated from the others or to transform a high impedance to a low one, but surely no consumer HiFi gear needs that. Is there some need in HiFi which I'm not aware of?

This is an honest question - and I'm not looking for answers like the box which is the subject of this thread which just adds distortion. :facepalm:
 

Robin L

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I have a question; why would anybody need a buffer, whether tube or transistor? I can see their use in distribution boxes where one input is routed to multiple outputs and each of those outputs must be isolated from the others or to transform a high impedance to a low one, but surely no consumer HiFi gear needs that. Is there some need in HiFi which I'm not aware of?

This is an honest question - and I'm not looking for answers like the box which is the subject of this thread. :facepalm:
My Ampex MX-10 needed a cathode follower if one wanted to hook it up to solid state gear. However, that 60 year old piece of gear was not consumer audio and was intended to attach to an Ampex tape recorder, so there might have been a different sort of impedance matching going on with that microphone preamp and that recorder.
 
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MakeMineVinyl

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My Ampex MX-10 needed a cathode follower if one wanted to hook it up to solid state gear. However, that 60 year old piece of gear was not consumer audio and was intended to attach to an Ampex tape recorder, so there might have been a different sort of impedance matching going on with that microphone preamp an that recorder.
I'm familiar with the MX-10. I hope you still have it because they're going for crazy-high prices on the interwebs, because, tubes. I'm surprised it needed impedance transformation though since the point of a cathode follower is to give it a lower source impedance, but still, it wouldn't be happy with a too-low input impedance. Ampex made balanced input transformers for their recorders which wouldn't load upstream gear with higher output impedances, and the typical input impedance of the tube machines was around 100k unbalanced.
 

MakeMineVinyl

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dougi

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I have a question; why would anybody need a buffer, whether tube or transistor? I can see their use in distribution boxes where one input is routed to multiple outputs and each of those outputs must be isolated from the others or to transform a high impedance to a low one, but surely no consumer HiFi gear needs that. Is there some need in HiFi which I'm not aware of?

This is an honest question - and I'm not looking for answers like the box which is the subject of this thread which just adds distortion. :facepalm:
I was looking at a buffer between my AVR pre-outs and amp. Amp input impedence only 10k ohm and this loads the pre-outs a bit causing measurable distortion at high levels. Using a buffer definitely (ie measured) reduced it but at practical volume levels the slightly added noise was more an issue than the slightly reduced distortion.
 

Robin L

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I'm familiar with the MX-10. I hope you still have it because they're going for crazy-high prices on the interwebs, because, tubes. I'm surprised it needed impedance transformation though since the point of a cathode follower is to give it a lower source impedance, but still, it wouldn't be happy with a too-low input impedance. Ampex made balanced input transformers for their recorders which wouldn't load upstream gear with higher output impedances, and the typical input impedance of the tube machines was around 100k unbalanced.
Nope. I had lots of different bits of tube gear. I think it's safe to say that's all behind me now.
 

levimax

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This is an honest question - and I'm not looking for answers like the box which is the subject of this thread which just adds distortion. :facepalm:

I had a Dynaco PAS 3 driving a Haffler DH-500... the problem with the PAS 3 is it needs at least 300 K input impedance to work right and the Haffler was more like 20 K Ohm so I needed to use a "buffer". I just built a simple buffer with op-amps and a 9 volt battery and it worked well.
 

Robin L

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I had a Dynaco PAS 3 driving a Haffler DH-500... the problem with the PAS 3 is it needs at least 300 K input impedance to work right and the Haffler was more like 20 K Ohm so I needed to use a "buffer". I just built a simple buffer with op-amps and a 9 volt battery and it worked well.
I remember the tape loop of my Scott 299B always cut bass when hooked up to a handheld digital recorder. Again, a 50 y. o. design, not intended to work into the 21st century.
 

jsrtheta

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You are, of course, correct and I was out in space... I'll blame it on hypocaffeination ;)
I guess a 6922 can do less harm as a buffer than they do in, say, a phono preamp/EQ :rolleyes:

Made Musical Fidelity some bucks in the X10-D. They shifted a lot of those.
 

solderdude

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I have a question; why would anybody need a buffer, whether tube or transistor?

The reason is that the Tortuga LDR-3 has a relatively high output R (LDR attenator with no active parts in the audio path) and he wanted a buffer in there that added a LOT of tube 'goodness', had a high input R and low output R.
He also wanted to add some gain if needed.
Then it appears he wanted balanced as well.
The downside is that the glorious 2nd harm. are converted in 3rd harm when you do this so that's why the result isn't particularly 'tubey' and has higher odd than even dist. Only the sloping spectrum of the added distortion and the glowing tubes remind of tubes.

It also isn't a cathode follower but a regular amplifier where he probably just changes some resistors. That's also why the distortion is unusually high.

As the buffer is intended to be used behind a volume control chances are distortion is way less when used that way in practice as the input voltage may not be 4V (balanced) but maybe 100mV.[/QUOTE]
 

jsrtheta

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When I first got into audio seriously in the '90s, I went through a couple of tube phases. I bought an Audible Illusions Modulus 3A, then two different Audio Innovations tube pres, ending with a Rogue system, tube pre & power. Then I calmed down.

In the past few years I've owned three cheapo tube buffers, one of the FX Tube 01, and I forget the other two model numbers. All cheapo. Oh, and I had a Little Dot for a while that I wish I'd never sold.

But I think the point here is being missed. You don't buy one of these buffers to obtain accuracy, and certainly not for high fidelity. They are toys. And why do you buy a toy? To play. We grow up and take ourselves so seriously, approaching audio with the gravity of a military campaign. And we forget what Kevin Ayers called the Joy of a Toy.

I don't slap a buffer into my rig expecting audio reproduction perfection. I slap it in there knowing it will, for a while, make me smile. It's nifty. It's a toy. After a while I pull it out of the rig and go back to listening to more accurate, clean, solid state sound.

But remember being a kid and playing, dive bombing Godzilla with jet fighters? None of it was real, and we knew it when we played, but we were having a blast.

The problem I see with the Tortuga is it is much too costly a component for simple play. It's more money than necessary for something that gets, at best, occasional use. And who buys a tube buffer that's balanced? Kind of overkill and, apparently, self-defeating. If your 12-year-old asks for some Hot Wheels, you don't get him a Ferrari. You get him a toy.

It is therapeutic to not take ourselves so seriously. And it is quite therapeutic to spend some time just playing. Relax, and if you like, drop $30-$50 on a toy. That's all it is. Enjoy!
 

Francis Vaughan

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This post is very telling of the design ... uh ... philosophy? ... yeah! ... philosophy! behind the buffer.
That is interesting. There are a couple of snippets of the PCB on the manufacturer's web site, and I was trying to reverse the circuit, and I gave up thinking "this can't be right, there must be stuff I can't see". But no, it really is that simplistic. But yes, the philosophy is curious at best. Given the effort and cost that has gone into the rest of the design, one wonders why such an approach was taken. As a device to create the usual tube bloom, this isn't how I would have gone about it.
 

magicscreen

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To the owner of the buffer: have you noticed differences in sound - for better or worse - when the buffer is plugged into your system?
Amir, have you tried the buffer in your system?
In a proper double blind test he would not.
 

tomchr

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Given the effort and cost that has gone into the rest of the design, one wonders why such an approach was taken.
That was my reaction exactly. With the two transformers in there you could easily have made one of them provide, say, 200 V B+. Then use a CCS load and you get a very linear cathode follower. You could get fancy and choose something like a White cathode follower or SRPP stage.

You could also have used a pair of small SMPSes to provide 48 V each. Hook a few in series and you get 150-200 V without too much fuss.

Obviously effort was put into this. It seems like an opportunity wasted. #whatever... :)

Tom
 
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