AudioCircle
Industry Circles => Tortuga Audio => Topic started by: tortugaranger on 18 Jan 2017, 09:40 pm
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Started a new topic for the tube preamp buffer tour. If all goes well I expect to be kicking off the tour sometime in the latter half of February.
This topic is solely for organizing/managing the tour and for participants to post their comments.
For general questions and discussions regarding the tube preamp buffer please use the topic "Hybrid Tube Preamp Buffer"
Ok, here are the tour rules:
1) Tour group limited to 12 participants
2) Each participant promises to play with the buffer for no more than 1 week (7 days) before sending in on. If you have scheduling problems please let me know.
3) When shipping it forward, participant agrees to insure the buffer for loss/damage at $1500 value.
4) You must ship forward using tracking. It can be USPS Priority, FedEx, or UPS.
5) Pack the unit up the way you received it with all the bumpers and plastic bag etc.
6) If the box gets buggered up too badly let me and know and I'll send out a fresh one.
7) The tour order will be according to geographic location such that each leg will be the least distance to minimize shipping cost.
8 ) The preamp must be shipped with the tubes removed and boxed up.
I will set up a group googledocs spreadsheet that all participants can have access to. Once you have access to the tour spreadsheet, please enter all your contact info, address etc. If you are uncomfortable sharing your contact information with the tour group please PM me to work that out.
In no particular order, here's the current lineup as of 1.18.17
1) konut
2) rklein
3) ozarktom
4) tjhub
5) 33na3rd
6) glynnw
7)
8 )
9)
10)
11)
12)
Standby folks in case someone drops out:
1)
2)
3)
4)
5)
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Gabba-Gabba-Hey! Looking forward to it.
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Welcome cappy!
1) konut
2) rklein
3) ozarktom
4) tjhub
5) 33na3rd
6) glynnw
7) cappy
8 )
9)
10)
11)
12)
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I want in. Just purchase two Yaqin SD-CD3's. This has got to be better :thumb:.
Thank you.
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And with wirenut we have 8.
1) konut
2) rklein
3) ozarktom
4) tjhub
5) 33na3rd
6) glynnw
7) cappy
8 ) wirenut
9)
10)
11)
12)
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Awesome :thumb:
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Golfrod is on board so we are at 9.
1) konut
2) rklein
3) ozarktom
4) tjhub
5) 33na3rd
6) glynnw
7) cappy
8 ) wirenut
9) golfrod
10)
11)
12)
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Yay! :thumb:
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Great news! :thumb:
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I would appreciate an opportunity to try it.
Thanks
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RustyJefferson has been added. We are up to 10. Two more to go plus a few backups.
1) konut
2) rklein
3) ozarktom
4) tjhub
5) 33na3rd
6) glynnw
7) cappy
8 ) wirenut
9) golfrod
10) rustyjefferson
11)
12)
Standby folks in case someone drops out:
1)
2)
3)
4)
5)
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please add me to the list :thumb:
lap
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Welcome orientalexpress! Two more to go plus the backups.
1) konut
2) rklein
3) ozarktom
4) tjhub
5) 33na3rd
6) glynnw
7) wirenut
8 ) golfrod
9) rustyjefferson
10) orientalexpress
11)
12)
Standby folks in case someone drops out:
1)
2)
3)
4)
5)
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Welcome dracule1. One more spot left (plus the backups).
To all participants, please PM me your contact info:
* full name
* address
* phone
* email
Rather than put participants' contact info into a shared spreadsheet, I will keep that info private. I will use your addresses to sort the order of the tour to minimize the shipping distances/costs. Once I have that done, I'll publish the tour participant list in the order we'll follow.
1) konut
2) rklein
3) ozarktom
4) tjhub
5) 33na3rd
6) glynnw
7) wirenut
8 ) golfrod
9) rustyjefferson
10) orientalexpress
11) dracule1
12)
Standby folks in case someone drops out:
1)
2)
3)
4)
5)
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Mitch2 rounds out the tour group. All full up!
To all participants, please PM me your contact info:
* full name
* address
* phone
* email
Rather than put participants' contact info into a shared spreadsheet, I will keep that info private. I will use your addresses to sort the order of the tour to minimize the shipping distances/costs. Once I have that done, I'll publish the tour participant list in the order we'll follow.
1) konut
2) rklein
3) ozarktom
4) tjhub
5) 33na3rd
6) glynnw
7) wirenut
8 ) golfrod
9) rustyjefferson
10) orientalexpress
11) dracule1
12) mitch2
Standby folks in case someone drops out:
1) dburna
2)
3)
4)
5)
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Hello Morten,
in the remote possibility that a EU tour is organized, I will be happy to join.
Thanks
-Roberto
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Hello Morten,
in the remote possibility that a EU tour is organized, I will be happy to join.
Thanks
-Roberto
I'd be happy to support a EURO/UK/Scandi tour if there's interest. Roberto (Italy) is in. Anyone else? :thumb:
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Here is the update on the TPB.V1 Tube Buffer TOUR.
First, the bad news. On Friday our CNC laser died hard. Looks like a combination of a toasted power supply and the controller board doesn't look good either. That means we are dead in the water in terms of engraving our front/rear panels. We are also about a week behind getting our panels anodized. The anodizing is just a matter of another week but getting the CNC laser back up and running is going to be a project. We have to rebuild it basically. The model we have is no longer supported plus it was marginal to begin with and a bit undersized for our needs. I've ordered practically a whole new system of components including new power supplies (2, one for the laser and one for the stepper motors & controller) and a new controller. If all goes well we'll be back up and running in a couple of weeks bigger and better than ever. But this CNC outage is going to delay the release of the buffer because we can't produce finished product without the CNC laser. Argh!
Now for the good news. The tour is going to proceed regardless of the CNC issue. To do so we're going to use the ugly prototype unit. Raw aluminum front and rear panels. Enclosure box with a hole in its side. Go ugly or go home. We are clearly not going for style points here so it's all about the sonics. Oh, and while I'm referring to the tour unit as our prototype unit it does have the actual final production boards/parts internally. But it has none of the upgrade options. No upgraded plate voltage super regulator. No Vishay foil reistors. No V-Cap coupling caps. If you end up liking it as it, it can only get better with the upgrades.
I still need name, address, phone and email for the 2 tour participants below. Sent you both a PM as well.
orientalexpress
mitch2
As soon as I have those addresses I'll finalize the tour routing. I plan on shipping out the buffer prototype unit this week.
Forward! :thumb:
Morten
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Here is the tour sequence. Starts off on west coast, then to TX/LA, then up into the midwest states and ends up on the east coast.
Since I've not heard from orientalexpress, he's been moved to the standby list and dburna is now on the tour.
I'll ship the ugly prototype out to golfrod later this week to kick things off.
In terms of shipping, I've found that shipping USPS Priority is the least cost and the fastest. They've been very reliable but please make sure you insure the unit for at least $500 in case of loss. Of course you can opt to use UPS or FedEX instead if you like.
1) golfrod - CA
2) 33na3rd - WA
3) konut - WA
4) dracule1 - TX
5) glynnw - LA
6) ozarktom - MO
7) dburna - IL
8 ) tjhub - WI
9) mitch2 - MI
10) wirenut - OH
11) rklein - OH
12) rustyjefferson - MD
Standby folks in case someone drops out:
1) orientalexpress
2)
3)
4)
5)
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And we're off! The ugly tour unit shipped out today. First stop Los Angeles. :thumb:
Wait, the tour's not ugly.
The buffer is ugly.
Well they aren't all ugly.
Just the tour unit is ugly.
Because it's our prototype enclosure.
With raw aluminum panels.
And has a hole in its side.
Because the laser broke. :duh:
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I would like to add my name to the list for standby.
Shakey
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Hi All - Just a update to the standby list
1) golfrod - CA
2) 33na3rd - WA
3) konut - WA (moved to end of tour due to DAC being unavailable)
4) dracule1 - TX
5) glynnw - LA
6) ozarktom - MO
7) dburna - IL
8 ) tjhub - WI
9) mitch2 - MI
10) wirenut - OH
11) rklein - OH
12) rustyjefferson - MD
13a) konut - WA 13b) slefley - WA
Standby folks in case someone drops out:
1) keven1031
2) skakeydeal
4) JerryM
5)
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I just realized I forgot to mention that the buffer unit out on the tour has its gain set at +3 dB and not at the default 0 dB level.
Gain is set via a cathode resistor that we had guessed would yield 0 dB at 11.5k ohms. After the tour unit went out we did the actual final gain measurements and it turns out 11.5k is perfect for 3 dB. Since the tour unit only has one of three gain resistors installed there's no way to adjust the tour unit gain up or down. Shouldn't be a problem. I ran that tour unit for many hours coupled with an LDR3.V2 passive and I did notice there was more volume headroom so no big surprise.
golfrod will be forwarding the buffer to one other participant in LA (existing customer I shoe-horned in) over the weekend who will give it a vey quick listen before sending it off to 33na3rd next week.
golfrod sent me a very brief note saying "you may be on to something here". More to follow I'm sure. :thumb:
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I'm really looking forward to hear how that 3 dB gain affects the vinyl side of my system!
Thank you Morten!
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I've had the new Tortuga Tube Buffer in the system for three days before handing it off to another local user of the Tortuga preamp yesterday. This will really be more of an impression that the buffer left on me than a real detailed review as I only had it for this limited time. The basic system I used it in had the following pieces: Antipodes DX music server>Sonore USB converter>Chord Qute Dac>Tortuga Tube Buffer>Tortuga Preamp or Wyred4sound STP SE modded Preamp>Wells Innamorta Amp> Audience Clairaudient 4+4 Speakers.
How would you describe the sound of the buffer and it's effect on the system? I think those of you who have experience with both solid state and tube components would understand best. With just one of the two preamps in the system you get a very clear resolved transparent picture with excellent extension top to bottom and very good soundstage in both depth and width. By adding the tube buffer the images get "meatier" with the transients getting slightly softer while retaining very good transparency. This was not a slowing and muddying effect but rather adding a bit of more dimensionality if you will. Another comparison might be a gloss photograph versus a matt finish one. I have a well reviewed Dodd tube buffer which I felt was already quite transparent with a sweet sound. Where I think the Tortuga Tube Buffer has bettered it is the two slight weak points of the Dodd buffer, bass extension and slight smaller scale in soundstage size. With the Tortuga buffer in the chain neither characteristic was reduced in comparison to just the preamps in the system. In fact a friend who came over to listen thought it was more open and layered. One last observation would be that the buffer is very quiet as I could hear no added noise even with your ear at the speaker.
So what would be my final assessment of the buffer? I think it's a success in that with it you will be able to add a "tube flavor" without really compromising the strong points of the Tortuga preamp. I didn't really get to observe the impedance matching properties of the buffer as the system is fairly well matched already.
Thanks Morten for the opportunity to try the buffer, great job!
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Hi Golfrod, I thought the normal position for the tube buffer was after the Tortuga controller, not before it. The input impedance of the buffer is, if I remember correctly, 100k ohms. The Tortuga single ended controller is capable of any input impedance from 1k to 99k, so I don't understand the benefit inserting the tube buffer ahead of the controller.
On the other hand, the output impedance of the Tortuga controller can be fairly high with (again if I remember correctly) values as high as 1600 ohms. The tube buffer specs indicate the output impedance of the tube buffer is around 40 ohms. That low output impedance of the buffer makes a better match for a power amp, especially if it has lowish input impedance.
I could be completely off track, but I'm curious as to where the buffer would normally be used in the component chain.
Best,
Robert
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Hi Robert, I don't believe that there is a "normal position" for a buffer but is rather determined by how you want to use it in your system. Morton has an article on his site ( Is a Preamp Buffer Right for You? ) which talks about various uses for a buffer. I've used several buffers including the well known Burson Buffer. They suggest you try a buffer before and after your preamp. My Wyred4sound SE preamp is buffered on the input and the output..... I only had the buffer for a few days so I mainly wanted to see how the buffer would work as Morten put it in his buffer article as a "sonic coloring agent". I'm very familiar with the sound of the system with the Tortuga preamp right in front of the amp and have no impedance matching problems as the amp has a high enough input impedance. That way I could better assess any changes or effects the buffer had on the sound as that would be the only variable..... I'm sure other participants will use it as you outlined and will report. Thanks, Rod
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Hi Robert, I don't believe that there is a "normal position" for a buffer but is rather determined by how you want to use it in your system. Morton has an article on his site ( Is a Preamp Buffer Right for You? ) which talks about various uses for a buffer. I've used several buffers including the well known Burson Buffer. They suggest you try a buffer before and after your preamp. My Wyred4sound SE preamp is buffered on the input and the output..... I only had the buffer for a few days so I mainly wanted to see how the buffer would work as Morten put it in his buffer article as a "sonic coloring agent". I'm very familiar with the sound of the system with the Tortuga preamp right in front of the amp and have no impedance matching problems as the amp has a high enough input impedance. That way I could better assess any changes or effects the buffer had on the sound as that would be the only variable..... I'm sure other participants will use it as you outlined and will report. Thanks, Rod
Rod makes an interesting point that frankly I hadn't spent much time considering. That point being that where you position the buffer - upstream or downstream of an existing preamp - may not matter provided you aren't dealing with an impedance matching issue. As Robert mentioned in his post below the presumption is you put the buffer downstream of a passive attenuator. The logic being this isolates (i.e. buffers) the source/attenuator/preamp from the downstream amp. On the other hand, notwithstanding that the output impedance of our LDR passive preamp (or any pot-in-a-box for that matter) varies with attenuation setting, as long as the preamp output impedance is low enough relative to the amp's higher input impedance, lowering/fixing the impedance into the amp by inserting a buffer might not buy you anything - impedance-wise. Said differently, when the bridging ratio between source and amp are sufficient, making it bigger yet yields little or no incremental benefit. The tube preamp buffer provides a very muscular output signal and whether that's upstream or downstream of a passive attenuator I suspect that characteristic will be evident either way. Same with the whatever euphonics are imparted by the tube stage of the buffer. I will be interesting to hear feedback from others on this. In fact now I have to go try it myself!! :thumb:
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Hello all. I'm the guy that Morten squeezed into the tour, and sort of split time with golfrod.
I really don't have too much to add to golfrod's comments. Happily, I don't think that any transparency was lost, which I think is one of the Tortugas' biggest strengths. In my system, the soundstage width was about the same, but the image was a bit larger. The tone was richer, without losing dynamics. I think a nice change especially if your system tends to the neutral to slightly thin, detailed side. My system is comprised of a prototype Well Tempered Turntable > Coda 06x phono stage > Tortuga pre > electronic crossover > 2 Music Reference RM-9 >DIY open baffle 15" and AMT. Quite different from golfrod's, but much the same impression it seems.
Thank you Morten for the listen, and off to the next tour participant.
Mas
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Hi Folks, I had the pleasure of listening to the Tortuga Buffer after ponger.
My system consists of three sources.
Michell Gyro Dec SE/Rega RB-600/Grace F9E>Avid Pellar Phono
Pioneer PLX-1000/Paradox Bodied Shure SC35C>Muse Model One Phono
Marantz CD6004>Rega DAC
Preamp is the Tortuga LDR3.V2 feeding either my modified Moscode 300, or Muse Model 100. Speakers are Audio Physic Virgo 2 and KEF R400b subwoofer.
I first tried the Buffer with my Modified Moscode 300. This amp has an usually high input impedance of 274 kilohm, making it an ideal candidate for use with a passive pre. Unfortunately, adding the buffer in front of the Moscode did not provide any meaningful improvement.
Now when I put the Buffer in front of my Muse Model 100 (Zin 50 kilohm), the buffer added dynamics and better bass!
50 kilohm is still pretty high, so I'm hoping we'll hear from some folks who try the Buffer with amps that have a Zin between 10-35 kilohm.
With my Muse in the system The Buffer added a bit of heft to the lower registers that was greatly appreciated on rock/pop tracks. The buffer was largely transparent, rivaling comparably priced preamps, but not as transparent as the LDR3.V2 by itself. I thought the buffer would really help the vinyl side of my system, so I was surprised that it was the digital side of my system sounded so dramatically better with the buffer. My Rega DAC has a Zout of 600 ohms, which is a little high, and the buffer really showed what impedance matching can do. The Buffer did indeed give LP's a firmer foundation, especially the Michell/Avid set up. I liked the tonal balance that the Buffer provided. I did not notice a change in the width or depth of the soundstage in my system.
I enjoyed my time with the Buffer and would like to thank Morten for having me on the tour. It was very educational. I feel like I have a better practical understanding of the relationship between gain, impedance, and current!
Jeff
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Hi Robert, I don't believe that there is a "normal position" for a buffer but is rather determined by how you want to use it in your system. Morton has an article on his site ( Is a Preamp Buffer Right for You? ) which talks about various uses for a buffer. I've used several buffers including the well known Burson Buffer. They suggest you try a buffer before and after your preamp. My Wyred4sound SE preamp is buffered on the input and the output..... I only had the buffer for a few days so I mainly wanted to see how the buffer would work as Morten put it in his buffer article as a "sonic coloring agent". I'm very familiar with the sound of the system with the Tortuga preamp right in front of the amp and have no impedance matching problems as the amp has a high enough input impedance. That way I could better assess any changes or effects the buffer had on the sound as that would be the only variable..... I'm sure other participants will use it as you outlined and will report. Thanks, Rod
I owned the STP-SE for several years. Very good piece of gear. I don't believe it is buffered both on input and output. That wouldn't make sense as only one buffer is needed to do what a buffer is supposed to do (with respect to impedance issues and providing a little bit of a boost in output voltage). Pretty positive the buffer is only on the output as the input stage is purely passive. It's the same setup as Morten's buffered preamp, but with a resistor ladder attenuator and solid state buffer. Sorry. Don't mean to derail. I have a custom built Tortuga based buffered preamp and have been following the thread here and there.
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We are having a brief pause in the tour. I've called the tour buffer back home for a very quick tweak to the output stage cap/resistor which provided noticeably improved sound in our testing. It will take less than 24 hours to make the change and send on its way. :thumb:
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Hi Mr Davidson, While I respect that you owned the Wyred4sound STP I beg to differ as I do believe the preamp is buffered both on the input and output. If you read the literature carefully as well as many of the reviews you'll see that it's even mentioned in the articles. In Srajan's latest review on 6moons of the STP SE stage2 (Jan 2017) you'll see in the first paragraph quote "the STP runs discrete buffers on either side of it's 0.5 dB-stepped attenuator matrix". As far as the reason why this would make sense is the impedance matching on the input and output is just as important on both the amp and preamp. A good buffer will have a high input impedance and a low output impedance which would allow this. I mentioned earlier the well known Burson buffer which I have used with great success and they also suggest you try a buffer in both positions. This is the best explanation I can offer as I'm actually very technically challenged :). Thanks, Rod
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Where we're getting mixed up is in semantics. A buffer consists of an input stage and an output stage. This equals 1 buffer total. The STP-SE doesn't have two buffers. The buffer's input stage and output stage are merely separated (by the attenuator), probably because it is solid state which affords this type of circuit design. Tubes inherently do the impedance conversion / matching (their input stage and output stage are built together in the tube), which is why a tube buffer stage is either entirely before or after the volume control (in a buffered preamp)....but it'd be kinda cool if one could design an "input" tube an "output" tube to make a buffer design like the STP-SE. :thumb:
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Where we're getting mixed up is in semantics. A buffer consists of an input stage and an output stage. This equals 1 buffer total. The STP-SE doesn't have two buffers. The buffer's input stage and output stage are merely separated (by the attenuator), probably because it is solid state which affords this type of circuit design. Tubes inherently do the impedance conversion / matching (their input stage and output stage are built together in the tube), which is why a tube buffer stage is either entirely before or after the volume control (in a buffered preamp)....but it'd be kinda cool if one could design an "input" tube an "output" tube to make a buffer design like the STP-SE. :thumb:
I agree this is partially a semantics issue. The confusion is compounded by the fact that there are buffers and then there are buffers. In circuit design it's very common to put a simple high impedance buffer at the input of say a preamp for isolation. Typical of such a buffer is a simple unity gain op amp as shown below.
(http://www.audiocircle.com/image.php?id=158996)
A consumer reading a manufacturer's product description reads that the buffer product has a buffer on the input and the output. Wow, a buffer with a buffer at both ends. Technically true but the meat & potatoes high performance end of most audio buffer products is the output stage.
In the case of our 2 stage tube buffer you would be correct in describing the tube itself as an input buffer (with optional gain). The output stage is a solid state buffer. Taken as a whole, it's an audio buffer.
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Interesting stuff Morten and thanks for further clarification. What you're doing seems pretty unique. I'm not sure I've seen another buffer that uses a tube as only the input stage....unless most tube buffer's are designed this way? I don't think they are.
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Interesting stuff Morten and thanks for further clarification. What you're doing seems pretty unique. I'm not sure I've seen another buffer that uses a tube as only the input stage....unless most tube buffer's are designed this way? I don't think they are.
This is the conceptual design but like most things the devil's in the details. You can call it a 2-stage hybrid buffer or you can call it a 0 to +6 dB gain preamp without a volume control - both are correct.
(http://www.tortugaaudio.com/images/tube_buffer_simplified_schematic.jpg)
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It's a gyrator concept. I used a similar concept to build my preamp that uses DHTs (I have 16-18db of gain though). Mine was based on the work of Ale of Bartola Valves. I won't discuss more than that here, because here is not the place, but it is the best sounding design I have ever heard and mates very well with a passive attenuator. I am sure the Tortuga version is amazing.
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The tour unit is back on the road after a longer stay in the barn than I'd planned. The changes only took a couple of hours plus some testing to confirm but it was finding the time to get it done.
The tour unit now has the upgraded VCap OIMP output caps. Both the output cap and resistor size was changed to optimize performance. To my ears the buffer now has even more coherent output than before. I also popped in a Belleson SuperRegulator which powers both the tube plate and the output FET. Sounds great on my rigs. Looking forward to everyone's feedback.
If anyone on the tour happens to have a pair of 6CG7 tubes sitting around feel free to substitute them for the 6H30's and let us know what you think. I tried this recently and the buffer is quite happy with 6CG7s.
Enjoy!
Morten
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I volunteer to be the very last AC member on the Tour. 8)
And yes, I have several different pairs of NOS 6CG7s here. :D
Have fun,
Jerry
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While not part of the tour per se we're starting to get feedback from tube buffer customers. Here's one that came in today on a balanced buffer used together with our LDRxB Balanced Passive Preamp.
There is an unmistakable quality of "you are there" in the room or hall with the musicians using this unit. It ups the ante in that regards from the preamp alone which was great to begin with. This makes for the first "active" preamp I've ever had that doesn't color the sound in some way. This is why I went to passives long time ago (ModSquad Linedrive) or later to integrated amps. Mission accomplished is right - in spades. (Randy Brown)
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Just shipped the buffer off to next person. Having used only a passive preamp for several years, I realize I was wrong in thinking any electronics at this stage would hurt the sound. I really liked the sound from this piece. I am not a good reviewer. I really don't listen for any particular aspects of the sound. In this case, it just all sounds noticeably better. Every thing sounds fuller - more fleshed out if you will. After almost 50 years in this hobby, I have reached the point that all I care about is if it makes me happy. This buffer does that in spades.
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Slow moving tour.
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Slow moving tour.
I sent the buffer back to the barn for some upgrades and then shipped it out again. That ate up a couple of weeks.
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Hi All,
Here's an update on the tour. We started off moving along nicely and then I called the buffer back for an upgrade which ate up a couple of weeks. Now it's bogged down with a couple of participants taking a couple of weeks each. Ozarktom promised to ship it onwards yesterday (4.21.17) but have no confirmation that happened.
dburna you are up next.
Also, finally had an opportunity to build a buffer unit using the optional Vishay metal-foil resistors in the signal path. To my ears it raised the bar just that much higher with a sweeter clarity. Pricey little buggers and frankly I had my doubts but the first few notes of music really got my attention.
1) golfrod - CA
2) 33na3rd - WA
3) konut - WA (moved to end of tour due to DAC being unavailable)
4) dracule1 - TX
5) glynnw - LA
6) ozarktom - MO
7) dburna - IL
8 ) tjhub - WI
9) mitch2 - MI
10) wirenut - OH
11) rklein - OH
12) rustyjefferson - MD
13a) konut - WA
13b) slefley - WA
Standby folks in case someone drops out:
1) keven1031
2) skakeydeal
4) JerryM
5)
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The buffer is now with dburna in IL for the next few days.
tjhub in WI you are next!
1) golfrod - CA
2) 33na3rd - WA
3) konut - WA (moved to end of tour due to DAC being unavailable)
4) dracule1 - TX
5) glynnw - LA
6) ozarktom - MO
7) dburna - IL
8 ) tjhub - WI
9) mitch2 - MI
10) wirenut - OH
11) rklein - OH
12) rustyjefferson - MD
13a) konut - WA
13b) slefley - WA
Standby folks in case someone drops out:
1) keven1031
2) skakeydeal
4) JerryM
5)
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I was the most recent person to have the Tube Buffer in my system. Just shipped it off to the next AC member today. I was also fortunate to have the ifi ITube2 in my system for a short while for a head-to-head comparison. It wasn't close -- the Tortuga has it all over the iFi....which it really should at 5x the price.
I'm not going to rehash what has been said already except to mention that I agree with it a great deal. I have a SS system that is very dialed in to provide a high degree of neutrality/accuracy, but it is not cold or sterile in any way. The Tortuga Tube Buffer provided just a bit more liquidity and image depth to the sound but without much/any sacrifice in detail. If anything, at times I felt it might have been less distorted than my SS system, but I think that was largely because I was enjoying the midrange so much.
Over time, I feel like maybe -- maybe -- there was a slight softening of transients at both the low and high end. However, it was a small price to pay in terms of overall musical involvement and presentation. The engineering behind this is top-notch. The use of the 6H30 "supertube" provides a dark background and a very clean presentation, even on my 96dB speakers.
Morten, you have (another) winner on your hands. I very much appreciated my brief time with the Tortuga and I'm pretty sure it will make the next AC listener a pretty happy camper.
Best regards, -dB
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I have been reluctant to post my impressions of the buffer because I only had it for 2 days before I sent it back to Morten and wanted to get my Bryston DAC back before I posted a full review. dburnas' review prompted me to change my mind. I too had the iFi tube buffer in for review. Both units added a substantial fullness to the presentation that I ascribe to the buffering. What the Tortuga added was quite extraordinary. My system, without a buffer, was like listening from the 50th row. The iFi moved me to the 5th row. The Tortuga moved me to the 1st row. Each instrument took on a 3D quality whereas I could hear micro-dynamics and intimacy I had never experienced before. dburna called it "image depth". I fully agree. I look forward to getting the unit back to reconfirm this experience.
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The buffer is now with tjhub in WI for the next few days.
mitch2 your are next!
1) golfrod - CA
2) 33na3rd - WA
3) konut - WA (moved to end of tour due to DAC being unavailable)
4) dracule1 - TX
5) glynnw - LA
6) ozarktom - MO
7) dburna - IL
8 ) tjhub - WI
9) mitch2 - MI
10) wirenut - OH
11) rklein - OH
12) rustyjefferson - MD
13a) konut - WA
13b) slefley - WA
Standby folks in case someone drops out:
1) keven1031
2) skakeydeal
4) JerryM
5)
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I have enjoyed my short time with the Tortuga Audio Tube Preamp Buffer.
It arrived on Wednesday without any issues and I appreciated the solid, no-nonsense design.
Unfortunately, when I saw it was single-ended only, I knew I was going to have trouble integrating it and making the most of my audition since I run all balanced connections and my amps only accept balanced inputs.
My system consists of;
Antipodes DX Level 3
Metrum Pavane DAC Level 3 (Adagio without the volume control)
SMc Audio buffered unity-gain line stage with AN Tantalum resistors (essentially the VRE-1)
Clayton M300 Class A monoblocks
Aerial 9 speakers
Aerial SW12 subwoofers (2 each)
Although I have been interested in Tortuga Audio’s LDR passive preamps, I do not own one. In addition to my main preamplifier listed above, I have a Goldpoint balanced passive preamplifier, using their latest SMD resistors and also a pair of balanced Endler Attenuators using Yageo metal film resistors. I mainly used the Tube Preamp Buffer with the Goldpoint passive preamp.
I worked around the connection issue by first connecting the Tube Preamp Buffer inputs directly to the single-ended outputs of the Metrum DAC and then sending the buffer outputs to the inputs of a pair of Jensen transformers that convert single-ended signals to balanced signals. There is an impedance penalty associated with the conversion but since the input impedance of my Clayton amps is 100K ohms, using the transformers typically works just fine, and much better than rca/xlr adaptors. The balanced outputs from the transformers were sent to the Goldpoint passive preamp and the balanced outputs from the Goldpoint were sent to the amps, so the attenuation occurred after the buffer. All the ICs used were 1M or less in length but the set-up was still more complicated than I had hoped.
The good news is that there didn’t seem to be any penalty for the complications. The Tube Preamp Buffer sounded great. As others have pointed out, the buffer is absolutely quiet, and surprisingly so since it uses two tubes. I heard a clean, clear sound, with nice body, nice tone, and realistic dimensionality. If there were any trade-offs, I thought I noticed a slight softening of the bass, leaning toward roundness and fullness instead of detail. These effects were not to an extent that detracted from the overall enjoyment of listening to the buffer, which always sounded musical. Without trying a more direct set-up using the balanced version of the buffer, I will never know what impact the extra cables and transformers had on the sound.
To verify what I was hearing, I took the Tube Preamp Buffer out of the signal chain so the only thing between the DAC and the amps was the Goldpoint passive preamp. The sound became a touch more dynamic and detailed but also a bit harder, sharper, and overall a little less musical. In my experience, the clarity of a passive preamp is initially attractive but over time I typically begin to notice a slightly flatter image, less body and tonal color, and maybe a bit less dynamic impact, so I have always gone back to whatever good linestage I had in my system at the time. The effect seemed a little less pronounced when I had an autoformer unit in my system (the Acoustic Imagery Jay-Sho) but I still liked the sound of my SMc preamp better. I believe that using an active stage or buffer (which is basically a unity gain active stage) improves impedance matching and optimizes signal delivery to the amplifier.
In a comparison between the Goldpoint/ Tube Preamp Buffer combination and my SMc unity-gain buffered preamp, I preferred the SMc unit and believe it displayed a bit better clarity, definition, dynamics, and tone without giving up dimensionality and fullness, and without displaying any hardness or sharpness. I have owned close to 30 really good preamps over the past 10 to 15 years and the SMc Audio preamp is the best of the bunch, so for the Goldpoint/ Tube Preamp Buffer combination to be anywhere close sonically is quite an accomplishment IMO.
In summary, I found the Tortuga Audio Tube Preamp Buffer to be well-built, quiet and to do exactly what it was meant to do, which is to optimize the signal between a passive attenuator or preamp and the amplifier that is being driven. When used in the signal chain with my Goldpoint passive preamp, it improved the flavor of the Goldpoint by providing a richer sounding tone and adding fullness and a touch of roundness that made listening to music more enjoyable. While these differences were not like night and day, they were noticeable to the point where I believe I would be satisfied long-term with the sound of the Goldpoint preamplifier/ Tube Preamp Buffer combination, but not with the Goldpoint alone. However, the Goldpoint/ Tube Preamp Buffer combination was not good enough to displace my SMc preamp.
I believe the Tortuga Audio Tube Preamp Buffer is a really good product that may be almost essential for people using passive preamps or attenuators alone. At a minimum, folks using passives should at least try the tube buffer. I would like to try the balanced version someday. IMO, Tortuga Audio could turn a triple into a home run by combining the Tube Preamp Buffer with their LDR passive preamp for a unity-gain, buffered, one-box preamp solution. Offer balanced and single-ended options with a volume display and remote and the result would be likely to compete with some really good preamps.
Thank you for the opportunity to audition the Tube Preamp Buffer. I plan to ship it out to wirenut on Monday.
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mitch2 thank you for your thoughtful review.
The buffer is sooon on its way to wirenut in Ohio this week.
1) golfrod - CA
2) 33na3rd - WA
3) konut - WA (moved to end of tour due to DAC being unavailable)
4) dracule1 - TX
5) glynnw - LA
6) ozarktom - MO
7) dburna - IL
8 ) tjhub - WI
9) mitch2 - MI
10) wirenut - OH
11) rklein - OH
12) rustyjefferson - MD
13a) konut - WA
13b) slefley - WA
Standby folks in case someone drops out:
1) keven1031
2) skakeydeal
4) JerryM
5)
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mitch2 thank you for your thoughtful review.
The buffer is sooon on its way to wirenut in Ohio this week.
1) golfrod - CA
2) 33na3rd - WA
3) konut - WA (moved to end of tour due to DAC being unavailable)
4) dracule1 - TX
5) glynnw - LA
6) ozarktom - MO
7) dburna - IL
8 ) tjhub - WI
9) mitch2 - MI
10) wirenut - OH
11) rklein - OH
12) rustyjefferson - MD
13a) konut - WA
13b) slefley - WA
Standby folks in case someone drops out:
1) keven1031
2) skakeydeal
4) JerryM
5)
I'm ready :thumb:
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The buffer arrived safe and sound today :thumb:. I like the build quality, Solid and Heavy.
I will be swapping it out with my 2 Yaqin CD3 tube buffers that use 6SN7 tubes.
I use one buffer after my phono stage, and a second buffer after my Dac.
The rest of my system is solid state, bi-amped.
I've already hooked it up to my phono stage and listened to 1 Robert Plant tune.
Glorious :o, much better then the Yaqin's right off the bat. Even with nice tubes in the Yaqin.
More about that later in a review. I'm off for some listening time.
Steve.
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The buffer arrived safe and sound today :thumb: . I like the build quality, Solid and Heavy.
I will be swapping it out with my 2 Yaqin CD3 tube buffers that use 6SN7 tubes.
I use one buffer after my phono stage, and a second buffer after my Dac.
The rest of my system is solid state, bi-amped.
I've already hooked it up to my phono stage and listened to 1 Robert Plant tune.
Glorious :o , much better then the Yaqin's right off the bat. Even with nice tubes in the Yaqin.
More about that later in a review. I'm off for some listening time.
Steve.
I've tried 6CG7 tubes (9 pin equivalent to 6SN7 octals) in the buffer and can confirm that they worked with no noticeable issues. Their gain was probably different but not so you'd notice right off compared to the 6H30's.
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A couple years ago the need for a new furnace forced the sale of my audio research / sonic frontiers tube gear and since then I’ve put together
a less expensive vintage SS system with the addition of 2 Yaqin CD3 tube buffers. Using tube buffers has added to the enjoyment and I’ll be keeping
my setup this way for a long time.
As mentioned earlier I use one Yaqin tube buffer after my Vista phono-2 and a second after my DAC.
A lot of time rolling 6SN7 tube’s in the Yaqin’s I've found some pretty good ones.
Installing the Tortuga tube buffer in place of the Yaqin after my phono stage was an eye opener.
Sound stage, channel balance, instrument definition, treble and mid range now have more energy and detail.
At first, I thought the added treble and midrange definition was a bit much but after more listening I came to enjoy it.
A couple of questions / thought’s I’d like to ask Morten.
First, as can be seen in my setup it’s easy to turn on the rear power switch but in a different setup a switch located on the front would be better.
Second, and this is probably not possible, since I have so many 6SN7 tubes is it possible to use them with an adapter in the Tortuga?
When the time comes to replace my above buffer’s I’ll be thinking “Tortuga”.
I really like the Tortuga tube buffer and would like to thank Morten for this opportunity.
I’ll be shipping the buffer off to rklein next Wednesday the 24th.
Enjoy and thank you,
Steve
(http://www.audiocircle.com/image.php?id=162580)
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Hi Steve,
Thank you for participating in the tour and for taking the time to post your thoughts. :D
Regarding your two questions:
1) No Switch On Front Panel - I agree this would be convenient. The reason there isn't one entirely a practical matter of there being no room for one within the constraints of our standard extruded enclosure. We packed quite a bit of hardware into that little black box. On the other hand, we did provide an indirect work-around to this limitation. While not present/functional in the prototype version out on tour, the final version of the tube bufffer has a 12V Trigger input jack in the rear which when plugged into the 12V Trigger output of any of our LDR passive preamps makes the turn on/off of the tube buffer fully automatic. When initially turned on via the 12V Trigger input, the front panel light will blink for approximately 10 seconds during which time the output remains muted and the tube heaters warm up. At around 8 seconds, the plate voltage is turned on and at 10 seconds the muting is turned off. This ensures no speaker "bumps" or sonic artifacts while the tubes power up. Similarly, when turned off the buffer output immediately mutes.
2) 9 pin to octal tube adapter - While the tube buffer can accept alternative tubes like a 6CG7 (9 pin equivalent to the octal 6SN7), using an a 6SN7 directly would require a 9 pin to octal adapter that also fits into the 1" diameter tube hole in the enclosure. While there are numerous examples of octal-to-9-pin adapters to be found, there are very few 9-pin-to-octals adapters available. There may well be one out there but a quick search suggests otherwise.
Cheers, :thumb:
Morten
A couple years ago the need for a new furnace forced the sale of my audio research / sonic frontiers tube gear and since then I’ve put together
a less expensive vintage SS system with the addition of 2 Yaqin CD3 tube buffers. Using tube buffers has added to the enjoyment and I’ll be keeping
my setup this way for a long time.
As mentioned earlier I use one Yaqin tube buffer after my Vista phono-2 and a second after my DAC.
A lot of time rolling 6SN7 tube’s in the Yaqin’s I've found some pretty good ones.
Installing the Tortuga tube buffer in place of the Yaqin after my phono stage was an eye opener.
Sound stage, channel balance, instrument definition, treble and mid range now have more energy and detail.
At first, I thought the added treble and midrange definition was a bit much but after more listening I came to enjoy it.
A couple of questions / thought’s I’d like to ask Morten.
First, as can be seen in my setup it’s easy to turn on the rear power switch but in a different setup a switch located on the front would be better.
Second, and this is probably not possible, since I have so many 6SN7 tubes is it possible to use them with an adapter in the Tortuga?
When the time comes to replace my above buffer’s I’ll be thinking “Tortuga”.
I really like the Tortuga tube buffer and would like to thank Morten for this opportunity.
I’ll be shipping the buffer off to rklein next Wednesday the 24th.
Enjoy and thank you,
Steve
(http://www.audiocircle.com/image.php?id=162580)
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The Tortuga buffer has spoiled me. I removed it and put back in the Yaqin buffer and it sound's like crap. :(
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The Tortuga buffer has spoiled me. I removed it and put back in the Yaqin buffer and it sound's like crap. :(
Got a solution for that Steve. :thumb:
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I received the Tortuga Tube Buffer and had the pleasure of it in my system for about 6 days. I had to put the buffer between my Holo DAC and the Bent TAP passive pre I am using. The reason for this is that the XLR to RCA adapters that I bought for this purpose were too tight a fit on my NORD One Up Monos.
Anyway, listening in this configuration was very pleasing to me. With the buffer in place, there was a change for the better in regards to the tone and tambre of orchestral instruments. Woodwinds, strings and even brass had a bit more depth. I played some complex orchestral pieces and with the buffer in the chain, I was further drawn into the sound being reproduced than sans the buffer.
The Tortuga buffer did not add a bunch of "tube goodness" to the sound. Rather, it enhanced the presentation by bringing the artists a bit closer to you. If you are running a SS system and listen to classical, this piece is worthwhile to try in your system.
My room is 14' by 14' with a drop ceiling. I have to be in a near field configuration with the speakers pulled out a good four feet from the front wall and three feet from the side walls with my listening position 7 feet from each speaker in a trilateral setup. This being the case, amplified bass on R&B, rock, even some jazz pieces sounded too loud and a bit unrefined in my smallish room. This could absolutely change if listening in a larger room. However, I have what I have and this problem did not rear it's ugly head on most acoustical recordings.
I don't have other tube buffers to compare the Torgtuga to but overall I was pleased with the changes the buffer brought to my listening experience.
The shipping box was a bit beat up so I had FedEx double box the unit and sent it off to Rusty in Maryland who received the unit yesterday.
Thanks for allowing me to participate in the tour! :thumb:
Regards,
Randy
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I had the pleasure of using the Tortuga buffer last week in my system as part of this tour. Thanks to Morten for giving me the opportunity to audition one of his components in my system. Very generous, indeed.
I tried using a buffer in my system for the first time about a year or so ago when I became concerned that bi-amping with 2 solid state amplifiers that had moderate input impedance, and a tube preamp with normal moderately high output impedance, was holding back dynamic performance. Sure enough, as soon as I installed it (original iTube buffer) between preamp and amplifier, the system just came to life. Improved bass punch, dynamics, drive, etc. I then replaced my tube preamp with a First Sound passive, as I didn't need the gain from the active and the tube circuit in the buffer was giving me the linear presentation I am after without being "tubey", but was also less "hard" compared to solid state preamps (which have low output impedance) I tried. The noise floor with my 102db efficient speakers became virtually silent as a result. I have not tried any other brands of buffers until the last month when I tried the Tortuga buffer and the new iTube 2 as part of the tours.
The Tortuga buffer arrived set to (I believe) 6db of gain. Morten says it is internally switchable to 0db, or 3db, also. I didn't ask to change it. Like the Original iTube I'd been using, and the iTube 2, the low output impedance of the Tortuga buffer gave it the ability to drive both the amplifiers easily, giving me the big dynamic sound I enjoy. It also has an exceptional midrange quality. Very refined, and natural. Instinctively, I was drawn to playing vocal tracks, and was impressed with the rich, textured presentation. I used the supplied EH 6H30s, and a pair of 6H30-DRs, and also a pair of Tung Sol 6CG7s. I felt the DRs had the nicest midrange, and the 6CG7s had the best extension.
For me, and in my system, there was a shortcoming however. There was a small attenuation of high frequencies that made the presentation very smooth, but removed the micro detail and "air" I'm used to hearing, out of the system. It is the classic "midrange magic" vs. "inner detail" debate. My preference is toward the detail side. I want full frequency extension. A friend who listened with me last week preferred the Tortuga's silky smooth presentation over the iTube, and I preferred the clarity and extension of the iTube.
I think this buffer could be an excellent addition for people looking for "tube magic" in their system without getting into tube amplifiers/preamps, as well as anyone bi-amping, who may benefit from better impedance matched components.
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Seems like the tour has stalled after RJ. Did slefley ever get the unit? I finally got my DAC back.