LDR300x.V3 Preamp Tour

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tortugaranger

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Re: LDR300x.V3 Preamp Tour
« Reply #20 on: 11 Oct 2020, 02:12 pm »

** Updated **

Here's the tour sequence lineup. We start off waaaay  west in Hawaii, then Washington, California, Arizona, back to the east coast in New Jersey, then North Carolina and finally full circle to Florida. The Midwest is missing - where'd you guys go?

After much hurry up and wait the tour kicks off this week. We've been doing a ton of work the last 2-3 weeks refining the firmware based mostly on initial feedback. glynnw dropped out of the tour because he went ahead and bought one instead...no patience ;)

Still have room to add a few as we move along.

Please remember your commitment to keep the tour unit for no more than one week. Which means if you receive it on a Monday you ship it on to the next person no later than the following Monday.

Enjoy and look forward to your feedback/reviews.

1) uncola - HI
2) MttBsh - WA
3) Delta77 - CA
4) Emiel - AZ
5) Bob2 - MI
6) sruffle - NJ
7) krustykat - NC
8') GentleBender - FL
9) jriggy - ??
« Last Edit: 11 Oct 2020, 09:24 pm by tortugaranger »

jriggy

Re: LDR300x.V3 Preamp Tour
« Reply #21 on: 11 Oct 2020, 02:57 pm »
You’re calling for me now here in the mid-west! And I was thinking about asking to join after seeing the tour recently.

Have always been interested in trying one of your offerings since I do like DAC direct to amp for some listening, so I thought I’d also probably enjoy a passive.

Bob2

Re: LDR300x.V3 Preamp Tour
« Reply #22 on: 11 Oct 2020, 04:04 pm »
I'm interested. 49286.

tortugaranger

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Re: LDR300x.V3 Preamp Tour
« Reply #23 on: 11 Oct 2020, 09:20 pm »
You’re calling for me now here in the mid-west! And I was thinking about asking to join after seeing the tour recently.

Have always been interested in trying one of your offerings since I do like DAC direct to amp for some listening, so I thought I’d also probably enjoy a passive.


I'll add you in.
Please send PM me your full name, address, phone # & email address.

tortugaranger

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Re: LDR300x.V3 Preamp Tour
« Reply #24 on: 11 Oct 2020, 09:20 pm »
I'm interested. 49286.



I'll add you in.
Please send PM me your full name, address, phone # & email address.

tortugaranger

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Re: LDR300x.V3 Preamp Tour
« Reply #25 on: 12 Oct 2020, 02:57 pm »
Well, looks like we filled in that Midwestern hole with 2 additions from Indiana and Michigan.

1) uncola - HI
2) MttBsh - WA
3) Delta77 - CA
4) Emiel - AZ
5) jriggy - IN
6) Bob2 - MI
7) sruffle - NJ
8') krustykat - NC
9) GentleBender - FL

uncola

Re: LDR300x.V3 Preamp Tour
« Reply #26 on: 20 Oct 2020, 08:49 pm »
 usps sent me a note saying it's being delivered TODAY  :D
edit:  oops, something else is being delivered today.  the Tortuga preamp is being SHIPPED today
« Last Edit: 20 Oct 2020, 11:09 pm by uncola »

tortugaranger

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Re: LDR300x.V3 Preamp Tour
« Reply #27 on: 21 Oct 2020, 06:36 pm »
usps sent me a note saying it's being delivered TODAY  :D
edit:  oops, something else is being delivered today.  the Tortuga preamp is being SHIPPED today

Yes, the tour unit has finally left the building and is on its way to Hawaii so we are off and running on this tour at last.

We've been doing a LOT of updating, improving and bug killing since the release of the V3 a few weeks back and feel the LDR300x.V3 is already fairly far up the maturation curve.

We ran into 2 problems worth noting; random lock-ups and sonic artifacts during volume change. Both have now been resolved.

It took a while to solve the random lock-ups but we finally got that taken care of. We only recently became aware of the sonic artifacts (soft putt-putt-putt-putt motorboating sound usually associated with unstable op amps - not the case here). The sonic artifacts were only present during volume change or when the screensaver was running (with the swimming turtle). The artifacts were from high frequency serial data bursts being sent to the the OLED display anytime the display was being updated. We didn't notice these artifacts during development for the simple reason that they were very faint - we had to put our ear next to the speaker/driver to notice. After some analysis we decided to stop having the turtle swim continuously when the screensaver is active. We also made changes to the serial data transmission firmware that substantially quieted these transmissions. In our view these sonic artifacts are now essentially undetectable (with normal ears) and, most importantly, are NEVER present at all during normal listening.

We hope you all enjoy the tour experience and we look forward to your questions, comments and suggestions.

Cheers,
Morten

tortugaranger

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Re: LDR300x.V3 Preamp Tour
« Reply #28 on: 23 Oct 2020, 05:39 pm »
Dear Tour Participants,

I thought I'd elaborate on the possible ways you can evaluate the LDR300x.V3 that can make for a more interesting experience.

Active vs. Passive - The tour unit comes configured as an active preamp. However, you can remove the top half of the enclosure in order to access jumpers JPL and JPR located on the Interface Board near the right side of the rear panel. By moving the jumpers on on JPL and JPR from the "A" position to the "P" position you effectively bypass the active gain/buffer board and can operate the preamp as a passive unit.

Active - Unity Gain or +6 dB - The active tour unit is set to unity (1.0X) gain hence there's no actual amplification of the audio signal within the preamp. The 2 unity gain modules can be swapped out for a pair of +6 dB gain modules provided with the tour unit. Please be aware that the gain modules must be aligned properly such that the white dot on the plug-in module is on the same side of the 4 pin module header as the white dot on the board.  Sound complicated but it will make more sense when you see it.

LDR vs Discrete Attenuation - The tour unit comes set up with an LDR attenuation module installed. This module can be removed and replaced with a discrete attenuation module that uses thin film resistors only. The LDR module has 100 steps of attenuation while the Discrete module has 127 steps of attenuation. Arguably a bit overkill at 127 steps but it was either that or 63 steps which, while plenty granular, would be considerably less than the 100 steps with the LDR. When swapping theses modules, please only do so by first powering down the preamp and either disconnecting it from your amp or making sure your amp is turned off. Common sense stuff.

When done with the tour unit and before packing it up and shipping it onwards, please put it back to its original default state of active, unity gain modules and LDR attenuation module.

Thanks and I hope you enjoy the tour.

Cheers,
Morten

P.S.  To remove the top half of the preamp case, remove only the top 2 corner socket screws on both the front and the rear panels. Leave the bottom screws installed. Then gently rock/pry the top half shell up and off the unit.



GentleBender

Re: LDR300x.V3 Preamp Tour
« Reply #29 on: 24 Oct 2020, 07:11 pm »
Can you pin this post to the top of the page? This info will be really helpful for those on the tour. I look forward to seeing what people say about the different settings before I get my hands on it.

tortugaranger

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Re: LDR300x.V3 Preamp Tour
« Reply #30 on: 24 Oct 2020, 07:28 pm »
Can you pin this post to the top of the page? This info will be really helpful for those on the tour. I look forward to seeing what people say about the different settings before I get my hands on it.

I would if I could figure out how to do it. I can make topics stick to the top but don't see a way to make a post be sticky within a topic. If someone knows if there's a why please enlighten.


uncola

Re: LDR300x.V3 Preamp Tour
« Reply #31 on: 25 Oct 2020, 01:25 pm »
the eagle has landed!  Just got home from work, unpacked it and took photos.  Will plug it in tomorrow :)
first reaction:  the discrete resistor attenuation module is to tiny!  I'm used to it taking up half the space inside a preamp or integrated amp with those relays and huge space taken up by all the resistors. 






LarryD56

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Re: LDR300x.V3 Preamp Tour
« Reply #32 on: 5 Nov 2020, 12:42 am »
    Morten,

    Do you have a list of the sequence of where the LDR300x.V3 preamp tour is heading? I have a few people who want to take a listen and they keep asking me when I might be expecting it to arrive. Thanks!

    Larry D.

MttBsh

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Re: LDR300x.V3 Preamp Tour
« Reply #33 on: 5 Nov 2020, 03:00 am »
Just as an update I received the tour unit Monday afternoon from Uncola and plan to send it off to Delta77 in a few days. Still need some quiet time to do some critical listening but really like what I've heard so far! 

uncola

Re: LDR300x.V3 Preamp Tour
« Reply #34 on: 5 Nov 2020, 04:12 am »
I took some pictures of the inside to help you guys change settings, I'll post them tonight after work :)

here I labeled where the settings change areas are
view full size to read the labels https://i.imgur.com/sdAODrZ.jpg

view of the passive/active pin jumpers.  left is active, right is passive
https://i.imgur.com/p5j3rhg.jpg

here's the gain setting modules..  make sure you align the white dot on the module with the dot on the pcb..  left spot has dot on the bottom, right spot on the top
https://i.imgur.com/KHqGWhr.jpg

the ldr/stepped attenuation modules just pop off and on.. you can see it only goes in one way because one side has two rows of pins and the other only one row
https://i.imgur.com/nBYK7Bg.jpg

I used this documentation to figure out the menus.
https://tortugaaudio.com/docs/epot-v3-operation-controls/

So I'm not a preamp guy at all, I started using preamp out on cheap headphone amps or passive alps rk27 preamps early on in my audio hobby but eventually eliminated them and used digital volume control in my dacs.  But trying the tortuga for a week has sold me on analog preamps and it just blew my mind with the increased dynamics and tactile texture from my philharmonitor 2 way bookshelves that I use near field.  Imaging was better and I was able to pick out instruments more clearly from the soundstage as well.  The imaging was so good I wondered if this is what people describe when they talk about tube amps.   I swapped out the LDR module for the stepped attenuation and it seemed slightly worse to me.  I didn't have time to try purely passive mode, just unity gain.  Not sure if the LDR's create the magic or the fancy VCAPS.  Interested in what other people who try purely passive mode think, if anything is lost other than volume. 
« Last Edit: 5 Nov 2020, 03:29 pm by uncola »

tortugaranger

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Re: LDR300x.V3 Preamp Tour
« Reply #35 on: 6 Nov 2020, 12:35 pm »
Hi All,

Just a quick update on the tour status. The preamp is currently in Washington with MttBsh this week.

Also, I'd left out LarryD56 from Idaho by mistake earlier.

Cheers,
Morten

1) uncola - HI
2) MttBsh - WA (has it now)
3) Delta77 - CA  (next up)
4) LarryD56 - ID
5) Emiel - AZ
6) jriggy - IN
7) Bob2 - MI
8') sruffle - NJ
9) krustykat - NC
10) GentleBender - FL
« Last Edit: 6 Nov 2020, 08:49 pm by tortugaranger »

kernelbob

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Re: LDR300x.V3 Preamp Tour
« Reply #36 on: 6 Nov 2020, 02:07 pm »
Regarding uncola's comment "Not sure if the LDR's create the magic or the fancy VCAPS."  When comparing the LDR module to the stepped resistor module, aren't the VCAPS in the system not involved in the swap?  My understanding is that with the attenuation module swap, the only change is between LDR versus stepped resistor attenuation.

Having the ability to swap the attenuation modules is a great feature and allows the user to easily isolate the sonic difference between their DNA.  I'm a long time Tortuga happy camper, running a Tortuga LDRxB and Tube Buffer in a biamped system with four monoblock amps.  I use the Tube Buffer ahead of my low input impedance solid state bass amps.  The more optimal impedance matching clearly improves not only the bass, but also the mid/treble performance.  I like the design of the new LDR300x-V3 which essentially integrates the Tube Buffer with the LDR controller.

Best,
Robert

tortugaranger

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Re: LDR300x.V3 Preamp Tour
« Reply #37 on: 8 Nov 2020, 05:34 pm »
I took some pictures of the inside to help you guys change settings, I'll post them tonight after work :)

here I labeled where the settings change areas are
view full size to read the labels https://i.imgur.com/sdAODrZ.jpg

view of the passive/active pin jumpers.  left is active, right is passive
https://i.imgur.com/p5j3rhg.jpg

here's the gain setting modules..  make sure you align the white dot on the module with the dot on the pcb..  left spot has dot on the bottom, right spot on the top
https://i.imgur.com/KHqGWhr.jpg

the ldr/stepped attenuation modules just pop off and on.. you can see it only goes in one way because one side has two rows of pins and the other only one row
https://i.imgur.com/nBYK7Bg.jpg

I used this documentation to figure out the menus.
https://tortugaaudio.com/docs/epot-v3-operation-controls/

So I'm not a preamp guy at all, I started using preamp out on cheap headphone amps or passive alps rk27 preamps early on in my audio hobby but eventually eliminated them and used digital volume control in my dacs.  But trying the tortuga for a week has sold me on analog preamps and it just blew my mind with the increased dynamics and tactile texture from my philharmonitor 2 way bookshelves that I use near field.  Imaging was better and I was able to pick out instruments more clearly from the soundstage as well.  The imaging was so good I wondered if this is what people describe when they talk about tube amps.   I swapped out the LDR module for the stepped attenuation and it seemed slightly worse to me.  I didn't have time to try purely passive mode, just unity gain.  Not sure if the LDR's create the magic or the fancy VCAPS.  Interested in what other people who try purely passive mode think, if anything is lost other than volume.

Thanks for participating and posting all the pics and info.

Quote
The imaging was so good I wondered if this is what people describe when they talk about tube amps.

Can't say that amps don't matter in regards to stereo imaging but I would argue that amps can't do better than what they're given.....whether tube or solid state. In my view, volume control devices can have an outsized impact on stereo imaging and sound quality generally. Our V3 series of preamp controllers do a great job of sustaining/resolving the stereo imaging.

Quote
Not sure if the LDR's create the magic or the fancy VCAPS.  Interested in what other people who try purely passive mode think, if anything is lost other than volume.

You'll find that the magic remains even without the active buffer/VCAPs. The active stage can lend a more definitive punch to the sound depending on the system it's installed in. But for systems with sources that have excellent robust output/drive stages there's minimal discernable benefit form the active gain/buffer stage unless you really need some gain to maintain adequate volume control headroom (i.e. "10" isn't loud enough and there's no 11). Most systems don't need any actual gain from a preamp.

The other scenario where the active gain/buffer provides a better solution than a passive alone is when driving into a low impedance amp (puts undue load on your source) or when driving into separate primary plus subwoofer amps from the same passive preamp output in which case the combined effective impedance of a passive plus 2 amps all in parallel can drop low enough to negatively impact sound quality. Adding the active buffer to the preamp mitigates this issue.

MttBsh

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Re: LDR300x.V3 Preamp Tour
« Reply #38 on: 11 Nov 2020, 05:36 am »
I have very much enjoyed the week with the LDR300x.V3 in my system, it is now in route to Delta77 in California.

I've had a Tortuga passive in my system for the past 5 years and it's in a different (higher) league from any other preamp I've heard including the Dodd battery powered pre it replaced, Eastern Electric and others over the years.  My Tortuga passive is a DIY model that's about three times the size and five times the weight of LDR300x.V3. I listened very carefully to the LDR300x.V3 and thought I heard a slight refinement to the sound, but when I put my older model back in the system it sounded every bit as good, in a blind test I would not have been able to tell the difference. This is not in any way a negative about the LDR300x.V3, it is an exquisite preamp that delivers crystal clear, deep, smooth and detailed sound. Anyone who hears a Tortuga for the first time is in for a real surprise. It's hard to come to terms with the fact that such a compact, lightweight device can produce such glorious sound, especially for a grand or under. I only listened in the active mode so can't comment on how it sounds in passive mode but I suspect any differences would be very small.  I really appreciate the styling and layout, how easily one can change inputs, volume, etc.

I want to thank Morten for his generosity in sending out tour models of his equipment to try out, his designs and implementation are truly state of the art.

Here is my system:
Source: Channel Islands Audio DMC-1 Network player/DAC
Preamp: Tortuga passive
Amp: Digital Amplifier Company STM King MK2
Speakers: Cain & Cain Abbys with Fostex T900A Horn supertweeters, dual subs
Cables: Zenwave powercords and interconnects

Delta77

Re: LDR300x.V3 Preamp Tour
« Reply #39 on: 15 Nov 2020, 09:11 pm »
Got the LDR300 installed about an hour ago..




First impression: I Like it.. Sounds very nice.. If I had purchased this one , it wouldn’t be going back..

I will give it some more time , and I will try to give a description of what I’m liking about this preamp...



To make the RCA cables reach I had to set the unit on its side, just as I did with my previous passive preamp.. (my new 300B is just humungo) working on a new stereo cabinet soon..