Cris you have come a long way lol. I too have learned a vol control was shown to me not my idea really. we learn as we go and for some like me kick helps lol.I would really go WITH VC and cover all (future) eventualities.
Maybe you don't even need a new Preamp because the Pacific Preamp section is really good.
With VC you have ALL options
Pacific dac: Lampizator's new top of the line dac
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Having at home IMHO ultimate toy for tube rolling i have to say that i fully admire your determination not to try other tubes except 242. Wondering what would happen if you accidentaly started the Pac journey with that PX25
I understand the temptation not to roll once you have the KR 242's in place. I actually started my GG2 experience with the RK KR PX25 but once I moved to the 242's, I sold the PX25s. Surprisingly, I actually have a new pair of RK KR 242's that have been sitting on a drawer for months. Thicker glass, better vacuum, better anode- should be better sounding, right? Frankly I'm so happy with the good old "regular" KR242s, I have no desire to try them...yet. Maybe sometime before the next pandemic
Same for the RK-KR 5u4G. Some day I'll try the Tak, but not anytime soon. If it ain't broke, don't fix it.
I understand the temptation not to roll once you have the KR 242's in place. I actually started my GG2 experience with the RK KR PX25 but once I moved to the 242's, I sold the PX25s. Surprisingly, I actually have a new pair of RK KR 242's that have been sitting on a drawer for months. Thicker glass, better vacuum, better anode- should be better sounding, right? Frankly I'm so happy with the good old "regular" KR242s, I have no desire to try them...yet. Maybe sometime before the next pandemic
Hi Marty
Please do all of us a big favor and compare the regular KR 242 against your RK 242.
You might be the only person I know (of) who has both at the same time.
But make sure you give the brand spanking new RK 242 a proper burn-in before you compare.
Initially my brand new RK 242 sounded rather flat and boring but with more hours they really startet to shine wonderfully.
Unfortunately my regular KR 242 where long gone by then, preventing me from comparing the two directly to each other.
Surely we need a video compare
He is customizing his Lampi gain after getting new amps. After that up to him if he wants to share videos of his analog and Lampi both
Regarding VC or no VC in the Pacific DAC. I have the balanced Pacific DAC without the internal volume control. I'm using a passive Tortuga LDRxB (the balaced version). For those unfamiliar with the Tortuga, it uses light dependent resistors for attenuation, setting the input resistance, and in my version the optional ability to switch absolute phase. All these adjustments can be done through the remote.
This allows me fine tune the impedance seen by the DAC's tube output stage without interrupting the music. The input impedance that is seen by the DAC's tubes is fixed using the Pacific's built in attenuator. The Tortuga lets me store any 9 user selected input impedances ranging from 1k to 99k (per phase if balanced), plus one fixed at 20k, with the selection of any value using the remote.
I have sets of PX4, 300B-98B mesh plate, and KR-242 output tubes. I find that the 242 is the best in my system and the higher gain is a perfect match with the Tortuga. The 242 is (in my experience so far) the best balanced top to bottom, very neutral, and with a very sweet clean treble. Soundstaging, dynamics, and especially instrumental timbre are their forte. I have a 274B and the stock KR-5U4G rectifier. The 274B is a bit more open and spacious than the 5U4G, but I'm trying to save the 274B for occasional use, and normally run the 5U4G since I leave the DAC on 24/7. I've heard that the 274B could sag earlier if run 24/7.
Regarding input impedance, I've found that all the tubes sound their best with and input impedance range between 88 and 97 kohms (again that's per phase for balanced). I have 9 settings stored in that range plus the factory fixed option of 20k. I select between a few of them to best match a recording's sonic signature, but normally use 95, 96, or 97 with the 242's. I believe the internal Pacific DAC attenuator presents a source impedance of 20k or 30k. I've tried using lower impedances (20k, 30k, 40k, etc.), but much prefer that higher range.
Best,
Robert
This allows me fine tune the impedance seen by the DAC's tube output stage without interrupting the music. The input impedance that is seen by the DAC's tubes is fixed using the Pacific's built in attenuator. The Tortuga lets me store any 9 user selected input impedances ranging from 1k to 99k (per phase if balanced), plus one fixed at 20k, with the selection of any value using the remote.
I have sets of PX4, 300B-98B mesh plate, and KR-242 output tubes. I find that the 242 is the best in my system and the higher gain is a perfect match with the Tortuga. The 242 is (in my experience so far) the best balanced top to bottom, very neutral, and with a very sweet clean treble. Soundstaging, dynamics, and especially instrumental timbre are their forte. I have a 274B and the stock KR-5U4G rectifier. The 274B is a bit more open and spacious than the 5U4G, but I'm trying to save the 274B for occasional use, and normally run the 5U4G since I leave the DAC on 24/7. I've heard that the 274B could sag earlier if run 24/7.
Regarding input impedance, I've found that all the tubes sound their best with and input impedance range between 88 and 97 kohms (again that's per phase for balanced). I have 9 settings stored in that range plus the factory fixed option of 20k. I select between a few of them to best match a recording's sonic signature, but normally use 95, 96, or 97 with the 242's. I believe the internal Pacific DAC attenuator presents a source impedance of 20k or 30k. I've tried using lower impedances (20k, 30k, 40k, etc.), but much prefer that higher range.
Best,
Robert
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The output imp of a pac depends on tubes including the recti. The volume control has no effect on imp in the way your passive pre does. The volume control effects the gain voltage into the tube gain stage. I have read that for the most part a passive volume control meaning no active gain stage lowers dynamics. This can be shown when lowering volume in the digital player and in a dac with a volume control of lowered too low. For this reason I’m not so sure the two step switch on dacs is useful in all systems. While it may help an active preamp from clipping its input it May lower dynamics on some. lastly may I ask what method did you use to measure output imp ? tube specs can be used as well as testing parameters under monitored and then measured.
Please post
Ty
Hi Alrinbow,
In my post regarding the adjustable impedance setting in the Tortuga, I'm not referring to the output impedance of the DAC, but instead to the input impedance that the preamp or controller presents. Several years ago, I took my Tortuga controller to Axpona and in an evening session in a room that featured a preamp and poweramp (5 figures each), we compared the performance of the system swapping out the preamp for the Tortuga. I initially set the input impedance of the Tortuga to the same (fixed) value of the preamp. All the attendees clearly preferred the Tortuga. What was surprising was that the bass was improved with deeper extension, control, and resolution.
After listening for a while, I tried switching the input impedance from the original 20 to 30, 40, 50, 60, 70, 80k. The results were that the system sounded best on the 50 and 60k settings. Finally, using a narrow range of values between 50 and 60k, the best result was at 57k. Insterestingly, the preamp in the room was from a vendor that had three product lines with the one at the show being from their base line. The input impedance of the corresponding units from the mid and top tier were 100k and 200k.
My experience with other DACs (solid state) in my system is that changing the input impedace of the Tortuga allows the identification of a sweet spot. However, the sonic signature of both my previous Lampizator tube Golden Gate and now my Pacific are much more responsive to different impedance settings, even a 1 kohm change. In fact, I use the Tortuga's impedance control to tune the DAC to individual recording characteristics. That may be hard to believe, but the Lampizator DACs, in my experience, the subtle changes in both the GG and Pacific presentations are easily audible.
Best,
Robert
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I thought so too since my Big 7 took a 3.15A but the one in the Pac says 6A. I just want to confirm before I buy one.
A new and exciting "Editors Review" of the Pacific by Dr. David Robinson of PFO:
https://positive-feedback.com/audio-discourse/lampizator-pacific-dac-2/
https://positive-feedback.com/audio-discourse/lampizator-pacific-dac-2/
Note: I copied my post from tube rolling thread in order for Pacific/GG2 owners to easier navigate through rotary switch settings
After looking into many DHTs and what we can use, I decided to write here two specs for different tubes.
Having 5 position rotary switch on Pacific and GG2, which is adjusting heater circuit in the DACs, with the numbers below we can easier navigate through different tubes and maybe look for some alternatives in the huge world of DHTs. First number represents heater voltage and second is heater current per tube model.
Using the figures below you can for example see that rotary switch for regular ad1 should be set in PX4 position while for Tesla ad1n in PX25 position.
If I made any mistake please correct me, as in several cases for one tube type I found a bit different numbers from different manufacturers.
Please note KR242 is spec wise not the same as Elrog 242.
PX25: 4V; 2A
RD27AS: 4V; 1.8-2.3A (adapter needed PX25 to UX4)
PX4: 4V; 1.0A
ad1: 4V; 0.95A (adapter needed ad1 to UX4)
ad1n: 4V; 2A (adapter needed ad1 to UX4)
KR242: 4V; 0.65A
101D: 4.5V; 1.0A
45: 2.5V; 1.5A
46: 2.5V; 1.75A (adapter needed UX5 to UX4)
345: 2.5V; 1.5A
300b: 5V; 1.2/3A
100T: 5V; 2.0A
KR842VHD: 5V; 1.8A
01A: 5V; 0.25A
12A/112A: 5V; 0.25A
71A: 5V; 0.25A
After looking into many DHTs and what we can use, I decided to write here two specs for different tubes.
Having 5 position rotary switch on Pacific and GG2, which is adjusting heater circuit in the DACs, with the numbers below we can easier navigate through different tubes and maybe look for some alternatives in the huge world of DHTs. First number represents heater voltage and second is heater current per tube model.
Using the figures below you can for example see that rotary switch for regular ad1 should be set in PX4 position while for Tesla ad1n in PX25 position.
If I made any mistake please correct me, as in several cases for one tube type I found a bit different numbers from different manufacturers.
Please note KR242 is spec wise not the same as Elrog 242.
PX25: 4V; 2A
RD27AS: 4V; 1.8-2.3A (adapter needed PX25 to UX4)
PX4: 4V; 1.0A
ad1: 4V; 0.95A (adapter needed ad1 to UX4)
ad1n: 4V; 2A (adapter needed ad1 to UX4)
KR242: 4V; 0.65A
101D: 4.5V; 1.0A
45: 2.5V; 1.5A
46: 2.5V; 1.75A (adapter needed UX5 to UX4)
345: 2.5V; 1.5A
300b: 5V; 1.2/3A
100T: 5V; 2.0A
KR842VHD: 5V; 1.8A
01A: 5V; 0.25A
12A/112A: 5V; 0.25A
71A: 5V; 0.25A
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