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    PH16 tube rolling positions question

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    mdelrossi

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    Post by mdelrossi on Fri Dec 07, 2018 10:05 am

    Hello,
    I know from reading on this forum that the first 2 tubes are for the RIAA, and the second 2 are for the buffer.
    So my question is, should I put 2 accurate EH 6dj8/6922's in the first position, and tube roll for different sound in the second 2. Or do I need all 4 to be the same?

    Also any suggestions on tubes would be great.
    I had the EH in there and recently got some amperex "good" tested tubes and it sounds a bit more tubey.

    System:
    VPI Prime HanaSL, Cinemag3440a SUT
    Primaluna Dialogue premium integrated
    Focal 1008be2
    AudioSensibility cables.


    Thanks
    mdr
    Peter W.
    Peter W.

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    Post by Peter W. on Fri Dec 07, 2018 11:13 am

    mdelrossi wrote:Hello,
    I know from reading on this forum that the first 2 tubes are for the RIAA, and the second 2 are for the buffer.
    So my question is, should I put 2 accurate EH 6dj8/6922's in the first position, and tube roll for different sound in the second 2. Or do I need all 4 to be the same?

    Also any suggestions on tubes would be great.
    I had the EH in there and recently got some amperex "good" tested tubes and it sounds a bit more tubey.

    You are beginning to understand the difference between Tube and SS.
    Which is much the same as between Accuracy and Precision.
    Solid-State audio amps may be made to be both precise - each one the same as its before-and-after on the assembly line - and accurate - straight-wire-with-gain. State-of-the-art in solid-state amps was reached no later than the 1980s. This is not even to suggest that all solid-state amps 'sound the same', but that the ability to make them so became common-place and well understood.
    Tube amps may be made to be precise, same-as.
    However their Accuracy is a moving target never quite achieved. It may come to pass that *this* tube amp happens to be quite accurate with *this* set of tubes in *this* configuration. Change the configuration, the tubes, or as they age, and all that also changes and the accuracy (remember: straight-wire-with-gain) is gone. Meaning that actual accuracy cannot be the goal with tubes - as achieving it is ephemeral.

    It is this that is the hardest for non-tube people to understand. It is almost the case that the purest definition of "audiophile" necessarily excludes tubes as an option, as one is never quite sure whether what comes out of the speaker is what went into the amp, or merely its first, second or third cousin, perhaps even a few times removed. Those who enjoy tubes (should be) are trying to achieve a mellifluous sound to THEIR ears. Not necessarily to yours. And tube users have long-since given up even the thought of accuracy except as a goal-only-in-concept.

    The much shorter answer is to try various combinations and permutations  and find out which one you like best - and stick with that, maybe. NOTE: Allow at least eight hours of actual listening to any given set-up (unless it is immediately offensive) before rendering judgment - and with a variety of signal.

    Enjoy!
    Dave_in_Va
    Dave_in_Va

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    Post by Dave_in_Va on Sat Dec 08, 2018 9:28 pm

    I have a PH 14 which (I think) is like yours but lacking the MC cartridge function.
    It came with JAN Philips 6922s. I swapped in some Dutch Bugle Boy 6DJ8s which was an improvement.
    Then I scored a pair of mid-'60's USA Amperex 7308s.
    They made a quite a difference.
    I feel that the tubes in a phono preamp are pretty critical and if you're going to spend some bucks on good tubes, the phono preamp is probably a good place to start.
    Just another internet tube opinion.
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    seeirwin

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    Post by seeirwin on Mon Dec 10, 2018 1:18 am

    I have a phono stage based on the PH16 that was built by Don Sachs. He suggests that the two tubes in front are the most important in terms of sound quality (he recommends NOS Sylvanias). For the back two, he says that new Gold Lions are hard to beat. Anyhow, I would start by rolling the front set of tubes. Have fun!
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    mdelrossi

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    Post by mdelrossi on Tue Dec 11, 2018 12:09 pm

    Thanks to all for your input.
    I gather the "front" set is the ones at the input.
    I'm on the look out for some 7308's and some Sylvanias.

    I was also looking at replacing the .22uf caps with something along the lines of the Jantzen superior or the Audyn true copper.
    Adding some switching to have MM and MC switchable, and ratios selectable for the MC.
    However, I'm enjoying this stage too much to start tearing it apart  Laughing  .

    Thoughts would be appreciated.

    Thanks
    mdr
    Peter W.
    Peter W.

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    Post by Peter W. on Tue Dec 11, 2018 12:52 pm

    Mini-Rant Warning:

    After basic QC and suitability standards are met, a cap is a cap is a cap is a cap.

    There is no reason on this planet to install capacitors that are unusual or remarkable or special if that quality is beyond the circuit they are in. Putting a Porsche engine in a Yugo does no one any good as engine does not suit the platform. And your time and treasure may be expended more usefully in another direction.

    Short of double-blind testing based on long-term listening, there is no evidence otherwise. Purveyors of these options pretty much 'see you coming' and line their pockets based on the gullibility of their clients.

    This is not to suggest that there are no difference in caps, or that one should race to the bottom when purchasing such. But it is very much to suggest that if one chooses a well-made cap from a reliable source suitable to the intended use, and, further, screens them upon receipt, that is enough.

    Tubes, on the other hand....
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    mdelrossi

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    Post by mdelrossi on Wed Dec 12, 2018 12:17 am

    @Dave_in_Va what was the improvement in the 7308s’?
    Dave_in_Va
    Dave_in_Va

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    Post by Dave_in_Va on Wed Dec 12, 2018 12:45 am

    The music sounded better.
    Sorry, I'm no good at audio-geek-talk.

    Watch eBay for 7308s or try over on Audio Asylum. White print, some say USN-CEP. You should be able to find them in the $75 to $100 range.
    corndog71
    corndog71

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    Post by corndog71 on Wed Dec 12, 2018 11:48 pm

    Peter W. wrote: a cap is a cap is a cap is a cap.

    I’ve heard a wire is a wire, a cap is a cap, digital is digital.

    Oh, when will it end!
    Peter W.
    Peter W.

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    Post by Peter W. on Thu Dec 13, 2018 8:37 am

    corndog71 wrote:
    Peter W. wrote: a cap is a cap is a cap is a cap.

    I’ve heard a wire is a wire, a cap is a cap, digital is digital.

    Oh, when will it end!

    It will end when there is direct, verifiable and repeatable evidence to the contrary.
    deepee99
    deepee99

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    Post by deepee99 on Thu Dec 13, 2018 10:41 am

    There's a not widely known fact that a 7DJ8 is in most cases a "drop in" equivalent to the 6922/PCC88 tube; in fact there's even a 6DJ8. Only difference is the one-volt filament voltage. No 7-volt rating is going to stress a 6.3-volt transformer tap. Most high-quality Europeans and Matsushita (post-war Japanese) made 7DJ8s, and same can be had for prices that are 30-70% less than the 6922s. Pin-out is identical and your amp and ears won't detect a difference but your wallet will. I've used them interchangeably in my PH-16. Include 7DJ8s in your quest for 6922 Nirvana and you will be nicely surprised.

    Peter W.
    Peter W.

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    Post by Peter W. on Thu Dec 13, 2018 11:07 am

    deepee99 wrote:There's a not widely known fact that a 7DJ8 is in most cases a "drop in" equivalent to the 6922/PCC88 tube; in fact there's even a 6DJ8. Only difference is the one-volt filament voltage. No 7-volt rating is going to stress a 6.3-volt transformer tap. Most high-quality Europeans and Matsushita (post-war Japanese) made 7DJ8s, and same can be had for prices that are 30-70% less than the 6922s. Pin-out is identical and your amp and ears won't detect a difference but your wallet will. I've used them interchangeably in my PH-16. Include 7DJ8s in your quest for 6922 Nirvana and you will be nicely surprised.


    The 7DJ8 wants 7.6V on the filament, at otherwise the same current requirements, so correct on no stress.
    There is a school-of-thought that 'starving' heaters improves the sound of some dual-triodes.
    In the Dynaco PAS, the 12AX7s are run at 11 V +/-

    Definitely worth a try... .
    deepee99
    deepee99

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    Post by deepee99 on Thu Dec 13, 2018 11:27 am

    One would think, too, that the "under-driven" heaters would last longer. I've got some European bulbs (220-240 VAC) that run forever in 120 VAC-rated lamps.
    A question I've not found answered is: Why 7.6 volts for anything? 6 and 12 makes sense: those are automotive voltages; planes run on 24 volts; and house batteries on boats was, until very recently, 32 volts, exception being the starting circuit, which is mostly 12 volts. So where did the 7 come from? It's not a multiple of 6, 12, 24, or 32.
    Peter W.
    Peter W.

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    Post by Peter W. on Thu Dec 13, 2018 11:47 am

    deepee99 wrote:One would think, too, that the "under-driven" heaters would last longer. I've got some European bulbs (220-240 VAC) that run forever in 120 VAC-rated lamps.
    A question I've not found answered is: Why 7.6 volts for anything? 6 and 12 makes sense: those are automotive voltages; planes run on 24 volts; and house batteries on boats was, until very recently, 32 volts, exception being the starting circuit, which is mostly 12 volts. So where did the 7 come from? It's not a multiple of 6, 12, 24, or 32.

    Goes back to the wet-cell lead-acid battery as promulgated by the Telegraph, then Telephone industries:

    2.1V
    4.2V
    6.3V
    8.4V
    10.5V
    12.6V
    14.7 V
    16.9V
    18V

    and so forth.

    Oddball filaments, mostly Euro in original origin came about from equally oddball combination series-parallel tube configurations in some equipment, where tubes became defacto fuses, and there were a lot of scarcity factors included. So, a tube that could lead three lives would get greater acceptance than one that could not.

    Not to mention aircraft operating at 400 HZ. Smaller wires and transformers saved all sorts of weight.

    peterh
    peterh

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    Post by peterh on Thu Dec 13, 2018 12:16 pm

    deepee99 wrote:One would think, too, that the "under-driven" heaters would last longer. I've got some European bulbs (220-240 VAC) that run forever in 120 VAC-rated lamps.
    A question I've not found answered is: Why 7.6 volts for anything? 6 and 12 makes sense: those are automotive voltages; planes run on 24 volts; and house batteries on boats was, until very recently, 32 volts, exception being the starting circuit, which is mostly 12 volts. So where did the 7 come from? It's not a multiple of 6, 12, 24, or 32.
    7dj8 is that same tube as PCC88, and they have in common that the filament current is 300mA.
    Which happens to be 7 V.
    A series string tube where all filaments are connected in series , this was common on TV-sets
    in europe.

    Peter W.
    Peter W.

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    Post by Peter W. on Thu Dec 13, 2018 12:47 pm

    peterh wrote:
    deepee99 wrote:One would think, too, that the "under-driven" heaters would last longer. I've got some European bulbs (220-240 VAC) that run forever in 120 VAC-rated lamps.
    A question I've not found answered is: Why 7.6 volts for anything? 6 and 12 makes sense: those are automotive voltages; planes run on 24 volts; and house batteries on boats was, until very recently, 32 volts, exception being the starting circuit, which is mostly 12 volts. So where did the 7 come from? It's not a multiple of 6, 12, 24, or 32.
    7dj8 is that same tube as PCC88, and they have in common that the filament current is 300mA.
    Which happens to be 7 V.
    A series string tube where all filaments are connected in series , this was common on TV-sets
    in europe.


    More so than that, Euro TVs were series/parallel, so a strange (to US) combination of options bringing all tube-sets to a single voltage from a common rail. Series-string TVs were common in the US as well, but not the mix.
    peterh
    peterh

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    Post by peterh on Thu Dec 13, 2018 1:43 pm

    Peter W. wrote:
    peterh wrote:
    deepee99 wrote:One would think, too, that the "under-driven" heaters would last longer. I've got some European bulbs (220-240 VAC) that run forever in 120 VAC-rated lamps.
    A question I've not found answered is: Why 7.6 volts for anything? 6 and 12 makes sense: those are automotive voltages; planes run on 24 volts; and house batteries on boats was, until very recently, 32 volts, exception being the starting circuit, which is mostly 12 volts. So where did the 7 come from? It's not a multiple of 6, 12, 24, or 32.
    7dj8 is that same tube as PCC88, and they have in common that the filament current is 300mA.
    Which happens to be 7 V.
    A series string tube where all filaments are connected in series , this was common on TV-sets
    in europe.


    More so than that, Euro TVs were series/parallel, so a strange (to US) combination of options bringing all tube-sets to a single voltage from a common rail. Series-string TVs were common in the US as well, but not the mix.

    As i remember it, euro TV set were serial filaments.Period. They were all filled with 'P' tubes.
    Peter W.
    Peter W.

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    Post by Peter W. on Thu Dec 13, 2018 2:12 pm

    [quote="peterh"
    As i remember it, euro TV set were serial filaments.Period. They were all filled with 'P' tubes.
    [/quote]

    I must have seen the few exceptions, then. I have a Parisian friend that collects vintage TVs (such as the very first RCA Color TV0 and similar, and when I restored a radio for the museum in Bahrain, they had a very odd Euro TV of the same vintage as the radio. I do not touch TVs.
    WntrMute2
    WntrMute2

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    Post by WntrMute2 on Mon Dec 17, 2018 6:38 pm

    Before you starve your heaters consider this graph. I'm not convinced of the validity but I sure wouldn't run my 7V heaters at 6.3V without being prepared to replace them often.
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