Nolafile

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Viewing 15 posts - 1 through 15 (of 18 total)
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  • in reply to: One SL speaker not working #535
    Nolafile
    Participant

    Sorry I missed you stating they are actually crackling.

    In my case the input resistors had cooked which also cooked the surrounding connections. All of which increased the input Z causing reduced output. But if this were the case you would likely detect a burnt smell. So that’s doubtful.

    Perhaps disconnect the amp and check for output voltages. Both a/c or dc. If you detect over 30mvdc or any a/c at idle send it to be serviced. Stats don’t like much dc offset. In fact as close to zero is always perfered.

    If it passes that then ring out you speaker wiring to make sure they are faultless. Perhaps the amp is having issues with the automatic transistor biasing circuits. And is dialing down into limp mode.

    Best,
    DD

    in reply to: One SL speaker not working #533
    Nolafile
    Participant

    I doubt the amp would have any bearing on the bias supply’s. Which you should be able to dial up to where the panels are crackling. Even without a amp hooked up. I’m guessing by the mid point on the adjustment you should hear something. If you don’t hear anything then it sounds bias supply related. As to why both would checkout within a small window of time. I don’t have an explanation for that unless the panels have somehow lost connection or conduction. So what compound was used on these to make the film semiconductive? I’m assuming it is not graphite like my older model.

    I’m assuming the bias supply’s are always energized. So do you monitor the a/c line voltage and or run a conditioner? Perhaps for some reason the voltage went high. It might be a good idea to comb thru the house wiring for suspect connections. An example being weird things start happening when a neutral connection goes high resistance.

    Best wishes,
    DD

    in reply to: Pristine II restoration #440
    Nolafile
    Participant

    Hey Fellas!

    Well here are the latest updates. The input circuit boards have been replaced with a tidy point2point install. I made solid copper heatsink/supports for the new power resistors. Which corrected the oem layout issues and really opened those resistors up to breath. I decided to stick with the oem 7 conductor twisted solid copper input wire. But paralleled a small silver stranded conductor to them. A few hours ago I got them back together and hooked up.

    One requires about 1/3 on the bias pot to obtain crackling. The other only around 1/5 and develops crackling along with popping. After applying audio it seems the 1/5 bias unit has a bit lower output than the other. Plus perhaps some panel issues. As u see moderate drive I can hear distortions and can see what appears to be a few areas where the membrane appears to be loose. So instead of HOS tonight I’m retreating back to the shop to pull the sock for a close inspection.

    Wish me luck as it seems I’m gonna need it.

    Cheers,
    DD

    in reply to: Pristine vs Dynastat #438
    Nolafile
    Participant

    Good work Ken. Many thanks for digging them up. Hopefully I can set aside time tonight to get on it all.

    DD

    in reply to: Pristine II restoration #429
    Nolafile
    Participant

    Good idea John. On the brilliance resistors I’m still debating ordering fancy Vishays. So far the engineering inquiry to them has not been followed up on. Half the input resistor order just arrived. The 50w resistors look pretty good. Idk how the original resistors were able to conduct the required input power with such small leads. These should definitely be a improvement. So this weekend the plan is to rework the backside of the EQ taps. Which at a minimum need to be dismantled, decarbonized and resoldered. Plus revarnish the side of the xformer laminations. Which burnt off causing minor light surface rusting. The input connections were also cooked loose and need a good polishing prior to reassembly. I may devise a point to point layout and discard the fiberglass input boards. As it all really need a bit more breathing room. After measurements on the larger replacement resistors. It looks like the input resistance will rise slightly from 7.5ish to 8.2ish ohms. And from 80 to 100 watt in rated wattage. Until recently I didn’t realize that these smaller panels require higher drive than the larger models. I normally run a 260wpc SS amp on my moderately inefficient mains. After this discovery I’m not sure if it is up to this task. But we shall see in a week or so. I think I may mount the interfaces on some filter stock 3/16″ or so off the bottom. And perhaps devise a topside vent. As I suspect a slight chimney flow wouldn’t hurt.

    DD

    in reply to: Atma-Sphere MA1 3.2 vs Pass XA60.8 amp #411
    Nolafile
    Participant

    So I gather that these newer PX panel are more efficient than prior offerings. So how much of a difference are we talking here? 1, 2, 12db? And what has improved to produce these improvements since the basic physics has remained the same?

    The Atma-Sphere’s I believe are a OTL design. Has anyone managed to incorporate a direct drive OTL tube amp bypassing the interfaces? I would imagine the efficiency losses are quite high just due to the interface coupling.

    DD

    in reply to: Pristine vs Dynastat #399
    Nolafile
    Participant

    Hi Ken,

    Glad to hear you still have them and thanks for the data. Do you happen to have any pics of the unsocked panels? Soon I’m going to closely inspect mine. And pics prior to doing so would really be great.

    Thanks,
    DD

    in reply to: Pristine vs Dynastat #397
    Nolafile
    Participant

    Hi Ken,

    It sounds like you’ve done a great job updating your Pristine II’s. Do you still have your original panels? Roughly what is the cost of the new panels along with the toroid?

    Thanks,
    DD

    in reply to: Sonic difference between non PX vs PX panels #396
    Nolafile
    Participant

    Greeting,

    I’m in the process of bringing my Pristine II’s back to life. On these different panels. Are pics available for reference? I’m assuming I’m dealing with pre-PX panels. But it seems the transition may have been around the time they were produced.

    Thanks in advance,
    DD

    in reply to: Pristine II restoration #391
    Nolafile
    Participant

    Ken,

    Thanks for the detailed listing. After examining the diagram it makes more sense. So the toroid is standing on edge and causes you to have to elevate the outer housing. Interesting. At least for the time being I’m sticking with the oem. As I want to get aquatinted with the original sound prior to stepping forward.

    I also notice that the later design has added -6db selections for the EQ settings. Which seems odd and I guess is related to the new design producing higher potentials. So I’ll have to research it, but I wonder if this has increased the older 88db efficiency rating?

    I see you’ve cleaned these banana jacks before. Remarkably I haven’t noticed these yet. Are they located recessed in the HV box? I notice the drawing refers to BJ at the connections on the box. They must be well hidden. I’ll have to have a close look tonight.

    Thanks,
    DD

    in reply to: Pristine II restoration #388
    Nolafile
    Participant

    Hi John,

    I kinda figured they most definitely released a revision. I think I’ll stick with the oem lower impedance. The revision doubles the amount of resistors to redistribute that damaging heat load. Increasing the overall inductance is likely counter productive to overall sound quality. So instead of the oem 3.75 ohm 40w 10% bundle. I’m going to try a single 4ohm 50w 5% ceramic spaced off on a homebrew breadboard. In theory that could be slightly lower in overall Z than the oem. Stepping up to 8 units is a large increase in inductance. I generally strive to keep parts counts to a minimum especially in signal paths.

    Perhaps it would reflect better with tube amps with the higher Z. But that depends on your output xformers. Most will drive the lower Z without complaint granted they may run a tad hotter. The overall plan here is to bi-amp with sealed passive subs. So the stats won’t even see anything below 50hz to begin with. Which should have the added benefit of unloading the panels of large excursions. And in this case it’s the higher frequencys where they dive down. Which leads to a few questions. On these brilliance pots, how much noticable change occurs from say 1 o’clock to wide open? That seems to be a range of around 4 ohms down to .4 on the pot. So the manual states they bottom out at 3 ohms Z. I’m assuming that is with the pot set to maximum? I wonder where it would bottom with 3 ohms added on the pot? I’m assuming around 4.5ohms minimal Z.

    Nevertheless I’ve got plenty to learn in the near future on operating these. And the manuals explaination of employing the EQ taps leaves plenty to be desired. At least it tells you one way how not to blow your amp. I can clearly see why they installed switches on the later models. As deciphering what little instructions lie in the manual is beyond normal human comprehension.

    The parts should be here soon within a week. And with a little luck they may live to sing again.

    DD

    in reply to: Pristine II restoration #385
    Nolafile
    Participant

    Here is the last picture. Thanks for all of your help!

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    in reply to: Pristine II restoration #381
    Nolafile
    Participant

    Sorry for the delay. Here are the pictures.

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    in reply to: Pristine II restoration #379
    Nolafile
    Participant

    Hi John,

    I just had a look at the diagram you sent. Thanks a million. Very interesting and I wish there was a breakdown of the audio board. By looking at the pic. I’d say they doubled the number of resistors in order to eliminate this burning issue. I may make a board from perf fiberglass using military silver/teflon wire for the traces. The burnt boards are pretty smelly to say the least and have to go. Let me see if I can now post a few pics from the desktop.

    Many thanks again.
    DD

    in reply to: Pristine II restoration #378
    Nolafile
    Participant

    Hi John,

    For the brilliance. Sorry I overlooked part of your question. I haven’t considered them for the other 8. But I guess it’s a possibility. So what can I expect to encounter under the bottom panel covers? They appear to be gun stapled on. I guess I should lay them over and closely inspect the terminations for corrosion to the panels themselves.

Viewing 15 posts - 1 through 15 (of 18 total)