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In Reply to: RE: Crystallizing tube amps posted by carcass93 on July 10, 2015 at 09:12:33
some will say you've drifted to the dark side (LOL!!!!)
Keep on experimenting.
FOR the BGT you do need a bypass capacitor. The nature and quality of the bypass makes a significant difference in the sound, much like a power supply. I would run about a 1uF film cap across the positive negative. I think you will be surprised at the outcome.
Smaller values will increase the top end but a 1uF seems to be sufficiently broadband in the audio frequencies. Depending on the make and exact value, the tonal balance will or can change dramatically. For analog, as you are employing it, the larger values are better. Smaller values like .15UF work better for digital/video.
BGT won't work well with the inputs as they are balanced and a true balanced circuit has a separate B- supply
YMMV and FWIW
and welcome to the club
Follow Ups:
Stu, Since this is an SET amplifier according to the OP, is it not likely that there would be no balanced circuit anywhere after the input jacks, and the XLR inputs are connected to the amps in SE mode? Thus no B- supply and probably no problem with the cap connection. (Maybe his preamplifier is balanced or at least has XLR outputs.) But can someone tell me what is the tweak related to the 47,000uF capacitor and 9V battery? I get that the battery may be serving to bias the capacitor, which greatly improves the performance of a polar electrolytic, but what does this mini-circuit do to the sound? Thanks.
Meaning that I don't have any RCA cables around, and wanted to reuse my balanced cables. BTW, whatever the case might be, these amps sound better via those XLR (transformer-isolated) inputs. To make comparisons possible, Cardas XLR-RCA adapters were used, so there's small chance they were the culprit - however, I highly doubt that.Experimentation with applying battery ground tweak to unused RCA inputs is on my to-do list.
Edits: 07/11/15
There have been a lengthy discussion on the Battery Ground Tweak (BGT) on this forum. I would recommend checking the archives.
Stu
Have brass screws to show for it - including those that hold the tweeter together :-).
For bypass caps - does voltage rating make any difference? The most I see on eBay are in the 100s of volts range, which is clearly not needed. Is that OK, or it's better to seek out those with lower rating, closer to the main cap's?
Really appreciate your encouragement, and keep pushing the envelope.
Oh my. Let me preface this by saying I discount nothing right off the bat as far as tweaking is concerned. Having said that, the teeny tiny logical portion of my mind goes, REALLY? Then again, how would things get discovered if from not only necessity, but also just randomly seeing what works. Now the next part of my curious post asks what led to experimenting with crystals/rocks etc. My assumption earlier was that it was random, but that was prolly in error. Surely there must have been something that steered you towards crystals & such rather than, say peanuts, or Zippo lighters (showing my age there). I'm truly intrigued. Oh, and forgive me if this is common knowledge amongst you guys/gals, I don't frequent this section often. I am curious yellow. *anyone else remeber that weird sixties film? okay never mind. Dave
Everyone thinks I'm strange except my friends deep inside the earth
google up Shakti. Ben Piazza, the designer, is an EE and a ME and has a white paper on his products. SHun Mook has many devices which use crystals although they cloak them in an air of mysticism. Their three founders were an American educated MD, and American educated engineer and a machinist. Alan Maher uses crystals as does Awe d-o-phile.
In some audio venues it is easier to hide tweaks with mysticism so those with a scientific bent will ignore it and will appeal to those with a mystical bent.
There is nothing mystical here, and everything is based on tried and proven science.
There are ample threads on this asylum going back many years (decades, almost) about the use of crystals and more importantly the principles upon which their use is based ( piezo electric effect). This effect is well established in the scientific community, BTW. That being said, very little research has really been done on the effect as we use it.
In addition to the piezo effect,crystals can have pyroelecric propertied (tourmaline). Some even have magnetostrictivee of crystal properties ( mostly metals)
We are NOT New Agers, BTW. The use of crystals , at lest in this forum has been verified by too .many listeners and the subject has died away for the most part
And as all things, you can take it or leave it.
of course YMMV and FWIW
Thanks for the info. I really wasn't trying to make fun. And now that you mention it, I do remember waaaaaay back as a kid, ads in comics for building your own working crystal radio - I think. And no, the new age thing wasn't part of my thoughts either,I just thought there had to be some kind of rationale behind using those items. As usual though, seeing all the things you referenced, I'm late to the table. Again, thanks for your post, but I will tell you this... if you guys start telling me that a crystal skull from South America, sitting on top of your speaker creates a better soundstage, I'm outta here. Dave
Everyone thinks I'm strange except my friends deep inside the earth
for coming own hard on you. It, just, well. I've taken so much abuse from the use of crystals.
The funny thing is that I was demonstrating the effect to a customer I had never seen before and who had inquired about the "rocks" scattered on my gear.
He was intrigued that he could hear the effect and then confided that he taught at MIT and had done some research on the very same effect. His comment was that the percent change would probably measured by counting the number of zeros after the decimal point. He was shocked that he could hear the effect.
No no, I didn't get that from your post - no apologies needed, but thanks! I appreciated the background info. If an uninformed guy like me initially sees some pretty shiny rocks on top of amps, he/I just think, "hey, how come he put pretty shiny rocks on his amp?" So now I know! Dave
Everyone thinks I'm strange except my friends deep inside the earth
But where's fun in that, compared to arguing on web forum?
For my own enlightenment, have you evaluated the crystals with blind listening tests? I always find that to be a useful method with which I look for consistency of identification over multiple trials.
Namely, when sighted listening reveals that differences can NOT be heard reliably.
Last time I engaged in blind testing was when evaluating effects of linear vs. switching power supplies for a CD ripper, used to produce WAV files. The experiment was inspired by a lengthy thread at another forum - you can find this in PC Audio forum archives here, if curious.
Such uncertainty is not the case here, with crystals. If you're concerned with removing various expectation biases, then again - these rocks cost nothing, and if anything, tubes look better WITHOUT those greenish-gray ugly pieces on top of them.
have you tried using non-crystalline "rocks" of similar size and density, as a comparator to determine whether what you are hearing is due to an effect dependent upon crystal structure vs the dampening effect that any objects of similar size and mass might have on tube microphonics?
... is good enough for me, as far as the proof that it's not dampening effect that's at play here.
nt
since we are using a 9 Volt battery, any voltage will work, I originally simply dug some out of my parts bin. Trouble is , every cap sounds different, and not being familiar with your sound, I am loathe to make any recommendations. I am not trying to hold back information, BTW.
You can parallel any film cap, any value for experimentation. I have 100's of good pulls so I often simply use what I have on hand.
IMHE I find that the best results come from caps I like in my power supply or use as coupling caps.
Hope this helps
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