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In a few more years, we'll have an even more delicious irony of people listening to their tube amps through digital hearing aids.
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The prince and the count always insist on tubes being healthy before they're broken -
RG...as per usual, Thanks for your (pardon the pun) input. Math is always enlightening...that is, up to the point that I can comprehend it. Your figures are kind of staggering. I think I am going to start with 22 mics and see how the amp does when it is pushed harder. That will be a while. This amp was built, had problems, and now I am reconfiguring the layout. Guess I am about half way done.
Rhodesphyr...thanks for the note. Always interesting to get a "realistic" account.
Thanks AgainComment
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Well Said.Originally posted by R.G. View PostAnd let me step in here with an heretical opinion.
It's difficult for me to imagine a less musical thing than running AC through rectifiers and filtering it in a capacitor. There are people who will swear that they can hear the difference between a tube rectifier and a closely matched set of silicon diodes and some resistance. I do not discount that this may be possible. But I suspect that there are very few people who can really do this. I think many more "hear" this because they have been told and believe that music is forever damaged by having any silicon junctions within 50 meters of where the music is made, and worse yet, THEIR hearing is suspect if they cannot.
So be it. I've tried and I cannot tell the difference between silicon rectification and other parts to match the conduction to be like a tube rectifier and an actual tube rectifier. And although I've never done a broad study, I have never encountered someone who could notice the difference without being asked.
There is always the option to use silicon diodes and some resistance to replace the 6X5. There is the further option to use more parts than one power resistor to fake the 6X5 conduction more closely.
Maybe you could hear the difference, maybe not.
Maybe.
I always get beat-up on The Gear Page when somebody asks about finding a old stock GZ34 that does not cost 100 dollars. When I make the comment that I do not think there is a need to use Tube Diodes anymore (I usually suggest a Weber Copper Cap) I get responses just as you say.....I do not have the ears to hear it.
I have to say I am guilty of not checking with Weber...I just "assumed" they would not have a pug-in for the 6X5.
One reason I went with this tube is because I had never seen it before. I pulled it from some type of old test equipment...thought it was cool that it ran on 6 Volt heat...so I gave it a try.
The chassis is also a rescue, and is already punched for a Recto Tube...space is REAL precious in this amp, so using the tube also gave me me some elbow room on the chassis floor.
But I agree with you 100%.
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I often use the Copper Caps too. My AC30 sounds just as good with a Copper Cap as with a vintage Mullard GZ34.Originally posted by trem View Post
Weber does sell a 6X5 replacement. The WX5...which can handle up to 70ma, has a 22V drop, and costs $22.
GregComment
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I often use the Copper Caps too. My AC30 sounds just as good with a Copper Cap as with a vintage Mullard GZ34.Originally posted by trem View Post
Weber does sell a 6X5 replacement. The WX5...which can handle up to 70ma, has a 22V drop, and costs $22.
GregComment
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How does the Weber replacement get its voltage drop, a 22V Zener?Comment
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The topic of faking a tube rectifier gets very little public play. Possibly this is because it's fairly easy, and possibly because of the heavy interference from the "Silicon is the Devil" crowd.
But Weber put out a note on how they do their Copper Caps. They use silicon diodes, a power resistor, and a negative tempco thermistor. The diodes and power resistor give the voltage drop at current, and the thermistor gives a little bit of a slow-down at turn-on time.
Vacuum diodes actually start conducting a little with about zero forward voltage. The electrons are there , floating in a cloud outside the cathode and popping out and back into the cathode to maintain charge neutrality on the cathode itself. As soon as there is any positive voltage on the plate, some of the electrons wander down there and get absorbed - current flows!
But this current takes a fair amount of voltage to come up to being significant. The necessary voltage means that the current rises slowly, until finally it's pulling a lot of the electrons out of the cloud at the cathode. A resistor in series with silicon diodes, which have a negligible voltage drop in a B+ application, is a pretty good approximation.
If you wanted to do a really bang-up job of approximating a vacuum diode, you could use zeners and additional resistors to fake the curvature of the conduction in the forward characteristic, capacitors to slow things down, lots of stuff. There's room there to work. However, all of this is getting dumped into a BFC (Big Freaking Capacitor!) right at the end of the vacuum diode, so there are some big questions about whether if you get about the right DC voltage and ripple (for the purists!) that you'd be able to hear a difference.
But I'm wandering. Weber uses a power resistor and an NTC thermistor for some delay.Amazing!! Who would ever have guessed that someone who villified the evil rich people would begin happily accepting their millions in speaking fees!
Oh, wait! That sounds familiar, somehow.Comment
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Thank you both for the info about Weber WX5.
RG - Thanks again for your...is it valuable or invaluable... input.
I have heard it argued that a player could not distinguish between the...should I say nonlinear sag... of a Tube Diode, and simply placing a Sag Resistor at the junction of SS Rectifier Diodes. But I am not really qualified to say.
Thanks AgainComment
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Actually, you ARE qualified. If you hear hear it and like it, it's good. If you can't hear it, it makes no difference. Your opinion is the only one that matters - to you.Amazing!! Who would ever have guessed that someone who villified the evil rich people would begin happily accepting their millions in speaking fees!
Oh, wait! That sounds familiar, somehow.Comment
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10-4...I agree with you 100%...with the exception of myselfOriginally posted by R.G. View Post
I have mentioned it before, but this is probably a good time to say it again.....I Do Not Play Guitar. I am just a washed-up drummer that got into "amp repair" by default. Seemed like every guitar player I played with was uneducated about his gear. I liked it, so I biased an amp that needed new tubes...and the rest is history.
But Anyway.....I think you are absolutely correct.
Way too many guys are afraid to admit (especially on a guitar forum) that they hear No Difference between a Mylar Dielectric, or one made from, plastic, rubber, oil, etc etc.
I do not want to open that door.....but suffice it to say, God did not intend for musicians to play their instruments in sound-proof rooms, trying to convince themselves that they can hear an advantage of using solid wire over stranded.
Anyway.....Thanks For Your Help...I REALLY Appreciate It.
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Nah, those really silicon challenged will use tube hearing aids:Originally posted by NateS View Post
Acousticon A-120 (Constellation) Vacuum Tube Hearing Aid
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Makes a mockery of a particualr amp brand dual and tripple rectifiers does'nt it?
Cheers,
IanComment
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Most of those - 95% - show up at my shop with the rectifier selector in the solid state position. Go figure...Originally posted by Gingertube View Post
I tell the owners they could put those rectifier tubes away, don't even bother havin' em in the amp but I gets the same old argument: "I read on the interwebs that it makes my amp sound right, or different, or sumpin', so leave 'em there."
This isn't the future I signed up for.Comment
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The amps sound louder on the SS rectifier setting.
I had a guy who thought there was something wrong with his amp when it was set for the tube rectifier setting.
"It's not as loud".Comment
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