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#1
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
Hi RATs!
I got an A7-D off Ebay for $60., about four times its price as a new kit in '56. It has new coupling caps. Hooked to the Neo-phone 5-1/4" on a flat baffle, direct. It sounds heavenly. The ehorn woofer does no harm I have an A7-E waiting for repairs. It has an 12SL7 for the phono stage, opposed to the "D", which has two line stage inputs. Happy Ears! Al |
#2
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
tubegarden wrote: Hi RATs! I got an A7-D off Ebay for $60., about four times its price as a new kit in '56. It has new coupling caps. Hooked to the Neo-phone 5-1/4" on a flat baffle, direct. It sounds heavenly. The ehorn woofer does no harm I have an A7-E waiting for repairs. It has an 12SL7 for the phono stage, opposed to the "D", which has two line stage inputs. Happy Ears! Al Hi RATs! Just got the A7-E working. Replaced the output coupling caps and bypassed the selector switch and tone cpntrols. Also replaced the broken B+ wire to the 12SN7 ... Joy! Stereo! Monoblocks! Happy Ears! Al PS new caps are Illinois Capacitor 0.1uF 630V, my reigning favorite under a buck |
#3
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
Hi RATs!
OK, I bypassed the tone controls on the "D", so now both amps are reasonably simple. Also sound OK Next, add chokes and oil caps Happy Ears! Al |
#4
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
Hi RATs!
My A7-E population is up to three. Also, an A7-D and an A7-C. Being in the dim future twilight years is fun, if you accept the madness as just the flavor of the decade. I imagine I could set up elaborate controls and learn to identify each of my old amps by their sound alone. I haven't got the energy nor interest, but, I have a fine imagination. I was always happy to know Goofy, the comic book character, was around in my early childhood, but, when I discovered Gyro Gearloose, my soul found a Fountainhead. Walt Disney was cool, but, he had a moustache, and modern Disney business practices do not allow moustaches ... it ain't evil we should fear, it is nice-nice. So, I am drenched in fine sound, with more flavors waiting patiently while many of you are busy using the online thesaurus to insult others. It's OK, my first wife's Mother collected books of insults. It is just the way some folks are wired. Radically changing an amplifiers topology is easy-peasy. Teaching you morons the meaning of the words self respect may take a bit longer. It is my life's work. Good thing I am old, it is pretty much given it is a waste of time We are meerly human. If your insults lack humor, what is left? If some of the tubes in my amps are only there to load the filament supply, it doesn't hurt anything. Sanity is not Holy, just another way to tell yourself you have a grip on the important thngs in life, as if there ever were any Happy Ears! Al |
#5
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
tubegarden wrote: Hi RATs! My A7-E population is up to three. Also, an A7-D and an A7-C. Being in the dim future twilight years is fun, if you accept the madness as just the flavor of the decade. I imagine I could set up elaborate controls and learn to identify each of my old amps by their sound alone. I haven't got the energy nor interest, but, I have a fine imagination. I was always happy to know Goofy, the comic book character, was around in my early childhood, but, when I discovered Gyro Gearloose, my soul found a Fountainhead. Walt Disney was cool, but, he had a moustache, and modern Disney business practices do not allow moustaches ... it ain't evil we should fear, it is nice-nice. So, I am drenched in fine sound, with more flavors waiting patiently while many of you are busy using the online thesaurus to insult others. It's OK, my first wife's Mother collected books of insults. It is just the way some folks are wired. Radically changing an amplifiers topology is easy-peasy. Teaching you morons the meaning of the words self respect may take a bit longer. It is my life's work. Good thing I am old, it is pretty much given it is a waste of time We are meerly human. If your insults lack humor, what is left? If some of the tubes in my amps are only there to load the filament supply, it doesn't hurt anything. Sanity is not Holy, just another way to tell yourself you have a grip on the important thngs in life, as if there ever were any Happy Ears! Al I am following your adventure, even though I don't have anything to say. Keep on posting. |
#6
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
thomas wrote: I am following your adventure, even though I don't have anything to say. Keep on posting. Hi RATs! The A7s are all homemade, from kits. The C and E's have a phono stage. It seems there was a tendency to hum ... each shows a different approach. None follow the schematic I have seen One has star ground. Each component that needs to be grounded has a wire to a common grounding point. Another has a dedicated filament transformer for the 12SL7 phono stage. My kind of insanity This one also uses all cotton braid covered wires. Not in the original kit It is refreshing to realize many have trod these pathways before me I am intent on changing the PS filter to C-L-C-L-C. But, all in good time. Meanwhile, this is the best match for the Neo-phones I have heard. And, I am hearing more than I thought likely, ever ... Perhaps a choke load on the plate of the 12SN7 VA ... Happy Ears! Al |
#7
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
Hi RATs!
A recording of organ got the voice coils rattling, so I put a 22uF oil cap in series with the little drivers. Rattle gone. The ehorn never has rattled Happy Ears! Al |
#8
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
In article . com,
"tubegarden" wrote: Hi RATs! A recording of organ got the voice coils rattling, so I put a 22uF oil cap in series with the little drivers. Rattle gone. What is a "Neo-phone"? The name sounds like it is a "New Telephone", but from the context you are using it in it sounds like you are talking about a speaker? Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#9
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
John Byrns wrote: but from the context you are using it in it sounds like you are talking about a speaker? Look up Neofone. Some have a hard time with neologisms... Peter Wieck Wyncote, PA |
#10
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
John Byrns wrote: In article . com, "tubegarden" wrote: Hi RATs! A recording of organ got the voice coils rattling, so I put a 22uF oil cap in series with the little drivers. Rattle gone. What is a "Neo-phone"? The name sounds like it is a "New Telephone", but from the context you are using it in it sounds like you are talking about a speaker? Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ Hi RATs! http://diyhifisupply.com/diyhs_speaker.htm Neo-Fone. Neo-Fone. Neo-Fone. Sound good. Not too expensive. Forgettable name ... Happy Ears! Al |
#11
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
In article ,
Here in Ohio wrote: On 7 Nov 2006 07:49:26 -0800, "tubegarden" wrote: Hi RATs! http://diyhifisupply.com/diyhs_speaker.htm Neo-Fone. Neo-Fone. Neo-Fone. Sound good. Not too expensive. Forgettable name ... Happy Ears! Al From the looks of the drivers and their impedance curve, I'm betting that any output above 1KHz is cone breakup. :-) If you're going the "full range" route, at least buy drivers from someone who knows what they're doing like Ted Jordan. He's worked out the best compromises for this type of speaker. http://www.ejjordan.co.uk/index.html For those of us less knowledgeable about the operation of speakers could you explain your reasoning here, specifically why you are "betting" that cone breakup begins at 1KHz? It isn't clear to me that Ted Jordan's speakers are a better compromise than the Neo-Phone, the best compromise depends on how you weight a speaker's characteristics. For example the Jordan speakers have an unacceptably low efficiency, while the Neo-Fones do better in this regard. The Neo-Fones also appear to have better low frequency extension, while the Jordan's seem to put a priority on extending the high frequency response to blue light. Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#12
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
In article ,
Here in Ohio wrote: On Wed, 08 Nov 2006 19:02:36 GMT, John Byrns wrote: For those of us less knowledgeable about the operation of speakers could you explain your reasoning here, specifically why you are "betting" that cone breakup begins at 1KHz? Look at the impedance curve. It starts going way up above 1K and, from what I've seen of cone drivers, that usually indicates they're resonating. Wouldn't resonances produce peaks in the impedance curve similar to the one just below 60 Hz? The rise is very smooth and follows a curve similar to that typically caused by voice coil inductance alone. In other words, exhibiting cone breakup. You have utterly failed to prove your point so far. I'm not disputing that there may be cone breakup, I am simply saying that I don't understand how you can tell from the published impedance curve that there is cone breakup? (The inductance of the voice coil also raises the impedance at high frequencies, so it's harder to drive a cone driver at precisely the point where it's having the most trouble.) It's also a 5.25" cone driver and those just don't work well for high frequencies. (They don't really work well for bass either.) :-) And the Jordan driver is much worse for bass, it's all a matter of the compromise you are willing to accept. It's physically impossible to make a full-range driver that works well. It's going to suck at either one extreme or the other (or maybe both). Jordan has pretty much given up on trying to move a lot of air in order to do a better job at the rest of the spectrum. (This is actually a good thing since it removes a major source of IM distortion.) You haven't explained how the Jordan driver minimizes IM? I was under the impression that at given acoustic output a larger cone will generally have lower IM, other things being equal. The smaller cone must move a longer distance, thus generating more IM. That Neo-Fone thing is a neither here nor there product that tries to compromise too much. Same thing with the Jordan, it just has a different set of compromises. Who cares if it's more efficient? The Jordan drivers are fine and it's not like we don't have good power amps with plenty of power in this day and age. This is "rec.audio.tubes", tube amps generally have a somewhat lower power output capability than semiconductor amps. Maybe you should ask them to supply you with some info on how much distortion these Neo-Fone things put out. I bet it's pretty horrendous. Unfortunately speakers and "horrendous" distortion go together. In short, this fad for "full-range" speakers is rather silly in the first place, but if you're going to buy into it you might as well choose drivers from someone like Jordan who actually knows loudspeakers and has been working on full-range for decades. Fine, but why doesn't he offer a model with the response range skewed towards the low end rather than to frequencies well above the range of human hearing, for those that would like a better compromise? (Indeed, I've heard speakers with 4 vertically stacked Jordan 50mm modules per side crossed over to a sub at about 150 Hz and they did a rather nice job.) What if a "sub" is not part of the game? I would rather give up the octave between 15 kHz and 30 kHz, in exchange for the octave between 75 Hz and 150 Hz. Regards, John Byrns -- Surf my web pages at, http://fmamradios.com/ |
#13
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-phone speaker (2006) Joy to my Ears
"John Byrns" wrote in message ... In article , Here in Ohio wrote: On Wed, 08 Nov 2006 19:02:36 GMT, John Byrns wrote: For those of us less knowledgeable about the operation of speakers could you explain your reasoning here, specifically why you are "betting" that cone breakup begins at 1KHz? Look at the impedance curve. It starts going way up above 1K and, from what I've seen of cone drivers, that usually indicates they're resonating. Not necessarily. You have to back out the rises due to voice coil inductance and cone mass. Wouldn't resonances produce peaks in the impedance curve similar to the one just below 60 Hz? Not necessarily. Cone break up involves the cone being decoupled from the voice coil. Below 100 Hz, the voice coil and the cone are tightly coupled so anything the cone does, shows up in the impedance curve. Above some high frequency, the voice coil decouples from the cone due to the compliance of the mechanical coupling, and the cone's motion is not transmitted back to the voice coil. The rise is very smooth and follows a curve similar to that typically caused by voice coil inductance alone. Agreed. In other words, exhibiting cone breakup. Cone breakup usually shows up in acoustical response curves. I see cone breakup quite clearly in this curve: http://www.ejjordan.co.uk/drivers/jx92.html I'd say that there is significant breakup above 4 KHz. Some decoupling of the cone related to the small peak at 2K. but not so clearly in this curve: http://www.ejjordan.co.uk/drivers/jxr6.html Looking again, I'd say that there is mild breakup above 6 KHz. Maybe some decoupling of the cone related to the small peak at 3K. |
#14
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-Fone speaker (2006) Joy to my Ears
Hi RATs!
I put a fresh quad of RCA 12A6 tubes into the A7s. Sounds wonderfuller. The Neo-Fone speakers are in the system. The V-Caps are in the system. The ehorn is in the system. (I like subwoofers) I am gonna be sixty in a few months. I'll pass on the super-tweeters. Or, rather, I'd fail ... Please, people, let us remember, audio is idiotic. I do it for fun, not revenge Happy Ears! Al |
#15
Posted to rec.audio.tubes
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Healthkit A7-D (1956) and Neo-Fone speaker (2006) Joy to my Ears
"tubegarden" said:
Hi RATs! I put a fresh quad of RCA 12A6 tubes into the A7s. Sounds wonderfuller. The Neo-Fone speakers are in the system. The V-Caps are in the system. The ehorn is in the system. (I like subwoofers) I am gonna be sixty in a few months. I'll pass on the super-tweeters. Or, rather, I'd fail ... Please, people, let us remember, audio is idiotic. I do it for fun, not revenge Happy Ears! Al DIY forever, Al! A bit too flea-powered for my hungry Maggies, you will note. Environmental activists overhere already signed a petition to shut down all my class A amplifiers, but didn't succeed yet ;-) -- "Due knot trussed yore spell chequer two fined awl miss steaks." |