What was old is new again.... Douk Audio FU32(832A) Vacuum Tube Headphone Amplifier Mini HiFi Stereo Preamp 127214904051 | eBay
Just one example of a few I stumbled onto.
Just one example of a few I stumbled onto.
Ha! I have the near same system except mine says stereo 70, handed down from my Dad.A friend of mine is an audiophile and has two Dynakit Mark IV tube amps and a Dyna Pas-3 tube preamp. He 3D printed a turntable and built his own speakers. MAN....there's nothing like the sound of jazz on vinyl being played through a high quality tube amp system.
Pics are from the web, but this is what he has.
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I really am not an expert/ connoiseur of fine audio systems. My ex super from the wheelchair joint was in a band when younger, still plays guitar, and fixes and builds guitar amps. He is always sending me some silly website of nonsense beliefs in the "audiophile" world, stuff like "ya gotta have braided speaker wire, etc." By that I mean HE is making fun of. He's pretty well setWhat was old is new again.... Douk Audio FU32(832A) Vacuum Tube Headphone Amplifier Mini HiFi Stereo Preamp 127214904051 | eBay
Just one example of a few I stumbled onto.
By the way, the tube in that thing is a WWII suplus, obsolete, dual tetrode VHF transmitting tube. It was never designed for audio use, and primarily designed for what is called "class C" meaning as far from linear operation that you can get. Tube audio amps must be class A operation, or B (Pushpull) or in between AKA "AB"
A single tube that is not push pull cannot produce decent audio if it is anything but class A operation
Here is the original RCA datasheet
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The reason these types of tubes were made at all is in fact because of early development at VHF frequencies. Some of the limiting factors at VHS is LEAD LENGTH which includes the wiring inside the tube, and INTERELECTRODE CAPACITANCE AKA "less is better"
So the thing about dual triod/ tetrode tubes is, you wired them up in push pull and with each tube set of elements nearly identical, they were easier to maintain "balance.
Also push pull means that each tube conducts during 1/2 the sine wave output, so that in effect, each tube is operating at 1/2 the frequency. AKA, if you had two tubs rated for say, 50 MHz and you were trying to operate them near 100 Mhz, you could use two in push pull and the effective freq limit is thus doubled
Here is an 829B VHF amplifier, which is very similar to what this 832A but would have been used for