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Most information/recommendations I've come across pertaining to the 5842/417A tube type are for use as drivers. Anyone have experience with and/or can comment on various 5842's/417A tubes used as phase splitters? I've used Raytheons and WE's, though think the Western Electrics were on their last legs and did not strut their stuff. It would be nice if I could improve upon the Raytheons without paying WE prices.
I am curious about the Ericsson and UK made Genalex tubes, as in general their tubes are steller. But I am unaware about their quality as phase splitters. And wonder if late production (late 1970's) UK made Genalex tubes used the same materials and had the high level of quality similar to their 1960's made tubes.
Thank you for any info!
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Options seem to be:
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Amperex US made gold pins - 1960's
Amperex US made mil spec gold pins - 1960's
Amperex US made mil spec gold pins - 1970's-80's
Ericsson Swedish made - 1960's (about as pricy as good WE's)
M-O Valve Genalex UK made - 1960's
M-O Valve Genalex UK made - Late 1970's
Raytheons - various vintages and mil spec
RCA's - likely 1960's (not US Ampererx re-branded)
Tung-Sols - 1960's
Western Electric - 1950's
Western Electric - Early to mid 1960s
Western Electric Mil spec - various vintages
Follow Ups:
To my ears the WEs are the best sonically and the Ericsons 2nd best. The Raytheons are OK but thinner sounding. The Amperexs tend to be bright. Used as phase splitters the differences may lessen, but I wouldn't bet on it.
Thanks for the input. FYI: The 5842/417A phase splitter requirement is within my amps so I won't be fiddling with adapting to a different tube type in place of a 5842. Regarding matching the 5842's, the manufacturer stated matched 5842s not required as the use is as a phase splitter without gain for Single-ended input only.
The manufacturer has experience with Raytheon and Western Electrics in this circuit application and mentioned the WE's are an improvement sonics wise. Thus my interest in upgrading to a 5842 that might better the Raytheon
The amps are true balanced amps, with balanced driver, gain and the push-pull output stage. If only my preamp was balanced I could use the amp's XLR input which happily bypasses the phase converter.
Thanks again for your advice!
why is there any phase splitter in the circuit?
Now I see why, having re-read your post. But I am not sure why you'd need two different input voltage amplifier/driver stages, one for balanced and one for SE operation; a balanced input can be driven in single-ended mode (just ground one side of the balanced voltage amplifier) and the output of the balanced stage can then drive the output stage in balanced mode, thereby obviating the need for a phase-splitter. But I guess there are many ways to skin that cat. (Metaphorically speaking; I do not endorse cruelty to animals.) Seems unnecessarily complex is all. The Atma-sphere amps are designed and operate as I've described above, for one example.
Edits: 12/20/14
Hello Lew. Thanks for your imput. If I understand your post correctly my explanation about these amps was too sketchy. These amps do not have individual gain/driver stages dedicated to RCA signal-ended signals and another set dedicated to XLR balanced signals. The following amplifies on my understanding of the operation of the amps.
Each monoblock has true balanced driver, gain and of course a balanced output push pull stage. Via the amp's XLR input, the hot signal (pin 2) feeds directly into the Phase A driver stage and the cold signal (pin 3) feeds into the Phase B driver stage. [Or is the gain stage 1st?] These signals continue balanced throughout the amp, e.g., there's a Phase A and a Phase B gain stage. FYI: For each monoblock there are (2) 6SN7 driver tubes and (2) 6SN7 gain tubes.
This design enables the signal input into the amps from a true balanced source to remain entirely in true balanced format as the signal passes through the amp--without phase inversion any place. And there should be sonic benefits for keeping the signal in balanced format from source to speakers. My understanding, which could be incorrect, is that when a balanced signal is input to some amps via their XLR inputs the signal goes through phase inversion via a transformer or other components, which adds complexity and causes some signal degradation.
Using the amp's RCA inputs on these amps simply adds a phase splitter in front of the above mentioned balanced driver stage--no other circuitry is added.
You won't do any better, and most are less microphonic than the WE versions.
You'd likely benefit from not using any version, and selecting any one of various better performing tubes IMHO.
I would buy a pile of the Raytheons and match them up in a jig to find two tubes with matched triodes that also match each other.
Sorry: I was thinking 5670 not 5842. You only need to find two tubes that match. It can sometimes be a challenge to find two matching high transconductance tubes, so I test those on the jig too and usually buy several more than I need in order to get a good match.
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