I "improved" the Pilot 240 i had a while back -- it's going to get improved again -- has just been sitting on the shelf for years. Telux multiple LED's in the EL84 cathode lines:
An externally hosted image should be here but it was not working when we last tested it.
The only difference between this and the original is the replacement of the cathode bias resistor with the TELUX led matrix. I am going to guess that R1,2,7 could be replaced by a potentiometer for the purposes of setup.
I have several Pilots but I have no experience with using LEDs for bias. I've been meaning to give them a try sometime.
Pilot amps are highly praised for their sound. The 232 is widely considered one of the best PP 6BQ5 amps around. The Pilot integrateds such as the 240, 245, and 246, are built around the same basic 232 design. I've always found it odd, however, that paraphase inverters (as used in those designs) are generally frowned upon from a technical perspective. Same holds true for the Magnavox console amps, which have a loyal (some would say rabid) following.
My understanding of design and technical detail is, admittedly sorely lacking. And I've heard all the arguments against the paraphase - "not elegant", "not balanced", etc.
I like what I hear with these designs, though. =8^)
. . . Charlie
Pilot amps are highly praised for their sound. The 232 is widely considered one of the best PP 6BQ5 amps around. The Pilot integrateds such as the 240, 245, and 246, are built around the same basic 232 design. I've always found it odd, however, that paraphase inverters (as used in those designs) are generally frowned upon from a technical perspective. Same holds true for the Magnavox console amps, which have a loyal (some would say rabid) following.
My understanding of design and technical detail is, admittedly sorely lacking. And I've heard all the arguments against the paraphase - "not elegant", "not balanced", etc.
I like what I hear with these designs, though. =8^)
. . . Charlie
I also have a Pilot receiver pulled out of the recycling bin in our town.
The 240 was given to me by the father of friend but it wouldn't make any noise whatsoever. (Slowly brought it up using a variac.) When I did power it up I discovered problems with the filter caps and some of the resistors were charred and way out of compliance.
5 of the Telux LEDs, should get the bias to the right level, but I'll bench test it first and relate the results.
The 240 was given to me by the father of friend but it wouldn't make any noise whatsoever. (Slowly brought it up using a variac.) When I did power it up I discovered problems with the filter caps and some of the resistors were charred and way out of compliance.
5 of the Telux LEDs, should get the bias to the right level, but I'll bench test it first and relate the results.
I'm with you Charlie. PP with a paraphase splitter, best thing I have built. Luckily I ignored all the techies opinions on this subject.
One of the most musical sounding driver stages. It was also used by L' Audiophile (Paris) in various amps.
Don't listen to opinions, listen to the amp 😉
Don't listen to opinions, listen to the amp 😉
Anyone have a link to schematics for:
The Pilot integrated such as the 240, 245, and 246,
Just curious..😀
Regards
M. Gregg
The Pilot integrated such as the 240, 245, and 246,
Just curious..😀
Regards
M. Gregg
The Magnavox circuit uses different coupling caps to the output tubes. Does that signify it is the regular or non floating paraphase? Is the Pilot actually a floating paraphase?
I was referring to the bias required for 6BQ5.
If the LEDs are connected in shunt the 2.67v is way too low. On the original schematic you posted, the cathode voltage is 11.5.
If the LEDs are connected in shunt the 2.67v is way too low. On the original schematic you posted, the cathode voltage is 11.5.
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each of the TELUX devices is a matrix of LEDs in parallel -- I made a model with 5 LEDs in series -- that's where the X5 comes up in the descriptor.
A bit more clear:
An externally hosted image should be here but it was not working when we last tested it.
In the Mag there are different coupling caps for the straight and the inverting out, and, as in the Pilot, there are also different cathode resistors. This is a regular basic paraphase, not the floating/see-saw. If you simulate the circuit on spice, and observe the low frecuency behaviour , you'll know why the different caps
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