No, not seriously. Sorry. Remember the EL6471's three-phase PSU! Of course I know that it could be rewired for common (one phase) AC supply, but there's still this tiny 4 µF filter capacitor left, which may suit for 300 Hz ripple with it's notches never getting close to 0 V, but will fail filtering a two-way 100 Hz ripple sufficiently.
Best regards!
I don't know. I also do not have any chance for a successful search at the moment. Maybe in the evening...
Best regards!
Best regards!
GU 46
Not sure if relevant, I saw the following amps on Patrick Turners site.
Using EL34's/ EL84's as drivers for 845 Triodes. They need crazy drive voltages.
http://www.turneraudio.com.au/re-engineeredamps.html
Not sure if relevant, I saw the following amps on Patrick Turners site.
Using EL34's/ EL84's as drivers for 845 Triodes. They need crazy drive voltages.
http://www.turneraudio.com.au/re-engineeredamps.html
Attachments
Philips EL6470 has single-phase power transformer:
In any case, Banat's version is equally as good, but with SS rectification.
In any case, Banat's version is equally as good, but with SS rectification.
These tubes are still available in Russia and the Ukraine. They are NOS and original packed with its unique certificate. Prices are around 30-40US$ per tube, shipment is about the same to Central Europe.
Check in eBay and ask the sellers for larger quantities.
Check in eBay and ask the sellers for larger quantities.
Thanks! That's about ten times the price of GU-50's. As we can easily extract about the same power form three pairs of these with a modest 800 V plate supply, they offer the better bang for the money, I'd say. We'd need a more elaborate driver section, though, as they must be operated in class AB2 to get 120 watts per pair and need a larger grid voltage swing.
Are the GU-46 valve holders also available in the East?
Best regards!
Are the GU-46 valve holders also available in the East?
Best regards!
I have seen sockets in Russian eBay-alternatives, but they are far too expensive since they are military material.
There seems to be an alternative made of some carton material (see thread of ClassZ, linked in an answer somewhere in the beginning of this thread). I will make these sockets on my own from procelaine material.
I have seen these GU-50s too, but i was somehow more impressed by the large glass bottles of the GU-46, even if it might become quite tricky to build something "economic" and useful.
There seems to be an alternative made of some carton material (see thread of ClassZ, linked in an answer somewhere in the beginning of this thread). I will make these sockets on my own from procelaine material.
I have seen these GU-50s too, but i was somehow more impressed by the large glass bottles of the GU-46, even if it might become quite tricky to build something "economic" and useful.
Wonder what's the values of the supply and all the other voltages. Wonder many of these contacts do. Philips seems to have kept many secrets on this design.
Best regards!
Best regards!
what would be about using the driving stage of the Philips EL6472 amp?
shown at Lilienthal engineering
http://lilienthalengineering.com/wp...71-feature-of-EL6472-amplifier-compendium.png
shown at Lilienthal engineering
http://lilienthalengineering.com/wp...71-feature-of-EL6472-amplifier-compendium.png
Same as in EL6471, isn't it? Might get somewhat tricky to achieve these E80L's, I think.
Best regards!
Best regards!
still some available on eBay, at 10$ per tube upwards... shipping excluded.
on the other hand, they seem to be designed to last 10'000hrs...
maybe worth a try... followed by EL34
on the other hand, they seem to be designed to last 10'000hrs...
maybe worth a try... followed by EL34
Guys let`s not forget expensive E80CC at AF input on that Philips power amp , also input AF transformer to ,
If balanced AF input is not necessary same as balanced GNFB as is by Philips amps but only SE AF input maybe something like this configuration of input/driver stage can also work and sound well to ?
If balanced AF input is not necessary same as balanced GNFB as is by Philips amps but only SE AF input maybe something like this configuration of input/driver stage can also work and sound well to ?
Attachments
Oh my...I think we can do without grid current, as ~300W is easy in Class A1. We also do not need any gNFB...why wreck things, and include an already marginal bandwidth output TX in the FB loop. I'd rather load all 6 chambers and play Russian Roulette.
cheers,
Douglas
cheers,
Douglas
Hi Douglas
Well that configuration with EL34 DC coupled to g1 grids of GU46 do not automatically mean constant grids currents flow and constant A2 class of operation , that effect will appear on full excitation of OPS , but is good solution to avoid blocking distortion caused from coupling caps and g1 resistors network ,and to get instant overload recovery in case if grids currents starts to flow ,
that my proposed schematic also do not means tons of applied GNFB , maybe just 5-10db max.
Regards
Well that configuration with EL34 DC coupled to g1 grids of GU46 do not automatically mean constant grids currents flow and constant A2 class of operation , that effect will appear on full excitation of OPS , but is good solution to avoid blocking distortion caused from coupling caps and g1 resistors network ,and to get instant overload recovery in case if grids currents starts to flow ,
that my proposed schematic also do not means tons of applied GNFB , maybe just 5-10db max.
Regards
With EL34's in circuit, I'd just use 'em as voltage amps. Full pentode rigging...and they won't be so worried about possible high plate voltage. Use the g2 voltage to tune them to their loads...🙂 On top of that I'd still do away with the gNFB, local as in Schade resistor, or direct from U-L tap E-Linear is useful for several reasons.
Split C-T grid chokes and coupling caps that are not small will take care of the finals.
cheers,
Douglas
Split C-T grid chokes and coupling caps that are not small will take care of the finals.
cheers,
Douglas