I guess you could float the heaters with a cap to gnd...
What power out do you think you are getting?
How does the sound compare...have you still got the bass as before?
Regards
M. Gregg
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One thing did occur to me...
Another 'advantage' of the PL509 type is a somewhat greater degree of safety from arc-over, due to the huge distance from Cathode to Anode--in comparison- to a 6C33 or 41C, 6H13S or any of the usual Voltage-regulator types....
However, The Screen-Grid is pretty close o the cathode and could suffer a short.
BUT as we have a highish (in comparison to speaker) series-resistor for the G2,--470 ohm, this would blow pretty quickly,--prob faster than the main fuses...
The Disadvantage of the E/PL509 would be the less power in comparison to the 6C33C when using only two valves per channel though...
It Must Be Noted, for those interested in making any OTL with these 'Line-Output' or Sweep-Tubes,--
The Russian 6P45S,--Although Marketed as the same, is NOT the same as a Proper, PL/EL509 with regards the Maximum Peak/Pulse Current that it can pass.
The 509/519 can allow up to 1.4A --In Pulse, while the 6P45S only 600mA under the same conditions.....
--I may get a couple of 6P45S, as they are cheap enough, Just to confirm/disprove this
I'm thinking that the rare and mega-bux 13E1 would be worth trying in an OTL, but unless I win the lottery anytime soon, I aint gonna be trying them!
Another 'advantage' of the PL509 type is a somewhat greater degree of safety from arc-over, due to the huge distance from Cathode to Anode--in comparison- to a 6C33 or 41C, 6H13S or any of the usual Voltage-regulator types....
However, The Screen-Grid is pretty close o the cathode and could suffer a short.
BUT as we have a highish (in comparison to speaker) series-resistor for the G2,--470 ohm, this would blow pretty quickly,--prob faster than the main fuses...
The Disadvantage of the E/PL509 would be the less power in comparison to the 6C33C when using only two valves per channel though...
It Must Be Noted, for those interested in making any OTL with these 'Line-Output' or Sweep-Tubes,--
The Russian 6P45S,--Although Marketed as the same, is NOT the same as a Proper, PL/EL509 with regards the Maximum Peak/Pulse Current that it can pass.
The 509/519 can allow up to 1.4A --In Pulse, while the 6P45S only 600mA under the same conditions.....
--I may get a couple of 6P45S, as they are cheap enough, Just to confirm/disprove this
I'm thinking that the rare and mega-bux 13E1 would be worth trying in an OTL, but unless I win the lottery anytime soon, I aint gonna be trying them!
I must admit I have not looked closely at the tube types for higher current..lower voltage..
I guess most have been used in existing circuits.
http://www.diyaudio.com/forums/tubes-valves/95723-testing-13e1.html
I have a couple of 509's in the loft..Mazda I think ..remember them in the old Tvs...
LOL yes the dreaded Ct...
now linked to the Htr's..I wonder..at earth...Regards
M. Gregg
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Just for fun,
HEATER SUPPLY USING SERIES CAPACITOR:
Compactron "AA3" AM tube radio
Just thought it might be of interest
Regards
M. Gregg
HEATER SUPPLY USING SERIES CAPACITOR:
Compactron "AA3" AM tube radio
Just thought it might be of interest
Regards
M. Gregg
In my collection of old used valves, Ive found a couple of sad looking Mullard PL519 valves, complete with bent pins and that Horrible brown deposits that Mullard valves always seem to generate after a while and have shoved them in place of the two NOS Mazda PL509 I had in there...
Think I'll use these for a while, the cathode-current through each one is just a little higher than the Mazdas, but only by around 5mA.
Between the 519 and 509 there's only a 5W dissipaion difference, all other factors much the same...
40KG6A is same as 519 too....
So far, They sound good, although I havent beeen able to play at, or near full power due to family considerations.....
Think I'll use these for a while, the cathode-current through each one is just a little higher than the Mazdas, but only by around 5mA.
Between the 519 and 509 there's only a 5W dissipaion difference, all other factors much the same...
40KG6A is same as 519 too....
So far, They sound good, although I havent beeen able to play at, or near full power due to family considerations.....
I remember the brown deposit well..always wondered if it was from the varnish or from some gases that came off the lacquer on the Circuit board in old Tv's.
Also the strange blue "arc/glow" that came on some that had a conductive graphite type "ring" put on the glass in manufacture...I was to young at the time to find out what caused it..
My friend at the time (we were only nearly 16) took off the "Cat strap" on a Crt after changing the tube over (as you do) trying to make a good TV out of two bad ones..Two weeks later no power since then and pulled of the HT sucker off the tube drawing an arc that jumped onto his hand...LMAO I don't know which was worse the sound of the CRT breaking on impact with the ground or his squeel...He went to work for the BBC...
Regards
M. Gregg
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Just to clarify for anyone reading this..
Cat strap = spring across the aquadag coating on back of CRT..
UIUC Physics Lecture Demo: Inside Scoop on a Television
Sorry off topic.. Back to OTL
Regards
M. Gregg <<not a TV engineer
Cat strap = spring across the aquadag coating on back of CRT..
UIUC Physics Lecture Demo: Inside Scoop on a Television
Sorry off topic.. Back to OTL
Regards
M. Gregg <<not a TV engineer
Ive run the PL509's now for a few days.
At the moment, I think they are definately Better than a 6C41C and possibly better than Half of a 6C33C
There is no loss of bass and there appears no 'compression' that the 6C41C seems to manifest at higher powers...
I feel--But have no real bearing on why-- That they would benefit for a little more +-B volts to get the best.
First off though, I must get some more Magnoval sockets to set up the other channel with PL509, then I'll add some extra windings to the toroid to get around 175-180V per rail, maybe a bit more....
Among all the valves I have, I found a PL509 that had a white-top, ie--down to air.
So, I smashed it and dissected the cage inside.
I was interested in the dimensions of the Cathode in comparison to the 6C33C that I smashed some years ago.--I still have tthe internals from that!
The Cathode of the PL509 (Oxide Coated Area) is approx 0.75-1mm Narrower than the 6C33C, But, is approx 3.5mm Longer.
--We are looking at the actual Oxide-Coating, not the whole cathode sleeve.
The Distances between items like the Screen-Grid to cathode are at least twice the distance of the cathode to plate of the 6C33C
The Anode Anti-Barkhausen Plates facing the cathode, Inside the anode structure of the PL509 is around 3mm from the cathode, so unless summit falls off inside the valve, It aint gonna short Anode to Cathode easily.
Only point that caused me concern for the 509's reliability would be the thin cathode connection to the pin on the base.
--6C33C wins hands down in this dept!--More of a Strap than a wire in the 33C...
I found another old 509 and tried that in the amp. It showed a loverly blue-glow inside the anode structure, and tinged with white. It was Not bright and I had to turn off the lights to see it well.
This caused a rather odd pumping/oscillation of the amp, where the speaker-cone pumped in and out around 2Hz.
This soon stopped, so I thought --leave it heat up nice and hot--Maybe we have some fireworks!....
After 10 mins, the blue-glow had completely dissappeared, No trace of it at all, and the valve performed fine, and is still working well....
Strange....
At the moment, I think they are definately Better than a 6C41C and possibly better than Half of a 6C33C
There is no loss of bass and there appears no 'compression' that the 6C41C seems to manifest at higher powers...
I feel--But have no real bearing on why-- That they would benefit for a little more +-B volts to get the best.
First off though, I must get some more Magnoval sockets to set up the other channel with PL509, then I'll add some extra windings to the toroid to get around 175-180V per rail, maybe a bit more....
Among all the valves I have, I found a PL509 that had a white-top, ie--down to air.
So, I smashed it and dissected the cage inside.
I was interested in the dimensions of the Cathode in comparison to the 6C33C that I smashed some years ago.--I still have tthe internals from that!
The Cathode of the PL509 (Oxide Coated Area) is approx 0.75-1mm Narrower than the 6C33C, But, is approx 3.5mm Longer.
--We are looking at the actual Oxide-Coating, not the whole cathode sleeve.
The Distances between items like the Screen-Grid to cathode are at least twice the distance of the cathode to plate of the 6C33C
The Anode Anti-Barkhausen Plates facing the cathode, Inside the anode structure of the PL509 is around 3mm from the cathode, so unless summit falls off inside the valve, It aint gonna short Anode to Cathode easily.
Only point that caused me concern for the 509's reliability would be the thin cathode connection to the pin on the base.
--6C33C wins hands down in this dept!--More of a Strap than a wire in the 33C...
I found another old 509 and tried that in the amp. It showed a loverly blue-glow inside the anode structure, and tinged with white. It was Not bright and I had to turn off the lights to see it well.
This caused a rather odd pumping/oscillation of the amp, where the speaker-cone pumped in and out around 2Hz.
This soon stopped, so I thought --leave it heat up nice and hot--Maybe we have some fireworks!....
After 10 mins, the blue-glow had completely dissappeared, No trace of it at all, and the valve performed fine, and is still working well....
Strange....
Alastair,
Are you getting the same power (volume level) as half the 6C33C?
I guess the question has got to be...is the cathode wire bigger than the fuse element in the fuses for + &- rails app 1.5A..
Regards
M. Gregg
Definately seems the same sort of level....
May be slightly more actually... Really should do some power-checks, Are you set up to test for output power?
I may be able to cobble something togeather if the scope is working in the loft...will sine voltage across large 10Ohm resistor just before clipping at 20Khz do?
LOL I guess your gonna say 1Khz...LMAO
Regards
M. Gregg
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Aye, the normally accepted test-signal is 1kHz sine-wave....
The 10 ohm resistor is OK, but an 8 ohm would be better, Could always stick a resistor of the appropriate value across it to make up 8 ohm, Prob a 2W one would suffice, across the Big 10 ohm....
IF you have Two large 10 ohm resistors, you could test the Output impedance of the amp, which would be interesting....
There's a few freebie so-called, spectrum analysers on the web so you could use the PC to generate the test-signal.
Ive used these, but for proper distortion analysis you need a good sound-card,--Which I aint got!
Scope is good though for checking things like square-wave response and to see just when the amp is at the point of clip...
The 10 ohm resistor is OK, but an 8 ohm would be better, Could always stick a resistor of the appropriate value across it to make up 8 ohm, Prob a 2W one would suffice, across the Big 10 ohm....
IF you have Two large 10 ohm resistors, you could test the Output impedance of the amp, which would be interesting....
There's a few freebie so-called, spectrum analysers on the web so you could use the PC to generate the test-signal.
Ive used these, but for proper distortion analysis you need a good sound-card,--Which I aint got!
Scope is good though for checking things like square-wave response and to see just when the amp is at the point of clip...
After bodging about,
I guess these will do..
Just hope the 7Watt holds up..LOL
In will have a play and post what I get!
Just for interest after working out the values over and over for resistors in the box ..I got lazy and used this..LOL
http://www.1728.org/resistrs.htm
Regards
M. Gregg
I guess these will do..
Just hope the 7Watt holds up..LOL
In will have a play and post what I get!
Just for interest after working out the values over and over for resistors in the box ..I got lazy and used this..LOL
http://www.1728.org/resistrs.htm
Regards
M. Gregg
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Ah--Yes, That'll hold up for testing!
I have some 20W resistors that I got from Rat-Shack some years ago, Ive used them up to around 70W RMS for a Very short time!
After that I resort to this--Although Not a good idea.....
(I have been known in the long ago past, to place the resistors into a cold cup of water...)
--Dont try this at home though....!
7.9 ohms Well--Cant get much better than that! After all, a Speaker doesnt have a completely flat impedance versus frequency anyway!
I have some 20W resistors that I got from Rat-Shack some years ago, Ive used them up to around 70W RMS for a Very short time!
After that I resort to this--Although Not a good idea.....
(I have been known in the long ago past, to place the resistors into a cold cup of water...)
--Dont try this at home though....!
7.9 ohms Well--Cant get much better than that! After all, a Speaker doesnt have a completely flat impedance versus frequency anyway!
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Ok here is half 6c33c..
using True RTA ,,not set up just as a signal gen..at 1Khz
All readings are with a X10 probe so you have to multiply...
Obviously it gets more distorted as you increase input..
The first one is 5.5V
Second is at 11V
using True RTA ,,not set up just as a signal gen..at 1Khz
All readings are with a X10 probe so you have to multiply...
Obviously it gets more distorted as you increase input..
The first one is 5.5V
Second is at 11V
Attachments
Full 6c33c..
At 8/9/10/11/12V...I did manage 13V however the 1.6A T fuse blew..so no picks ...didn't want to try it again..drawing 1.7A
Again X10 probe so you have to multiply..
Regards
M. Gregg
At 8/9/10/11/12V...I did manage 13V however the 1.6A T fuse blew..so no picks ...didn't want to try it again..drawing 1.7A
Again X10 probe so you have to multiply..
Regards
M. Gregg
Attachments
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