As you can see from some pics something fell on my amp. Chipping of the pain. Emergency surgery busy as we speak. Output transformers also had a touch up...but must be improved...
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Thank you again Bas, I'm indeed used to 50k log pots at the inlet of my amps and I would say I'm quite happy with them.
Just wanted to know if this could be possible upgrade, but at the moment I'll keep the old solution.
Just wanted to know if this could be possible upgrade, but at the moment I'll keep the old solution.
I can already tell you Francois it's a keeper. Definitely worth building. I have been playing with a single ended el84 the past couple of years. And whilst I loved it. I kept wondering what a bigger tube could do...in terms of handling the 12 inch drivers...though efficient. I got my answer. I know it sounds basic...because a watt is a watt. But it has way more bass and sounds more in control.
Apart from the PSU it is exactly the same as Bob's schematic.
Apart from the PSU it is exactly the same as Bob's schematic.
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Regarding watts: Which output power do you achieve?
I'm quite convinced that Bob based his 11 to 12 watts claim exclusively on his 6P45S simulation model, not on real performance. As written in another tread, I had to severely modify his design in order to increase output voltage swing before the screen grid takes over the cathode current's biggest part. I used a brand new PL519 of European provenance during my measurements and had not more than a mere 8 watts before clipping. This made me think that there are many ways to achieve such output power more conveniently and more economically (think of 12 watts heater power and 35 watts DC plate input power with the PL519).
With this aspect the design was a big disappointment for me, despite of it's admittedly very good sound.
Best regards!
I'm quite convinced that Bob based his 11 to 12 watts claim exclusively on his 6P45S simulation model, not on real performance. As written in another tread, I had to severely modify his design in order to increase output voltage swing before the screen grid takes over the cathode current's biggest part. I used a brand new PL519 of European provenance during my measurements and had not more than a mere 8 watts before clipping. This made me think that there are many ways to achieve such output power more conveniently and more economically (think of 12 watts heater power and 35 watts DC plate input power with the PL519).
With this aspect the design was a big disappointment for me, despite of it's admittedly very good sound.
Best regards!
Hallo Kay,
I have no idea what output power it has. But then again it was not one of the reasons I built it. I was just looking for something more than an EL84 could provide. I believe you when you say it comes nowhere near 11-12Watts.
Kind regards,
Bas
I have no idea what output power it has. But then again it was not one of the reasons I built it. I was just looking for something more than an EL84 could provide. I believe you when you say it comes nowhere near 11-12Watts.
Kind regards,
Bas
Bas, Kay,
have you compared this solution to UNSET?
How do this sound compared to George's solution?
Thanks
have you compared this solution to UNSET?
How do this sound compared to George's solution?
Thanks
Thanks. I've become fond of pcb's. If he goes out of beta with that I might just try it. But alas..no experience with that design yet.
Bas, look at the UNSET thread. It uses cathode drive rather than screen drive. One of the builders posted that he is making 17 watts at 5% distortion with B+=400V, using a 26HU5 tube, with specs similar to EL509. He used a 3k primary SE output transformer. Efficiency seems quite a bit higher than your screen drive amp with 1.6k primaries.
https://www.diyaudio.com/community/threads/unset-beta-board-build.376124/page-12#post-6958401
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Thanks Francois. I did have a look. But I have too many other projects I want to finish first.
Hi Bas,
I have searched through the topic but did not find the schematics that you have used to build the amplifier. I am assuming that the 7k5 resistor is connected between the G2 on the EL509 and Ground? The Synola had a connection like this but I found that it is not required as G2 already provides a path to ground.
If I am right you could just remove the resistor. Would love to hear what your findings are 🙂
Hello Kay, of course Bob used simulations. I dimly remember he even admitted so himself, maybe on Usenet group rec.audio.tubes. Real world looks different, indeed. Also watch out for negative impedance areas due to Dynatron effect.
Kind regards, Tom
They should operate in roughly the same way, but from what I have understood 6P45S is a more beefy tube compared to the EL509. Nothing against the EL509 though, I love it in enhanced triode mode 😉
Hi lechuck,
not only "should operate in roughly the same way" - it is just the same tube with same parameters except upped Pa,max. "Enhanced triode mode" is nothing but screen drive using marketing speech 🙂
Kind regards, Tom
not only "should operate in roughly the same way" - it is just the same tube with same parameters except upped Pa,max. "Enhanced triode mode" is nothing but screen drive using marketing speech 🙂
Kind regards, Tom
I agree that it's the same, but Enhanced triode mode sounds fancier 😆
I have not used the 6P45S yet, only the EL509/PL519's. The 6P45S is still on my list of tubes that I want to build an amp with.