The Other 13E1 SE-OTL

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Ray P
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#91 Re: The Other 13E1 SE-OTL

Post by Ray P »

Mike H wrote: Tue Apr 23, 2019 3:38 pm Interesting, lot of family tidying to do is there? :lol:
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#92 Re: The Other 13E1 SE-OTL

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#93 Re: The Other 13E1 SE-OTL

Post by Ray P »

Today I all but finished assembling the power supply chassis and to prove it I had the filaments of the 13E1s glowing nicely (you can just see the red glow in this picture);

Image

The filaments are running on AC and I measure 25.8VAC across them so pretty much spot on, though that's without any B+ supply connected.
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#94 Re: The Other 13E1 SE-OTL

Post by Cressy Snr »

Ray P wrote: Sun Apr 28, 2019 9:53 pm The filaments are running on AC and I measure 25.8VAC across them so pretty much spot on, though that's without any B+ supply connected.
I wouldn’t think the heater voltage would change when the HT is applied. Just a reminder: before you use them in anger, cook the 13E1s for an hour or so on just heaters, in order to allow the getters to mop up any residual gas.

That aside, I think you’re in for a real treat when you get this amp going. :)
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#95 Re: The Other 13E1 SE-OTL

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Image Watching.
 
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#96 Re: The Other 13E1 SE-OTL

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Cressy Snr wrote: Mon Apr 29, 2019 2:12 pm I wouldn’t think the heater voltage would change when the HT is applied. Just a reminder: before you use them in anger, cook the 13E1s for an hour or so on just heaters, in order to allow the getters to mop up any residual gas.

That aside, I think you’re in for a real treat when you get this amp going. :)
Thanks Steve. I was forgetting the 13E1 isn't a DHT so the filaments aren't part of the amplifier circuit.

After I was happy everything was stable I left the 13E1 filaments powered up for an hour or so as you suggested; they got nice and toasty!
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#97 Re: The Other 13E1 SE-OTL

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Ray P wrote: Tue Apr 30, 2019 7:00 am .... they got nice and toasty!
Yep, they get a bit warm. Wait ‘til you get them conducting. :D
Mind you, Nick told me at his place, that in terms of heat output, 13E1s are pussycats compared to the 6C33C. :shock:
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#98 Re: The Other 13E1 SE-OTL

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Cressy Snr wrote: Tue Apr 30, 2019 1:54 pm
Ray P wrote: Tue Apr 30, 2019 7:00 am .... they got nice and toasty!
Yep, they get a bit warm. Wait ‘til you get them conducting. :D
Mind you, Nick told me at his place, that in terms of heat output, 13E1s are pussycats compared to the 6C33C. :shock:
The heat issues with 6C33Cs was one of the things that influenced me to switch to the 13E1 after you rediscovered them. That said, I've had no interest in taking on the 6C33C project parts so I guess one day I'll build it and get some first-hand experience.
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#99 Re: The Other 13E1 SE-OTL

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As I mentioned on Steve's 13E1 project thread, I have a Mean Well SMPS that is capable of delivering 26V 4A and I'm thinking of trying it for the 13E1 filaments (I've been using AC so far) - not expecting the sound to be transformed in any way but 13E1s aren't common or cheap so considerations are about avoiding stressing them unnecessarily because of the vagaries of the mains voltage.

If I were to use it (the SMPS) are there any tips about optimising the implementation? For example laptop bricks generally have a ferrite close to the laptop barrel connector - maybe I should just get hold of some of those leads from dead laptop supplies?
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#100 Re: The Other 13E1 SE-OTL

Post by Mike H »

Two thoughts - 1. If the valves are that precious, maybe some sort of soft start up, a series resistor will probably be enough. 2. Common mode rejection choke type filter where it goes into the amp, lots of suitable CM ferrite chokes and caps on RS site. Google for info about CMR filters.
 
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#101 Re: The Other 13E1 SE-OTL

Post by jack »

A "common mode" filer on the input to the SMPS will stop some crap from the SMPS escaping back onto the L&N and thus helps protect noise from entering the system via the other PSU components. It has next to no effect on the DC produced by the SMPS.

Note that apart from CM noise coming from the SMPS, there is likely to be some EMI and possibly differential noise too.

Differential noise is dealt with separately.
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#102 Re: The Other 13E1 SE-OTL

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Though any EMC conformant supply should already have taken steps to limit the RF pushed back into the supply. However the clue as to if the supply is properly conformant is normally given by its price and who sold it.
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#103 Re: The Other 13E1 SE-OTL

Post by Wolfgang »

This would be another way without SMPS. It's safe against mains fluctuations (unless dramatic) as the DC/cap buffers it. It would need the perfect transformer or some extra power resistors to get to the exact voltage. But it works.
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#104 Re: The Other 13E1 SE-OTL

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Thanks for the tips on using SMPS for the filaments chaps. The module is made by Mean Well, which I think indicates a measure of quality coincident with Nick's point. I'll follow up on the common mode filter suggestion too - may come back for a bit more of a steer when I manage to get confused!

The other point to make is that the filament supply will be located seperately so some seperation but also scope to experiment further in time.
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#105 Re: The Other 13E1 SE-OTL

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Just thinking out loud about the options for powering the 13E1 filaments, any thoughts on a DIY circuit for a linear supply that would be suitable? 13E1 datasheet gives filament spec as 26V @ 1.3A or 13V @ 2.6A.

There are voltage regulator devices that seem to have the right voltage and current numbers on paper but I'm thinking about heat dissipation/reliability; am I right in thinking that keeping the difference between Vin and Vout is the critical thing regarding heat rather than the how high Vout is, coupled with the loss in the reference voltage of the device?

Ta
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