Did use the 6211 and 6212 in a phono preamp. But then got out of that medium and don't remember any other specifics other than the much lower B+ requirements
I like the 6n16 and 6n28 minitubes to.
https://www.diyaudio.com/community/threads/6n16-preamp.392420/#post-7179695
https://www.diyaudio.com/community/threads/mini-me-phono-preamp.242855/
https://www.diyaudio.com/community/...lanced-preamp-for-purify.369253/#post-7155079
https://www.diyaudio.com/community/...-preamp-and-power-supply.393318/#post-7264748
https://www.diyaudio.com/community/threads/6n16-preamp.392420/#post-7179695
https://www.diyaudio.com/community/threads/mini-me-phono-preamp.242855/
https://www.diyaudio.com/community/...lanced-preamp-for-purify.369253/#post-7155079
https://www.diyaudio.com/community/...-preamp-and-power-supply.393318/#post-7264748
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@Koifarm
Thanks for the reply.
Really impressive work that you have there.
I could see that you use encapsulated transformers. I have always been curious if I should go down the same route and scrap all switching converters I have (1 buck and 1 boost). The other possibility would be to use toroidal transformers.
I just want to make the amp as quiet as possible.
Don't you get hum, because of the heaters being fed with AC?
Thanks for the reply.
Really impressive work that you have there.
I could see that you use encapsulated transformers. I have always been curious if I should go down the same route and scrap all switching converters I have (1 buck and 1 boost). The other possibility would be to use toroidal transformers.
I just want to make the amp as quiet as possible.
Don't you get hum, because of the heaters being fed with AC?
I feed the heaters always with DC. The preamp on the right photo is very quit. See the measurement in that thread. No hum or hiss. I also use SMPS for tube amps. Works also great for me.
https://www.diyaudio.com/community/...urifi-1et400a-amps.379211/page-3#post-7045290
https://www.diyaudio.com/community/...urifi-1et400a-amps.379211/page-3#post-7045290
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These days I do the same.
In such a custom PCB, most of the time I just use a SMPS.
Those are also available in PCB blocks like those transformers.
Witch some additional and very simple filtering that gives a very nice clean heater voltage 🙂
I have problems with the noise generated by this boost:
https://www.ebay.co.uk/itm/292914470534?hash=item4433101e86:g:n9gAAOSwyTtcOGHu
The buck converter is fine:
https://www.ebay.co.uk/itm/195267362576
https://www.ebay.co.uk/itm/292914470534?hash=item4433101e86:g:n9gAAOSwyTtcOGHu
The buck converter is fine:
https://www.ebay.co.uk/itm/195267362576
I found the 6n17 tube very microphonic, that should be great for a guitaramp to get more sustain.
How sounds/works that with 12V anode supply? Or is that a 12v transformer used for output?
How sounds/works that with 12V anode supply? Or is that a 12v transformer used for output?
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There are these very simple 78xx compatible buck converters these days that perform quite well.
They are a bit easier to place on a PCB 🙂
Most people prefer the 6N21B to the 6N17B, but I only had the later.
I know that the way I've chosen the symbols is not ideal.
So, the 12V are delivered by an external laptop power supply (I am using a 16V instead). That then connects to the boost converter which will output 220V for the output transformer and valves.
So what is inside the "DC input" rectangle, connects to the "HV 220V" rectangle using the boost converter between both.
Crappy drawing. Isn't it ?
@b_force
I tried, initially, to use a 7806 for the heaters but that thing got really, really hot. Then I had the idea of placing an external power transistor to help the regulator, but never got the balance between the two right. The problem is that, if I use a 12V power supply, I will have 6V drop across the 7806 and both valves are pulling 700mA or so. Finally, I gave up and used a buck, which runs cool. 😎
I tried, initially, to use a 7806 for the heaters but that thing got really, really hot. Then I had the idea of placing an external power transistor to help the regulator, but never got the balance between the two right. The problem is that, if I use a 12V power supply, I will have 6V drop across the 7806 and both valves are pulling 700mA or so. Finally, I gave up and used a buck, which runs cool. 😎
Sorry for late answer.
Which is I don´t know. I have them in stock but never got around to "play" with them.
@Koifarm has a lot of experience though 😉