6C33C SE-OTL

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andrew Ivimey
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Re: 6C33C SE-OTL

Post by andrew Ivimey » Wed Apr 11, 2018 10:51 pm

That's nice to know! Cheers.
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Ray P
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Re: 6C33C SE-OTL

Post by Ray P » Sun Apr 15, 2018 11:18 am

I've decided to breadboard a mono version of the 6C33C SE-OTL sketched out by Broskie in his TCJ (see the first post of the thread).

Just purchased some 6C33C-B valves and a cheap 60W SMPS for the filament supply (circa 12V @ 3A).

I've also piqued the interest of the Stateside friend who took the lead on the work of developing the tweaked version of the Transcendent 300B SE-OTL that I currently use. We're currently chewing the cud on possible driver stages. One obvious option is to use the driver stage from the 300B SE-OTL as it is performing a similar role in that design and, simplistically, would see the substition of a single 6C33C for the four 300Bs.

An alternative driver stage that looks a good option is the Broskie Aikido Cascade that he featured a while back in TCJ. This one uses an Octal 6SN7;
Aikido Cascade.PNG
Good fun.

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andrew Ivimey
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Re: 6C33C SE-OTL

Post by andrew Ivimey » Sun Apr 15, 2018 2:38 pm

12 volts at 3 amps will work for a while but they will overheat and die. My experience is that you need at least double the ampage stated. Maybe this is because old valves aren't lap top computers and I have found that speccing to what the valve needs does not sit comfortably with the switched mode PSUs.

I have found the 6S33S-es for whenever...
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.

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Re: 6C33C SE-OTL

Post by Ray P » Sun Apr 15, 2018 4:22 pm

andrew Ivimey wrote:
Sun Apr 15, 2018 2:38 pm
12 volts at 3 amps will work for a while but they will overheat and die. My experience is that you need at least double the ampage stated. Maybe this is because old valves aren't lap top computers and I have found that speccing to what the valve needs does not sit comfortably with the switched mode PSUs.
Thanks Andrew. The cheap and cheerful 60W SMPS I've ordered is rated for 5A @ 12V, however, I only bought it for the mono breadboard build so I'm not anticipating a long service life for it; if the project works out I'll investigate something better.

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Re: 6C33C SE-OTL

Post by ed » Sun Apr 15, 2018 6:19 pm

andrew Ivimey wrote:
Sun Apr 15, 2018 2:38 pm
12 volts at 3 amps will work for a while but they will overheat and die. My experience is that you need at least double the ampage stated. Maybe this is because old valves aren't lap top computers and I have found that speccing to what the valve needs does not sit comfortably with the switched mode PSUs.

I have found the 6S33S-es for whenever...
<pedant-mode>
I'm thinking that individual experience is needed these days as I've found great variations in the SMPS I've used. The perforated steel case ones I've used have all been advertised as LED drivers and performed well for heater duties. The computer supply ones I've used have been less than robust under duress, and although specced at high current values I wouldn't trust them for heater duty at their current limit....mine have got hot...my perforated steel case ones have never got hot.
</pedant-mode>

ymmv
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andrew Ivimey
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Re: 6C33C SE-OTL

Post by andrew Ivimey » Sun Apr 15, 2018 7:17 pm

Okay that sounds sensible Ta.

What does ymmv mean though!
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Re: 6C33C SE-OTL

Post by pre65 » Sun Apr 15, 2018 7:23 pm

andrew Ivimey wrote:
Sun Apr 15, 2018 7:17 pm
Okay that sounds sensible Ta.

What does ymmv mean though!
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Re: 6C33C SE-OTL

Post by simon » Sun Apr 15, 2018 7:28 pm

A little off topic but I have one of those perforated LED lighting SMPS ed, which I intend to use with a class D subwoofer amp. It was cheap and cheerful from China so there were no instructions...

I've never used one before and there are 3 (IIRC) sets of terminals, but no indication if they're multiple connections for a single supply or separate supplies. I hope it's a single supply. What's people's experience with these things, is it likely to be a single supply?

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Re: 6C33C SE-OTL

Post by andrew Ivimey » Sun Apr 15, 2018 7:31 pm

I got me voltmeter out and... it was all I could do, I reasoned.

Ymmv isn't as friendly as I imagined, or maybe I was thinking about ymmv. - all very confusing.
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.

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Re: 6C33C SE-OTL

Post by Ray P » Sun Apr 15, 2018 7:35 pm

Here's a link to the SMPS I ordered...

https://www.ebay.co.uk/itm/AC-110-220V- ... 2749.l2649

Ray

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Re: 6C33C SE-OTL

Post by pre65 » Sun Apr 15, 2018 7:43 pm

simon wrote:
Sun Apr 15, 2018 7:28 pm

is it likely to be a single supply?
Yes. :)
People are like stained-glass windows. They sparkle and shine when the sun is out, but when the darkness sets in, their true beauty is revealed only if there is a light from within
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Re: 6C33C SE-OTL

Post by ed » Sun Apr 15, 2018 8:54 pm

Hi Simon

is it like one of these?
smps50.jpg
if it is I've always assumed the rating figure is total and that the 2 outputs are from the same supply...Can't answer for sure as I've only used one output from each supply. The one good thing about these is that they are floating, so you can make a balanced supply if you have 2 of them. I wouldnt suggest trying a balanced supply from one smps.

The one on the right is 12v 12A and the one on the left is 24v 5A but they seem to be the same layout inside. I have some 5v 5A with single terminal, same as Ray's and they are good for the full load without getting hot.

The ones on the right were used for feeding the Coleman regs for the sv572 and they gave about 9amps and never even got warm. The Coleman regs generated some heat though!.
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Re: 6C33C SE-OTL

Post by simon » Sun Apr 15, 2018 10:43 pm

Hi ed, thanks - yes it looks similar. I would have thought that if there were two supplies the blurb would mention it as a selling point. Guess it just shows my ignorance of SMPS.

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Re: 6C33C SE-OTL

Post by Ray P » Thu Apr 19, 2018 7:08 am

I took delivery of three 6C33C-B valves yesterday. They're smaller than I imagined but have a very solid/substantial look and feel.

I also received the SMPS for the filaments and have a suitable valve socket on the way.

General direction of travel is to build the driver stage based on the Broskie Aikido Cascade circuit using 6SN7s. Regulated supply for the driver stage and a CLCLC arrangement for each 6C33C.

I need a small transformer with around 315-320V secondary to power the regulator for the driver stage if anyone has one lurking that I could borrow for the breadboard build. The driver stage draws around 13mA. The reguator wll be a Neurochrome Maida type so no shunt current needed.

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Re: 6C33C SE-OTL

Post by Ray P » Sat Apr 21, 2018 10:51 am

I have a friend in the USA who I worked with on the Transcendent 300B SE-OTL development project and we've now buddied up to work on this 6c33c SE-OTL project.

As thinking is progressing, and parts arriving, to the stage where an initial build is imminent I'll start a new thread in the 'Everyone's Projects' topic.

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