Remember These?

What people are working on at the moment
User avatar
Ray P
Shed dweller
Posts: 2526
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

Re: Remember These?

Post by Ray P » Thu Nov 08, 2018 5:16 pm

Just looking at the 13E1 datasheet; if you run the filaments at 26V you should have much less heat to dissipate as the current is only 1.3A.

User avatar
Ray P
Shed dweller
Posts: 2526
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

Re: Remember These?

Post by Ray P » Thu Nov 08, 2018 5:27 pm

I think I'll start to keep an eye open for a pair of 13E1 valves.

Cressy Snr
Social Sevices have been notified
Posts: 8041
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

Re: Remember These?

Post by Cressy Snr » Thu Nov 08, 2018 5:34 pm

Ray P wrote:
Thu Nov 08, 2018 5:16 pm
Just looking at the 13E1 datasheet; if you run the filaments at 26V you should have much less heat to dissipate as the current is only 1.3A.
Yep, I still have the 225VA, 25V transformer I used on the "Alexandra Palace" 13E1 SE amp I built around 9 years ago. So I'll be running 26V heaters, as that's the voltage it gave.
Ha - ha said the clown. Has the king lost his crown, is the night being tight on romance?

Cressy Snr
Social Sevices have been notified
Posts: 8041
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

Re: Remember These?

Post by Cressy Snr » Thu Nov 08, 2018 5:48 pm

Ray P wrote:
Thu Nov 08, 2018 5:05 pm
Better get some PCBs in the post for you then Steve?

PM me whenever...
Ray, you have a PM. :)
Ha - ha said the clown. Has the king lost his crown, is the night being tight on romance?

User avatar
Ray P
Shed dweller
Posts: 2526
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

Re: Remember These?

Post by Ray P » Thu Nov 08, 2018 5:50 pm

Cressy Snr wrote:
Thu Nov 08, 2018 5:48 pm
Ray, you have a PM. :)
So do you Steve

User avatar
Ray P
Shed dweller
Posts: 2526
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

Re: Remember These?

Post by Ray P » Thu Nov 08, 2018 5:53 pm

Steve, here's the 6C33C amp schematic for info on the 6SN7 stage (and current sink).

Image

Cressy Snr
Social Sevices have been notified
Posts: 8041
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

Re: Remember These?

Post by Cressy Snr » Thu Nov 08, 2018 6:07 pm

Cheers.
Ha - ha said the clown. Has the king lost his crown, is the night being tight on romance?

Cressy Snr
Social Sevices have been notified
Posts: 8041
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

Re: Remember These?

Post by Cressy Snr » Fri Nov 09, 2018 1:08 pm

I'll do the PSU serving the output stages as per the Rozenblit Mini Beast and have ordered the correct chokes off Mouser UK.
Need another supply for the Aikido stage. I'll have to look through my transformers for a suitable one for that job.

The 2x115V, 1KVA toroid I bought off Phil should do a nice job of powering the output stages, via a centre tap rectified, CLCLC setup and not get hot. There'll be enough heat off the 13E1 pair, without having to deal with additional off the transformers. Ideally, the only significant heat I want is off the valves themselves.
Ha - ha said the clown. Has the king lost his crown, is the night being tight on romance?

User avatar
Ray P
Shed dweller
Posts: 2526
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

Re: Remember These?

Post by Ray P » Fri Nov 09, 2018 1:30 pm

PCBs went in the post this morning Steve.

I'll post some details about using them later.

Cressy Snr
Social Sevices have been notified
Posts: 8041
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

Re: Remember These?

Post by Cressy Snr » Fri Nov 09, 2018 2:32 pm

Thanks Ray.
Ha - ha said the clown. Has the king lost his crown, is the night being tight on romance?

Wolfgang
User
Posts: 49
Joined: Mon May 07, 2018 3:08 pm

Re: Remember These?

Post by Wolfgang » Fri Nov 09, 2018 3:40 pm

Steve, please note the resistor must be 3W not 1,5W. Ray posted an older schematic where this hadn't been corrected.

I am sure you have already calculated some basic stuff but I just wanted to mention that the Mini Beast is a different thing, starting with the B+ psu. Unfortunately I don't have the schematics for this amp for more details but TS uses more or less the same building principles in every amp. Best example is the Pinnacle which is basically a 300B SE OTL with only one output tube and some additional filtering for very low noise floor.


The 13E1 is an interesting tube and I couldn't stop myself from running some basic numbers, imagining how I would build it. I hope you don't mind my little brain storming exercise.
Considering the benefits of CCS for OTLs (less distortion, easier adjustment of the tube to changing load of the speaker) and considering the much better sound of the TL783 compared to other regulators, I would start here. The only limitation is the Imax of 700mA. So I would keep it closer to 600mA with very good heat sinks and adjust B+ in order to get to the output power I am aiming for.
The Mini Beast uses 3 output tubes per stereo channel which should give some advantage regarding lower output impedance and necessary NFB compared to a single 13E1. For more details one would have to compare the data of the tubes with real numbers. That might make it necessary to run the 13E1 a little hotter so that there is enough gain left after NFB. The output voltage of the B+ transformer would need to be chosen according to this which could be higher than for the Mini Beast. I am using the Mini Beast for comparison because you mentioned that you are using the same B+ psu. Considering the best balance between regulator, gain, power load line of the 13E1 and necessary B+ I would define finally how much gain I would need from the input stage. This could be more than the 6SN7 in the above configuration can make available if you aim for 2W per tube, considering the necessary NFB for keeping the output impedance low enough for driving your speakers under all conditions. But this depends on the impedance of your drivers (I guess its single driver) . To know the lowest impedance would be a very important input at this stage.

Cressy Snr
Social Sevices have been notified
Posts: 8041
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

Re: Remember These?

Post by Cressy Snr » Fri Nov 09, 2018 4:07 pm

Hi Wolfgang,
Thanks for that. I'm looking ag 160V at 500mA, which means 80W dissipation on the 13E1. The output stage PSU will be pulling around 1amp, so I'm on top of the requirement for more gain. Whether a 6SN7 cascade would be sufficient, given the feedback that might be needed, I'm not sure, but this is an experiment, so there's plenty of scope and I have a number of ideas if the 6SN7 is insufficient.
Ha - ha said the clown. Has the king lost his crown, is the night being tight on romance?

User avatar
Ray P
Shed dweller
Posts: 2526
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

Re: Remember These?

Post by Ray P » Fri Nov 09, 2018 11:05 pm

Wolfgang wrote:
Fri Nov 09, 2018 3:40 pm
Steve, please note the resistor must be 3W not 1,5W. Ray posted an older schematic where this hadn't been corrected.
Whoops, I miised that - sorry.

User avatar
Ray P
Shed dweller
Posts: 2526
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

Re: Remember These?

Post by Ray P » Fri Nov 09, 2018 11:24 pm

Ray P wrote:
Fri Nov 09, 2018 1:30 pm
PCBs went in the post this morning Steve.

I'll post some details about using them later.
Steve, I think the picture below shows you most things you'll need to know about using the PCBs. Essentially, I designed them to mount on the chassis top plate, hence the socket on the top and the components below. The inner ring of pads for the valve socket are for CMC sockets (I like the teflon ones) but you can use the outer ring for more conventional ceramic PCB sockets, however, I did find that one pair of that type of sockets had pins that wouldn't fit the pad holes (but a liitle work with dremel should do the trick if you encounter this and much better than drilling out the pads as you'll destroy the through hole plating making soldering the sockets to the PCB much harder).

If you want to mount the PCB to the chassis floor just mount the components on the same side of the PCB as the socket.

The PCB allows you to mount the TL783 on the board or remotely - the labelling on the board covers all the connections to off-board stuff (for a 6C33C of course). The feedback resistor sits between the two film caps - wolfgang has used a multi-turn pot here to allow experimentation/adjustment of the feedback - PCB allows for a pot or a through hole resistor.

I guess I'm teaching you to suck eggs so I'll leave it there.

BTW, the boards are 2oz copper and I have another half dozen should you need a couple more.

Anyway, I hope it all works for you and I'll look forward to following your journey.

Image

Cressy Snr
Social Sevices have been notified
Posts: 8041
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

Re: Remember These?

Post by Cressy Snr » Sat Nov 10, 2018 10:39 am

Cheers Ray,
I'll look forward to getting hold of the board and getting something underway. :D
Ha - ha said the clown. Has the king lost his crown, is the night being tight on romance?

Post Reply