CCS for tubes/valves: PCBs

[billbo]

CCS ccts

Hi all.
Sorry for the late input.
I have circuits for CCS's which work remarkably well. I will post them when I dig them up from the archives. It uses either an MJE350 or an MJE340 accompanied with a zener, capacitor and a couple of resistors. No need for circuit boards. It can be mounted on a single 8 way terminal strip. (vero board opitional). I have been using them for years and swear by them. Dramatic increase in fidelity and dramatic decrease in distortion and noise.
Regards
Billy D...

 

[billbo]

Line Pre amp

If anyone interested I have posted my line pre amp using a 12au7.

 

[billbo]

Pre amp

I have also added feedback to my preamp which reduced the output noise and improved distortion figures. Mainly I did it due to there was too much gain so I halved it approximately.
Regards
Billy D...

 

[Burnedfingers]

billbo


I have been a thorn in the sides of people with this thread pushing for some type of action on it. It would be a shame to confuse them now since they are in motion on the project. Personally I like the direction and theme of the project and don't think any more modifications are needed. There are a bunch of us that have comitted to the handy compact board that will eliminate the flying parts normally associated with such a modification.

 

[dsavitsk]

fyi, using the HV PNP version as a plate load, the CCS crapped out (I believe that to be a technical term) at about 20mA. Switching to a 2N2907A it happily runs along at 32mA for me. The TO-18 package of the 2907 just requires some minor lead bending to fit it to these boards.

 

[Burnedfingers]

Switching to a 2N2907A it happily runs along at 32mA for me.

What transistor crapped out? number?

 

[dsavitsk]

The BC557 -- not the high power one. It didn't go up in smoke (and continued to work fine when I dialed down the current), but the top LED went out and the current leveled off right at about 20mA.

I should add that the supply voltage was about 225V (it is a choke loaded supply so it is pretty well regulated) and from the CCS to ground I used a 2K5 resistor.

 

[Burnedfingers]

Its good to know that the 2N2907A works well. That will save me the trouble of trying to source the BC557's.

 

[billbo]

line amp

Sorry guys. Just inputing my "two bobs" worth of info.
Regards
Billy d...

 

[SY]

By the "top" LED, do you mean the one used as a reference? Or the one used to bias up the cascode?

 

[dsavitsk]

The reference -- that is, the one that connects directly to B+. Top, because typically when it is pictured in a schematic as on top of a plate, the top most one as drawn.

 

[SY]

You might try increasing the voltage of the second LED. If you've got a red one in there, go to a green or two reds in series. Also, if the current through the LEDs is too low, things can choke- what are you running there?

 

[dsavitsk]

Also, if the current through the LEDs is too low, things can choke- what are you running there?

It was (or should have been) ~3mA when it turned off. I'll investigate this a little further when I get a chance.

 

[Burnedfingers]

I hate to ask again but where are we on this?

 

[Burnedfingers]

Sebasion & Tony have brought progress to this one so i'm hoping we'll know how much money to start collecting soon.

Is there any progress on this yet?

 

[jrebman]

I'm interested. Will stay tuned and look for an announcement.

-- Jim

 

[Burnedfingers]

I hate to be a pest but........how about an update on this.

Is it still a go? :smash

 

[dsavitsk]

I hate to be a pest but........how about an update on this.

Instead of being a pest, why don't you just do it yourself? It should take you about an afternoon to learn Eagle enough to lay out some boards and send them to Olimex. Or, use Express PCB and it will take you about 20 minutes to learn, and another 20 minutes to get it done.

 

[Burnedfingers]

Instead of being a pest, why don't you just do it yourself? It should take you about an afternoon to learn Eagle enough to lay out some boards and send them to Olimex. Or, use Express PCB and it will take you about 20 minutes to learn, and another 20 minutes to get it done.

I guess I'm really not in the mood to read a reply like this. If I had the patience to do PC board work I sure as hell wouldn't have waited 2 years for something to happen.


It would seem that there was enough interest before to get this off the ground. It is very unfortunate for all that were interested to have the ball dropped now. The real topping is that you can't get a reply from those that were going to do something.

I guess DIY actually does mean do it yourself and do not count on any cooperation or help from others.

 

[dsavitsk]

I guess DIY actually does mean do it yourself and do not count on any cooperation or help from others.

Funny how that works. Turns out that running a group buy is a lot of work and responsibility.

There was a group buy last December for boards based on these designs as well as another one based on the 10M45 (see post #29 in that thread). In the end, there was enough interest for the 10M45, but not for any of these. Perhaps you missed it. If you ask the organizer very nicely, he might have a couple of extra boards on his desk that he could part with ...

You can still get Bottlehead's CCS kit, or K&K Audio's kit, or DIY HiFi Supply's kit. Indeed, SY still had a few of these boards floating around just a few months ago. Further, you can build these easily on a piece of Radio Shack strip board, or dead bug style on a small piece of plastic that you drill a few holes in.