Tube Rectified?

[DortoH]

Has anyone tried a tube rectifier in place of the semiconductors?

If so could you please post information on what you had to change to make this possible.

Thanks!

[Thermion]

Has anyone tried a tube rectifier in place of the semiconductors?

If so could you please post information on what you had to change to make this possible.

Thanks!

I used tube rectification in my first ST35 project. Some of the details are contained in my earlier post titled, "REV C Completed." (look on page 3) I like to use tube rectification whenever possible. I basically copied the old Dyna ST70/MKIII power supply and used Ned's Dyna filter choke. I also added a chassis mounted cap for that classic look.

If you plan to use a tube rectifier, you will need to increase the voltage somewhat on your PT. There is a voltage drop across the rectifier tube and the filter choke. A 300-0-300 PT works well with the dyna choke and a 5AR4.

JT

[TerrySmith]

I use a tube rect, see the thread "Nother nifty Heathkit amp", it's on the first or second ST-35 list. All I did was wire the socket, omit the diodes, add a jumper. For the first capacitor, reduce it to 40uf - 50uf. In place of the 50 ohm resistor, I used a Hammond 156R choke. The power trans is a 270HX, 275-0-275. My B+ ended up at 354v. And, it is dead quiet!

[Guest]

Well I follow along with most of it I still have a few newbie questions.

Replace 50Ohm with Hammond 156R choke, understood.

Reduce first capacitor to 40-50 uf. C9 on the schematic?

"Wire in the socket" I would like a bit more detail information here if you could. IE socket pin 1 to ...... pin 2 to ..... etc......

I understand the basics of how a tube rectifer works, and I know I like the way they sound, just need help in the actual wiring :)

If someone can help me with this I will be sure to document it real well and make it available to all :)

Thanks!

Rod

[DortoH]

BTW that last post is me, not sure why I showed up as guest. Stupid cookies :)

[Shannon Parks]

Replace 50Ohm with Hammond 156R choke, understood.

Reduce first capacitor to 40-50 uf. C9 on the schematic?

"Wire in the socket" I would like a bit more detail information here if you could. IE socket pin 1 to ...... pin 2 to ..... etc......

I understand the basics of how a tube rectifer works, and I know I like the way they sound, just need help in the actual wiring :)

If someone can help me with this I will be sure to document it real well and make it available to all :)

Here's an earlier post:
http://www.diytube.com/phpBB2/viewtopic ... t=heathkit

It has a schematic in jpeg and PDF. The 11-pole terminal strip is like the Rev C & D terminal strip except for an extra ground connection in the middle. This should get you going in the right direction.

Shannon

[DortoH]

Perfect! I will have to see how I can fit that, but i got a 12x10.2 chassis so it should be no problem!

[DortoH]

OK lets take a look at these modifications.

[img]removed%20http://dortoh.ca/crap/1.jpg[/img]

and

[img]removed%20http://dortoh.ca/crap/2.jpg[/img]

Pic 1 is the wiring to the PCB and Pic 2 is the PCB

Does this look correct?

Changes made, in case they are not obvious, are:

-Added 5AR4 rectifier tube V7
-removed Diodes D1 and D2
-removed Resistors R35 and R35
-Added 1.5H 56R chocke L1
-Changed C9 to 40-50 UF
-Added 6.8UF capacitor between SW2 and L1

Hope these pics are OK :? If they don't load they can be downloaded at
http://dortoh.ca/crap/pic.zip (105K)

Rod

[Shannon Parks]

Try this instead:
Power Supply
Logical Connections with Hammond

Switch to a 272HX to account for the voltage drop of the 5AR4. Use a 33uF, 450V cap for C9. You can use the same two-pole connector from the parts list to use for the choke hook-up. Try to use a choke with low DC resistance - the Dyna C-354 is fine. But you don't necessarily need a choke, either, and could stick with the paralleled 100 ohm resistors. With push-pull cancellation we can get away with murder as far as ripple on the B+. Look at an Eico HF-60 schematic. Enjoy!

Shannon

[dhuebert]

Can you recommend a Hammond power supply transformer to use with the 6L6GCs and the 5AR4?

Don

[tubes4hifi]

Hi Don and all,
the 6L6GC can handle alot more voltage, if Hammond had a 350+350v with enough current I would recommend that, but they don't, so you're gonna have to go with their 400+400 @ 200ma which is the 278CX.
The others don't have enough current. Personally I would use a stock or exact replacement trannie from a Dynaco ST70, it's perfect at 360+360 at 250ma.
Roy www.tubes4hifi.com

[Guest]

oops, not the 278CX, it should be the 278X
the 278X has a 5v winding for a tube rectifier, the other one doesn't
I would still use the Dynaco PA060 or replacement, ideal
Roy www.tubes4hifi.com