Take a look at this

[jestaudio]

Could somebody more knowledgeable than me take a look at the valve rectifier and diode rectifier set up and tell me if its correct, something does,nt look right on the valve rec to me ,

[dcribbs1412]

Could somebody more knowledgeable than me take a look at the valve rectifier and diode rectifier set up and tell me if its correct, something does,nt look right on the valve rec to me ,

I'm not as knowledgeable as most here, but I have built this amp using this layout. The Tube/SS switch seems to work fine...not sure what you are asking. Rocking little amp BTW

Darin

[tictac]

The tube rectifier is wired wrong... Look at a correct schematic, Fender Pro Reverb, Princton Reverb etc.. for proper connections; or GZ34 / 5AR4 datasheet...

TT

[overtone]

have taken a look and I don't actually see an error. But looking at these C*tone layouts makes me really giddy, and this one is a real roller coaster. Up and down, left to right, now lets disappear over here and double-back over there... woo... best thing is to draw the schematic out and check it through for yourself.

I think I "get" all the things that Nik was going for but it ain't what I would do, but it depends what you want? What are you actually after?

Best, tony

[martin manning]

The tube rectifier is wired wrong... Look at a correct schematic, Fender Pro Reverb, Princton Reverb etc.. for proper connections; or GZ34 / 5AR4 datasheet...

TT

I don't see anything wrong there. The vacuum rectifier is backed up by silicon diodes, one in series with each anode, protecting against a short and increasing alowable anode voltage.

[jestaudio]

The tube rectifier is wired wrong... Look at a correct schematic, Fender Pro Reverb, Princton Reverb etc.. for proper connections; or GZ34 / 5AR4 datasheet...

TT

thats what i thought, every other layout i,ve seen has had the tube rec wired totally different, maybe i,m missing a trick here

[mmmoser]

I built this circuit (although I did a bit of layout changes) and the tube/solid state switching does work as advertised. Now that I've done it, I think I would stay with solid state and not bother with the extra tube for the rectifier. YMMV.

[rdjones]

The tube rectifier is wired wrong... Look at a correct schematic, Fender Pro Reverb, Princton Reverb etc.. for proper connections; or GZ34 / 5AR4 datasheet...

TT

Fender Princeton/Princeton Reverb schematics have a mistake that's been perpetuated through the decades.
AA964 and AA1164 schematics with GZ34 rectifiers show the B+ being drawn from pin2. (Fender's layout is correct but the schematic is wrong)

5AR4/GZ34 rectifiers (as well as 5V4 and a few others) have their cathodes connected to pin 8.
Drawing B+ from pin 2 on an indirectly heated cathode type rectifier pulls the HV supply through the entire length of the filament.
This will "work", but it adds stress to the filament and can effect hum and voltage drop.
This won't affect directly heated cathodes (5U4, 5Y3 etc) because the filament is heavier, pulls more current of their own and are designed to pass the HV.
Still, convention is to supply B+ from pin 8.

[img:150:167]http://www.nj7p.org/tube/bases/5L.png[/img]


regards,
reddog

[jestaudio]

The tube rectifier is wired wrong... Look at a correct schematic, Fender Pro Reverb, Princton Reverb etc.. for proper connections; or GZ34 / 5AR4 datasheet...

TT

Fender Princeton/Princeton Reverb schematics have a mistake that's been perpetuated through the decades.
AA964 and AA1164 schematics with GZ34 rectifiers show the B+ being drawn from pin2. (Fender's layout is correct but the schematic is wrong)

5AR4/GZ34 rectifiers (as well as 5V4 and a few others) have their cathodes connected to pin 8.
Drawing B+ from pin 2 on an indirectly heated cathode type rectifier pulls the HV supply through the entire length of the filament.
This will "work", but it adds stress to the filament and can effect hum and voltage drop.
This won't affect directly heated cathodes (5U4, 5Y3 etc) because the filament is heavier, pulls more current of their own and are designed to pass the HV.
Still, convention is to supply B+ from pin 8.

[img:150:167]http://www.nj7p.org/tube/bases/5L.png[/img]


regards,
reddog

now i,m confused, which is the correct way, the marshall scematic i,m looking at has pins 2 and 8 as the heater, 5 and 7 for the secondrys and the rectified voltage being drawn from pin 8, the omly reason i,m really interested is i am thinking about impletmenting a diode rectifier as well into the design with thew insperation being the stray cat scematic i posted

[overtone]

...now i,m confused, which is the correct way...

High Voltage AC goes into the rectifier GZ34 on pin 4 and 6
5v AC heaters go to pin 2 and 8
Take the DC rectified off Pin 8 as outlined above by rdjones

You are seeing the diodes mounted on the normally unused Pin 3 and 7 in that layout, from there the AC goes through the diodes to pins 4 and 6. Hope that is clear. Look at the data sheet for a GZ34, you should see there that the pin 5 and 7 are also not "used".

The switching of the DC after the rectifier gives me the willies. I'm thinking that eventually that switch will start to arc over.

[jestaudio]

...now i,m confused, which is the correct way...

High Voltage AC goes into the rectifier GZ34 on pin 4 and 6
5v AC heaters go to pin 2 and 8
Take the DC rectified off Pin 8 as outlined above by rdjones

You are seeing the diodes mounted on the normally unused Pin 3 and 7 in that layout, from there the AC goes through the diodes to pins 4 and 6. Hope that is clear. Look at the data sheet for a GZ34, you should see there that the pin 5 and 7 are also not "used".

The switching of the DC after the rectifier gives me the willies. I'm thinking that eventually that switch will start to arc over.

that makes sense now, typical that there are 2 versions of the same way of doing things, thanks for the clarification,

[marcoloco961]

...now i,m confused, which is the correct way...

High Voltage AC goes into the rectifier GZ34 on pin 4 and 6
5v AC heaters go to pin 2 and 8
Take the DC rectified off Pin 8 as outlined above by rdjones

You are seeing the diodes mounted on the normally unused Pin 3 and 7 in that layout, from there the AC goes through the diodes to pins 4 and 6. Hope that is clear. Look at the data sheet for a GZ34, you should see there that the pin 5 and 7 are also not "used".

The switching of the DC after the rectifier gives me the willies. I'm thinking that eventually that switch will start to arc over.

Are the diodes for protection if the rectifier tube goes? And what is the purpose of the cap across 4 and 6? Noise in general, or noise when switching. Something else?

Sorry, if these are painfully stupid or obvious questions. I just hadn't seen this done or discussed before anywhere.

[overtone]

If in doubt always ask and Martin did actually state it above already:

...The vacuum rectifier is backed up by silicon diodes, one in series with each anode, protecting against a short and increasing alowable anode voltage.

When you see a cap there it is usually an idea from the HiFi crowd to stop "ringing" from the diode switching on and off. Really, I have no idea what "ringing" people are hearing, so I have never taken the trouble.

Read through these pages, do some testing, let some sparks fly and you should be up to speed on this area:
http://www.freewebs.com/valvewizard/fullwave.html
http://www.freewebs.com/valvewizard/bridge.html

best, tony

[marcoloco961]

If in doubt always ask and Martin did actually state it above already:

...The vacuum rectifier is backed up by silicon diodes, one in series with each anode, protecting against a short and increasing alowable anode voltage.

When you see a cap there it is usually an idea from the HiFi crowd to stop "ringing" from the diode switching on and off. Really, I have no idea what "ringing" people are hearing, so I have never taken the trouble.

Read through these pages, do some testing, let some sparks fly and you should be up to speed on this area:
http://www.freewebs.com/valvewizard/fullwave.html
http://www.freewebs.com/valvewizard/bridge.html

best, tony

My bad, I did miss Martin's above statement. I thought that is what they were, but the cap had me wondering if it was something other than a safety feature. Thanks for the links, that helped clarify things a little more. I understand the principle of the SS rectifier, but have no real hands-on experience with tube rectifiers. I have one of Merlin's books and hopefully someday I will begin to understand it better. Still just a little (lot) over my head.