Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Auke Jolman on August 13, 2015, 03:49:04 pm

Title: gz34 vs diodes
Post by: Auke Jolman on August 13, 2015, 03:49:04 pm

Hi again,

I'm back with the folowing.

I've build an amp with a GZ34 for rectification. The PT has 290 -0 - 290 V. The amp is functioning fine. I want to have the posibility to choose between that and rectification withn4007 diodes. I removed the GZ34 and put the 2 diodes from pins 4 and 6 and joint them at pin 1 and then measured the voltage at pin 1 relative to ground and got a reading of 270V

Why is this so low. I can not get my head around it. Can anyone give me some directions as to what might be the problem.

Thanks in advance.

Auke

Title: Re: gz34 vs diodes
Post by: John on August 13, 2015, 04:32:56 pm

If you don't have your filter cap hooked to pin 1, that might be why.


And you have both diodes pointed the same way, right? (not that I've ever had one back'ards)

Title: Re: gz34 vs diodes
Post by: Auke Jolman on August 13, 2015, 04:51:19 pm

Hi John,

I believe the diodes are in the right direction. I measured the voltage seperatly bu disconnecting them at pin 1 and both read 135 V.

Could you tell me why it is important to connect the filter cap.

Thanks.

Title: Re: gz34 vs diodes
Post by: Willabe on August 13, 2015, 04:54:26 pm

It needs to have a filter cap hooked up to hold the diodes dcv charge.

Without the cap it's only dcv pulses and your meter wont read it right.

Title: Re: gz34 vs diodes
Post by: sluckey on August 13, 2015, 05:18:51 pm

Why are you connecting the diodes to pin 1?

Title: Re: gz34 vs diodes
Post by: Auke Jolman on August 13, 2015, 05:34:32 pm

Hi Willabe and John,

Thanks for the explenation. I connected the filter cap and the reading is ok.

Hi Steve,

I used pin 1 as because I thought that it was a convenient point. I plan to put the switch directly under de tube socket and don't need long leads thst way.

With kind regards,

Auke