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Zener Diode Question

Posted: Thu 03/11/21 8:42 pm
by Kcz5o
I purchased a Ceriatone Son of Yeti kit. The only information that came with the kit was a jpeg layout that is somewhat difficult to see. The jpeg show two blue and two red zener diodes. The packing list show that 2 are 1N4747a diodes (20 watt I think) and two are 1N4739a (9 watt). Does anyone know which are indicated by the blue and which are indicated by the red? Might have bit off more that I can chew. Didn't even give the specs for the transformers. I found what looks like a similar one on their website for a different amp to identify the PT leads. I've attached the layout jpeg and a amp chassis jpeg. Thanks much!
SonoFYetiLayout-1Dec2019.jpg
chassis.jpg

Re: Zener Diode Question

Posted: Thu 03/11/21 10:26 pm
by Kcz5o
The more I think about it it wouldn't matter correct? If I switched them around it would reverse the switch and if I happened to put the two different diodes together on each side it would just sound the same on both sides. Sound right? Thanks

Re: Zener Diode Question

Posted: Fri 03/12/21 1:31 am
by TriodeLuvr
The 4747A is a 20V, 1W Zener. The 4739A is 9.1V, 1W. Sorry, can't tell you which location they should be in without seeing the schematic.

Jack

Re: Zener Diode Question

Posted: Fri 03/12/21 7:00 am
by JMPGuitars
Kcz5o wrote:
Thu 03/11/21 10:26 pm
The more I think about it it wouldn't matter correct? If I switched them around it would reverse the switch and if I happened to put the two different diodes together on each side it would just sound the same on both sides. Sound right? Thanks
Correct. If you want to match the build, I'm guessing the red ones are the 9.1V, as those are usually red diodes. Just mind the orientation of the stripes, and you should be fine.

Thanks,
Josh

Re: Zener Diode Question

Posted: Fri 03/12/21 8:20 am
by Kcz5o
Thanks, I didn't get a schematic and the layout isn't really clear either.

Re: Zener Diode Question

Posted: Fri 03/12/21 9:24 am
by geoff 1965
this is'nt a ceriatone schematic but it's obviously someone's take of the amp,anyway it show's the "era" switch in question and the orientation of the diodes.
Yeti, Son of.gif

Re: Zener Diode Question

Posted: Fri 03/12/21 4:22 pm
by TriodeLuvr
What do the diodes look like that came in the kit? The datasheets say both types are glass. The photo you posted shows that too, with one being clear glass that allows viewing the red inner structure, and the other being gray/black.

Jack

Re: Zener Diode Question

Posted: Sun 03/14/21 5:11 pm
by katopan
Looking at the layout pic, the two chains are connected at one end and go to the switch at the other end. For the leads to the switch not to cross over, it depends which value you want in circuit for which switch position. ie. It doesn't really matter and if it turns out backwards, swap the switch wires over.

Like has already been suggested, it would seem that the red ones would correspond to the glass type and the blue would correspond to the silver ones.

Re: Zener Diode Question

Posted: Fri 03/19/21 11:37 am
by Kcz5o
I am starting to get this together and have another question. I hope its alright to post on this diode post rather than start a new topic. In the diagram from Ceriatone (shown in first post) it shows that the input shielded wire is grounded at the input, and then the ground wire at the other end of the cable is hooked to a 1meg resister going to pin 2 of the 12ax7. Am I understanding the diagram correctly. Thanks again for all the help.

Re: Zener Diode Question

Posted: Sat 03/20/21 6:03 am
by Bieworm
Sorry, but I don't understand why members of this site even look at other schematics. Josh has done a lot of efforts to create clear layouts of a lot of 18W variants. In the download section of this site you'll find a lot of schematics and layouts that are more than clear ...
The 1M resistor is to be soldered across the cliff jack input, and not at pin 2 of the input triode. There is a grid stopper resistor that has to be soldered right there at pin 2, but that's a 10k, or a 22k on the ceriatone. You put a terminal near V1 and solder the grid stopper from the terminal to pin 2. From the terminal you run a shielded wire to the input jack's hot tip, grounding the shield only at the input side. You must avoid the other end of the shield touching anything else, so it's best to seal it off with heatshrink tubing.
20210320_115254.jpg

Re: Zener Diode Question

Posted: Sat 03/20/21 8:29 am
by geoff 1965
i have to disagree with that,this is'nt your typical 18 watter,the configuration he described is correct to the layout and schematic,this ceriatone is very high gain with some trickery so maybe it needs to be like that?

Re: Zener Diode Question

Posted: Sun 03/21/21 9:11 am
by Kcz5o
Thanks much. I will give it a try as it is layed out and if there are issues try the above suggestion.

Re: Zener Diode Question

Posted: Sun 03/21/21 11:54 am
by TriodeLuvr
Kcz5o wrote:
Fri 03/19/21 11:37 am
In the diagram from Ceriatone (shown in first post) it shows that the input shielded wire is grounded at the input, and then the ground wire at the other end of the cable is hooked to a 1meg resister going to pin 2 of the 12ax7. Am I understanding the diagram correctly. Thanks again for all the help.
Yes, that's how it's being done. The cable shield is being used to ground the 1M resistor. The shield is only grounded at the input jack (using the ground wire connected from there to the turret board).

Jack

Re: Zener Diode Question

Posted: Sun 03/21/21 12:18 pm
by TriodeLuvr
Bieworm, the layout you posted shows wires on pins 1 and 6 of V1 that are both labeled "shielded wire." However, there's no ground connection at either wire. Is the label wrong?

Jack

Re: Zener Diode Question

Posted: Sun 03/21/21 12:46 pm
by Bieworm
TriodeLuvr wrote:
Sun 03/21/21 12:18 pm
Bieworm, the layout you posted shows wires on pins 1 and 6 of V1 that are both labeled "shielded wire." However, there's no ground connection at either wire. Is the label wrong?

Jack
It's a layout from Josh. I don't think he draws the grounded side of shielded wires. But it's common practice the shielded wire is grounded at one end

Re: Zener Diode Question

Posted: Mon 03/22/21 6:18 am
by JMPGuitars
Bieworm wrote:
Sun 03/21/21 12:46 pm
It's a layout from Josh. I don't think he draws the grounded side of shielded wires. But it's common practice the shielded wire is grounded at one end
I never draw the grounded side of shielded wires. People should know it's not shielded if it's not connected on one side...and I don't care for debates about which side to ground.

Though I tend to ground the side near the tube sockets using the terminal ground lug for the shield.