A Rocket born - newbie voltage questions

[duriehill]

Thanks Mark

Yea, I think the only real 'problem' I discovered was the pickiness of the V1 and V2 preamp tubes, for modern choices. This certainly introduced the most hum and noise. The grounding and filter cap placement was me just being picky - I like a quiet(esh) amp.

[duriehill]

I'm having a hard time sourcing a chassis bolted reverse zener - does anyone know of a part number, or where one can be bought in the UK? Looking for 50V, above 20W

Thanks

[martin manning]

I had a quick look, and couldn't turn up anything. They seem to have gone out of style. I would put a terminal strip in and chain some smaller leaded Zeners together, say four 12V 5W.

[Firestorm]

I'm having a hard time sourcing a chassis bolted reverse zener - does anyone know of a part number, or where one can be bought in the UK? Looking for 50V, above 20W

Thanks

They are still being made, but finding a stocking distributor is the hard part, especially if you want the reverse kind with the anode on the stud. NTE leaps from 10W to 50W and the 50W ones are expensive. The 50V NTE part number is NTE5275AK (you could also use 76, 77 or 78). Magnatec makes them too, in their BZY93 series.

Finding these in the UK seems beyond difficult.

[duriehill]

Yeah, it does seem very hard to find anything around with a cathode case.

I did think about using one with an anode case and using a non-conductive (electrically) heat sink between it and the chassis - if such a heatsink exists?

Martin; this is my current set up of 5x 5w 10v zeners on tag strips. I've put extra buss wire at each tag to slightly heat sink..

https://tubeamparchive.com/download/file.php?id=32545

I just wonder how reliable this is, and if others have had long-term success with a similar set up?

[duriehill]

I've just re-read your post Martin with the suggestion of a terminal strip. I think that's a great idea and will give it a try with something similar to this:

http://www.screwfix.com/p/hylec-triple- ... wwod5CUAgQ

Thanks

[Teleguy61]

Great thread, thanks.
I am thinking about a Rocket build and your discussion of issues is very enlightening.
Good luck with it.

[Zippy]

I did think about using one with an anode case and using a non-conductive (electrically) heat sink between it and the chassis - if such a heatsink exists?

Regarding physics of materials: Most materials with high thermal conductivity are also good electrical conductors.

[M Fowler]

I did a google search and came up with vendors?

http://www.vetco.net/catalog/product_in ... ts_id=4343

[cap217]

Can you explain this more:

- Bass pot resistor/wiper. RJ suggested in one of his posts tweaking the tonestack on the bass control. When you max out the bass control the mid's take a huge dive. I removed one end of the resistor from the third leg of the pot and connected it to ground. This leaves one end of the mid resistor connected to the wiper on the bass pot and the other one connected directly to ground.



I am interested to hear about this and using it on my ac30 bass pot. I think this is what people are recommending to me in my thread but Im not sure.

[duriehill]

I did think about using one with an anode case and using a non-conductive (electrically) heat sink between it and the chassis - if such a heatsink exists?

Regarding physics of materials: Most materials with high thermal conductivity are also good electrical conductors.

Yeah, but I did some research on the idea out of interest and there seems to be a few ceramic sinks out there:
http://www.amecthermasol.co.uk/family.p ... y=28&gr=28

[duriehill]

I did a google search and came up with vendors?

http://www.vetco.net/catalog/product_in ... ts_id=4343

Thanks - I may look into that I think if the chained 5w zeners don't work out.

[duriehill]

Can you explain this more:

- Bass pot resistor/wiper. RJ suggested in one of his posts tweaking the tonestack on the bass control. When you max out the bass control the mid's take a huge dive. I removed one end of the resistor from the third leg of the pot and connected it to ground. This leaves one end of the mid resistor connected to the wiper on the bass pot and the other one connected directly to ground.



I am interested to hear about this and using it on my ac30 bass pot. I think this is what people are recommending to me in my thread but Im not sure.

I read this topic that RJ posted, very interesting:
https://tubeamparchive.com/viewtopic.php?t=6332

[cap217]

Can you explain this more:

- Bass pot resistor/wiper. RJ suggested in one of his posts tweaking the tonestack on the bass control. When you max out the bass control the mid's take a huge dive. I removed one end of the resistor from the third leg of the pot and connected it to ground. This leaves one end of the mid resistor connected to the wiper on the bass pot and the other one connected directly to ground.



I am interested to hear about this and using it on my ac30 bass pot. I think this is what people are recommending to me in my thread but Im not sure.

I read this topic that RJ posted, very interesting:
https://tubeamparchive.com/viewtopic.php?t=6332

That was for 100% max on the bass which mine never gets close to. That thread didnt get into much detail but the controls are interactive and if I want more bass, turning down the treble and cut can get me there. All 3 work together. Now on my Z Wreck, it acts differently. More normal and not interactive as much. Its also more bass heavy and highs because I can keep the Z set to around noon-1 and get all the bass and treble I need. Not a lot of tweaking is needed with it.

[duriehill]

The bass pot resistor position change/tweak just prevents the mid/high frequency dive when the bass pot is at/near max.

Since the tweak you could say that there is less interaction from the bass control as this phenomenon no longer happens.