Vox Layout & Power Supply

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fabiomayo
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Vox Layout & Power Supply

Post by fabiomayo »

Hi everyone.

Could anyone help me check this layout for a future Vox build?
Points I'm unsure about:
1) Grounding:
1.1. all power supply filters at one point, plus the power tube cathode
1.2. all preamp grounds connected to two buss wires grounded
at the input end of the chassis (isolated jack)
1.3. Output trasnf common grounded thorugh the jack to the chassis

2) Input switching and common grid stopper for both inputs. Is that ok?

3) Choice of power supply caps:
3.1. Splitter coupling caps - bigger AC30 values or smaller AC15?
3.2. Power tube cathode bypass - AC15 50uF or AC30 250uF?

Thank you all.
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Allynmey
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Re: Vox Layout & Power Supply

Post by Allynmey »

I'd change that EZ-81 to a GZ-34 to start :shock:

Looks like a cool project keep us posted on your progress. :D

Allynmey
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fabiomayo
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Re: Vox Layout & Power Supply

Post by fabiomayo »

Thanks, Allynmey.

Yes, the rectifier. The power started out as a AC15 power amp. I'll put
a strudier rectifier there. Maybe less than the GZ34?

I'm still on the parts ordering process..... :cry:
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fabiomayo
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Re: Vox Layout & Power Supply

Post by fabiomayo »

Ok. An update. No work today :D

Different grounding scheme. Single buss bar for board and pots.

What do you think?
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David Root
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Re: Vox Layout & Power Supply

Post by David Root »

Much better. Single bussbar with only one single ground to chassis at the preamp end.
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fabiomayo
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Re: Vox Layout & Power Supply

Post by fabiomayo »

I'll be posting updated layouts soon.

Meanwhile, can anyone help me with the current loads of each
power supply node? Here's what I got from the tube manuals online:

B+7: EF86 plate and control grid: ~3.0 - 3.6 mA
B+6: 1 triode (12AX7): 1.2 mA
B+5: two triodes (12AX7): 3.4 mA
B+4: one tridoe (12AX7): 1.2 mA
B+3: two triodes (PI): 3.4 mA
B+2: 4xEL84 grids (G2): ~ 30 - 44 mA (250 - 300 v)
B+1: That's my question. 4xEL84 plates and OT: ~150-180 mA ????

Thanks.
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fabiomayo
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Re: Vox Layout & Power Supply

Post by fabiomayo »

Reviving the thread with a very stupid question. In the following schematic, will my 'entrance B' work? If so, could I blend the channels just by adjusting their volumes? I understand there'll be som differences in volume.

Thanks.
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novosibir
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Re: Vox Layout & Power Supply

Post by novosibir »

fabiomayo wrote:... will my 'entrance B' work?
If you'd donate the 12AX7 still a plate resistor and a supply voltage... it will 8)
fabiomayo wrote:If so, could I blend the channels just by adjusting their volumes?
Yes, like with cable patched independent inputs.

Larry
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fabiomayo
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Re: Vox Layout & Power Supply

Post by fabiomayo »

novosibir wrote:If you'd donate the 12AX7 still a plate resistor and a supply voltage... it will 8)
So funny :wink:

Thank you for the reply. I thought it would work but what do I know? :lol:
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