VBIGC troubles...

[sith]

hi there...
I want to build VBIGC like Joe Rasmussen or Nuuk did.
I'm still a bit confused about a couple of things.
Can I use the same transformer for LM circuit and valves (+/-30V)? I'm also not sure about valve connections - whether I have to connect all pins on each valve or only one half per channel (one triode).

[Nuuk]

Sith, I would stick to separate transformers for amps, valve buffers and heater supplies.

If you use one valve per channel, then you use half the valve, ie 3 pins and two more for the heater supply on each valve.

[elizard]

Originally posted by Nuuk
Sith, I would stick to separate transformers for amps, valve buffers and heater supplies.

If you use one valve per channel, then you use half the valve, ie 3 pins and two more for the heater supply on each valve.

I was actually taking a look at the tube gc recently, and it seems quite an idea that i'd like to explore. Is there an advantage to using 2 valves as opposed to using 1? (Or is there an advantage to using 1 as opposed to 2?)

[sith]

Sith, I would stick to separate transformers for amps, valve buffers and heater supplies.

Great, thanx for replying.

was actually taking a look at the tube gc recently, and it seems quite an idea that i'd like to explore. Is there an advantage to using 2 valves as opposed to using 1? (Or is there an advantage to using 1 as opposed to 2?).

Well, as far as I know, when using one valve per both channels it is possible to get channel crosstalk. So if you want to do it properly it is one valve per each channel.

[elizard]

Originally posted by sith

Well, as far as I know, when using one valve per both channels it is possible to get channel crosstalk. So if you want to do it properly it is one valve per each channel.

Makes sense to me

I actually checked the price of the valves, and at around $6/piece (from parts connexion), i'd go with 2 without thinking about it

[Nuuk]

I went with two valves to keep as near as I could to a dual mono design.

If you use different sets of pins on each valve, you can swap the valves over later to extend their lives!

[Ropie]

Is that the only reason you use different pins on each valve - to be able to swap and extend their lives, Nuuk? I thought it was to obtain stereo

[elizard]

Originally posted by Ropie
Is that the only reason you use different pins on each valve - to be able to swap and extend their lives, Nuuk? I thought it was to obtain stereo

I think what he means is to use two valves for the amp (one for each channel). Then, on say the left channel you use pins a, b, c, and on right channel you use x, y, z. Then, later you can swap the two valves so that the valve you were using on left is on the right, and vice versa. That way, you use both halves of the valve (first half before the switch, second half after the switch).

[sith]

Is that the only reason you use different pins on each valve - to be able to swap and extend their lives, Nuuk? I thought it was to obtain stereo

Well that is benefit, in this case you have double triode in one valve. It is wise to connect different pins on each channel, to be able to switch them in time.Of course it is possibe only with this type of tubes (double triodes).

[elizard]

One question with the schematic. Can it be used w/o the volume pot?
So basically use it as a power amp (like i'm using my IGC right now)?