My unfinished gaincline chassis

[ScottRHinson]

Originally posted by Peter Daniel



You are not saying that because of my suggestion to place it in a center?

My reasoning to put it centrally is following. This is quite a big chassis by GC standards. If this is stereo amp, you should definitely use dual mono layout, with ea channel on either side and probably using side panels for heatsinking. This leaves the center space empty and it's a perfect place to mount transformer, or maybe even two. Also AC input should be placed centrally and both RCA jacks and binding posts separate on both ends of rear panel. Placing transformer centrally makes for better balanced chassis as well, not to mention having the same resonances for both channels

I'm sorry Peter, but I disagree. The cheapest way to reduce noise in an electrical system is distance...pure and simple. The best way is a well thought out grounding system and Faraday cages around the noisy and quiet parts to separate them.

I assume EMI is what you mean by the term resonance?

I have never liked a dual mono layout because it becomes much easier to make a mistake in running signals near power lines, either the full wave primary or rectified secondary lines. Those secondary currents can get all over the place if your not careful and easily set the noise and distortion floor for the amplifer.

Can it be done well? Yes. Is it much harder. Yup. If I were the builder of this amp, I'd get a big piece of aluminum bar stock and wedge it into one side of the amp. If it were the right size it could tie the side to the top and bottom thermally and even the front and back. I'd mount the gainclone chips to that, and you have a huge thermal mass to cool the chips. You can keep the chips as far away from those nasty power supply lines and realize the lowest noise floor, quietest amp you can.

Scott

[Peter Daniel]

This will work too. I guess it's a matter of preference. With a big chassis like that you can use almost any layout. I just like symmetry and separation between channels.

[Bricolo]

The 1st solution has the transformer on the side

advantages:
less EMI from the transformer

disadvantages:
I can't use a long axis for the volume pot


the 2nd has the transformer on the middle:
advantages:
I can use a long axis

disadvantage:
EMI




In both cases, I can place metal plates around the transformer
but it I do this, in the 2nd case, the AC inlet wires aren't in this small housing

[Bricolo]

2nd one:


note that with the 2nd option, I can use both sides as a heatsinks (maybe this isn't critical with a gainclone)

[ScottRHinson]

Originally posted by Bricolo
The 1st solution has the transformer on the side

advantages:
less EMI from the transformer

disadvantages:
I can't use a long axis for the volume pot


the 2nd has the transformer on the middle:
advantages:
I can use a long axis

disadvantage:
EMI




In both cases, I can place metal plates around the transformer
but it I do this, in the 2nd case, the AC inlet wires aren't in this small housing

I see that you've got dual potentiometers for volume control. I'm going to modify/clarify some of my advice. Bring the power wiring straight forward from the transformer on the right side. Run it side to side along the very front of the chassis, then back to the GC amps on the left side along the left side.

Now take the speaker output straight back and exit the far corner (this is different than I said before, now that I see the layout this makes more sense). Bring the signal lines in next to the speaker out and keep them as short as possible. I'm guessing you want to have a symmetrical front panel? If you're not attached to it, put both pots on the left 1/3 of the chassis, it will still look pretty classy and you'll be able to keep the signal wiring perpendicular, or orthagonal (spelling?) to the power lines as much as you can. Make sense?

Scott

[Peter Daniel]

Here's a nice example of what I was talking about: http://www.hifis.com/brink/brink.htm

[Bricolo]

Originally posted by ScottRHinson





I see that you've got dual potentiometers for volume control. I'm going to modify/clarify some of my advice. Bring the power wiring straight forward from the transformer on the right side. Run it side to side along the very front of the chassis, then back to the GC amps on the left side along the left side.

Now take the speaker output straight back and exit the far corner (this is different than I said before, now that I see the layout this makes more sense). Bring the signal lines in next to the speaker out and keep them as short as possible. I'm guessing you want to have a symmetrical front panel? If you're not attached to it, put both pots on the left 1/3 of the chassis, it will still look pretty classy and you'll be able to keep the signal wiring perpendicular, or orthagonal (spelling?) to the power lines as much as you can. Make sense?

Scott

Yes, I want a symmetrical front pannel

[Bricolo]

Originally posted by Peter Daniel
Here's a nice example of what I was talking about: http://www.hifis.com/brink/brink.htm

That's the layout I was also thinking about

But where is the AC inlet?

[Peter Daniel]

Originally posted by Bricolo


But where is the AC inlet?

It is probably coming through the bottom, directly to the transformer.

[Peter Daniel]

I wouldn't recommend dual volume pots as it's very inconvenient to adjust volume. Why not a single pot?