a thing of beauty, well done!!!!
I see you are using coax for the run from the rear rca sockets to the front volume control, ever considered using a thicker gauge copper core coax?
The center conductor looks a little on the thin side, rg-59?
Not that it matters much.
It just seems to be a bit of a waste to have so much copper bus running around and then use cheap grade coax for the run to the front volume control.
I see you are using coax for the run from the rear rca sockets to the front volume control, ever considered using a thicker gauge copper core coax?
The center conductor looks a little on the thin side, rg-59?
Not that it matters much.
It just seems to be a bit of a waste to have so much copper bus running around and then use cheap grade coax for the run to the front volume control.
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thanks very much! basically that coax was what i had on hand, i think it was from an old oscilloscope probe lead, so i figured it had to be well shielded. probably overkill. the conductors are indeed tiny but i can't imagine it would make a difference at the tiny signal current at the input..?
I wouldn't spend too much on getting some proper coax, but I work on the idea that if something makes a difference and I assume that it won't but it does then I have lost out on an opportunity to improve the sound quality, and for the cost of a few dollars worth of coax, thats a small price to pay for my peace of mind.
Nobody here I think will tell you that by going to a larger copper conductor will make a difference, its a personal preference of mine as I am moving all of my rca connections over to BNC and RG-6 Quad shield coax (not copper coated steel, pure copper.) which has an 18 AWG center conductor.
By removing one last slim remote possiblity of there being a change or reduction on the sound quality by going to BNC and RG-6 Quad for a few dollars I am ensuring that the signal gets the best possible chance to make it into that tube and be amplified.
I'm not the type of person to go out and buy $50,000 dollar cables, RG-6 Quad pure copper core is where I draw the line and I cut and crimp my own BNC RG-6 cables.
If I can prevent $50 from going to corrupt cable companies by promoting the use of home-made BNC and RG-6 quad then my work is done, $50 could get you 100 metres of rg-6 and 6 or more bnc rg-6 connectors.
But then again as you said its what you had laying around.
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Be careful of the phase of the output transformer. Otherwise you will have positive feedback to the cathodes, instead of negative feedback.
The ratio of 1/2 primary (1650 Ohms) to 4 Ohms of winding is about 20, which will feedback about about 5% of the 1/2 primary voltage.
Suppose the basic Ultra Linear gain stage is about 10, with the cathode feedback that would be 50%; that could be perhaps about 6 dB negative feedback.
(I think I got that calculation right).
The ratio of 1/2 primary (1650 Ohms) to 4 Ohms of winding is about 20, which will feedback about about 5% of the 1/2 primary voltage.
Suppose the basic Ultra Linear gain stage is about 10, with the cathode feedback that would be 50%; that could be perhaps about 6 dB negative feedback.
(I think I got that calculation right).
unfortunately not.. if i had a scope handy i'd have taken a look. but beyond getting a circuit together that a majority on the forums approve of, i'm happy to sit back and listen to some music.
thanks for the calculation! i'm pretty sure i got it right, after all, with those Edcors everything is clearly labelled and color coded.
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