Im looking at incorporating this into my preamp im designing.
Does anyone see any issues with this design?
Has anyone built something similar?
I see a few advantages using such a volume control, is there anything i need to know about?
I expect that having a matched pair of tubes is important.
An externally hosted image should be here but it was not working when we last tested it.
Does anyone see any issues with this design?
Has anyone built something similar?
I see a few advantages using such a volume control, is there anything i need to know about?
I expect that having a matched pair of tubes is important.
This seems to be for musical instrument purposes. For home audio, short the two input
150k resistors, and increase the output coupling capacitors to at least 0.1uF.
Carefully test a breadboard of this circuit before building it, to see if it works well enough.
150k resistors, and increase the output coupling capacitors to at least 0.1uF.
Carefully test a breadboard of this circuit before building it, to see if it works well enough.
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Yes im looking at prototyping it first. Since it had a left and right channel, i was assuming this was for hifi.
I dont sorry, but ive seen this schematic thrown about here in a couple of other threads, and also in this forum, where another similar schematic has beem posted with the larger coupling caps as you suggest.
Antique Radio Forums • View topic - Remote volume control ideas
Antique Radio Forums • View topic - Remote volume control ideas
It appears the gain is high enough so you will want an input attenuator [the 150k resistors]
with some sources. Check the maximum gain and input acceptance level.
with some sources. Check the maximum gain and input acceptance level.
With the likes of a phono stage input, would 150K be enough?
I might need to increase this possibly for other sources like a CD or other digital source do you think?
I might need to increase this possibly for other sources like a CD or other digital source do you think?
Not sure what the maximum gain will be, but usually a phono stage will have a lower nominal output level than CD,
tuner, or tape. You'll have to do some measurements on the breadboard version to see what the range of working gain is.
tuner, or tape. You'll have to do some measurements on the breadboard version to see what the range of working gain is.
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OK, well it gives me something to work with anyway.
I also expect that those 0.1 coupling caps should be done away with on the input side, unless its connected to a gain stage beforehand?
I also expect that those 0.1 coupling caps should be done away with on the input side, unless its connected to a gain stage beforehand?
The low-value output coupling caps were probably intended to suppress control feed-through, because the control voltage directly affects tube anode current.
I see that the second schematic is using 0.1 uf caps, so I assume that they had made some corrections.
So its safe to assume that 0.1 will be fine if coupling directly to the first gain stage in the amp?
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