6A3sUMMER:
It's not you; it's a (very common) misconception about the term differential. The OP actually means something more like "balanced voltage output", which is not even necessary if feeding a truly differential input. Conventional outputs can't be "differential", although they can be impedance balanced and/or voltage balanced.
All good fortune,
Chris
It's not you; it's a (very common) misconception about the term differential. The OP actually means something more like "balanced voltage output", which is not even necessary if feeding a truly differential input. Conventional outputs can't be "differential", although they can be impedance balanced and/or voltage balanced.
All good fortune,
Chris
If the signals are balanced from the DACs, then a properly designed differential stage will keep them balanced.
And yes, there are many other ways to build the next stage(s) that will retain that balanced result.
And yes, there are many other ways to build the next stage(s) that will retain that balanced result.
the op wanted to use the el cheapo ready made chinese line amp using 6j1/6ak5 triode mode pentode tubes, and he wanted to experiment, hey at that cost, what has he to lose?
and if the output of the DAC is already balanced to begin with, then all the more he can use four of those to buffer the DAC outputs to a level that his amp can be happy with..
https://www.lazada.com.ph/products/...4l.searchlist.list.17.756b1017KnPz4a&search=1
and if the output of the DAC is already balanced to begin with, then all the more he can use four of those to buffer the DAC outputs to a level that his amp can be happy with..
https://www.lazada.com.ph/products/...4l.searchlist.list.17.756b1017KnPz4a&search=1
It is the wrong application, but it works in this implementation. There isn't any good reason to do this other than I already have the buffers sitting doing nothing. Yes, I'll probably build some version of a cathode follower with 6922s.
It works. One stereo preamp per (differential) channel from the dac. It sounds like it did single ended. Way too much gain. Looking at the 5654w tube data sheet (which is the tube in it right now) I can plot a load line from 8.5 MA to 60v, biasing the tube t -3 volts. These tubes should really be run closer to its limit of 190v for anyone serious about good tube sound. Although it doesn't sound any worse than the counterpoint and golden tube preamps I used to own.
The components on my boards are numbered differently than any schematic I have seen for this pre. Obviously the things will need to be re-jiggered for cathode follower. I have the power supply built with a separate supply for the heaters. I'll keep you posted.
My computer keeps freezing trying to upload this pic. I'll keep trying.
The components on my boards are numbered differently than any schematic I have seen for this pre. Obviously the things will need to be re-jiggered for cathode follower. I have the power supply built with a separate supply for the heaters. I'll keep you posted.
My computer keeps freezing trying to upload this pic. I'll keep trying.
I'm not even sure how these tubes are working with 60v B+. With the approx 5k combined plate load and cathode resistors, there is about 12ma, which is over the 11ma plate current in the data sheet. I'll have to measure it before I take it apart.
On paper, I can't get this to swing more than a volt either way without running out of current or voltage and I think clipping will be asymetric based on where the swing gets cut in relation to the grid curves Not very sure). I'll try rearranging the circuit from GC to CF and see what happens.
Yes. I am more concerned with impedance to ground. Maybe I should be concerned with Voltage in this case as I'm not sure there is really a noise issue in play here.