Nice one for so rapidly made. I think I had tried those tubes briefly, maybe. Try a few brands. They all have interesting traits.
What design are those series regs? Zeners and a pass element, or something chip based?
Maybe you had to make it sim for a bit longer time in mS?
I have been following this thread on and off for a while. Salas et al, I have a few questions:
I gleaned from the responses to Buzzforb that the circuit sounds best with 2X the Salas SSHV2 instead of the Maida referenced on the schematic?
Buzzforb mentioned effects on his heater voltage due to something he did to the SSHV2 (it was late when I read this). Was he talking about the LV Salas regulator or just the regulated heater circuit shown on the schematic?
I have just in the last week become aware of the group buy for the SSHV2, which is already closed but I see that some Johnny-come-latelys have been advised to contact Teabag anyway – which I plan to do. Here is my question – is the SSHV2 the same as the circuit shown by Salas in his link to Maida circuit – or is Salas’ SSHV2 design shown somewhere else? I ask in case I cant get boards from Teabag.
Salas – this thread really makes me want to build this circuit.In fact, I have been thinking about trying to figure out how to combine it in one box with DanL’s version of Hagerman’s octal coronet phono circuit.
regards
mike
Buzz's here for details, me I had conceived and made the original one, they are different builds in execution.
SSHV2 is one and same, the one in the link & group buy. Here SG & Buzz4B were some of the first to build it, point to point even.
These are Pimm/Sorenson regs (2008). Output voltage is constant over time, the rough beginning is typical for voltage doublers. Only difference is in the semis used: IXYS DSEP 30-12 (1200V, low switching loss, short recovery). Could it be the extra 50V compared to 1N4007.... nah!? can't be
An externally hosted image should be here but it was not working when we last tested it.
The mysterious overvoltage was caused by the HV-tranny, giving 9% higher output than the label promised. Luckily it has an extra primary tab so the regs receive the intended 480V now, radiating little heat.
The way I develop there's room for improvement. Starting with a basic setup and experimenting with different parts I listen for (or measure) their effect on reproduction. For me this is a major part of enjoying the hobby. The pre is built with old and abused industrial parts I had at hand. The cathode bypass (Roedenstein 1.000uF/40V) come from a switching PS, the coupling caps (0,5uF/750V) from an oscilloscope, the load resistors are (inductive) wire wound from a taperecorder. From an engeneering position the pre should deliver the goods with these parts, and it does. After one day I feel some stress is released and reproduction is settling somewhat. Some of the sharp edges I wasn't familiar to hear in my music are getting softer. Dynamics are realistic, not impressive (like the first time I listened to a digital source), not romantic soft (like the first tube amp I came across). Mind you, these are brand new 6V6, AC-heated.
The amplification is a little strong for my needs: with a 100K pot most adjustments are made within the seven and nine o'clock position. Can the load be lowered a little to this goal or are we doing so drifting away from the sweet spot? Perhaps I can find a pair of 2:1 interstages.... Hmmmm
The way I develop there's room for improvement. Starting with a basic setup and experimenting with different parts I listen for (or measure) their effect on reproduction. For me this is a major part of enjoying the hobby. The pre is built with old and abused industrial parts I had at hand. The cathode bypass (Roedenstein 1.000uF/40V) come from a switching PS, the coupling caps (0,5uF/750V) from an oscilloscope, the load resistors are (inductive) wire wound from a taperecorder. From an engeneering position the pre should deliver the goods with these parts, and it does. After one day I feel some stress is released and reproduction is settling somewhat. Some of the sharp edges I wasn't familiar to hear in my music are getting softer. Dynamics are realistic, not impressive (like the first time I listened to a digital source), not romantic soft (like the first tube amp I came across). Mind you, these are brand new 6V6, AC-heated.
The amplification is a little strong for my needs: with a 100K pot most adjustments are made within the seven and nine o'clock position. Can the load be lowered a little to this goal or are we doing so drifting away from the sweet spot? Perhaps I can find a pair of 2:1 interstages.... Hmmmm
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Do you have copy of an example of one of your amps?
in fact , no (if you're thinking on pre-amps)
I'm just another one of Big Mouths , without any proper builds
frankly - all I have documented is already known - my old WOT (later in different iteration) ,
, PSM "Not-Realy-Lightspeed" etc.
its both cascode ( for constant voltage mode purpose) and CCS load ;
combined with use of toob with relatively low Ri and highish xconductance ....
to use Allen's words - that is not your usual Miss Piggy CF , but thingie able to pump up current in both half of period , as needed
Could you explain further? This is somewhat contrary to what i understand about cathode/source followers. Is it due specifically to the use of tubes as transistors would not seem to fit this explanation, in my limited understanding.
The tube cathode follower has low gain while a MOSFET has enough gain. Driving a low impedance (large capacitance) with a tube goes at the expense of bandwith.
there is a low impedance and low impedance
meaning - if you need to drive high capacitance - better change that high capacitive stage
whatever you use to drive it , it's a mess ........
btw.
ohms and mA are the same in toob and sand world
that's why I like them mixed , toobz and sand
meaning - if you need to drive high capacitance - better change that high capacitive stage
whatever you use to drive it , it's a mess ........
btw.
ohms and mA are the same in toob and sand world
that's why I like them mixed , toobz and sand
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