|
Re: alright then... [message #29983 is a reply to message #29982] |
Tue, 21 December 2004 19:34 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
PakProtector
Messages: 935 Registered: May 2009
|
Illuminati (2nd Degree) |
|
|
Hey-Hey!!!, As far as voltage goes, there is no sense running up near max ratings. Once comfortable with some of the basics, and the circuit is working as expected, it is safer to push things around a bit. There might be something else to change by then...On the rectifier thing, we need four diodes for a full bridge, since there is no certer tap to ground( the grounded CT, and two diodes is basically two out of phase half wave rectifiers ). Two diodes( one at each end ) form the curent path, one with the banded end to the filter, and the other with the un-banded end to ground. We keep the two with the unbanded ends to ground, and put a pair of vacuum diodes in place of the others, with the cathode( the hot part in a valve, banded end for SS ) to the filter. It is PN-junction noise free due to the vacuum diodes. this made sense while I wrote it...and still when I read it. I have my fingers crossed. regards, Douglas
|
|
|
Let the game begin [message #29984 is a reply to message #29981] |
Tue, 21 December 2004 19:39 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
colinhester
Messages: 1349 Registered: May 2009 Location: NE Arkansas
|
Illuminati (3rd Degree) |
|
|
Please scan it and pass it around to those you know are interested (i.e., Wayne, Manualbloc, myself). You might want to make a general posting requesting emails for those whom are interested. Please keep the schematic as clear as possible for us new guys. I'm trusting you on this one. If there are various concepts / variations on the power supply side, please share. How easily are they simulated in PSU Designer? (I think that's the name.) Can we just pick one PS to go through the mathematical work-up? What other parameters of the PS can be calculated and can we discuss why they are important? What should we look for in terms of sourcing parts? I would also like to see theoretical discussion, not entirely by you (way too much effort for one person,) of the signal path. I realize this is old hat for you, but there are new guys (OK, me) out there that really want to learn this stuff. If they are anything like me, hands on is a much easier way to learn. I realize the Holidays are upon us, but I think we can start some of the "thought experiments" anytime......Colin
|
|
|
|
Re: alright then... [message #29986 is a reply to message #29985] |
Tue, 21 December 2004 19:59 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
PakProtector
Messages: 935 Registered: May 2009
|
Illuminati (2nd Degree) |
|
|
Hey-Hey!!!, I like the 5687 a lot. I will let you know about the next iteration when I have it built. In the mean time, I would caution you about trying Mercury vapor diodes like 816 and 83 until you are a bit more comfortable with the undeside of your own creation.The other sticking points to a later iteration don't seem like sticking points anymore to me. Build the simplest one and they seem to evaporate with familiarity and practice. The linestage sounds good. I have not listened to it with the single MOSFET plate load CCS in a ling time. It is easy to modify it to a cascode circuit later. The single *IS* simpler and easier to deal with at first. I would not have suggested it if I were not confident in the result. regards, Douglas
|
|
|
|
|
|
|
Some basics :-) [message #30003 is a reply to message #29978] |
Wed, 22 December 2004 13:26 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) |
Damir
Messages: 1005 Registered: May 2009
|
Illuminati (2nd Degree) |
|
|
CCS mean Constant Current Source, and you can imagine it like very high AC load resistance (hundreds of kOhms, even MegOhms), connected at the very high B+ supply (kiloVolts). Then our load line becomes horizontal, and in combination with linear tube like 5687 we have very little distortion and amplification about tube mu. Output resistance of the common cathode line stage is load resistor in parallel with tube anode resistance. For 5687, rp
|
|
|