Thanks Salas,
My next thought goes back to some original warnings of the DC B1 and offset, assuming using with a capless F5 or Aleph-P may be problematic here, is it simple enough to put a 1uf-5uf cap in series or shunt with the input?? I am assuming that if the DCB1 is set well operationally, then using it is not a problem unless there is a failure. Of course, using some expensive drivers, I may want to consider putting a cap somewhere.
My next thought goes back to some original warnings of the DC B1 and offset, assuming using with a capless F5 or Aleph-P may be problematic here, is it simple enough to put a 1uf-5uf cap in series or shunt with the input?? I am assuming that if the DCB1 is set well operationally, then using it is not a problem unless there is a failure. Of course, using some expensive drivers, I may want to consider putting a cap somewhere.
AndrewT said:
Its better not to have yet one more contact in series with the signal, but I remember a thread of a guy with a gain clone that his amp oscillated and dc drifted when his preamp was muting to ground (or floated, never got clear on that.) Do you consider it generally safe to ground mute?
Link
Tea-Bag said:
Use 1 cap in F5's input if you find it tolerable, without a cap input amp you are taking a risk. In our case if one side of the regs fails, the DC B1 is going to pass serious DC. Of course I see much less chance at the low load the regs work and the heavy Mosfets, maybe far lower risk than some F5 output Mosfet failing or in any non single ended solid state amp for that matter, but the risk is yours to take or not. I have described all that in the most early posts so to be understood. I don't officially recommend any DC input amp for total safety with DC B1. OK an asteroid can hit our planet any day. Not even cosmos is bullet proof safe.
would be easy to connect the relay terminal to an existing connection on the output side of the 220r/1k0 that buffers the load from the active stage.Salas said:
I do not see the need for any extra series contacts.
It's upto to the design team to ensure the output remains stable when the load is the grounded output resistor.
I am missing something here. Looking at the schematic in post http://www.diyaudio.com/forums/showthread.php?postid=1884287#post1884287 (is that the one we are still talking about?) I see that the output has 1M across it, so we already have a connection to ground that the subsequent stage sees. I also note that we already have an output relay in D27.
Am I looking at the wrong schematic? (As a side note, maybe we can have a pointer to the schematic on the GB Wiki.)
peter
Am I looking at the wrong schematic? (As a side note, maybe we can have a pointer to the schematic on the GB Wiki.)
peter
Hi
yeah thats the schematic of the deluxe b1, the recent discussion about the mute relay is for the basic b1. The dc offset becomes a concern if you turn off the Basic B1.. the dc offset rises from 3mV to 400mV.
Salas suggest of adding a mute relay for the Basic B1 just to prevent this problem.
The Deluxe B1 is working perferctly on my F5.. its been playing all day now..
yeah thats the schematic of the deluxe b1, the recent discussion about the mute relay is for the basic b1. The dc offset becomes a concern if you turn off the Basic B1.. the dc offset rises from 3mV to 400mV.
Salas suggest of adding a mute relay for the Basic B1 just to prevent this problem.
The Deluxe B1 is working perferctly on my F5.. its been playing all day now..
Great work guys. Great to hear that the deluxe works well.
My own preparations:
And the results from matching the first dozen or so of 30 2SK170BLs:
I got a good yield from the 2SK170s, I have 10 very closely matching pairs and 4 sets of not-so-closely matching pairs and the just 2 real singletons. Much better than I thought it would be. The 2SJ74 I bought at the same time are not so good at matching, only got 2 pairs out of 9 units. Must do the 2SK117 I have as well soon and see how they fare out.
Fran
My own preparations:
An externally hosted image should be here but it was not working when we last tested it.
And the results from matching the first dozen or so of 30 2SK170BLs:
An externally hosted image should be here but it was not working when we last tested it.
I got a good yield from the 2SK170s, I have 10 very closely matching pairs and 4 sets of not-so-closely matching pairs and the just 2 real singletons. Much better than I thought it would be. The 2SJ74 I bought at the same time are not so good at matching, only got 2 pairs out of 9 units. Must do the 2SK117 I have as well soon and see how they fare out.
Fran
Regarding aux power for relays, used for LDR att
Could it be regulated for 5V as well, to feed a Lightspeed LDR att?
Maybe just by using another small reg board
This way of "stealing" power from just one rail I suppose works due to the reg design
Does this mean that its possible to just connect an aux 5V reg board, to fed the LDR att
Could it be regulated for 5V as well, to feed a Lightspeed LDR att?
Maybe just by using another small reg board
This way of "stealing" power from just one rail I suppose works due to the reg design
Does this mean that its possible to just connect an aux 5V reg board, to fed the LDR att
