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donsachs

Responses from donsachs

300b lovers
Lastly, I have said this before in this thread.  It is about your design goals.  We could make a low powered amp that uses 45 tubes in push pull and it would produce maybe 5-10 watts and stay in class A.  I am sure it would sound incredible.  If y... 
300b lovers
What @pindac described is exactly what I heard when I first built the rather primitive initial "silicon assisted" stereo version of this circuit with a CCS on the plate of the driver tubes and a single regulated supply for each channel.  I could h... 
300b lovers
NFB covers a lot of sins.  You have to do everything right to have a stable circuit without it.  It is actually considerably more complicated than that, but that is a good way to think about it.   That allnic amp ad boasts a perfect square wave re... 
300b lovers
@spazzghettie  Looks like a nice amp.   LC coupled and they use all DHT tubes.  On the downside it is single ended so it won't have the bass punch nor the power of a push pull 300b.  Also, I have moved on from LC coupling as I prefer custom inters... 
300b lovers
I have only had 3 or 4 pairs of the tennis ball psvane 6sn7 tubes come through here and I have yet to see a microphonic pair.  I still prefer the sound of the Linlai E-6SN7 though.   @1markr  I think you will love the Linlai WE300b.  They take may... 
300b lovers
@1markr  I have not heard the original WE300b, but I have heard many of the $400-500 per quad 300b tubes and then I heard the Gold Lion 300b, which was a definite step up.   Then I got the Linlai WE300b copy and it is a far better tube than the Go... 
300b lovers
The treasure globes are most likely just hand selected psvane tennis ball tubes.  They are indeed also a very good 6sn7 if they will physically fit in your application.  The Shuguang WE6sn7 series was wonderful as well, but sadly all things Shugua... 
300b lovers
I use the Linlai E-6SN7 pretty much exclusively.  A very well balanced tube that rivals any of my NOS ones and I can buy all of them I want.  The PSVane tennis ball shaped ones are also quite good, but I prefer the Linlai in my gear.  Point is tha... 
300b lovers
Rolling your own is always cheaper and can be fun!  I would highly recommend that people build good quality kits if they can do so.  It is a great way to start.  
300b lovers
I would do a full wave bridge if you have the choice   
300b lovers
Yes there are current production 45 tubes, but they are ridiculously expensive.   As soon as Linlai decides to make one it will be much more reasonable and quite good I am sure.  You can still get some of the TJ full music ones at about $350 a pai... 
300b lovers
@charles1dad I am sure it is a great amp.   Looks like my usual sources have 6EM7 for $15 a tube or so.  If you love the amp, you probably already have bought a few for the drawer.  If run conservatively I would expect them to last a long time, s... 
300b lovers
@atmasphere the ST70 power transformer spec was allegedly 2 x 6.3 V windings @5A each.   Pair of el34 is 3 A, even a pair of 6sn7 is only 1.2A, so that should be only 4.2A.  Should be safe   
300b lovers
@atmasphere Hi.. you are only running 3 6sn7 tubes.   Input tube and then a long tailed pair driver on each side using a single 6sn7....  
300b lovers
@atmasphere Actually, I have rebuilt a few ST-70.   I agree, the rectifier is inadequate, but so is the driver section, which is at clipping at or just before the output section clips.   I have heard a couple of drop in boards and the octal versio...