The Stax thread (New)
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Feb 15, 2013 at 4:56 AM Post #21,016 of 24,807
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 Hi Spitzer,
 
Thanks for the reply, I think I have a bad tube since if I switch tube positions, the problem is now on the other channel and the previous channel is now OK !
 
These are brand new  ECC99 tubes from JJ so maybe there is somthing about their quality control that is lacking ?. Never thought that a brand new tube would act like that?  I use mostly older NOS tubes in much of my audio gear that are still going after 40+ years !
I have a replacement ECC99 on the way so hopefully I will be able to up and running soon.
 
Actually I have two SRM-T1 units , one that is still bone stock and this one I am modding to ECC99 tubes. I want to be able to compare them directly to see what sonic changes or improvements occur.  
 
I will report my findings as soon as I can.

Hi kkqew,
 
Great. I love the sound of my T1S but compared to my SRM-3 it lacks bite. Would be almost too good to be true if you could improve the power output of the T1 without touching its sound sig.
 
I would be surprised if JJ had become significantly better. I never came across a "decent" sounding JJ tube. My best driver tubes are all vintage US triple mica black plates - the best of the best with extra support rods.
 
Just my 2 cents.
 
Feb 15, 2013 at 7:15 AM Post #21,019 of 24,807
Quote:
I never came across a "decent" sounding JJ tube.

 
*shrug* The JJ ECC802S is the best 12AU7 type tube I have heard in my Crack.
 
Feb 15, 2013 at 8:03 AM Post #21,020 of 24,807
I did the ecc99 mod to my t1s,
bass is less boomy,high frequency extension is a bit better 
soundstage is a bit wider
 
the stock GE 6CG7 has thicker mids,better vocals
 
& please use AMRG plate resistors if possible
the sound of kiwame is blurred
 
Feb 15, 2013 at 8:44 AM Post #21,021 of 24,807
Thanks for your comments guys. I wait what kkqew will find out.
 
Feb 15, 2013 at 10:43 AM Post #21,022 of 24,807
Quote:
 Hi Spitzer,
 
Thanks for the reply, I think I have a bad tube since if I switch tube positions, the problem is now on the other channel and the previous channel is now OK !
 
These are brand new  ECC99 tubes from JJ so maybe there is somthing about their quality control that is lacking ?. Never thought that a brand new tube would act like that?  I use mostly older NOS tubes in much of my audio gear that are still going after 40+ years !
I have a replacement ECC99 on the way so hopefully I will be able to up and running soon.
 
Actually I have two SRM-T1 units , one that is still bone stock and this one I am modding to ECC99 tubes. I want to be able to compare them directly to see what sonic changes or improvements occur.  
 
I will report my findings as soon as I can.

 
Bad tubes are more the fault of the tube dealer than JJ.  They do some testing at the factory but the final tests of each tube should be done by the tube seller. 
 
Feb 15, 2013 at 6:54 PM Post #21,023 of 24,807
Noobish question here...
 
So I have a Japanese SRM-717 unit here (using it with a step up/down transformer) which I'm currently using single-ended, but I'd like to give the balanced  connection a shot to see if it makes any meaningful difference at all.. but from what I've read earlier there is something about the Japanese unit xlr connector pins being reversed or something like that? Mine's a Japanese 100v unit so the pin 2 is the negative polarity. Does this mean that this particular unit is not compatible with the xlr-outs on North American-made DACs or that I have to get a specialized cable or something like that?  I have nearly no experience with using xlr cables, only simple plug and play RCA cables most of the time so I have no idea how this works and what's safe/not safe, etc.  
 
Thanks in advance.
 
Feb 15, 2013 at 7:41 PM Post #21,024 of 24,807
Yes it does invert the phase but basically you needn't care, it is hard to tell if there is any difference in sound. Absolutely no harm at all.
 
Setting the voltage to 117V and skipping the voltage transformer might make it a bit better though.
 
If you have a "true" balanced source then XLR input is always preferable.
 
Feb 15, 2013 at 10:13 PM Post #21,025 of 24,807
So , I got my ECC99 tube replacement quicker than expected and yes all is ok now.
 
I agree that tube dealers should be checking tubes but JJ's  track record is not that great especially for certain types of tubes.
 
Funny I have an older B&K tube tester but since the ECC99 is a newer tube I did not have any guideline as to what settings I should use to test it.
 
 
Prelimanry evaluation of the ECC99 mod vs the stock T-1 has begun, so far mids are little more prominent with better dynamics but with perhaps a little more grain, still early though, I need to listen for a week or so to get a better feel for the differences though.
 
Feb 16, 2013 at 10:01 PM Post #21,027 of 24,807
Quote:
If your tester has a 12BH7 setting then you can test the ECC99 on that.  They are similar but not identical. 

 
 
Good idea I will try that to see how that tube measures up.
 
Also another weird thing I noticed is that both of my Stax  T-1 units have their AC neutral lead and not the hot lead connected to the inlet fuse ?  With a three prong AC plug inserted I measure ~ 60 volts from chassis to ground "real earth" If I use a cheater plug and turn the three prong plug around so that the hot AC lead is now fused I then measure only 9 volts chassis to ground !
 
Are all T-1 units hooked up incorrectly with regards to proper AC orientation or is this somehow related to the way the Japanese AC power grid is set up ??
  I am loacted in Canada where we run on 120 volts and 60Hz and most if not all equipment is fused using the hot AC lead. 
 
Feb 17, 2013 at 6:30 AM Post #21,029 of 24,807
Japanese sockets are usually only 2-pin usually with only sockets for high-power equipment such as air conditioners and washing machines having an earth/ground screw. Except in older places, the sockets have different sized positive and neutral pins, but the plugs on most equipment have 2 small pins so the plug can go in either way. I can only recall one or two things I've ever come across here that had distinctly polarised plugs.
 
The confusion comes in that the socket polarity is the same as the USA. China uses the US plugs, but with reversed polarity (or you can think of it as the earth/ground pin being above the positive and neutral pins rather than below). China also has another standard that is identical to the Australian system including polarity.
 
Feb 17, 2013 at 7:24 AM Post #21,030 of 24,807
I apologize that this is somewhat branching off-topic, but I wonder why all of these different regions adopted such vastly different power standards and have made no effort to reconcile them in this day and age. I'd think it would put a real damper on the importation/exportation of almost everything electronic.
 
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