I've finally got the RCA-XLR , balanced to unbalanced problem worked out and the last little bit of hum gone also . It seemed some of the hum was a ground loop and putting two prong to three prong "cheater" plugs on all the components , mainly the amp , got rid of 99% of all hum noise.
There is one last minor noise problem which may or may not be easily fixable . I think it is from the wood case being so rigid and that I didn't use any sound deadining material inside the case , since I figured the wood would act as a sound deadiner . When you tap on the case with it powered on you can hear a slight thump sound through the speakers , not a ringing microphonic sound but a solid sound . I'm guessing the vibrations are being transmitted through the case to the board and being slightly amplified by the tubes , because the case is so rigid ? I put dampners on the tubes and that helped some and also on the hard rubber feet I bought for the case , I put little round disks like you put on bottom of a vase to keep it from scratching , I used one of carpet material and one of rubber material on each foot and that helped out alot . If I were to do this again I would mount the board a little differently maybe rubber isolators on both sides of the board and under the stand offs ? The noise is not totally gone but acceptable and about all I can do with it at the moment . I don't think I'll ever play this loud enough for noise vibration to be a problem to transmit any noise to the speakers .
Now the important part , How does it sound ? Awesome . I've played a bunch of different music so far , Rock , hard , soft , Psychedelic . Blues, Reggae , Classical even some Country . Moody Blues days of future past , SRV , Rush , Doors , Floyd ,Willie Nelson Merle Haggard , Spirit , Van Morrison , Elvis Costello , Roy Buchanan, Beach Boys , Ect Ect .
I'm listening through the Jensen coupling caps now and have about 25-30 hours on it so far and it sounds like it has smoothed out already . The highs were a "little" harsh , buzzy sounding at first . The soundstage is not much wider than with the SS preamp but is deeper and all the way across the room . The bass , the drums are tight and not muddy at all , bass guitar is smooth and not buzzy sounding . The vocals are very nice and accurate sounding . The highs now that they have smoothed out some are already better sounding without the slight brightness and little "essy-hissy" sound they had .
I think I'm finally hearing what "That Tube Sound " really means . The music overall has a smoother less hard edged sound than before , almost a little ambience to it . I'm really liking this so far ! The piano sounds like its in the room , and Stevie Ray's guitar on Tin pan ally
. Once it breaks in it can only get better right .
The NOS tubes I'm useing now are a pair of mid 1940's Sylvania JAN-CHS-6SN7W , A pair of 1957 JAN-CHY-5692 CBS Hytron , And a 1944 Sylvania JAN-CHS-6X5GT/G rectifier . The CBS Hytron tubes ( which are supposed to be the same as the RCA red base 5692's ?) are chunks , they are heavy and look well made . I can see why they say these are 10,000 hour tubes ! I also got a pair of good used JAN-CRC-6SN7GT VT-231 RCA's and Sylvania 5692's to try out later.
Like I said I'm running the Jensen caps right now , I'll try out the Jupiters and see how they sound once these break in a while .
A couple last pics .
You can see the audiophile grade foot dampeners in this picture.
They helped alot .
I like how the white of the dampners look too .
And the whole system.