[Silent One]

Inside his listening room...
 
I raced home 

early. So, I could get started 

early. Only to stumble 

early...at installation. My mid-year 2010 Mac mini music server has an irregular; odd shaped bottom. Majority of the real estate is that of a rubber cover. T-e-r-r-i-b-l-e resonance. 
 
I was aware of this challenge going in. But I needed for the new footers to arrive in order to make a better visual assessment. My spikes only need to utilize the corners, which are aluminum. So, for now, I sit! Well, there's Head-Fi but...
 
At some point, I'm going to need to be able to fabricate something. Maybe a bottom plate out of Maple with a large depression in the middle, for the rubber cover to sit down in. Kind of like the last Mac platform I had. And then place the footers underneath the new bottom chassis. The only challenge, and it's huge, is tuning whatever solution I come up with. If the ideas are slow to come, I'll slide 'em underneath the DAC or amp.

 

[rosgr63]

Thanks xcalibur &SO for the info.
 
So the list is:
 
 
                          5998                     6AS7G               Adapter            Recommended
 
 
3DG4                  Yes                         Yes                       No                      Yes
 
GZ33/37              Yes                          No                       No                Owner's Risk
 
5U8C                   Yes                         No                      Yes               Owner's Risk
 
5AU4(Long Plate)   Yes                         No                      No                Owner's Risk
 
596                      Yes                         No                      Yes               Owner's Risk

 

[Silent One]

Nice effort! Though, I could be misunderstanding the table (or the Do's & Don'ts). Because I have run both the USAF-596 & 5U8 with the Russian 6AS7's...

 as well as 5998's.
 
The 5998 is preferred but every now and again, I really miss and appreciate just how quiet the Russian 6AS7's are. Sometimes, I'll throw 'em for that silence and blackness.

 

[rosgr63]

SO it's probably wrong, I thought it was not safe to use the 596 & 5U8C with the 6AS7G.

 

[Silent One]

Quote:

SO it's probably wrong, I thought it was not safe to use the 596 & 5U8C with the 6AS7G.

 
No, you're right. I was merely confessing to doin' what I wanna, you know..."Owner's risk." And after awhile, couldn't remember right from wrong. Ah, now it's coming back to me (Glenn's advisory). 
 
That's a clean looking table, too. Like me, 

are you a Rhodia notepad man? I'm guessing it would speak to the engineer in you. I'm a life-long user of their graph notepads in various sizes.

 

[rosgr63]

I am actually using Notes and CircusPonies Notebook for cataloging my tubes.
 
I just drafted this table and will present in in a nice format once I know the info is correct.

 

[2359glenn]

Quote:

Thanks xcalibur &SO for the info.
 
So the list is:
 
 
                          5998                     6AS7G               Adapter            Recommended
 
 
3DG4                  Yes                         Yes                       No                      Yes
 
GZ33/37              Yes                          No                       No                Owner's Risk
 
5U8C                   Yes                         No                      Yes               Owner's Risk
 
5AU4(Long Plate)   Yes                         No                      No                Owner's Risk
 
596                      Yes                         No                      Yes               Owner's Risk

 There is no risk in any of these tubes. The 596 being the lowest current of the bunch might have a shorter life but it should be OK.
When I say shorter life maybe 5 years instead of 10. These tubes are not like new production that burn out easy.
And no harm will come to the amp whichever one of these tubes you use. And there is the one everyone hates but has the same
specs as the 596  270ma that would be the 5U4GB really not a bad tube.

 

[rosgr63]

Thanks Glenn,
 
So the list would be:
 
 
                                5998                     6AS7G               Adapter           
 
3DG4                         Yes                         Yes                     No                    
 
GZ33/37                     Yes                          No                      No              
 
5U8C                          Yes                         No                     Yes             
 
5AU4(Long Plate)         Yes                          No                      No
 
5U4GB                        Yes                         No                      No
 
596                             Yes                         No                      Yes          

 

[Xcalibur255]

I've noticed the 5V3 has identical plates to a 5U4GB, clearly related.  The 5V3 has higher heater current otherwise they seem similar.

 

[john57]

The 5V3 and the real 5V3A (reduced heater current) was a disaster for me. The specs stated that it had plenty of current capacity. The tube will arc and sound like a shotgun went off.

 

[Xcalibur255]

Yeah.  Your amp is biased for around 20mA more current per output tube is my understanding so I can definitely see that happening.  It seems to barely be okay with my amp.  The tube will arc during startup with a 6AS7 but I didn't see anything with 5998s in. 
 
All of this was really just to refresh old listening impressions of these tubes, nothing too serious. 

 

[Silent One]

Changing preferences with the custom built, OTL backed system. In what could be called an engaged listening session - sunset to sunrise - I decided to tip across the street...under a cover of darkness. That, I did not successfully negotiate crossing in a straight line, resulted in the lone alley cat tracking my every move. Better it, than the LAPD. 

 
Anyway, Thursday night, I installed the trio of brass footers under my Mac mini music server. Further tuning lies ahead, like damping discs. But enough happened, in order for me to change from my previously preferred Amarra music player and over to Audirvana Plus w/Direct mode; Integer mode, as my current number one audio player. In the middle of the night.
 
The great thing about having cafes located on opposing corners is choice. When I decide Amarra is once again serving tea I'd like to enjoy, I'll simply tip back across the street. Until then...
 
With this change in presentation, this also means going back and re-evaluating all tubes.

And finding out where the NOS 3DG4 rec fits in as well. I need to move beyond the current 16 hours, though. Seems, there's always something to do in this hobby, 

 from tweaks to 

 upgrades!

 

[2359glenn]

rosgr63s amp with P250 direct heated triodes as drivers RCA 6AS7s and RCA 3DG4.
 

 
rosgr63 amp with 6SN7 as driver RCA 6AS7s and RCA 3DG4
just remove the P250s or LP2s and put in a 6SN7 or 12SN7
has 6 volt or 12 volt switch.
 

 

[john57]

Glenn you new amp for rosgr63 reminds me a bit of the expensive Cavalli Audio Liquid Glass Amplifier protype that I head at the RMAF show in Denver with the tube rolling options.

 

[2359glenn]

How did the Cavalli sound and can it take direct heated triodes.
I am thinking of making a amp that uses the USA  type 01A tube as a driver.
Highly micro phonic but sound good when you get a good pair and they are cheep
so no problem buying a bunch of them.