watchnerd
Grand Contributor
I've been playing around with tube rolling (insanity, I know, but I recently retired) in my Fi Yph phono stage.
I'm no EE, but from what I understand it's a pretty simple circuit. Goofy subjective review here, but you can at least see some pictures and a bit of the components inside:
Note, I don't actually need to use this as my phono stage, as my amp has a perfectly decent solid state phono section, especially for MM carts. This is all for amusement.
Over the past couple of weeks, I've been swapping in 18 different tubes, following a uniform warm up procedure, and listening to the same record for consistency, and the same volume setting on the amp.
What I'm not doing: trying to measure the electrical output between tube swaps on the amp, which is clearly a methodology blind spot. The hope is that, as they're all 6DJ8-compatible tubes, the error bars on output voltage wouldn't be grossly wide.
So here is the list of tube. A few are current production, but most are NOS:
Without lapsing into audiophile review slop, I do hear differences. Some are clearly defects, but others are hard for me to explain:
1. Differences in noise/hiss (not surprising, some are in worse conditions than others, or simply lower quality)
2. Some have more surface noise from the LP than others.
3. Differences in pops and ticks. For some tubes, the pops and ticks stand our more than others.
4. Differences in soundstage width / stereo separation
5. Spectral differences. Differences in bass vs mids vs treble emphasis, almost like an EQ has been applied.
6. Differences in dynamics. Some are more compressed sounding, others are closer to closer to solid state.
Given the circuit is pretty simple, what electrical qualities of the tubes could account for this?
Or could some of this be do to changes in the loading of the cartridge caused by a change in tube? (I'd think not, but...)
I'm no EE, but from what I understand it's a pretty simple circuit. Goofy subjective review here, but you can at least see some pictures and a bit of the components inside:



Note, I don't actually need to use this as my phono stage, as my amp has a perfectly decent solid state phono section, especially for MM carts. This is all for amusement.
Over the past couple of weeks, I've been swapping in 18 different tubes, following a uniform warm up procedure, and listening to the same record for consistency, and the same volume setting on the amp.
What I'm not doing: trying to measure the electrical output between tube swaps on the amp, which is clearly a methodology blind spot. The hope is that, as they're all 6DJ8-compatible tubes, the error bars on output voltage wouldn't be grossly wide.
So here is the list of tube. A few are current production, but most are NOS:
Brand | Model |
Amperex (Orange Globe) | 6DJ8 |
Amperex | 7308 |
BEL | E88CC |
Brimar | ECC88 |
EH | 6922 |
GE | 6DJ8 |
JJ | E88CC |
Mullard | E188CC/7308 |
National | 7DJ8/PCC88 |
Philips SQ | E88CC |
Reflektor | 6H23P-EB |
Siemens | E88CC |
Siemens | E188CC/7308 |
Sylvania JAN | 6922 |
Telefunken | PCC88/7DJ8 |
Tesla | E88CC |
Toshiba | PCC88/7DJ8 |
Tungsram | E88CC |
Without lapsing into audiophile review slop, I do hear differences. Some are clearly defects, but others are hard for me to explain:
1. Differences in noise/hiss (not surprising, some are in worse conditions than others, or simply lower quality)
2. Some have more surface noise from the LP than others.
3. Differences in pops and ticks. For some tubes, the pops and ticks stand our more than others.
4. Differences in soundstage width / stereo separation
5. Spectral differences. Differences in bass vs mids vs treble emphasis, almost like an EQ has been applied.
6. Differences in dynamics. Some are more compressed sounding, others are closer to closer to solid state.
Given the circuit is pretty simple, what electrical qualities of the tubes could account for this?
Or could some of this be do to changes in the loading of the cartridge caused by a change in tube? (I'd think not, but...)