the art of valve rolling [ should say the dark art !]
- Thread starter hifinutt
- Start date
les24preludes
pfm Member
That was an OK video but it doesn't dig very deep - quite a lot of hot air. And some anecdotal stuff like "long anodes sound better". It's also limited to the valves (Golden Lion) and amp types he has a vested interest in. So not really of much general use.
So to add some more solid information to that video, the place to start with tube rolling is Franks Tube pages, link below.
This invaluable site contains the manufacturers' tube data sheets for pretty much all commercially made valves. If you are serious about tube rolling, you start here.
1. Heater voltage and current. Do your proposed substitute tubes have the same voltage and current? Current is important - if you put in tubes that exceed the manufacturer's spec you can overheat the heater winding and potentially case failure.
2. Do the substitute tubes have the same pinout? The data sheets show the pinout. You need to check that it's the same as the original. For instance EL34 and 6L6 aren't always compatible - it depends what's connected to pin 1. Again, mistakes can cause equipment failure.
3. Operating point. Here you need some tube knowledge to interpret the "curves" i.e. current/voltage graphs that show how the tube behaves in a circuit. If the curves are different to any degree you might stress the circuit and again cause damage.
Two other useful sites are these - they give the history and compatibility of all common tubes.
Changing tube types isn't something you do lightly - if you don't know how to check the above basic information, then stick to the same tubes that the circuit was designed for. Remember that tube circuits use high voltages. Tube rolling can be a lot of fun and also a potentially wallet draining pastime for the enthusiastic roller. It's harmless if you stick to the rules. if you don't then caveat emptor.
So to add some more solid information to that video, the place to start with tube rolling is Franks Tube pages, link below.
This invaluable site contains the manufacturers' tube data sheets for pretty much all commercially made valves. If you are serious about tube rolling, you start here.
1. Heater voltage and current. Do your proposed substitute tubes have the same voltage and current? Current is important - if you put in tubes that exceed the manufacturer's spec you can overheat the heater winding and potentially case failure.
2. Do the substitute tubes have the same pinout? The data sheets show the pinout. You need to check that it's the same as the original. For instance EL34 and 6L6 aren't always compatible - it depends what's connected to pin 1. Again, mistakes can cause equipment failure.
3. Operating point. Here you need some tube knowledge to interpret the "curves" i.e. current/voltage graphs that show how the tube behaves in a circuit. If the curves are different to any degree you might stress the circuit and again cause damage.
Two other useful sites are these - they give the history and compatibility of all common tubes.
EL 6, Tube EL6; Röhre EL 6 ID1831, Vacuum Pentode | Radiomuseum.org
Tube EL 6 or Röhre EL6 ID1831, Vacuum Pentode, Europe side contact P8A (Au P, 8SC) and Power/Output shown. Radio tubes are valves.
www.radiomuseum.org
Changing tube types isn't something you do lightly - if you don't know how to check the above basic information, then stick to the same tubes that the circuit was designed for. Remember that tube circuits use high voltages. Tube rolling can be a lot of fun and also a potentially wallet draining pastime for the enthusiastic roller. It's harmless if you stick to the rules. if you don't then caveat emptor.
chris@panteg
pfm Member
I've tried a bit of tube rolling in the past but very little nowadays.
For me it just doesn't seem worth it.
I've never noticed anything but subtle improvements when tube rolling.
My current phono stage is the Puresound P20 which is the upgrade to the P10.
I have a nice Brimar ecc83 and a an original Tesla ecc88 which I could try rolling in the P20 but I just can't be arsed quite frankly.
It just sounds so sublime with the valves that Guy Sergeant has specified.
I'm going to leave it as it is .
For me it just doesn't seem worth it.
I've never noticed anything but subtle improvements when tube rolling.
My current phono stage is the Puresound P20 which is the upgrade to the P10.
I have a nice Brimar ecc83 and a an original Tesla ecc88 which I could try rolling in the P20 but I just can't be arsed quite frankly.
It just sounds so sublime with the valves that Guy Sergeant has specified.
I'm going to leave it as it is .
Salamander
pfm Member
@chris@panteg I don't have much experience with valves, I've swopped a couple in the past and the difference was subtle, however I put a couple of new 12AU7's in my amp last week and I was shocked at the improvement. It could be worth a try and only 5 minutes of your time.