U52/5u4g/5ar4, etc.Rectifier tubes

[MylesBAstor]

Anyone played with and compared these rectifier tubes in their amps, preamps, phono section, etc? What are your experiences with currently available vs. NOS tubes out there such as the Mullards, Tungsol, RCA, etc?

 

[mep]

Myles-You can't go wrong with the real Mullard 5AR4 tube. They are known to last 40 years and they sound great. The only 5U4G tubes I have used are NOS RCAs and they are just dandy. If you want to try a real Mullard 5AR4 tube and you don't have one, drop me a line and I will send you one to play with. I think I have exhausted my supply of 5U4G tubes in guitar amps that I fixed and sold.

Mark

 

[tony ky ma]

5U4G and 5AR4, same wiring, can be replaced without change anything, but one is direct heating and the other is in-direct heating, so the 5U4g will send out high voltage faster than 5AR4, if tubes in amp is all in-direct tubes, HV come in before they heat up is not a good thing, install a delay timer is add another contact also no good, the only can be done is to separate HV and LV supply, turn on heater LV for amp's tubes first and then switch the HV can keep tubes last longer
tony ma

 

[MylesBAstor]

5U4G and 5AR4, same wiring, can be replaced without change anything, but one is direct heating and the other is in-direct heating, so the 5U4g will send out high voltage faster than 5AR4, if tubes in amp is all in-direct tubes, HV come in before they heat up is not a good thing, install a delay timer is add another contact also no good, the only can be done is to separate HV and LV supply, turn on heater LV for amp's tubes first and then switch the HV can keep tubes last longer
tony ma

Thanks Tony. The phono stage presently uses a 5U4G rectifier in the PS and there's no issue as the unit mutes its output for a minute after turn on. I can't give you all the details yet but the PS is designed to be robust enough to use a variety of rectifier tubes like GZ37, 5AR4, 5U4g. It comes with a 5Z3PJ stock so imagine that can be improved though the mid-60s Mullard ST type 378 tried was not as good as the stock tube. Maybe there was something wrong with the tube since it makes no sense. Can't remember the last time a NOS sounded worse than a Chinese equivalent.

 

[tony ky ma]

Thanks Tony. The phono stage presently uses a 5U4G rectifier in the PS and there's no issue as the unit mutes its output for a minute after turn on. I can't give you all the details yet but the PS is designed to be robust enough to use a variety of rectifier tubes like GZ37, 5AR4, 5U4g. It comes with a 5Z3PJ stock so imagine that can be improved though the mid-60s Mullard ST type 378 tried was not as good as the stock tube. Maybe there was something wrong with the tube since it makes no sense. Can't remember the last time a NOS sounded worse than a Chinese equivalent.

Hi Myles
The original design in use of direct heating tube to replace with a in- direct one should have no problem, but I don't think they care of this matter from the beginning, most of brand name design to put a time delay mute only on the sound out-put for no noise before heating up, we diyer always care of life time of expensive NOS tubes, so I like separate into HV and LV supply, there are a tweak to wire with two switches , you turn on one first no matter which one must be the LV power, till both on for HV power, see picture, up grade power supply (add more supply like one for each tube in amp ) always will have a big positive return
cheers
tony ma

 

[MylesBAstor]

OK I understand Tony Makes sense

 

[tony ky ma]

OK I understand Tony Makes sense

Best sounding rectifier is 866A mercury vapor but too much preparation works for this tube, second choice is gas filled 3B25 and 3B28, NOS price is still cheap around $30
tony ma

 

[MylesBAstor]

Anyone played with the new Emission Labs 5U4G tubes?

 

[MarinJim]

Anyone played with the new Emission Labs 5U4G tubes?

I tickle mine once a day.