I love Western Electric 420a / 5755 in a guitar amp
Whoever mentioned 420a / 5755 is not working in a guitar amp is wrong. I bought a couple of 420a. I built adapter sockets and dropped in V1 and PI positions. They sound amazing. To me it sounds like its got good bass and middle range. I felt like it sounds similar to Telefunken 12ax7 smooth plate with less gain. Its got uncolored and pure tones!!
For me, i dont like gain level 100. Even with telefunken 12ax7, i feel like i lose all the definitions.
Spending a few years with RCA Black plate 12ax7, i found myself RCA 12ax7 black plate sounded too dark and somehow muffled and also feel like there is no definitions.
5751 Rca command is very good but very expensive.
You should try We 420a. They are not as expensive as mullard or Rca 5751 command series.
420a has spring construction so it should be less microphonic.
Many people say 420a has less noise as well.
Im not a tech. But, in my opinion, it sounds awesome in my marshall jcm 800 and jcm 800.
Clear top 420a is more expensive. I have heard all vacuum tubes must have getter to get rid of unwanted gas coming from outside when its very hot.
I love western electric 420a!!
Whoever mentioned 420a / 5755 is not working in a guitar amp is wrong. I bought a couple of 420a. I built adapter sockets and dropped in V1 and PI positions. They sound amazing. To me it sounds like its got good bass and middle range. I felt like it sounds similar to Telefunken 12ax7 smooth plate with less gain. Its got uncolored and pure tones!!
For me, i dont like gain level 100. Even with telefunken 12ax7, i feel like i lose all the definitions.
Spending a few years with RCA Black plate 12ax7, i found myself RCA 12ax7 black plate sounded too dark and somehow muffled and also feel like there is no definitions.
5751 Rca command is very good but very expensive.
You should try We 420a. They are not as expensive as mullard or Rca 5751 command series.
420a has spring construction so it should be less microphonic.
Many people say 420a has less noise as well.
Im not a tech. But, in my opinion, it sounds awesome in my marshall jcm 800 and jcm 800.
Clear top 420a is more expensive. I have heard all vacuum tubes must have getter to get rid of unwanted gas coming from outside when its very hot.
I love western electric 420a!!
Rewired Preamp to accept 5755
I built a stereo "Alembic" preamp for my bass rig. I jumper the channels and run both sides into to a Crown 1000 solid state amp and a pair of JBL E140 15 inch speakers in individual vented cabs. Usually mic a speaker thru PA for most venues.
A couple years ago I bought 30 or so 5755 NOS Mil Spec top getter Raytheon tubes which have been sitting on a shelf.
I rewired my tube sockets and plugged them in.
I understand that the data sheet calls for a huge (900K ohms) cathode resistor and big plate resistors.
But I hooked em up (typical 1.5 K cathode and 100 K plate resistors) and ran my bass and it sounded amazingly good.
IIRC, I had about 250V on the plates of the 12AX7's that were in there before.
Anyway, virtually noiseless, clean, clear and diverse tonal palette.
I wonder how long they will last running them with the wrong resistors.
I welcome any comments. My apology for reviving an old thread. Hope there is still some interest on this topic.
I built a stereo "Alembic" preamp for my bass rig. I jumper the channels and run both sides into to a Crown 1000 solid state amp and a pair of JBL E140 15 inch speakers in individual vented cabs. Usually mic a speaker thru PA for most venues.
A couple years ago I bought 30 or so 5755 NOS Mil Spec top getter Raytheon tubes which have been sitting on a shelf.
I rewired my tube sockets and plugged them in.
I understand that the data sheet calls for a huge (900K ohms) cathode resistor and big plate resistors.
But I hooked em up (typical 1.5 K cathode and 100 K plate resistors) and ran my bass and it sounded amazingly good.
IIRC, I had about 250V on the plates of the 12AX7's that were in there before.
Anyway, virtually noiseless, clean, clear and diverse tonal palette.
I wonder how long they will last running them with the wrong resistors.
I welcome any comments. My apology for reviving an old thread. Hope there is still some interest on this topic.
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