Dror520
Well-known member
Hey, In My Mark IV that I bought used a couple of months ago I found out I have these tubes in My amp. Are they good or should I swap them with something else ?
Mesa 7025 STR 12ax7-A ECC83
- Thread starter Dror520
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If they sound/work okay,leave them.Will something else sound better?Maybe,its all a matter of personal taste.It can get expensive chasing the perfect tone.There are a couple of guys here,Mav and Wolf for instance who can give you very good advice on what tubes will do what.But until you have an idea of what is missing in the amp,tonewise,or you are happy with the amp for now,just enjoy it.
stokes said:
+1. Take more time to really get to know the amp first.
Dom
Dror520
Well-known member
I don't want to replace them ... I just want to know how are these tubes conceder as good tubes ? rare tubes ? the best tubes ? what ?
Your original post gave the impression that you would consider changing them, that's why I suggested getting to know the amp first.
Mesa will usually go with robust tubes, so lifespan should not be a problem. That's good.
The 7025 was originally selected as a very low noise tube of 'hi-fi' quality. Problem is that most current tube distributors will use '12AX7', ECC83 & 7025 in their descriptions because they are interchangeable in the circuit. I don't know if they were just the best tubes from a production run of 12AX7's, or if they were designed and constructed differently, someone else may care to elaborate on that.
If they are old tubes they may be 7025's. I'm thinking they may have been the prelude to the Mesa SPAX7, a "Special Requirement Preamp Tube" selected for low noise and microphonics.
I could not find one on Ebay so they may be rare.
If you are happy with the tone and response of the amp then they are GREAT tubes, regardless of the label. I have a few VOS 12AX7 that I don't use with my Roadster, and it's not because they are bad tubes.
If your looking to experiment so you can compare their performance that's great, just make sure you mark the tubes with their original positions in the amp so you have a reference point to return to.
Dom
Mesa will usually go with robust tubes, so lifespan should not be a problem. That's good.
The 7025 was originally selected as a very low noise tube of 'hi-fi' quality. Problem is that most current tube distributors will use '12AX7', ECC83 & 7025 in their descriptions because they are interchangeable in the circuit. I don't know if they were just the best tubes from a production run of 12AX7's, or if they were designed and constructed differently, someone else may care to elaborate on that.
If they are old tubes they may be 7025's. I'm thinking they may have been the prelude to the Mesa SPAX7, a "Special Requirement Preamp Tube" selected for low noise and microphonics.
I could not find one on Ebay so they may be rare.
If you are happy with the tone and response of the amp then they are GREAT tubes, regardless of the label. I have a few VOS 12AX7 that I don't use with my Roadster, and it's not because they are bad tubes.
If your looking to experiment so you can compare their performance that's great, just make sure you mark the tubes with their original positions in the amp so you have a reference point to return to.
Dom
