[Feuergeist76]

Just rolled in the AVVT PX4M, and I'm absolutely speechless - the sound is fabulous. It's maybe unfair to benchmark it with the EH 300B, but it's no comparison at all. It's like they said in the 6moons review, the BA is opening up with the PX4. Wow! It's like opening the window instead of looking through the glass.
 
Cheers
 
Feuergeist

 

[setamp]

  Just rolled in the AVVT PX4M, and I'm absolutely speechless - the sound is fabulous. It's maybe unfair to benchmark it with the EH 300B, but it's no comparison at all. It's like they said in the 6moons review, the BA is opening up with the PX4. Wow! It's like opening the window instead of looking through the glass.
 
Cheers
 
Feuergeist

How do the EML 300b's sound in comparison? 

 

[r one]

 
How do the EML 300b's sound in comparison? 

interesting comparison

 

[setamp]

I have re-read this thread and I'm still not certain I understand the sonic differences between the PX4 and the 300B.

I am currently using a Royal Princess 300B with a Mullard ECC32 driver.  I have tried the vast majority of possible drivers but have only heard the RP 300B.

If I were to switch to a AVVT PX4 (or AVVT PX4 or EML PX4) what differences can I expect to hear?  
If I could improve anything, it would be to eliminate a small bump in the low mids / upper bass and to tighten up the bass a bit.  My mids are beautiful, warm and upper mids are perhaps a touch soft as far as leading edge.

Can anyone offer an opinion?

 

[rgs9200m]

I didn't think PX4s and 300Bs were interchangeable. Am I wrong? Thanks.

 

[CEE TEE]

^On my BA, there is a 300B / PX-4 switch on the back of the amp.  Labeled as such.  
 
The Power Supply also has to be changed to either 5V for the 300B or to 4V for the PX-4.  
 
Some PX-4 also need adapters for the bases.

 

[rgs9200m]

Thanks CT. I should have said I have a Pinnacle (unfortunately, with no switch). Thanks.

 

[rosgr63]

As far as I know all 300B's have UX4 bases.
Most modern production PX4 also have UX4 bases, but vintage ones have B4 bases so a B4 to UX4 adapter is needed to run them on some  BA's.
The Pinnacle can run PX4 only but can accept either UX4 or B4 bases. 

 

[alcyst]

^On my BA, there is a 300B / PX-4 switch on the back of the amp.  Labeled as such.  

The Power Supply also has to be changed to either 5V for the 300B or to 4V for the PX-4.  

Some PX-4 also need adapters for the bases.

I must have an earlier BA, mine has "B" and an implied "A". The B is down. And a handwritten message in Tip-Ex (Wite-Out for americans) that looks like "16" or "1b". Hopefully someone will produce PX4s around the time mine wear out so I don't have to guess which "B" is.

 

[setamp]

My ECBA has the switch in the back where Up is PX4 and down is 300B.  I have the Yamamoto tube sockets that accept both UX4 and B4 bases.

 

[r one]

I must have an earlier BA, mine has "B" and an implied "A". The B is down. And a handwritten message in Tip-Ex (Wite-Out for americans) that looks like "16" or "1b". Hopefully someone will produce PX4s around the time mine wear out so I don't have to guess which "B" is.

you've got a serial number hand written at the backside. what is yours ?

 

[Radio_head]

Mine's just got a butterfly there...

 

[alcyst]

 
you've got a serial number hand written at the backside. what is yours ?

 

[rgs9200m]

  As far as I know all 300B's have UX4 bases.
Most modern production PX4 also have UX4 bases, but vintage ones have B4 bases so a B4 to UX4 adapter is needed to run them on some  BA's.
The Pinnacle can run PX4 only but can accept either UX4 or B4 bases. 

Thanks Rosgr for that info. 

 

[rosgr63]

I have been using an RFT 6SN7 driving a pair of AVVT's AV300B SL C37's for sometime now and I am very pleased with the result.