• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Ampeg PF-50T Humbuster

#204
coach nuts said:
Do you know where on the circuit to bleed the caps from?
Click to expand...
That's not something I'm going to get involved with, because if you don't know how, why and where, you don't belong inside an amp for safety reasons.
 
  • Like
Reactions: KF2B, ENG4, azwhofan and 5 others
#210
> Generally, yes but it's not something that I would recommend relying on personally.
+1: Never think it's safe without measuring first.

Practically, what I do: remove power lead so the amp is not connected to mains.
Switch on power and stand-by (of course the amp will not power up)
Play a couple of power chords on the bass/guitar connected to the amp - amp connected to load (to possibly drain the caps) - in the case of the PF it has an internal load by default, so you can have the LS jacks disconnected.
Wait 15 minutes
Check voltage on all pins of 6L6, notably on 3 and 4 (plate and screen), it should be zero.
Check voltage on front and back of the diode of the bias circuit, it should be zero.
Turn of mains and stand by off
If all that is fine, go ahead and mod.
 
Last edited:
  • Like
Reactions: JimmyM
#211
Bertr said:
> Generally, yes but it's not something that I would recommend relying on personally.
+1: Never think it's safe without measuring first.

Practically, what I do: remove power lead so the amp is not connected to mains.
Switch on power and stand-by (of course the amp will not power up)
Play a couple of power chords on the bass/guitar connected to the amp - amp connected to load (to possibly drain the caps) - in the case of the PF it has an internal load by default, so you can have the LS jacks disconnected.
Wait 15 minutes
Check voltage on all pins of 6L6, notably on 3 and 4 (plate and screen), it should be zero.
Check voltage on front and back of the diode of the bias circuit, it should be zero.
Turn of mains and stand by off
If all that is fine, go ahead and mod.
Click to expand...
The amp had zero volts running through it. Mod went without a hitch. Thanks for all the help!
 
  • Like
Reactions: JimmyM and Garret Graves
#215
Add me to the happy camper list and many thanks to mnats, bertr, beans, agedhorse, doner, and the rest of you!
20191028_213716.jpg
20191028_213656.jpg
 
Last edited:
  • Like
Reactions: beans-on-toast, JimmyM and Garret Graves
#216
To give an update for those PF-50Ters in the UK.

I've just come back from Polar's site in Bexhill and Rob checked out my head to see if the mod had been performed. It had which is great news!
He also said that he personally performed the MOD not only on my amp but on all of the last batch PF50Ts. These would have been the discounted run selling last year and early this year.
so whilst i didn't have any specific issues with my head it is good to know that the mod has been done.
He was also telling me that Yamaha are not currently making the PF50T at the moment but couldn't advise on any future plans. He said he thinks the issue was with the high prices point (in the UK at least) and Polar sold the last batch at a loss.
Have to say the service and communications I got from the team at Polar was first class and whilst i hope i never have to utlise my warrantly i know i'll be in good hands if i do.
 
  • Like
Reactions: Zbysek and JimmyM
#217
GR7G5TER said:
To give an update for those PF-50Ters in the UK.

I've just come back from Polar's site in Bexhill and Rob checked out my head to see if the mod had been performed. It had which is great news!
He also said that he personally performed the MOD not only on my amp but on all of the last batch PF50Ts. These would have been the discounted run selling last year and early this year.
so whilst i didn't have any specific issues with my head it is good to know that the mod has been done.
He was also telling me that Yamaha are not currently making the PF50T at the moment but couldn't advise on any future plans. He said he thinks the issue was with the high prices point (in the UK at least) and Polar sold the last batch at a loss.
Have to say the service and communications I got from the team at Polar was first class and whilst i hope i never have to utlise my warrantly i know i'll be in good hands if i do.
Click to expand...
Oh, Yamaha is making amps at the moment...they're just not talking about what they're making other than the Heritage 50th Anniversary SVT :D Yamaha knows that it's a very bad idea to buy a major amp company and rush release product, especially when they have plenty of inventory to sell in the meantime. One needs only to look at the first two years that LOUD owned Ampeg to know what a disaster it can turn out to be. Head of the company lost his gig over it and other signs of incompetence. So they're taking their time. I don't know the status of the PF series under LOUD, but I do know the brass likes the PF tube amps. I think we'll all know more come Winter NAMM.
 
  • Like
Reactions: GR7G5TER, punchclock and azwhofan
#219
I'm sure you are much closer to the action than me. I'm sure they are making Amps, was just that they aren't making the 50T and the UK distributor at least can not get their hands on any at the moment.
I am excited to see what the combined Heritage of Ampeg with a company like Yamaha will bring. ☺️
 
#220
GR7G5TER said:
I'm sure you are much closer to the action than me. I'm sure they are making Amps, was just that they aren't making the 50T and the UK distributor at least can not get their hands on any at the moment.
I am excited to see what the combined Heritage of Ampeg with a company like Yamaha will bring. ☺️
Click to expand...
The UK dist. can't get any more at the moment? I interpret that as a good sign for at least the 50T. Owner of Polar shouldn't have been in such a hurry to sell them at a loss :D
 

Latest posts

Top Bottom
Back