Ampeg PF-50T Humbuster

[beans-on-toast]

What you’re describing is certainly good for recording and everything else.

The tone is very good, a quiet amp is the icing on the cake and such a pleasure to play through.

Thanks for the comments and updates.

 

[ENG4]

Not sure where to post this, so maybe a veteran can post it in a more visible location. Sweetwater has the AMPEG PF-50T on sale through the end of FEB for $749.99. As Garrett Graves can attest, they can appropriately check for and perform the mod if the amp needs it.
Best...

 

[basso_profundo]

Not sure where to post this, so maybe a veteran can post it in a more visible location. Sweetwater has the AMPEG PF-50T on sale through the end of FEB for $749.99. As Garrett Graves can attest, they can appropriately check for and perform the mod if the amp needs it.
Best...

Oh, my poor wallet....$750 for a new PF-50T...so tempting...

 

[Garret Graves]

Be sure to ask them to check it otherwise, it’s a gamble.

 

[basso_profundo]

Be sure to ask them to check it otherwise, it’s a gamble.

Does Sweetwater have a code/number for the mod?

 

[rjmsteel]

Just ordered one at Sweetwater today. Communicated as best as I could to the Sales Associate about the "Humbuster" possible issue, check for hum and if necessary mod fix. He said the shipment is inbound tomorrow for more units and I asked the sales rep. to document our discussion in there notes AND to look up this thread on TB for reference. He said OK he would do what I asked including my request to email the findings if any modifications or other issues were to be addressed. I hope they do as they say and all goes well.

 

[Garret Graves]

Does Sweetwater have a code/number for the mod?

Not aware of a code for it- but the sales rep will pass the information forward to techs. It’s called simply the “humbuster” mod. Here is my receipt 1.2 hours labor that they covered under warranty.

 

[basso_profundo]

Not aware of a code for it- but the sales rep will pass the information forward to techs. It’s called simply the “humbuster” mod. Here is my receipt 1.2 hours labor that they covered under warranty.

Cool - thanks!

 

[rjmsteel]

Just got the call from my rep and email Tracking link from Sweetwater that my PF-50T Shipped today. Apparently they are by default checking for the Hum issue on all of these units (it was finishing up in testing when we talked) before they ship, according to the sales rep, including mine which I was told passed.

These units have been on backorder since I ordered it on February 5th. See Post #186 above.

The rep knew exactly all about the hum concerns and the fix, if required. Pretty much said they would like see action planning in regards to the concerns but in honor of ethics to the rep and Sweetwater I`ll just leave it there. Really great that this community has the capability to even bring the knowledge of the issue up so we have a fully functional product upon receiving. Thanks to all who have invested the time in this thread to bring up their findings so the rest of us purchasing going forward can ask for tech to perform Testing before shipment.

Shipping UPS Business straight to my plant (work) where our UPS driver knows me and exactly who to drop it off to.

Should be a fun Monday!

 

[rjmsteel]

Well OK, I got my PF-50T Today and sounds great! And now for the bad news. No hum, however I am getting the ~ sounds like springs rattling against metal sound that AboutSweetSue experienced ~ and it is coming out of my speaker. Grrr.

When I tap on the front control panel it occurs as well. I also noticed the bias LED lit green at one point and both the green and the red LED lit another time looking at rear panel.

At first I thought I had a loose dust cover on my G112 driver, but when I switched to my 115 cabinet I knew it was the amp.

Too late to evaluate any more and am busy over the weekend to look any further into it. Don`t want to have to return/swap units with or to SW.

Did I mention the amp sounds great

 

[twinfallsbass]

Well OK, I got my PF-50T Today and sounds great! And now for the bad news. No hum, however I am getting the ~ sounds like springs rattling against metal sound that AboutSweetSue experienced ~ and it is coming out of my speaker. Grrr.

When I tap on the front control panel it occurs as well. I also noticed the bias LED lit green at one point and both the green and the red LED lit another time looking at rear panel.

At first I thought I had a loose dust cover on my G112 driver, but when I switched to my 115 cabinet I knew it was the amp.

Too late to evaluate any more and am busy over the weekend to look any further into it. Don`t want to have to return/swap units with or to SW.

Did I mention the amp sounds great

Sounds like a microphonic tube. My PF50 had a pramp tube that went micro, you never know what happens during shipping. It should be covered under warranty and either Yamaha or sweetwater should send you a replacement if that is indeed what it is.

 

[beans-on-toast]

I too was going to suggest a microphonic tube. Butfirst, remove the cage. Then remove the tube shields on the small tubes. Do this by gently pushing down, tristing, and pulling to remove the shield. Reseat each tube in the tube socket.

If you have good spares, try them.

 

[JimmyM]

I'll add that using a new Tung Sol 12au7 helped a lot.

 

[JimmyM]

My apologies...I didn't use a Tung Sol...I used a new Mullard, which didn't sound much different if at all, but it did clear up a good bit of the microphonics. Still got a little but it's liveable. I just don't tap it while I'm on a gig

 

[rjmsteel]

After some reading I now think I have a case of filament rattle or loose grids on one of the new tubes; or perhaps a loose socket in this new PF-50T..... I could be wrong, although!

As you can probably tell I have not been using Tube amps for a while (a long while) but I`m starting to get the hang of what`s going on. Like my B18N I purchased from my good friend and spoke about earlier in the Portaflex thread, I`m going to a tech I spoke to in Chicago with these amps when I have some time and the weather is better. Hopefully soon.

From another thread on Telecaster TDPRI: Amplifier forum Blues Jr.
"Sure, new tubes can have filament rattle or loose grids, right out of the box".

 

[Martin Beer]

The phase inverter position in these amps does seem to be prone to microphonics. I put in a NOS Philips 5963 which sorted it for a couple of months , and when I started hearing slight ringing from that I tried placing a rubber grommet over the top of the tube where the spring retainer contacts it. That seems to have done the job for mine.

 

[Garret Graves]

Help needed- got the PF-50 back from service center. It now a few weeks later has a static noise, continual and inconsistent. I reacted to this by chopstick testing the tubes, nothing. Plugged into another power source and used new cables, still static. Swapped the power tubes for new JJ 6L6, swapped the two 12AX7s, but don’t have a 12 AU7 to swap at this time. The static noise is still there. Any thoughts? What should I do next? Thanks all

 

[agedhorse]

Contact the authorized service center.

 

[Garret Graves]

Contact the authorized service center.

Thanks will do.

 

[TemplesOfSyrinx]

Just wanted to say thank you to @mnats and @Bertr for the humbuster fix. Picked up a PF50-T used and had my local tech perform the mod. Quiet as a church mouse now.