PF50T problem

[beans-on-toast]

I find it good practice with any new tube amp to remove the tubes, one at a time, and clean the tube pins and the tube socket contacts, then reinsert the tube. The cleaning can be done with deoxit and carefully with a soft inter-dental brush (pharmacy). In a pinch, scrub the contacts with 99% isopropyl alcohol or vodka. Sometimes the mechanical action with the brush and solvent is enough. Do not SPRAY deoxit directly onto the tube socket metal contacts and everything else, that's why you scrub just the contacts with a brush. As Jimmy said, simply cycling the tubes in and out of the tube socket can clean them enough.

What's behind this? During transport, the tubes can become unseated, reseating them can fix that. Cleaning the contacts is extra insurance. It can help remove any oxidation that was present on the components when in the factory when the amp was assembled or remove any that accumulated during the ocean/container voyage from China to the port of delivery. I've seen this contamination not only on tubes but also on jacks as well as open switches in new amps. It was enough to affect the operation of the amp, a simple cleaning resolved it.

 

[jthisdell]

I am not sure what this means, but it sounds naughty

Actually little delicious pancakes and what some call "Dutch Gin" (but is actually not gin at all and pre-dates gin by +100 years)

 

[ThinCrappyTone]

Actually little delicious pancakes and what some call "Dutch Gin" (but is actually not gin at all and pre-dates gin by +100 years)

I’d hit that!

 

[BassmanPaul]

Heading to Amsterdam to see my daughter next week, looking forward to some poffertjes and genever (not necessarily together)

Have a safe flight, a wonderful time and don’t get too fat!!

 

[TonH]

Heading to Amsterdam to see my daughter next week, looking forward to some poffertjes and genever (not necessarily together)

Have fun, eet smakelijk en proost!

 

[BassmanPaul]

eet smakelijk en proost!

If he does I hope he doesn’t do it on the plane!! LOL

 

[Funkabilly]

The OP is referring to the status light at the front of the amp: Red = Standby, Purple = On. It doesn't sound like those colors were emanating from the tubes. Also, These amps do not need a dummy load, a selling point for some folks. Glad to hear it's worked itself out.

Correct, and yes it is a new amp. I bought it from Sweetwater, so I'm sure they will work with me on this problem. I will put it to the test Saturday night.

 

[steelbed45]

Correct, and yes it is a new amp. I bought it from Sweetwater, so I'm sure they will work with me on this problem. I will put it to the test Saturday night.

This +1. I used the 48 mo. promo to purchase an SVT-7 Pro that arrived last week. They had just received the shipment in, so it wasn't old stock. Anywho, this amp's fan went straight to max speed and just stayed there. I mean loud, like it was getting ready for takeoff. But hey, one call to Sweetwater, and they shipped out a replacement, along with a handy return sticker. I'm happy to say the new amp's fan is much quieter.

Sorry I couldn't help with the amp, but just wanted to relay that their CS with me was excellent on my new Ampeg.

 

[JohnnyChatter]

This may help. I’m assuming your tubes just were not seated well or had a moment of being fussy. Maybe the power to the amp from the wall was acting up also. The manual says to change your tubes every year which seems a bit often to me but being an amp that’s easy to bias and cheap to retube it may be fun to see how different tubes sound now and again.

As far as arguing about what type of amp is better why does it really matter? It’s dumb to let people get under your skin or to be so closed minded to think that tube, hybrid, or class D is the only option. First world problems!

 

[Cave Puppy]

Correct, and yes it is a new amp. I bought it from Sweetwater, so I'm sure they will work with me on this problem. I will put it to the test Saturday night.

Exactly where I got mine, too! They did the Humbuster mod for free under warranty and installed new tubes (even though the tubes were "new").

 

[lowendrv]

Did you make sure to set the impedance switch properly by the speaker out on the amp? An impedance mismatch could have potentially caused issues. It's also important to remember that you cannot run a tube amp without a speaker load attached, or damage could occur. This means that every time you want to change the impedance on the amp, or unplug the speaker for any reason, the amp should be powered off.

PF50T can be run with no load . That is one of the things that make it cool beside the two DI's

 

[lowendrv]

I need to point out that the pf50t only works with no speaker load in 1 of the two impedance settings ( not sure which, see the manual )

Ampeg printed it wrong . They have since said is was OK on the 8 or 4 ohm setting

 

[CryingBass]

Ampeg printed it wrong . They have since said is was OK on the 8 or 4 ohm setting

Hey - thanks for the update. I have one and never new that!

 

[CryingBass]

I find it good practice with any new tube amp to remove the tubes, one at a time, and clean the tube pins and the tube socket contacts, then reinsert the tube. The cleaning can be done with deoxit and carefully with a soft inter-dental brush (pharmacy). In a pinch, scrub the contacts with 99% isopropyl alcohol or vodka. Sometimes the mechanical action with the brush and solvent is enough. Do not SPRAY deoxit directly onto the tube socket metal contacts and everything else, that's why you scrub just the contacts with a brush. As Jimmy said, simply cycling the tubes in and out of the tube socket can clean them enough.

What's behind this? During transport, the tubes can become unseated, reseating them can fix that. Cleaning the contacts is extra insurance. It can help remove any oxidation that was present on the components when in the factory when the amp was assembled or remove any that accumulated during the ocean/container voyage from China to the port of delivery. I've seen this contamination not only on tubes but also on jacks as well as open switches in new amps. It was enough to affect the operation of the amp, a simple cleaning resolved it.

Great advice Beans. From personal experience, I suggest the Vodka approach when deoxit is not around. Ok, Vodka all the time. I found that Rogue Dead Guy Ale does not work as good.

 

[Funkabilly]

1st thing I did when I got home from work, was take the tubes out and take the deoxit to them. I didn't have anything to get in the sockets. I haven't had any problems since the first problem mentioned. I have a gig Saturday night, so we will see if the problem is gone.

 

[Martin Beer]

I do get the impression that the valves shipped with the PF50T might not be great. Mine had a new pair of 6L6 (under warranty) after only a couple of hours use, and then the 12AU7 went badly microphonic. I've no other complaints about mine though.

 

[Ekulati]

Not really dude. You still think class d and regulated supplies have any value in a bass amp.

And pretty aware of how much musicians love tube amps.

Likewise never wasted any time trying make tube amps with mini power tubes for TV sets lol

Likewise owned KT88 amplifiers that successful operate these " new" " bad tubes" without failure

Ampeg sold, Mesa Boogie bass amps discontinued. Guess the Japanese will show you how it's done.

All you need is 2x or 4x 6L6 , 6550 or KT88
Just operate at the data sheet recommendation. Which includes understanding what topology does and doesn't support max screen values

Since I know little about tube amps, surely I am blind to the literary genius which inspired this eloquent prose.

 

[Funkabilly]

Ok, I have another observation. The transformer on the right gets really warm, and the one on the left stays cool. Is that normal?

 

[Cave Puppy]

Ok, I have another observation. The transformer on the right gets really warm, and the one on the left stays cool. Is that normal?

Mine does the same thing. It’s normal. I’m pretty sure the cool one is the pre-amp transformer and the hot one is the power amp transformer.

 

[beans-on-toast]

The power transformer runs hotter than the output transformer. On some amps it gets very hot. It is designed to withstand the heat. Otherwise there would be a fan.

The power transformer is on the side of the chassis with the power switch.

If the heat is a concern you can blow air onto the power transfomer with a very quiet fan such as the one below.

https://www.amazon.com/Caframo-7-Inch-White-Chinook-Fan/dp/B001398L2G?th=1