Of course there's the low wattage tubesters club and the fascinating giving with big iron thread.
I'm looking for ideas on gigging with something like the ampeg pf-50T or an ashdown 30W. Need to send a signal that includes the full tube amp to an amp to push a stage rig (150-300W). And/drop same over to PA.
I attempted the transformer derived xlr to 1/4 transformer into an amp loop return but that was a spectacular line noise fail.
Seems like there must be some compact power amp out there that will take in the transformer derived xlr and still have the power to drive a medium size bass cabinet?
I you are getting a ground loop from the Transformer out, you could try an isolation transformer. For fun I tried slaving my Mk2 and Mk1 Ashdown LB30s. I connected them through the Effects loop, but got a pretty nasty hum. I inserted my Ebtech HE-2 between the amp and it cleared the noise.
I have an older Ebtech HE-2 that is 1/4" only. Ebtech also made a version with 1/4" and XLR jacks, the HE-2-XLR. The 1/4" jacks accept TS or TRS plugs, so they automatically work with either balanced or unbalanced signals. I believe they will not work if you use a TRS connection with an open ring.
Ebtech is part of Morley and it looks like they may be consolidating the product line under the Morely brand. You can still find some Ebtech branded products, but the Morley versions seem to be taking over.
MHE 2
The other thing you need to be concerned about is signal level. I have not played with the Preamp and Tranformer output on my PF50T, but from what I have read the Transformer out is typically a lower level signal. The level will be impacted by the Gain, Tone, and Volume settings. A better solution may be to run the Transformer out into a small mixer. Then use the mixer to drive a power amp.
Honestly I think a better solution is to just get an amp that is big enough to do the job. I own vintage SVTs and the PF50T has a very similar sound and feel. I would say the PF50T seems a bit cleaner, more focused, and less grindy. Also it does not have as much push in the low mids and does not transition to OD in quite the same way. The next step up for you would be the V4B. My impression is the V4B will sound more like the PF50T than the SVT. They all sound like Ampegs though.
I own quite a few bass-specific low wattage tubesters. I went on a bit of a binge over the last year or so
. Ashdown LB30 Mk1 and Mk2, Ashdown Little Stubby, Ampeg PF50T. I normally play these through a pair of Genz Benz 1288T Uber Quads. The combined sensitivity rating is 100.5dB, which is essentially the same as an Ampge 810E. I often noodle while I am watching TV and all of these amps are right at their clean limit. Sure you could gig them, but they will run out of headroom pretty quick. Surprisingly, most if not all of the 30W Ashdowns seem slightly louder than the PF50T. All were bought used, so maybe the tubes in my PF50T are used up.
There are cabs with sensitivity ratings over 100dB 1w/1m. If the find a cab with a 103dB 1W/1m, it's equivalent to doubling the power of the amp to 100W.
FYI you also get +3dB with a tube amp if you can double the cabs. For example the combined sensitivity rating for a pair of 810Es is 103dB. Unfortunately, this is a 2 ohm load, and the PF50T is only rated at 4 and 8 ohms.
If you get a cab with a 106dB rating then it would be equivalent to quadrupling the power 200W. Cabs with super high sensitivity ratings tend to be fairly rare and also generally expensive. Many are also fairly large. Do some analysis and make a sensible decisions...is it better to increase power or buy more or better speakers?
I am sure you can make the PF50T work with an isolation transformer, mixer, and power amp...IMHO it's not a very practical solution though. Way too much stuff to carry around and hook up...and way too potential points of failure.
Good luck!
