Thinking about putting a pair of 5881's in my Galaxie head. I haven't pulled the chassis and measured the B+ or plate voltage yet. But, as 5881's typically won't tolerate the higher B+ 6L6's will...wanted to see if anyone measured? I'll likely pull it and check anyways. If it's known to be too high I'll likely not bother with it.
Well, no replies...I measured. 427VDC with 6L6's idling at 25mA...that pretty much nixes risking a pair of 5881's in it.
Doc, if you see this - I'm guessing the bias current is kept a bit lower than we might typically see with 6L6's due to the lower power rating of the Triad OT and, accordingly, not to fry that baby? Not reading up on the specs for the original Super, I'd assume pushing any 6L6 toward it's upper safe limit is going to put that special OT at risk. (? - unless it's beefier than the original).
Amp as it is - I love it anyways. Getting looser and a little glassier, it makes for a fine pedal platform on the clean side. The 6L6's should last a long while at that bias.
I did pop in a Type 3 PPIMV in the extension cab hole. (I only need one cab...else I daisy chain on the cab-side). Given how this amp runs (hot preamp), you really only get about a 1/4 turn of useable MV turning with a PPIMV. It's not my ideal regarding control (I'm considering a pre-PI MASTER...remains to be seen)...but for the times I use this at home, it does the job without the need for an attenuator. Easily reversible to factory, got me to replacing the worn jacks at the same time. Interesting...this is one of the NEWEST amps I've opened on my bench and it has the most wear on the jacks. What can you say? The amps with the most desirable tone are always going to get the most play time...eh?
I'd say my fave setting on this amp is 'clean channel with a little hair' and a couple of your fave pedals in the front end.
Post by wraparound (Steve) on Feb 28, 2018 9:23:56 GMT -7
I think T-ROCK used 6l6-WGB in his Galaxie which I think is a military grade 5881 short bottle. I kept my bias at 27/28 ma per the recommendations in the support section of the Z site. I know others that run up towards 34ma but I found that too congested and not worth the trade off in reduced tube life. I still have a pair of Groove Tube 6l6GTE that came with my amp and the Orange graphics are still bright with no sign of burnout. They still sound solid too. It’s a great amp!
Yes, the 5881's could push more output, but only if that OT will hold up. At the voltage/current it is (my amp)...you're looking at a 10.7 watts plate dissipation or about 43% of 25W. But, it works well with that Triad OT. That wattage doesn't reflect audio volume and...when it work...it works!
The nice part? It's such a conservative setting that you have very loud amp...with a nicely driven preamp section to get you "over the top" as needed...and it keeps the operation of the 6L6's as such that you should get a very long life per set, so long as there are no other manufacturing issues compromising the tubes or too much "roadie" abuse.
Not only that, you're looking at only 3db difference between 40W & 80W...so, trying to goose the amp from 30-40 to 50w is just futile and unnecessary. And, like you said...no gain for much less tube life.
What I really like about the amp, from a tech perspective, is the ability to make slight mods and completely reverse them. Just like the PPIMV I did to it. I'll likely leave it...but, I'm still tempted to jump in with the pre-PI MV and get a better pot swing. After having a listen and a long peek inside, and the way the preamp is setup, a pre-PI MV just makes more sense.
Well, after parts came in and I finally had some time for my own amps, I changed my mind about utilizing the 5881's. I set them up at 33mA and B+ settled in at 410V so about 13.5W/tube which is 59% of the rated max of 23W. The cleans are much fuller and warmer than the 6L6's in it.
I had acquired a closed-back 1x12 to pair with it (my goal was to keep this as a real light setup). I was given to speakers to try in it. G12 V-Type 70 and a Red Coat CV-75. I installed the V-Type at first, then went to the Red Coat. It took all of a 20 second listen and I was immediately back to the V-Type. The sensitivity of that speaker was amazing in a closed-back cab and it was still full and loose in spite of the closed back restriction. The Red Coat was sterile, brittle, no low end at all. (May be ok in open back? I doubt that much difference)
Overall the pairing was awesome when finished. Maybe I'll construct and open back panel for it in the future? But, I'm extremely satisfied with the tube lineup in it now which is,
Tung-Sol 12ax7 in V1 JJ ECC83S in V2 EH12ax7 for the PI (it was the most balanced in tube tester stage comparisons) Tung-Sol 5881's for output. (410V, 33mA)
With a PPIMV (Type 1 cross-line using 1M, 2W PEC pot), the preamp stages sing at low volume when desired.
roscoenyc: You know in school when they talked about "your permanent record"? Well, this is it! Learn to spell! Don't be stupid!
May 21, 2020 8:19:01 GMT -7
premiumplus (Dave): Due or do? Which or witch? Knob or nob? Their or there? Bass or base? Too much time on my hands...
May 24, 2020 6:31:30 GMT -7
roscoenyc: Ah, the incessant tire kickers. oh jeez.
May 25, 2020 6:57:46 GMT -7
GuitarZ: Needed some noise to fill a break in a tune I'm recording. It was too quiet. Just happened to have some High Quality Dr Z Ghia noise to fill the void. "Heal Your Sound with Dr Z! It's not just a guitar tone prescription!"
Jun 13, 2020 8:29:27 GMT -7
GuitarZ: Must be great to be a skunk. Eating bird food about 10' from our sun room. I'm clapping and yelling. At best, it might have given me one "yea what?" look while continuing to dine. At one point, there were two skunks and two racoons.
Jun 14, 2020 18:49:33 GMT -7
captainron (Ron): Hueter Toledo, just another business of today that doesn't care about tomorrow!
Jun 25, 2020 12:51:43 GMT -7
KeithA: Hueter Toledo....that business is gone to the dogs
Jun 26, 2020 8:22:26 GMT -7
easyed: Guitar Z, I encountered to ultimate garbage raiding combo once. We'd been having problems with the garbage cans being raided by raccoons for weeks. Late in the evening I heard rattling at the cans. I went out and found that he'd allied with a skunk. "OK"
Jun 30, 2020 11:40:27 GMT -7
GuitarZ: EasyEd - Someone at work topped us both. The inside of their car had been somewhat ransacked. They were blaming their son. They checked the video. It was a Bear! I'll stick with the racoons, skunks, foxes, and squirrels.
Jul 1, 2020 16:47:50 GMT -7
bigboki: In this age and time when everybody are struggling and especially S&Ms I am amazed to see that kind of ignorance. I am really sorry for your experience dear Dr Z but it is for the better. You don't want to do business with those kind of people anyway.
Jul 4, 2020 8:17:40 GMT -7
GuitarZ: Didn't want to restart the plumbing thread, so I figured I'd ShoutBox this. How the heck does cleaning the aerator on a faucet cause a leak to start under the faucet? Huh? Arggggh!!!!
Jul 10, 2020 7:40:17 GMT -7
The Bad Poodle Experience: well, Mike, it shouldn't have been the cause of a leak. double-check your work.
Jul 10, 2020 12:56:49 GMT -7
GuitarZ: I updated in the Plumbing thread that the Moen website says that a faulty aerator can cause a handle/base leak. Eiyy! I really don't understand how plumbing works. I was ready to double check all connections. But, the leaking stopped with cleaned Aerator.
Jul 11, 2020 18:13:56 GMT -7
jhen86 (jordan): Just got an email from Sweetwater rep that Z Wreck Jr's are back in stock. Just wanted to give everyone a heads up.
Jul 28, 2020 10:57:28 GMT -7
Lefty: Say a prayer for me fellas, I'm going to replace a bathroom faucet this weekend.
Jul 30, 2020 8:26:34 GMT -7