..or..well it isn´t. Or...it is. Or... Well,whatever.
It works like this. Back in the mid -60´s in Berlin in Germany were Stange und Wolfrum and STW built amplifiers. As PTP as they come.
Now.
They did so at a level where Telefunken came to buy their products and market them under the Telefunken logo,and i guess tells a bit huh.?
That brings that the brand of tubes used...yeah well...
Seller wouldn´t ship abroad so i asked my German friend Moritz to pick it up for me and then send it up here.
So.
LVM-120? Dafuq does that bring? It brings that this piece of kit will most likely end up becoming a bass amp,and there´s ample reasons for this. In short this thing produces power beyond reason for guitar use.
But?
It just says 120 right? As in 120 watts? Well....*laughs n chuckles*. U keep that thought. U just keep that thought...
See. The reason i jumped at this LVM-120 is that i already own the LVM-60 and the LVM-30. Just as well built amps and the point here is that the "minescule" little 30 uses a quartett of EL-84´s run above 400VDC which brings that the little 30 will hand us an easy 50 watts.
Now.
We´re used to that a pair of EL-34´s will be good for approx 50 watts clean. With the right transformers and pushed beyond clean at approx 450 volts DC or so we see them approx 50 turn into both 70 and 80 watts with a little luck.
Enter the LVM-60.
Cause see..the 60 indeed uses a mere pair of EL-34´s it´s just that it hands the plates of the EL tubes....just shy of 800VDC and i guess you can see where that´s heading right.? *ROTF*
...to add insult to injury so does the LVM-120. Use just shy of 800VDC at the plates that is. U do the math.
From the looks of it some moron has had it apart and got the top and bottom wrong when bolting the thing back together. Whatever...
AFAIK the LVM-60 and LVM-120 are basically the same circuit. Got the schem for the 60 so..
LVM-120. The one word that describes it is...massive.
Dead on arrival tho. All good i guess,albeit always a crap game.
Yeah. Just...yeah.
No BS no exaggeration. Those are by FAR the largest transformers i´ve ever encountered for a quad EL-34 amp. In fact the transformers onboard will belittle the ones of a "300 watt" quad 6550 Ampeg. Them a pair of BIG mofos! Right there!
As you approach the amp and you come to realize the size of them things you kinda start to chuckle and giggle,they´re THAT out of proportion.
Now,the amp sports a steel chassis alright but the actual "cab" parts are just very thin sheetmetal. That said this thing weighs a fair pair of kilos no matter... Go figure.
So. That there is the output transformer. Sports taps for 4/8/16 Ohms outbound and a line level one. If i´ve done my math right that there thing should have an Ra-a of approx 5-6k to cater to the quad of EL-34´s being run at the voltages they are. Gonna check that and see what falls out of the bag. I put a regular ECC-83/12AX7 on there to give you an idea of size.
...and the powertransformer in turn is even...bigger. Same 12AX7... DAMN that thing is big!
DOA.
I got real happy as i flipped the hood of this thing and realized that the tubes were indeed the stockers. TFK for ya folks! Bingo!
Weeeeeeeell.....
...that turned into a friggin laugh as i put them to the test on my U-Tracer. Look at them two numbers low right. This..this is the definition of beating a dead horse.
Those two numbers,if they show below 60% the tube in case is up for replacement. Tell you what,and that rate 2% remaining makes for a tube well used (up)! DAMN!
DOA. Indeed. So..i scavenged my stash for a fresh set of EL-34´s. The fuse for B+ voltage was shot. Supposed to be 630mA and had been replaced with a 1,4A one,still shot.
Figures i´d say seing the wear rate of the powertubes. The small signal ones btw,3pcs of ECC-83 and an EF-86,were all good to go and then some.
So..replaced the fuse and let her rip,standing by to adjust bias.
POOF...
630mA fuse skyhigh. Hm. Took to measuring the e-caps then. The ones in series for the "main hit" (Ie;the almost 800 volts) checked out fine. The first hit for the lower voltage part of the amp tho...not so much.
Zero Ohms vs chassis.
http://iloapp.elegic.com/data/_gallery/public/178/150966640641339400_resized.jpg?width=1280&height=720
Schematic for it. Neatly stashed away inside.
Replaced that shorted out e-cap and let it rip once again. Sure enough...came up to stand on its own two feet,adjusted bias and...we were good to go.
Flicked the switch and just jumpered a pair of 1/4" jacks in there. One inbound and one outbound. Yes Sir...we had sound. Decent amount of oumpfh too no doubt.
Guess that´s all good but..? What now?
It´ll turn into a bass amp alright. Thinking of making it twin channel and as simple as they come. Instead i plan to evaluate the trouble,if it´s worth it,to put a multiband EQ together for both of the channels.
Gonna talk it over with the basist of the two bands i play and see what comes out of the bag.
That said?
These amps are absolutely top notch quality for those in the market to pickup a platform to work from,producing their own take on an amp. In fact,to the level where i´d be real hard pressed to dig something of higher quality up.
Made in West-Germany when that actually stood for something.