Quite a bit of Mr Handyman this time out but...i mainly bought this one for the transformers. Vortexion is an old British brand that was highly reknown for their studio stuff. Very much like the German made Klein&Hummel.
This though..came to strike me as an earlier piece...
Radiomuseum claims these as "1950 ? "...and i for one would state that..and then some. That atop it is a portable tube amp. Ie;it could be run off of a 12V car battery via a so called vibrator.
Uhu. Usable output impedances even with todays standards,which of course made my decision simpler. TBH i was clear on the need for a chassis swap already from the start so..
I by NO means claim to be any sorts of expert on this but..i´ve had my mittens into an old tuber or two by now and..the parts this one´s made of simply weren´t used in the -50s to my knowledge. Hence i believe these to be just a tad older. Old wax capacitors and what not...
That´s the entire preamp. The bypass caps for the cathode resistors are of the variety that bolts to the chassis. Odd to be sure..
Reeeeight. Mr Handyman. So.
These bricks are supposed to sport a pair of 5881´s in push/pull right. Then it´s of no use that Mr Handyman shoved a 6V6 in there is it. All of the capacitors were shot and..Mr Handyman had solved that by replacing the first hit one with one of 350VDC voltage capacity. Seing that the PT hands us approx 370VAC between tap and chassis...yeah well...
Primary taps are easy to swap atop the endbell of the PT.
As you can gather the transformers of this thing are on the hefty side. OT on top,a choke of 20H in the middle and the PT ...out of pic.
A 6J7 and a 6C5 makes for the entire preamp and this heads into an interstage transformer as PI.
The vibrator in turn...yeeeeeees...that´s what they´re called. A Motorola one no less.
Wiring is dry rotted and/or chafed it isn´t even funny. Like an old Italian made Binson approx.
Well,i got the thing going in as much that i could determin that the transformer and choke were still in the game. For the better i guess.
Couldn´t contain myself so i took to making the thing come alive in its most crude form on the bench. Didn´t sound worth a damn but..it was alive at least.
The 20H choke? What´s up with that?
Well,back in the day several manufacturers opted to sport a choke between the hightension centertap and chassis ground to minimize ripple. I´ve hotroded several Gelosos so equipped for instance,where the setup works rather well.
In this case tho...nah. Just nah. DC resistance of that thing is like 1000 Ohms so just..HELL no.
All said and done ALL of the wiring was dryrotted and needed replacing. Down to the bundles coming off the various transformers.
Right. No words needed.
Endbell got a tad of paint and the voltage selector i picked apart and cleaned.
Yes i´m a nerd and yes i´m a moron. It´s just that i find it kind of neat keeping at least a few things of the stocker. Ergo them octal sockets have been completely picked apart and cleaned,retensioned and are now ready for business as usual again.
Now we´re getting an idea where this is headed i guess. That smaller "transformer" there is a different choke i opted to use of 5H. Way more appropriate for the task as being installed inline with the voltage rail.
The wiring for the OT. As it turned out it had become damaged to the point where the one wire off of the one side of the OT had come lose. Not the end of the world tho.
Uhu. Added saver diodes for the rectifier tube,taps for a bias board..fuseholders...IEC jack...you know the drill by now.
As of right now i have no idea what to make out of this one. Time will tell i guess.
