![]() But they're all 5e7s.īack to the issue of choke placement and sonics I raised in post # 57: I suppose that means a 5e7 (and probably most other Fender amps as well) are really more like a family of amps that conforms more and less to the paper specs of the model. Not only did Fender simply use whatever is available, it sounds as if their transformers did not all conform to tight tolerances, spec-wise. The folks at Mercury Magnetics view this simply as part and parcel of the reality of cloning parts of vintage Fender amps. If they're cloning a 360-0-360 PT from a 5e7 and calling it a "lower B+" relative to some other clones of 5e7 PT's they've made, I cannot imagine what some other of their PT's put out, voltage-wise! He recommended one of their power transformers that is a clone of a 5e7 PT. I indicated that I wasn't looking for lots of clean headroom. For example, when I spoke to the fellow at Mercury Magnetics the other day, I asked him about their various 5e7 power transformers. We also know that while the 5e7 (and 5f4) schematic and layout lists a B+1 of 415V, the PT's often ran them much hotter. And this is only to focus on one spec of those OTs. If we take anything that Mercury Magnetics makes and calls "tone clone" as a guide, we can deduce that 5e7's sometimes had 2.67R output transformers, sometimes had 4R output transformers, sometimes had 2R output transformers, and sometimes had output transformers with multiple taps-2R, 4R, and 8R. And yet it seems that some of these same amps had much bigger chokes that could handle the current better in that position. ![]() For example, we know for a fact that some 5e7s used very small chokes (rated for 90 mA current) as choke input filters to handle the entirety of the amp's B+. I’ll follow along.interested I am.Ĭlick to expand.Yes, this notion of a "standard" is interesting. Pity that missing control, eh? Nice looking build.whoever did it. 1987 circuit sitting in that chassis.but missing the middle tone control circuit. It appears to me that there is a Marshall Md. It looks like someone ordered a cab and chassis for a 5F4 Super.built they didn’t build that amp. Ex: I have a ‘homebuild’ tweed cabbed 2x10 combo here. However, I can look at an unknown circuit and get a fair idea what is there. I knew I had a long way to go.still ain’t all the way there.never will be. I remember looking at an amp on his bench while he was identifying this or that aspect of the circuit.without a schematic. I was thinking after my last post that you would be asking that question! ( ^). ![]() I knew enough to be able to ascertain dates and originality.but I didn’t study actual circuits in an6 depth at that time.beyond schematics. I was so naive to think that what I was seeing on the schematic was what was there and there were never any variance. So.I never studied those circuits in those amps to the point of noting the placement of the choke. I had to finish both jobs.so I started doing amp work. When he left town, I became a tech by default after having two BF amps worked on by two different young men who knew some formal electronics.associate degrees for both in electronics. I did watch him work some.but I should have availed myself of his offehr. He offered to explain things to me, let me watch, work alongside. I knew a very good tech and he did all of the work I needed done.no matter what the problem. I didn’t want to lose money or cheat anyone by selling misrepresented items.whether through intent or ignorance. Buying and selling will make a cautious person who understands those details.caveat emptor. In that pre-internet era, I was buying and reading magazines and books and learning about these vintage amps that way and through hands-on experience of identifying/dating them by codes.old school. ![]() Prof, I owned those two Bandmasters and the low power Twin before I started working on amps. Granted, it's a 6v6 model, but the 8160 PT was a big transformer, and the choke on this thing dwarfs the OT. The thing is a hella lot bigger than the OT. Again, higher than the standard 90mA Fender choke from later years.Īnd this article about restoring a 6v6 Tweed Super has a chassis pic and specified it's the 14684 choke. Weber's Tweed choke by Heyboer is a 125mA choke based for the 14684. We chose this one from an original for its tone." "The FC-TTWIN is approximately 60 ohms, 150 ma, and 3.5 H. It's made by Mercury Magnetics, this is what they sent me: I got the specs on the choke used to build my 5E8-A Twin. It's for a Tweed Twin, but MM's clone for it is certainly higher than a 90mA choke, and they said the parts varied, so who knows what was standard: Here is from a thread on ampgarage (forgive me if it's been posted already). Well, we may have stumbled upon one of the most discussed and unsettled topics in Tweed amp history - choke specs.
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