Because one JTM50 isn't enough.....

[RetiredUnit1]

No particular reason other than the one I have has Mercury Magnetics, and I wanted to compare with Dagnal-ish transformers from Heyboer. This place had some pretty good prices.....




And I decided I wanted to redo the layout a bit differently as well....... The PT is a stand-up, so I don't have to plan around that big-o hole in the chassis. I have a little more to do to finish this off.

 

[coltonius]

No particular reason other than the one I have has Mercury Magnetics, and I wanted to compare with Dagnal-ish transformers from Heyboer. This place had some pretty good prices.....


View attachment 43783

And I decided I wanted to redo the layout a bit differently as well....... The PT is a stand-up, so I don't have to plan around that big-o hole in the chassis. I have a little more to do to finish this off.

View attachment 43784

Please follow up when it’s done and you’ve compared! I tend to favor Heyboer whenever possible, but I’ve got some projects in queue that will necessitate Mercury: a 5F6A head that can accommodate EL34s + output impedance switch, for instance.

 

[RetiredUnit1]

Please follow up when it’s done and you’ve compared! I tend to favor Heyboer whenever possible, but I’ve got some projects in queue that will necessitate Mercury: a 5F6A head that can accommodate EL34s + output impedance switch, for instance.

The JTM50 is virtually almost identical to the 5f6a, and Jim Marshall himself said he copied the Bassman to make it although he opted for solid state rectification.

So you could probably use heyboer JTM50 transformers for a EL34 5F6A. This is the layout I made of the 59 Bassman using 6L6. And under that is my now finished JTM50 layout, which I just finished a couple hours ago. At least I think it's finished, I still have to do a second pass on all every connection to be sure I didn't skip anything.

I'm transitioning from premade chassis to DIY. I have a company that will laser cut any layout I have, and I have a sheet metal brake for bending the sheets into boxes. So I'm starting to think about things like modifying chassis to have custom switches, or ohm selectors, etc.

 

[HamishR]

I like Heyboer transformers - as long as they are specced out by someone who knows what they want. For example I believe Heyboer makes the transformers for GDS 18 watt amps and I've used a few sets of those and they sound wonderful. Marstran transformers were Heyboer I think and they are some of the best '60s style Marshall trannies I've heard - the '68 spec 1987 I built with those was one of the most authentic sounding Marshall clones I've built.

But I end up using MM a lot for the reason you alluded to, @coltonius. They produce such a cool range of "what if" transformers. I use their Fatstack PTs all the time so build tweeds with EL34s, for example. And I recently discovered that using a slightly lower B+ in a 5E3 can make a killer sounding amp, kind of how Clark does.

 

[RetiredUnit1]

I like Heyboer transformers - as long as they are specced out by someone who knows what they want. For example I believe Heyboer makes the transformers for GDS 18 watt amps and I've used a few sets of those and they sound wonderful. Marstran transformers were Heyboer I think and they are some of the best '60s style Marshall trannies I've heard - the '68 spec 1987 I built with those was one of the most authentic sounding Marshall clones I've built.

But I end up using MM a lot for the reason you alluded to, @coltonius. They produce such a cool range of "what if" transformers. I use their Fatstack PTs all the time so build tweeds with EL34s, for example. And I recently discovered that using a slightly lower B+ in a 5E3 can make a killer sounding amp, kind of how Clark does.

You can also raise the cathode resistor from 250r to 300r to give the 5e3 a bit more headroom. Sounds very neil youngish..... I live close enough to MM to pick up the transformers and save freight, and there's a costco really close so I can do a two-fer. I get "the good guy" discount because I've ordered over 30 transformers from them. Used to be that I saved money buying MM because of the freight and the discount, but even taking that into account the same transformers for a 1987 are about $250 *less* from Heyboer.....

 

[HamishR]

Yeah MM aren't cheap! I wish Heyboer made a bigger range like MM. Plus ordering from Mercury has become more difficult since the passing of Patrick. For some of my recent 5F4/5E7 builds I've been buying the PT and OT from Mercury but the chokes from Mojo when I buy the chassis and tagboard. I struggle with spending US$60 on a choke! Most of the Mojo transformers seem to made by Heyboer but I don't like the sound as much as the MM trannies.

I spend a decent amount of time biasing my 5E3s (or any cathode biased amp) to be close to 100% plate dissipation, which seems to be the magic figure. Fixed bias I go for around 60% because I can't hear any benefit from biasing to 70%. But for cathode bias I like 100%. It is quiet, has excellent headroom and when cranked gives the best overdriven sounds IMO. So the bias resistor can vary depending on the transformers and the tubes. Strangely enough in my last 5E3, which had a lower B+ PT from MM and JJ 6V6s which are rated as 14W the cathode resistor ended up being 270ohms. But I've had to go up to 470 to get some amps to bias at 100%.

At 100% a 5E3 can sound full, fat and articulate, almost like a plexi but sweeter. A Les Paul is fab. I like to use a speaker like the Celestion G12H Creamback, so the break-up is mainly coming from the amp. I don't really care for the over-saturated fuzz of a badly biased Deluxe.

 

[RetiredUnit1]

Yeah MM aren't cheap! I wish Heyboer made a bigger range like MM. Plus ordering from Mercury has become more difficult since the passing of Patrick. For some of my recent 5F4/5E7 builds I've been buying the PT and OT from Mercury but the chokes from Mojo when I buy the chassis and tagboard. I struggle with spending US$60 on a choke! Most of the Mojo transformers seem to made by Heyboer but I don't like the sound as much as the MM trannies.

I spend a decent amount of time biasing my 5E3s (or any cathode biased amp) to be close to 100% plate dissipation, which seems to be the magic figure. Fixed bias I go for around 60% because I can't hear any benefit from biasing to 70%. But for cathode bias I like 100%. It is quiet, has excellent headroom and when cranked gives the best overdriven sounds IMO. So the bias resistor can vary depending on the transformers and the tubes. Strangely enough in my last 5E3, which had a lower B+ PT from MM and JJ 6V6s which are rated as 14W the cathode resistor ended up being 270ohms. But I've had to go up to 470 to get some amps to bias at 100%.

At 100% a 5E3 can sound full, fat and articulate, almost like a plexi but sweeter. A Les Paul is fab. I like to use a speaker like the Celestion G12H Creamback, so the break-up is mainly coming from the amp. I don't really care for the over-saturated fuzz of a badly biased Deluxe.

Have you tried any of the Fanes available at Avatar speakers? I put a M65 in my 5e3 I made with Mustards, *great* breakup....

I bought out a seller on eBay who was liquidating all his 6v6 stop sign RCA's at Christmas. Bad timing for him, *no one* bid against me and I ended up with 10 pairs for about 60 bucks, lmao.... switching from JJ's or TAD's to a pair of these is just breathtaking....

Avatar-U.K. Fane M65 8 ohm and 16 ohm in stock – Avatar Speakers

Here are two Demo videos: https://www.youtube.com/watch?v=PvorTPUDXj4 Great for hard rock and Metal. Check out this Youtube video: https://ww...

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