- Build Rating
It's been nearly four years since I built an amp... and that was also a Hiwatt DR504 clone (Mojotone Custom 50 kit). I absolutely love the one I built years ago. The only "problem" is the size and bulk. I don't take it out as much as I'd like, because the head itself is fairly large and heavy, and that vertical 2x12 is actually not much smaller than a 4x12. So what I wanted was all the goodness of a DR504, but in a 1x12 combo form. And I plan to get a 1x12 extension cab, so I can stack this new combo on the extension cab, and still have a vertical 2x12 setup when space permits.
I actually already had a 1x12 Hiwatt-style amp: my first amp build was the Trinity Triwatt, which is not a faithful clone of a Hiwatt circuit, but a close cousin: it was originally designed for a switchable 6v6 or kt66 output section. (They used to offer it in DIY kit form.) I had one of the newer kits which also included an option for EL34 output tubes. I originally built it with the 6v6/kt66 output. I felt it didn't have enough clean headroom. So I re-wired the output transformer, and made a couple minor circuit tweaks so I could use it with EL34 tubes. That didn't seem to make a huge difference in clean headroom. It's a great amp otherwise, but the true DR504 has the magic I want.
This time around I went with Ceriatone for the actual amp kit, the Hey What 504. I went with Ceriatone because they include by default a bias adjustment circuit. The Mojotone kit I had did not include any way to adjust the power tube bias, short of actually re-soldering different resistors. When I asked them about this, they claimed it was because they wanted their Custom 50 kit to be as true to the vintage Hiwatts as possible. I don't agree with that, but looking at their kit now, they do include a bias adjustment pot. But it's still a pot that's soldered in to the power supply circuit itself. Meaning, you'd have to take the amp chassis out of the enclosure to change tubes and bias. It wouldn't be hard to mount that to the chassis, but doing it neatly, along with external bias probe points would require drilling a steel chassis. No thanks! The Ceriatone comes by default with an externally-mounted bias pot and bias probe points (just like my Trinity Triwatt). So tube swaps and re-bias is easy-peasy.
I did buy the transformers from Mojotone. They are made by Heyboer and are supposed to be faithful reproductions of the original Partridge transformers used in vintage Hiwatt amps. These massive, over-spec transformers are generally considered to be part of the Hiwatt magic.
I've built a lot of pedals since I built the previous DR504, and I forgot how time-consuming an amp build is. A pedal build is instant gratification by comparison! I estimate I spent somewhere around 20-30 hours to build this. But the build was otherwise unremarkable. I tried to keep the lead dress neat. It think it's OK... not great, but not terrible. Look at pics of the lead dress as done by Ceriatone, Hi-Tone or Reeves - those are absolutely first-class, and truly honor the Hiwatt legacy.
Initially it didn't work - no sound at all. Ultimately, I determined it was one of two things (maybe both): one of the preamp tubes not making good connection/not inserted fully, and/or a couple sketchy solder connections. I got some debugging help from the Amp Garage. My main takeaways from the debugging experience: even if the amp is working, it's worth your time to poke and prod all the wires, components and solder joints with a chopstick while it's running, to try an ferret out any marginal solder joints. Also, rotating the amp 180 degrees for visual inspection can be very revealing.
Once I got the sketchy solder joints fixed up, I spent more time strumming and perturbing the circuit with a chopstick - I couldn't get it to cut out any more, so I feel pretty confident about it. Enough so that today I loaded into the custom 1x12 cabinet that Sour Mash Guitar Cabs made for me. This is the second cab I've had Sour Mash make for me. They do great work and their prices border on too-good-to-be-true. While I in theory could make my own cabinet, my carpentry skills are pretty mediocre. I enjoy DIY electronics, but my woodworking projects always leave me frustrated. I had the cab covered in brown "country western" tolex, as used by Homestead Amps. That look might offend the Hiwatt purists, but I think it looks great!
I got it all boxed up today and spent about an hour just playing - actually playing for enjoyment, rather than debugging. It sounds just like it should - the same as my other DR504 clone. But now I've got it in the 1x12 combo cab, and it can be my main amp, both for gigging and practice. Once I've truly put it through all its paces, I plan to sell both the Triwatt and the Mojotone.
I actually already had a 1x12 Hiwatt-style amp: my first amp build was the Trinity Triwatt, which is not a faithful clone of a Hiwatt circuit, but a close cousin: it was originally designed for a switchable 6v6 or kt66 output section. (They used to offer it in DIY kit form.) I had one of the newer kits which also included an option for EL34 output tubes. I originally built it with the 6v6/kt66 output. I felt it didn't have enough clean headroom. So I re-wired the output transformer, and made a couple minor circuit tweaks so I could use it with EL34 tubes. That didn't seem to make a huge difference in clean headroom. It's a great amp otherwise, but the true DR504 has the magic I want.
This time around I went with Ceriatone for the actual amp kit, the Hey What 504. I went with Ceriatone because they include by default a bias adjustment circuit. The Mojotone kit I had did not include any way to adjust the power tube bias, short of actually re-soldering different resistors. When I asked them about this, they claimed it was because they wanted their Custom 50 kit to be as true to the vintage Hiwatts as possible. I don't agree with that, but looking at their kit now, they do include a bias adjustment pot. But it's still a pot that's soldered in to the power supply circuit itself. Meaning, you'd have to take the amp chassis out of the enclosure to change tubes and bias. It wouldn't be hard to mount that to the chassis, but doing it neatly, along with external bias probe points would require drilling a steel chassis. No thanks! The Ceriatone comes by default with an externally-mounted bias pot and bias probe points (just like my Trinity Triwatt). So tube swaps and re-bias is easy-peasy.
I did buy the transformers from Mojotone. They are made by Heyboer and are supposed to be faithful reproductions of the original Partridge transformers used in vintage Hiwatt amps. These massive, over-spec transformers are generally considered to be part of the Hiwatt magic.
I've built a lot of pedals since I built the previous DR504, and I forgot how time-consuming an amp build is. A pedal build is instant gratification by comparison! I estimate I spent somewhere around 20-30 hours to build this. But the build was otherwise unremarkable. I tried to keep the lead dress neat. It think it's OK... not great, but not terrible. Look at pics of the lead dress as done by Ceriatone, Hi-Tone or Reeves - those are absolutely first-class, and truly honor the Hiwatt legacy.
Initially it didn't work - no sound at all. Ultimately, I determined it was one of two things (maybe both): one of the preamp tubes not making good connection/not inserted fully, and/or a couple sketchy solder connections. I got some debugging help from the Amp Garage. My main takeaways from the debugging experience: even if the amp is working, it's worth your time to poke and prod all the wires, components and solder joints with a chopstick while it's running, to try an ferret out any marginal solder joints. Also, rotating the amp 180 degrees for visual inspection can be very revealing.
Once I got the sketchy solder joints fixed up, I spent more time strumming and perturbing the circuit with a chopstick - I couldn't get it to cut out any more, so I feel pretty confident about it. Enough so that today I loaded into the custom 1x12 cabinet that Sour Mash Guitar Cabs made for me. This is the second cab I've had Sour Mash make for me. They do great work and their prices border on too-good-to-be-true. While I in theory could make my own cabinet, my carpentry skills are pretty mediocre. I enjoy DIY electronics, but my woodworking projects always leave me frustrated. I had the cab covered in brown "country western" tolex, as used by Homestead Amps. That look might offend the Hiwatt purists, but I think it looks great!
I got it all boxed up today and spent about an hour just playing - actually playing for enjoyment, rather than debugging. It sounds just like it should - the same as my other DR504 clone. But now I've got it in the 1x12 combo cab, and it can be my main amp, both for gigging and practice. Once I've truly put it through all its paces, I plan to sell both the Triwatt and the Mojotone.
! But for real, that's awesome! I know Mercury Magnetic transformers have a great reputation, and also a reputation for charging accordingly. 
