Hiwatt Custom (DR) series: every version
Every version, how to tell them apart, how to date one, and what to check before you buy. 4 versions, 1967–1984.
Hiwatt's Custom heads are the 1970s British amps built for headroom and power: Normal and Brilliant channels, a shared tone stack, presence and master volume, Partridge transformers and neat point-to-point wiring. The circuit grew out of the Sound City 100 heads the same builder made in 1967–68, and the line ran until the founder's death in 1981, with production continuing elsewhere until 1984. The model number is the quickest way to tell the power: DR504 (50 W), DR103 (100 W), DR201 (200 W), DR405 (400 W).
The versions, in order
Sound City 100 heads (Hylight-built) (1967–1969)
Before Hiwatt
100-watt Sound City heads built by Hylight Electronics with Partridge transformers; customised examples became the DR103.
How to spot one
- Sound City branding, from the London shop that sold them.
- Partridge transformers, as on the later Hiwatts.
- Two channels (Brilliant and Normal), each with high and low inputs, and a shared tone stack with presence.
- Four EL34 output valves and a solid-state rectifier.
Specs
| Power tubes | 4 × EL34 |
|---|---|
| Rectifier | Solid-state (silicon diodes) |
| Phase inverter | Long-tail pair |
DR103 Custom 100 (Late 1960s–1981)
Hiwatt
The best-known Hiwatt: 100 watts from four EL34s, Normal and Brilliant channels and a master volume.
What changed from the Sound City 100 heads (Hylight-built)
- Customised Sound City 100 heads made for a touring band in 1968 became the basis of the first Hiwatt model, the DR103.
How to spot one
- Four inputs: Normal and Brilliant channels, each with high and low inputs and its own volume.
- Shared Bass, Treble, Middle and Presence, plus a Master Volume.
- Four EL34s with a solid-state rectifier, and a Partridge output transformer.
- Point-to-point wiring on turret boards with military-spec parts and heavy internal shielding.
- Some front panels carry a “Custom Built” legend above the Master Volume.
Specs
| Power tubes | 4 × EL34 |
|---|---|
| Rectifier | Solid-state (silicon diodes) |
| Phase inverter | Long-tail pair |
| Rated power | 100 W |
| Construction | Hand-wired turret board |
| Channels | 2 |
DR504 Custom 50 and SA combos (1970s)
Hiwatt
The DR103 layout at 50 watts on two EL34s, as a head or in SA112 and SA212 combos.
What changed from the DR103 Custom 100
- Power tubes: 4 × EL34 → 2 × EL34
- Rated power: 100 W → 50 W
- Half the output valves (two EL34s) for 50 watts, also offered in combos.
How to spot one
- The same Normal and Brilliant layout, tone controls and master volume as the DR103.
- Two EL34 output valves for 50 watts.
- The SA112 and SA212 put the 50-watt circuit in 1×12 and 2×12 combos.
Specs
| Power tubes | 2 × EL34 |
|---|---|
| Rectifier | Solid-state (silicon diodes) |
| Phase inverter | Long-tail pair |
| Rated power | 50 W |
| Channels | 2 |
DR201 Custom 200 and DR405 Custom 400 (1970s)
Hiwatt
The Custom layout scaled up to 200 and 400 watts, mostly for bass and very large stages.
What changed from the DR103 Custom 100
- More output valves and bigger transformers for 200 and 400 watts.
How to spot one
- Normal and Brilliant channels like the DR103.
- Model DR201 is 200 watts; model DR405 is 400 watts.
- Larger chassis and transformers than the 100-watt head.
Specs
| Rectifier | Solid-state (silicon diodes) |
|---|---|
| Phase inverter | Long-tail pair |
| Channels | 2 |
Hiwatt Custom buying checklist
Date it
- Potentiometer and transformer date codes are the most reliable way to date a vintage Hiwatt.
- Partridge transformers point to the founder's era; production by others continued from 1981 to 1984.
- Sound City-branded 100-watt heads with Partridge transformers date from 1967–69.
Check it’s original
- Check the transformers: original Partridge parts carry their own type numbers and are often the first thing replaced after a failure.
- Hiwatt wiring is famously neat and dressed; untidy or re-routed wiring points to repairs or modifications.
- Later Hiwatt-branded amps made by other companies are a different build; the model number alone doesn't make a vintage DR103.
What usually needs work
- Old filter capacitors are due on any 1970s Hiwatt; replace them before running the amp hard.
- The four EL34s are the main wear item; set the bias after a change.
- Heavy internal shielding and tidy wiring make these amps quiet; new hum usually means a failing capacitor or valve.
Questions buyers ask
What does DR stand for?
The initials of Hiwatt's founder, who designed the amps and built them with a small team.
How is a Hiwatt different from a Marshall?
It's built for headroom rather than early overdrive, with a master volume, Partridge transformers and very tidy point-to-point wiring.
Are Sound City amps really early Hiwatts?
The Sound City 100 heads of 1967–68 were built by the same company, and customised examples became the DR103. Later Sound City models were made by others.
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