Retro is everywhere, but can we go back to simple tube tone, in a newly designed and newly available amp?

Quick Summary

The Supro Delta King 12 is one of three sizes in the Delta King family. There is an 8” version at 1 watt, a 10” version at 5 watts and this one at 15 watts. It’s an all tube Class A amplifier using a single 12AX7 in the preamp and a single 6L6 in the power section. There is a built in FET boost and a drive channel from Pigtronix. It sounds closest to a tweed style Fender, clean with easy breakup when pushed. There is a single input, three band eq and a long spring reverb. It also has a line out, ostensibly to feed your DAW. Price here in Canada is $799 MAP. The units are designed in the United States and manufactured in China.

The Details

In addition to the lacquered tweed finish, this amp is available in all black with the same TV set speaker opening. The design is simple and meant to evoke those early amps. Unlike an old tweed, this amplifier has a master volume, so you can set the level of gain to get the level of drive that you want without having to run it really loud. As bedroom or practice amp, it’s a fair choice.

There is no effects loop, but the amplifier being so simple, takes pedals quite well. It handled an Analogman Beano Boost, a JHS Morning Glory in both modes, a JHS Clover, a Walrus Audio Delay and a Walrus Audio Fathom with no issues at all.

I placed the amp in a traditional room with sheetrock and wood walls and carpeted floors and found it to be a bit boomy, so modified the treble and mids up and the bass down a bit to get a sound that appealed to me. That’s what EQ is for really, to make the sound more palatable.

The manual, including the covers is all of eight pages long, two of which are legalese.

Clean Tone

As I mentioned, this is a very simple design and if your guitar pushes at all, maintaining a clean tone requires that the Volume be turned down with overall loudness controlled by the Master Volume. The amp is quite touch sensitive so changes in picking dynamics come through clearly. With my white Strat with the Seymour Duncan Everything Axe pickups, a bit of crunch is achieved very easily in normal humbucking mode, and takes a change in volume settings at the amp to do so when in single coil mode. If you are using higher output pickups, getting a pure clean tone is going to take some work.

Boost Function

This is an FET boost that has it’s value preset with no variation. In that regard, I find it ok for pushing the amp into a bit of overdrive, but it also makes things louder. The amp is wired to take a dual footswitch although my demo unit did not come with it. I tend to like a clean boost where I can get the added tone dynamics while remaining overall volume neutral. This is not an always on Boost circuit and while there is nothing wrong with it, I much preferred being to kick in and out the JHS Clover and have a lot more control over the boost function. Since the boost is built in, one should not expect the flexibility or variability of an external boost pedal, so take that into account.

Drive Function

This is not really a separate channel. It’s referred to as a Pigtronix FAT High Gain mode. The documentation is rather sparse, and it appears to be part of a Pigtronix FAT staged gain OD/Distortion, but without any dedicated EQ, so you are manipulating the amp’s regular tone controls. This is fine if your whole song is played with drive on or drive off, but if you are punching in and out, you are going to get significant volume and tonal response differences. In my opinion, the drive function always sounded very nasal. I did not like it and would not consider it a value add for the amplifier. Far better was to ignore the drive function completely and use an external pedal. I used a JHS Morning Glory in both the red and blue modes and it makes a great tone through the amp, and allows you to remain output level neutral if you are so inclined.

Line Out / Power Amp In / Footswitch

Being able to run a line direct to an interface to a DAW or a PA is a very popular function today. The Supro Delta King has a line out jack. The documentation is negligible but the company support email is very responsive. Their prompt response was a bit disappointing. The line out is TS unbalanced. This means a limited cable run to your interface because of the lossy nature of an unbalanced line. Moreover most interface line inputs are TRS balanced. You also cannot mute the power amp, so silent recording is not an option. There is no independent output level control for the line out as is commonly found on similarly equipped amplifiers.

For me, this option is not as well executed as it could be, but I have to consider the target price point and the likely buyer. If I wanted to record this amplifier, I would choose to put a microphone in front of it. That’s not hard, and has worked for decades, and I kind of get it since the amp is supposed to be effectively a Supro from the Fifties. Thus my feedback to Supro is either do the line out properly or drop it completely.

There is a power amp in that bypasses the preamp section entirely, if you wanted to use an external preamp instead of the Supro preamp. This is not a use case of interest to me, so I spent no time on it.

There is a TRS jack allowing you to connect a two button latching footswitch for activation / deactivation of either the boost function or drive function independently. The amplifier does not come with the foot switch or the cable. Call that a missing element. While TRS dual footswitches are not free, nor are they stupid expensive and to sell an amp without this necessary tool included smacks of cheapness.

Speaker

The DK12 speaker is designed by Supro to try to achieve the tone of ‘50s vintage field coil speakers. It sounds fine, albeit a bit bassy to my ears. Good for Supro for making the effort, although I cannot help but wonder if they would have been better served audibly and from a marketing perspective by partnering with Celestion.

Spring Reverb

People love or hate reverb. I am of the former and the long spring tank in the Supro Delta King sounds terrific. It’s a classic simple spring tank. There’s a knob for how much reverb you get. That’s it. Sometimes plain and simple just works best. I found for what I now call “base reverb” (with thanks to the inestimable Dan Steinhardt), I’ve got it set at about 1/3 on. If I want more, I can turn it up and it sounds like it should, or I can use a reverb pedal to augment the amp’s built in spring. While I much preferred the Fender Tone Master system for recording, the Supro’s spring tank kicks the Fender digital reverb to the curb and into traffic. Real springs sound better to me.

The Look

While I understand fashionability, it does not play into my playing or auditory experience. That said, if I were buying a Delta King, I would get the tan tweed finish over the plain black. It just looks cooler. Fit and finish are excellent and the cabinet construction is of poplar. It weighs about 28 pounds in this dense little package. This is a much smaller box but is only six pounds lighter than the Tone Master Super Reverb with 4 10” speakers. It’s portable to be sure, but you might not want to be humping it up and down a bunch of narrow stairways.

Samples

The two samples contained here are short clips using a Les Paul Axcess using the native humbuckers rolled off to between 7 and 8 and using the bridge pickup. This gives a decent clean tone out of the amp without any pedals, until you dig in when breakup starts. As noted earlier, I prefer to use overdrive pedals with the Supro clean rather than try to manipulate the controls on the amp live to get a pleasing tone. Your mileage can and may vary in your approach. The signal route is a JHS Morning Glory in the Bluesbreaker mode, then a JHS Clover Boost with volume level neutral, to a Walrus Audio ARP87 delay and then through a BBE Sonic Maximizer into the input on the Supro. All the EQs are set at 12 o’clock and the internal reverb is at 10 o’clock. The sound from the amp is captured by a single on axis Shure SM57 running direct into the microphone input on a UA Apollo Solo. I replaced my Focusrite Solo with the Apollo Solo because I have a substantial investment in UA plugins. However no plugins were used on these samples. As the computer connected is Windows 11, the DAW in question is Adobe Audition. Each original track is duplicated twice and panned Left and Right 75 respectively, with the supporting duplicate tracks reduced in output by 6dB. I do this to increase the soundstage of a single guitar.

The Supro is a nice sounding amp and while it breaks up faster than I personally would prefer, it is an excellent general purpose amp, and you can hear the tube “feel” even with minor overdrive from the Morning Glory. I find the amp very responsive, with no latency and no lag and am very impressed with how good this very simple amplifier circuit behaves. As with all tube amps, I strongly advocate turning the amp on, but leaving it in Standby for at least a minute to bring the tubes to some level of warmth before driving them. Doing so prolongs your tube life and also reduces that cold tube brittleness. When turning off, again, my recommendation is putting the amp in Standby for a minute or so prior to shutting down the power.

Conclusions

The Supro Delta King 12 is a lovely little Class A all tube basic amplifier. It’s spring tank reverb is beautiful. The built in FET boost is limited due to a lack of controls and I personally did not care for the sound of the Pigtronix FAT drive function. The unit is well constructed and does a fine job of delivering that basic ‘50s tube amp sound. You won’t get that glass clean tone as you would from a blackface Fender, but the amp is not built for that. At $799 for 15 watts and a 12 inch speaker (CAD) it’s a very good price for an all tube all analog amp. Pricing is similar to a Fender Pro Junior IV, Marshall Origin 20 or VOX AC10. In that range, in my opinion, you get more for your dollar with the Supro and would definitely recommend giving one a go.

My thanks as always to the good folks at The Arts Music Store in Newmarket Ontario for arranging for my short term demo unit.