Reinhardt Sentinel

By Jack Devine

One of the great misconceptions in the guitar community is that for cleans you need a Fender and for distortion you want a Marshall. To a point I can agree with that. I think the folks that say such things haven’t spent a lot of time with older Marshall amps. The irony is that the early Marshalls are patterned after larger Fender tweed amps, and as such boast some spectacular clean sounds and great dirty tones. These clean sounds are not surfy clean but thick and complex with the ability to push a little harder into the amp and make it give up a touch of overdrive. These old Marshalls like the JTM 45 provided amp designer Bob Reinhardt the inspiration for this month’s amp review: The Sentinel.

The Sentinel uses a pair of KT-66 tubes (or 6l6) to put out about 35 to 40 watts of great old school tone. If you’re familiar with a 4 input Marshall, say a JTM-45 or 1986/7 style circuit…you’re going to feel right at home here. There are a few tweaks here and there that kind of refine the circuit and a switch that allows for the amp to sound like an aluminum panel Marshall from the 70’s-It’s the same basic tonal elements with a touch more gain and a brighter tone that accentuates the upper mid-range.

When I first get an amp I always check to see what the clean tone is. I find that there’s often a basic character or sonic DNA that’s present when clean that stays constant through out the amps gain range. I was immediately put in my comfort zone. I dialed up a nice clean tone in about 5 minutes and just moved the inputs around to see what the Sentinel was all about.

I find these four-hole, plexi-style amps offer a tremendous amount of flexibility with different types of guitars and pickups, and the Sentinel definitely bears this out. By using the inputs for their inherent gain levels, I was able to get my strat really clean or drive the front end with a humbucker with similar knob settings. Then I started experimenting with the Volume controls. There are two. When jumpered together, Volume one generates a full and deep tone and Volume two provides a lovely kind of sparkle and when cranked a bit, you get that terrific grit. After all this I flipped the Vintage/Modern switch on the back of the head and got a dose of grunty raw snarl that is very much the hallmark of a 70’s Marshall lead circuit. Cool to have both on tap.

I’m more about the thicker, throaty sounds available in the Vintage mode and as such went back there and started letting the amp do its thing. Quickly I found myself playing the main riff that became the clip for this review. I really like it when an amp or guitar can bring something special out of me. Funny thing is…I have a Marshall so it’s odd that the Reinhardt would push me into the creative place! For one reason or another the ideas just started coming and I had the basic idea for the track in about 20 minutes. Cool!

The EQ knobs are straight ahead and will not puzzle anyone. They sound good and musical throughout their range. No real rocket science needed to understand this stuff, they’re very intuitive and immediate controls. With the controls around noon the amp has a very even tone that could be brightened up or rolled off to suit a player’s taste or a specific guitar. I will say that the voicing of the amp was not overly polite…something I find all too often in today’s amps. There should be a certain raw, feral nature to an amp like this, and I for one amp glad that Bob didn’t refine the amp into a toothless version of the Marshall circuit.

I used the lowest gain input in the darker channel and then blended the brighter channel to taste. This ensures a wonderful warm overdrive, but allows there to be some bite to cut through the cream. Volumes were both around 6. One difference between the Sentinel and the JTM-45 is that there’s much better bass voicing here. The original circuit is too bassy in my opinion and some revoicing is usually a must with the JTM-45s I’ve had in the past. I suppose Bob saw the need to bring this amp up to modern spec in terms of tightness. So, consequently I was able to actually have the bass knob higher than 2 and not have it woofy or mushy sounding. Cranking the Treble, Middle and Presence controls seemed to bring about typical results. Extreme settings still sounded very musical however, with my taste preferring the mids and highs around 6 and the presence at noon. They sounded great pretty much wherever with just a little more sparkle or snark depending on how you like it.

The amp is very nicely made with a sturdy feel and stylish appointments. There’s a bunch of custom colors available too, for example my demo unit was an awesome lime green with the Reinhardt dual racing stripe in white- very cool indeed. I was sad to see it go, but then again I suppose it went to a better place…that is it went to be played by Mark Knopfler. Mark has been using Bob’s amps for a while now and wanted to try the Sentinel. That says something to me, that a player like Mark, who has a lot of great gear and could easily get paid to play another company’s amps elects to buy amps from Bob Reinhardt. Anyways…I like to think that lime green amp is playing Sultans of Swing or Money For Nothing and having a good time doing it.

Gripes? None really. There’s a reason why this type of amp is in demand, it’s sounds great and does so many things really well and with ease. I suppose if I wanted to be really nitpicky there could be more gain available? Not for my needs mind you but some might be surprised that even when fully cranked the amp is clear and punchy with no pre-amp fizzy gain but rather full of gutsy thick power tube crunch. I like that but I bet someone could complain…

Granted I do have a real affinity for this type of amp. I currently own a 1972 Super Bass and let me say the sound of the Sentinel is right on the money. Not the same mind you- these are different circuits but very much the same type of experience playing this amp as when I play my Vintage Marshall. I must say that I’d love to hear this amp in a 4 x KT-66 version- that would truly be something.

The clip is Sentinel in Vintage mode only. It’s all strat with only the amp volume knobs, inputs and pickups changing to achieve the range of tones. The main guitar is set clean (ish) with just enough gain to break up when I dig in but add a lovely compression and warmth when picked softly. I used the neck pickup for the main theme and when the bridge comes in I use the bridge and middle setting. I used my Ho attenuator and a Lexicon FX unit to get volume levels down and add some delay and reverb. The cab is a 2×12 with two Scumnico 65 watt speakers wired in dual mono so that the FX are out of one speaker and the amp is dry in the other. I miked the rig with an AKG 414 and ran into pro tools via a Chandler LTD. Abbey Road edition mic pre amplifier.


There’s the lead guitar track that enters at the top of the bridge. That’s using the same settings as the main guitar except the bright volume is dimed and the pickup is the bridge. This tone is really sweet to me because there’s still a lot of clarity, dynamics and single coil character there, yet there’s sustain…plus I can still tell it’s a strat because there’s not too much goopy gain all over the place.

The other guitars that come in all crunchy are the same strat on the bridge pickup double tracked with both volumes dimes and the input switched to the most sensitive. This is the most gain I could coax from the amp in Vintage mode. The sound is very usable and fun. For a diversion during my tracking session I took out my 335 and played some fun stuff ranging from Cream era Clapton, AC/DC and early ZZ Top- what a blast.

At the end of the tune I take a little solo and the set up was just like the first lead break, cranked bright volume, low gain input, but this time I used the neck pickup. I really love the mix of clarity and warmth and found that I was easily able to get the track sounding and feeling the way I heard it in my head. There’s a raw nature to the tone that seems natural, not overly manicured like many other amps these days. I’m certain that Bob could do that, but I’ve got to say congrats for leaving that stuff in there…flawless is NOT perfect. That is to say, that the little quirks that old Marshall amps have are what make them special sounding and do the things that they do so well. Nice to hear them presented in the Sentinel!

Anyone looking for this classic platform would be well served to check out a Reinhardt- in addition to the Sentinel there are like 20 other amps this guys makes! Bob is a straight shooter and as likable a guy as I’ve met while doing these reviews. So check out his website at or give him a call. I suppose that’s it! Hope you enjoy the clip and look for a discussion of the review in the amps and cabs and clips section of TGP.

Stay tuned and stay positive,

Jack Devine