Hiwatt Custom 100 DR103 - The worlds most MUSCULAR amp! 

At what point is this Man going to be recognized as one of the Worlds leading "Guitar " / Amp Scholars? 😎🍻🤘

Johan - You've had a LOT of great sounding amps on this page over the years, but this may well be the king. This one is just about perfect on every frequency. Smooth - yet ballsy. Absolutely killer.

Well, the early 4 holers will have quite a bit of variations as there are custom wirings among them. Also the two holer doesn’t let you jump the channels except with a Y cable. This is how I usually run my late 60’s 103, jumping normal into bright, that’s where the BIG sounds is. And any cab except a purple back fane loaded 412 will just sound congested with it. Have tried loads of variations to realize this. So to really experience the dr103 bliss you will need the right cab.

Great video, as always! Hiwatt switched to PCB from turret board construction sometime in 1979. Mark Huss is an expert in Hiwatts and doesn't think there's much audible difference going just on construction method. The later 70s Hiwatts had some circuit tweaks compared to earlier versions, and the changes roughly (but NOT exactly) correspond from the change from 4-hole inputs to 2-hole inputs. A brief summary of the changes: 1. Change from a split cathode to a shared cathode with a slightly colder bias on V1 and a significantly larger cathode bypass capacitor on V1 (150uF vs 47nF on the 4-hole bright input and unbypassed on the 4-hole normal input). Net result is increase in gain and bass response from 1st stage and a small (IMO likely inaudible) decrease in input headroom. 2. Use of a common plate mixer rather than a resistive mixer to blend the channels. Net result is approximately a 3db gain boost due to the parallel triode if jumpering channels. The absence of mix resistors on the 2 hole version due to the new mixer arrangement functionally eliminates a voltage divider in the volume controls, so that'll be worth some gain feeding into V2 (total amount depends on the volume settings you're comparing). Net result: slight increase in gain. 3. The later 70s versions (and thus more than likely the version shown here) had a different style of phase inverter where the cathode follower passes no signal and is only used to bias the phase inverter. In my experience and in Greg Fryette's opinion, this actually results in a cleaner phase inverter section with a more hi-fi character. In other words, the net result is actually a marginal decrease in distortion coming from the phase inverter section and a more hi-fi character associated with the later phase inverters.

For me the uniqueness of Hiwatts is that it combines gain and note clarity at the same time, like no other amp can.

Damn.....this might just be my favorite of any amp you've EVER had on the channel. Sounds amazing in every single clip. Just fantastic.

I thought I was going to prefer the Les Paul with this amp, but when you switched to the Tele just wow!

Really cool vid! I'm lucky enough to have a 1974 DR504 that I bought in 1980 (for $245!!!). It was my only gigging amp thru the 80"s that I used with a 1978-79 Randall 4x12 cab loaded with Celestion G12-65's. Muscularity and clarity are 2 words that describe these old Hiwatt amps. Oh and don't forget LOUD! The other guitar player in my band used a JCM800 2203 half stack and my 50w Hiwatt rig with a decent distortion pedal easily kept up with it, if not surpassed it in punch and clarity. Something else about Hiwatt amps is that they make great pedal platforms. Don't get me wrong, I love a good Marshall, but there's something very special about a Hiwatt.

either this amp sounds amazing or your recording technique has improved or both. either way; frankly one of the best sounding amps yet!

Guitar does NOT get much BETTER than thru HIWATT! THE sound of the mighty SLADE! \m/

A DR103 was the first circuit I ever tried my hand at building for someone else. Got to watch it play its first show over this past weekend. Proud papa moment. Edit: I used a Sound City 120 Mk4 chassis and converted it.

do yourself a favor and crank that sucker with a bass and do your best John Entwistle impersonation!

Love the 100W DR103. Gosh I miss the days when these older amplifiers could be purchased on the cheap................

Jeg elsker Hiwatt. Jeg ejer et 4x12 kabinet, en ven ejer et hoved fra 1970'erne. Virkelig punchy. I love the sound Pete Townsend (The Who) was getting in the time when he was using these amps. Wish I could have seen them, I suspect it would have been overwhelmingly loud!

Hmm, let’s see, which vintage British amp to buy next? Haha! I’ve got a Marshall and Orange, so will the next be Vox, Laney, or *HIWATT*? Seriously, they are amazing. Got to play a 70’s DR103 once, and it was just a knockout, so much punch and clarity, without being a even bit shrill.

In 1979 I bought a Hiwatt SA 212/50 combo from a music store on 48th St. In NYC: 4-HOLE variant; point-to-point wired (signed inside by Harry Joyce...); Fanes; Partridge Trannies & a master volume that didn't really increase the "dirt" out of the preamp-needed to be really cranked (1 or 2 o'clock) before it STARTED to get (gloriously) gnarly; I sold it because I was a skinny 20-something and it clocked in at nearly 60 lbs. I'd give anything for a do-over...🙄

What a stellar sounding amp! What was so striking to me was how huge the Strat sounded in position 2 (?) and that Johan was playing riffs on the LP neck pick-up. You know you are onto a winner when an amp encourages you to play in new ways.

Pete Townshend with The Who was the greatest ambassador for Hiwatts, followed by David Gilmour with Pink Floyd and The Romantics. I believe the guitar player for Lover Boy used them as well and maybe even the band Blondie.

Please do a head to head of DR 103 vs. Music man HD 130(I own). I gotta know what I'm missing

Hi, Johan! Thank you for the explanation! I never tried Hiwatt, but with Tele and Strat its awesome! See you! S.

I really dig these recent recordings where you've ditched the reverb plugin and gone with a proper hall mic. Big improvement imo!

My first serious tube amp, a Hylight DR 201 with the matching correct cab, mine was "reworked by Fast Eddie" in Detroit, it was said that the amp was used/owned by the Romantics. My 4 channel 200 rig had the channels cascaded and I thought that was how all Hiwatts were, but I sold it in the mid 1990's and recently started buying them again, only to understand why so many call them "pedal platforms". But not my Biacrown DR 100, no pedals needed, it overdrives similarly to my modded 201. For me they are home. Does anyone know where my 201 is? It has 6 EL 34's. I have a 72 201 with KT's, wanna trade? I like my 72 but I'm still looking for my old 6 EL 34 Fast Eddie modded rig that I should have never sold. I believe it is still out there, and I believe it will find its way home.

Chimes like a bell! Love the sounds across the range!

I had a couple of 2 input DR103's back in the 1990's when you could get them for a song. Probably the most missed of my "never-should-have-sold" amps. Nice to hear that sound again. 👍

Hey Johan, I own both an early 70s 4holer as well as a late 70s 2holer and have them all over my channel to demo Pedals. Generally, yes, the 2holer has more gain but also a unique little peak in the mids and smoother highs compared to the 4holer. Might be just a super slight difference when playing the amp clean by itself but when stacking gain pedals in front it gets more noticeable. Thanks so much for your great content! :)

I can tell you one thing: the terms "2 holer" and 4 holer" were coined by yours truly on the old PlexiPalace message board back around 2000. Nobody referred to these amps in that manner before I did. Where's my royalty check Johan! :P -klyniss

Wow. Hiwwatt DR103 + Tele = Aural Bliss. Thank you Maestro!

I really believe I would give my Twin with JBLs and my Marshal 800 for this Amp

Sounds great! But....sympathy for that poor patch cable @3:46!

Appears to be a 1k shared cathode at V1 rather than 1.5k but otherwise everything appears to follow the late 70s two input pattern going by the MHuss schematic/layout. As for when when Hiwatt went PCB, Mark Huss would be the guy to ask.

Johan,have you A/B ed a Hiwatt Dr103 early 1970’s and the new 2021-2022 Hiwatt DR103 amps?

Doesn't Gilmour use the DR103?

That is such a dream amp Johan, I think it's used in my favourite album Hemispheres (among many other)

I have a 3 input Biarcrown DR103. Normal, bright and linked inputs. Only ever use linked because that's the first thing everyone does when they get a HiWatt - link the two inputs. It is a glorious sound indeed. What is perhaps more notable is how good they sound even when turned down "quiet". The clarity and detail is unmatched. Hard to believe that one of these 100W monsters can make a good home/bedroom amp but they do. Also good for causing structural damage and liquifying internal organs when called upon to do so but the clarity remains even when pushed.

More dynamic (as in less compressed) than a Marshall, and more neutral voiced (as in less mid-focused). Great amps, but a bit too prog for me.

By 1981 the Dr 103 had quite a bit more gain than the ealry 70s Dr 103s used by Page and Gilmour .

Man, if someone ever released a Johan Segeborn amp and cab sim/IR pack, I would be all over it.

Muscle Man Shoals Beefheart. Fatty sound. Led Paul's rule!! HiWatt used by The Who, Pink Floyd etc.

Hi Johan and listeners,,,have you heard of ROOST AMPS

Great playing Johan 🎉 Ronnie Wood got a great tone from his Strat through a Hiwatt working with Rod Stewart. 👍

Hey Johan, when are you going to do a review of the new Marshall Studio JTM ST20H?

Like you said, Muscular. That amp is incredible.

The 80's Hiwatts were notorious for overheating problems that would melt the solder joints. If they are all redone with more heat resistant solder they can last for years but no guarantee.

Do any modern affordable Hiwatt amps sound like this?

Not point to point but still easy to work on and nice looking circuit boards.

That amazing amp looks like brand new!

I had the 1x12 combo of that version from the late 70s-- weighed a ton. I actually didn't like the way the extra preamp tube added more gain and compression. The HiWatt tone stack is unusual. You can see how it adds versatility compared to other passive stacks if you download the Duncan Amps TSC 1.4 app. I've used it for many years with no issues. Try setting the Bass to 5.5 and the Treble to 1. Move the Middle between 5 and 10 and see how the midrange peak changes. Then, leave the Middle anywhere between 5 and 10, and move the Treble between 0 and 2 to completely change the Mid to Treble relationship. No other passive stack does that. Then, try it out on the amp.

I have the 1979 model. The bright channel offers the best clarity and punch. The normal channel is smother and fills the room more.

have this amp. Did the crossover distortion mod on the inputs and added two bias control knobs.

I really like this one. The recording sounds 1. punchy 2. it has picking dynamics 3. your chords ring out clearly. Does it feedback with any more gain?

Check out Mark Huss' great Hiwatt pages! I have a '76 4-hole (giggity!) with Fanes in a 4 x 12. Tonally this one really sounds the same other than the difference in speakers. It's probably not as noisy thanks to the PCB, and it seems like it's easier to get it to break up (I guess because of more gain). Linking the channels on mine in classic fashion definitely does the trick though. What a beast of an amp, pure rock n' roll, clear as a bell at stupid volume. It's really too much for me these days but it's so hard to let go of a piece of history. Great video as always Johan!

Add a mono y cable to that and blast both channels simultaneously. 😮‍💨

I have a -71 4-holer that I've used a lot for bass and also guitar. A bandmate 10 years ago had two 2-holers, so I had a good chance to compare. I think the "feel" might be what differs the most. The 2-holers, I found, felt more similar to my -67 Super bass in the way they compressed. They are "helping" you a bit more... The 4-holers are very unforgiving.. Every mistake, weak or sloppy note, are presented loud and clear..

Sounds really good. Are those 2 holers like the dr103 with very little breakup in the preamp and the only way to make it distort is to have it wide open? My old Hiwatt produces exactly 100w before breakup. That’s not funny.

I’ve got a DR103 from 1972! Love it so much✌️

What is it in it's circuit design that makes it unique?

Great stuff as usual Johan!

You make every thing sound good that's a problem when trying to be critical about sound:). What I know about Hiwatt comes from Steven Fryette his channel fryette amps is a greate sorce on vintage hiwatt. Watch his episode on Joe Baressis amp and Dave Friedmans Hiwatt amp mods. He states that Hiwatt needs Fanes and that marshall+fanes=bad and hiwatt+celestion=bad. He also helped Fane develop there new reissue speakers and talked about that on his show, and he is a funny guy for shure. You blending in the JBL probably made it much better. Another point Fryette made about the hiwatt circuit is that the later DR103 circuits had a horrible sounding clipping circuit that came from engineers trying in a bad way to produce a higher gain amp. His episodes about Hiwatt amps all centers around trying to fix this bad clipping circuit and revert it to his favorite hiwatt. How you set the amp made it sound good so I don't now maybe this is a good example of a hiwatt circuit or you set it up good. Thanks for great content!

FYI, these amps tone and dynamics can never be "modeled" or "profiled" so don't even think about it or believe it if you see it... I have come close by playing DI into a mixer or using 18volts in dirt pedals to increase headroom. But the amp modelers and profilers dont get it at all... I have had 2 hole and 4 input HIWATT dr-103s. To me the 2 inputs are just a little louder in gain section. Run all preamp tubes w/ 12ax7 even phase invert for 4 input models.

Would my Hiwatt dr103 work with 6" Eminence PA speakers 300 watts which is used in the Acoustic guitar amps such as the Heinrich? Thanks

Wow

Somebody once said, if you're lucky enough to own a vintage Hiwatt, you're lucky enough. Well. I own two. One 1980 two-hole DR-503, complete with NOS Mullards and a mid-70s DR-201 (4xKT88 version), with Mullards in the preamp. The 503 I've paired with a Simms-Watts 4x12 cab with original Fanes, and I've also have a cab with two of the fabled Crescendo 12A speakers. The 201 I play with Bass. It'll rip your ears right off. I'm not a fan of the Hiwatt/Celestion combo. I've tried it with both a 4x12 pre-Rola G12M/75Hz cab and a 2x12 pre-Rola G12H/55Hz cab. Both cabs sound awesome with my 1988 Marshall 2204. BTW, I also didn't like the Marshall/Fane combo.

Great review and tasty playing! Will you do a comparison video of a Marshall jtm45 2245 reissue and a Marshall studio jtm ST20H? Cheers!

Try and get an early 70's HiWatt speaker cab with purple backs.

I've got a CP504W and it's the most amazing amp I've ever played! It's basically a Townshend-spec Custom 50 in white w/ four bendable inputs. Yours sounds amazing too! Probably better than mine! Cheers!

What a great sounding amp!! Excellent stuff as usual, thanks Johan.

Top of the chassis looks very similar to a sound city, are those partridge transformers?

That Les Paul really sings with the Hiwatt

Unbelievable good Sound. Maybe the best I ever heard except Keith Richards tweed Twin.

I have an earlier biacrown dr103 and it looks identical on the outside

3:28 best sound- almost the crunch in great black crowes tunes.... diverse amp that is for sure.... though the tele sound is amazing every time too

this was the dark days of Hiwatt apparently , sounds good though

Great tones Johan! The LP is so thick and creamy! Yum! Nice one Johan.

Thank you, I am unfamiliar with these like yourself, now I got to play one! lol

Sounds gorgeous. I'm sure I heard some Live at Leeds in there....

I am sure the Who used Hi watt when they set the record for the loudest gig in the states

Agree with everyone else. This amp sounds glorious!

I would love to know what this amp would have cost in 1980-1981. I'm sure even then this would have been quite an investment. John you always have something cool and interesting for us my friend, thank you.

Fantastic sound!!!

Johan you should play the DR 103 through G12H30 55H speakers. Those are the speakers both Page and Alex lifeson used with their 100 watt Hiwatts . Lifeson also used Fane loaded Hiwatt cabs for awhile but he switched back and forth between using Marshall 1982 cabs and Fane cabs .

Loved the 78 DR103 I had for bass, grunt and early break up and better eq with a jazz bass than Ampeg. Practically though too loud for guitar imo unless yr playing stadiums.

Some contemporary players use old Hiwatts to get fantastic glassy grit and punch. Dmitri Coats from OFF! Duane Dennison from Jesus Lizard/Tomahawk

nice bass note riff on the tele near the end Johan, you should use it for something

If I had the money and space, this amp would be mine. With a Hiwatt cab, with Fane speakers, though.

that hallway mic makes it sound so much bigger with the natural reverb

That tele could conquer the world with this amp setup

I miss my old hiwatts, had a Custom 50 from the 70s and an early 80 Biacrown OL-103 Lead 100, that had resistors in the power supply catch on fire and it burned up the board, but it sounded nice until it blew up! When I built my dumble type amp, I built it with dual tone stacks like the HRM amps but put a Hiwatt style tone stacks in the second stage and 4x6CA7s, when you lift the first tone stack it's basically a DR103 with a master volume.

Never given Hiwatt much thought, but damn this sounds amazing.

That's very well designed and laid out PCB construction. You're not going to see any difference in reliability or tone between that and handwired.

The combo of a Tele with a DR-103 is like candy to my ears. Especially for the way Johan plays. Match made in heaven!

What were the settings on the pre-amp?

fantastic amp, Johan, great demo, thanks

That amp sounds so clear. A really thick and hi-fidelity kind of tone. Love it.

That amp (sound and playing) gave me goosebumps :D

Love the Tele & Strat tonez with this beast :D

Johan, do you know if the Custom 50 SA112 1x12 combo model is the same amp as a DR504? I think so. I am the owner of a 1977 SA112, amazing amp but I should use it with an attenuator to get all the magic it can offer. Without an attenuator, it’s OK but it’s missing the power amp clipping.

great video as usual. thanks so much!

Holy reverb.

Sounds great

Luscious