NAD on the way

[212Mavguy]

After picking up a 90's vintage Harry Joyce a while back, I developed a coveting of a 70's Hylight era Hiwatt with Partridge iron, the stuff of rock and roll legends. Not being a legendary quality player is just fine, playing through a finely tuned hand wired tube amp is inspiring enough in itself. The fingers refuse to stop until significant pain is encountered...

 

This one is less common and not understood well. Even though it's a PA amp, there are a couple of interesting things that make it the personal choice over the 4 holers. I already have one of those anyway. I am thinking that the echo in and out is another name for a simple serial effects loop. 4 holers of that vintage didn't have fx loops originally. Dumbulator circuits in the serial fx loop take the performance of the amp to a greater degree, a better method of volume control and increased harmonic content for the much quieter venues found today.

 

The other more obvious opportunity is six parallel preamps with individual tone stacks and volume controls. Some or all of those can be paralleled for the player's tonal tastes. Or several instruments on a stage rack can be left plugged in all at once to the same amp. Some players like the sound of a single gain stage as opposed to adding stages in parallel or cascading additional gain stages.

 

Finally, the line out is cool to go into the main board at a venue to get the signal straight from the rich sounding trannies to work with.

 

So here's the auction. It'll arrive in a week and a half. To say I got the screaming deal of the century is about right. 70's Hylight Hiwatt 4 holers regularly go for more than triple the ending price. This isn't one of those, but it most definitely will take no back seat to any of those in the tone department. The preamp tubes were described as all original, the power tube quad is basically unobtanium except for very fat wallets. The parts of this amp will sell for much more than the auction closing amount, but I am going to leave the amp intact. Some of the original Mustard caps were replaced, with new stuff, easy for me to source some NOS Mustards to restore to original type parts/tones.

 

http://www.ebay.com/itm/Hiwatt-DR112-ReCapped-Quad-NOS-EL34-Tubes-Excellent-/222578335415?ul_noapp=true&nma=true&si=am6FOFBavHTSc514rbqzpRjo6hM%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

[kennyv4]

Congratulations on being able to purchase what you have lusted after.

[212Mavguy]

Thanks. Just needed to react when the opportunity presented itself. What will be most interesting will be setup and operation both as a standalone, then as a master, and as a slave amp. There will be a lot more to explore than what appears initially. Gonna need to order some parts to build some unusual parallel input setups.

[smokedtires]

Cool amp, enjoy!

[212Mavguy]

Just got through unpacking and running it. Live at Leeds anyone??? WoooooooooHoooooo!

[tbonesullivan]

WOOWOO! That's some vintage awesomeness right there!

 

I've always wanted to find a Sunn Colliseum PA head so I can get that vintage Leslie West sound. I think maybe Hendrix used them for a while too.

[Genericmusic]

[pressure]

When I saw Jimi Hendrix in Chicago both he and Noel Redding we're playing thru 2 Sunn amps with 2 stacks, that's a total of 16 12" speakers and 2 heads for each of them! Mitch Mitchell was however in between them playing an unmiked drum kit.

[212Mavguy]

Thanks! I had been drooling over this type of Hiwatt for some time. My first big tube PA amp is a Fender 160PS vocal amp. It's a lot of fun to play through. But compared to the Hiwatt its preamps are noisier.

 

This 1974 vintage head runs as quietly as can be...like Dumble clone quiet. I have had more playing time accumulated and have really, really REALLY had a blast playing through it! The first thing I checked out was running the instrument into each input. Well, channel 5 was dead silent. I looked in to see whether I could wiggle the preamp tube, but a massive metal power tube shield is in the way. I'll have to yank the chassis to investigate, no biggie since if it's not a socket issue I can take pin voltage readings and find what to fix that way. That left five inputs working. It sounded like channels one and two each came from the same tube, three and four from another, and there was a third tube's unique palette out of six.

 

I grabbed an a/b/y switch and went to the next set of questions: could I get the smooth rich girthy lead tones territory? Would be cool to get tones that sounded David Gilmour-ish. I started off by using what I though were sensible volume and tone positions, straight up noon on channels three and four volume, treble, and bass. When I combined the channels by using that switch an increase in girth was readily apparent.

 

As I was playing the amp, I really enjoyed the way that the clean notes sounded. There was a nice reaction to touch. Harmonic content was full and rich. The notes seem to sustain more musically than with other amps, It is difficult to describe the big Hiwatt amp cleans with any words. My ears have not found any more pleasant than what Dave Reeves and Harry Joyce's works of art produce. However, there are a lot of high frequencies present, and they really pop during aggressive chord hits thanks to the Partridge Iron and rock solid power supply. There is a reason why Hiwatts have a rep for being both very bright and very loud...

 

Then I started cranking the gain knobs. Hiwatts are not known for having or being operated with huge amounts of gain. I found trouble, plenty of it when I cranked those gains way up with traditional tone knob settings. Whether playing through a single input or using the a/b/y box to play into two in parallel, the problem was that the distortion sounded crackly, and at an aggressive chord attack a loud crashing sound ensues, like in some of Pete's chords when he is playing aggressively in old recordings, you can hear that crash sound for a short time after the pick attack, most of the time for a small fraction of a second, but ti's most definitely there. So now I know how to get authentic tone...great. Now how do I solve that and get the breakup to sound more like my Harry Joyce Custom 30? I know that amp's dirty tones are gorgeous, and I can hear that in the decay of the Hiwatt once the bad attack sounds die out.

 

So I started to treat this PA amp with two channels going more like what I do with my Harry Joyce. It's a four holer like most Hiwatts, normal and bright inputs, higher and lower impedance holes for each input. I set about creating a similar situation with the Hiwatt, I used the tone knobs to artificially create a normal and bright channel. In earlier experiments to get a Gilmour-ish singing lead tone I had found the best results by having the gain in the normal channel a good amount more than the bright, like a quarter knob turn difference. The bright channel's relatively cleanliness covers the grunge up, and the extra gain from the normal channel enhances sustain and harmonic bloom. So I started messing around with the tone controls. in channel 3 after a lot of listening and comparing I set the bass nearly maxed, and the treble nearly off. The other channel had been set with the bass at noon and the treble to 1:00. In most amps, a high bass setting is a harmonic killer. So be it, so what? I have another half of a tube to run the other, bright channel for the harmonic detail, there would be no loss when adding them together. And that's exactly how it worked out. It was smoother now, and nicer sounding in the sustain, but still things needed smoothing out more at the attack. Everything was there from a nice big bottom all the way up to the pixie dust on top, 3D tones for sure!

 

I had been thinking that maybe the high preamp gain and the low master volume might not be helping that situation. Soooo...I added a bit of Dumble tech...Ceriatone's c-lator was placed in the echo in/out sockets, which was another name for a serial effects loop. This was the "big" experiment. To my knowledge I'm the first person to stick a C-lator into a Hiwatt PA head FWIW.

 

This ability of this particular amp model, having a serial effects loop is definitely the most important feature I was looking at in choosing this PA head over the 4 holers. Could using a C-lator in the Hiwatt's loop offer the same benefits as when using one in a Dumble circuit? I had spent some serious coin to find out...I anticipated that the c-lator in the loop would solve the "HIwatt loud" volume control issues handily, what I did not count on was how while using it all of the horrible distortion sounds at attack went completely away and I was left with the choice from richly gorgeous filth to pristine cleans. The c-lator allowed me to set the master volume at noon instead of 8:00. The output of the C-lator dropped what would have been an injurious volume amount down to small room gigging levels and the nasty noises at attack WERE COMPLETELY GONE!!!!!!! So now I had this incredible medium gain singing tone, so I dialed the gains back into the clean zones for both channels. I was STILL getting a wonderful, singing sustain with CLEANS.and the top end which was easy to have way too bright had mellowed to just about perfect. The C-lator circuit as well as extra cable length capacitance added some high cut to the tones. While all this was going on, I was playing through a TC Nova multi-effects pedal in the loop. When I added the C-lator, I ran the C-lator into the amp loop and ran the Nova in and out of the C-lator's circuit now effectively embedded into the Hiwatt. Now I had high gain tones with delay and reverb that sounded sweet instead of the ragged decay from shoving time based effects into the front end of a highly distorting amp. All of the effects came through gorgeously.

 

I doubt other non loop equipped Hiwatt players can get these tones at all. I also doubt their abilities to operate at practical gig volumes as well as self-indulgently, deafeningly loud. And I have only combined two of the six pre channels...so there is a lot more tonal ground to cover.

 

Might have to plug that Heritage bass into it...

 

Before I yank the chassis out and fix channel 5. There's likely more to come, this is just from the first day playing through it.

[bolero]

congrats!!

 

 

I had a chance to buy one of those approx 10 years ago for $300 or so

 

 

should have!!

 

oh well

 

 

enjoy the amp!

[212Mavguy]

Keep yer eyes peeled, sir. The PA heads are the least expensive, yet possibly the most capable and versatile of the Hiwatt builds. I probably paid not a lot more than what you passed on back then given the value of a dollar at that time. The quad of NOS-ish RFT el34 cost the seller almost half of what the auction ended at. Including shipping, I paid less for this Hiwatt than the suggested retail for today's Chinese Fender Deluxe Reverb in a music store.

 

Something that is and has been going on in the amp building world underground is folks buying old Sound City amps for the chassis and Partridge Iron and then going to sources like Mark Huss' Hiwatt Pages online to get the Hiwatt model schematics and gutshots, then cloning those later, more refined Hiwatt circuits into the gutted Sound City heads with the Partridge Iron. When completed correctly the results are spectacular.

 

Further playing through the Hiwatt caused another experiment. These amps have always been well known as great pedal platforms. I have stuck my pedals in front of as well as different styles of effects loops in various amps of mine in the past. I was not prepared for how the Hiwatt interprets those effects. They sound realy, really attractive to the ears!

 

I did a dry/wet two amp setup with that Hiwatt and a 50w clone of Robben Ford's Dumble #102. Both amps have serial effects loops. 102 has clean and dirty channels with channel select and preamp boost switches on a control pedal. I used the Hiwatt as a dry amp, sent the signal from the Hiwatt's slave out to the D-clone's instrument input, then ran the effects pedals in that amp's loop. I ran my Hilton volume pedal into the front of the Hiwatt. Usually I run that pedal in the loop, but wish for similar volumes from both amps while playing louder or softer dictated sticking it in front of the dry amp.

 

So now the amalgam of tones was the equivalent of stepping up to an a mythical soda fountain with 45 year old mixers offering hundreds of different milkshake flavors crafted from home made ice creams. That sweet... The D-clone has a great master that works well at practical volumes, the c-lator takes care of the need to control the Hiwatt's volume output at the same time. And as is the case with using a Dumbulator type of tube effects loop buffer in a traditional solo amp setup, the overall rig volume is handles by a single knob on the C-lator, retaining the balance between both amps as volume rises and falls. Schweet!

[212Mavguy]

The honeymoon continues...There was a major hiccup this morning...This Hiwatt head had a fair amount of work done right before I bought it, the seller played it only a half hour after picking it up from the tech before putting it up for sale. When I took it out of the box, channel five did not pass signal. All the others worked fine. The project of the day was supposed to be running the guitar into four of the six channels in parallel. When I fired up the amp this morning channels one and two were dead now. Half the channels 86'ed. No good. So took the chassis out of the headshell, hooked it up to a cab, powered it up and started off by pulling the preamp tube shields. The selller had said that he thought that all the preamp tubes were original. Well, they turned out to be a sextet of Shuguangs. Oh well. I yanked them.. Subbed in a sextet of vintage mostly 12ax7 glass salad. I looked at all the wiring inside, and came up with a suspect for the phase inverter. After putting in the other tubes, I placed a 12ax7 in that position and played to a certain volume. To verify I ran a 12at7 for a few minutes. Sure enough, my hunch proved out. Then I started looking at heater filaments in all the pre tubes, I was thinking that maybe the heaters were out on v1 and that would explain both dead channels...Sure enough, my suspicions were confirmed. V1 was cold.

 

While looking at the sockets I noticed some recent soldering...on v1 and v2 I found what looked like cracked or cold solder joints on the heater pins, courtesy of the tech. I reflowed with a 40 watt pencil, pretty hot but quick to the touch. After reattaching the power cord I hit the mains switch...le voila ici! V1 is a go, that took care of dead channels one and two. Yanked the power cord again and started on the other dead one. Channel five turned out to be a couple cold solder joints, I noticed a couple resistor bodies lightly touching a ground bus wire, I adjusted the lead dress. Still no go. I started wiggling wires and found another funky solder joint. The Iron was hot, a couple seconds later it turned out that was the fix needed.

 

With all six channels now functional, I filled up the preamp with the first three tubes all different makes, an Amperex globe print Mullard Blackburn went into v1, an RFT went into v2, and a Siemens E83cc went into V3, the phase inverter in v4 was rolled, and a nearly new GE green print 5751 was chosen from the candidates. Buttoned everything back up and did some four channels in parallel stuff, experimented quite a bit with multiple gain and tone settings. The tones were amazing, could get plenty of grind or some of the most sparkling gorgeous, dynamic cleans I have ever heard. Sounds easy? Nope, I'm not that smart at all. Took my all day to figure out what was wrong and how to fix it, no schematic, and luckily found all the faults without breaking out the multimeter. When wiggling the stuff, I looked for things moving at the solder joints. In channel 5,there were two bad solder joints from that tech again...a quick touch with a hot iron tip fixed all.

[t0aj15]

It sounds to me like that tech should find another line of work.

[212Mavguy]

Actually this tech did a very clean looking job. All of the solder jonts were neat, no excess solder. Probably close to 15 vintage tone caps were yanked and replaced at the same time as all of the massive filter caps as well as all of the cathode bypass caps in the preamp. The volume of work performed on this amp before I got it was significant. There are a lot more parts in a PA head than a typical Hiwatt. There are 20 pots on this thing. It will be pretty expensive to source the original parts, the replacements were well chosen tonewise. I think that actually he was pretty meticulous to find that many leaky tone caps in the first place!

 

But the root cause was his soldering iron that was too low in wattage to properly heat the work.

 

When I was a young teen racing slot cars I did a lot of soldering on brass tubing as well as rewinding Mabuchi can motor armatures for more speed than stock. My iron was a Weller 25 watt pencil. I still have one of those. But I like their 40 watt unit more, it runs hotter and is almost as easy to get into tight spaces. Plus, the 40 watter comes with two different tips, one with a small end and one with a fat one... but each tip is made of a way more massive chunk of metal than found in the 25 watt unit. If they put a tip that big in the smaller iron it would take too long to heat up.. The fatter one is capable of doing chassis grounding solder joints very well, the massive tip ensures a lot of heat storage for dissipating into the work. It also has small lights that let the operator know that it is plugged in.

[bolero]

wow, you seem to be truly using your gear to it's fullest potential!!

 

always enjoy reading these gearhead adventures. thx for posting

 

ps I still have a bunch of slot cars. 24th, 32nd, and HO scale. haven't raced them in years, but my brother still builds 32 & 24 scale model kits, details thm like crazy, and races them with a bunch of other guys who all have huge tracks. very cool. he solders brass tubing & plates for the chassis, like the old days

[212Mavguy]

Haah. then I'm sure he has a Pittman 85 stashed around somewhere in the motor collection...

[DetroitBlues]

Sounds like you're ready to open your own repair shop. That's a lot of hunches most of us would never have attempted or known where to look.

[212Mavguy]

I wish...not.  My work speed is too slow.  Am way too picky about parts selection.  Takes too long to get some of the point to point connections mechanically crimped properly tight before soldering... I'd go broke.

Case in point:  I got into the guts of the Hiiwatt again today for a bias check, some more reflowing of suspicious looking solder joints, an inventory of what original tone caps had been replaced, and a lot more tube rolling.  The 5751 I put in the PI was a tad noisy.  It took all day, but it is finished and sounds absolutely glorious.   

The crashing sound I heard at mid gain pick attack and the horribly crackling distortion at higher gains during the time playing before now turned out to be crossover distortion from the power tubes being biased waaay too cold, around 35-40% instead of 55-65%.  In addition, matching was slightly off on one side.  After measuring 500 volts on the plates, I decided to go for a 65% setting.  At that higher setting, I swapped two tubes so that the el34 plate current going to  the OT primaries was as closely balanced between the sides as possible, less than 3 ma difference between the two pairs when finished.  Then rolled some tubes, yanked the Siemens e83cc in v3 for channels 5 and 6, stuck in a very rare old British Tungsram build with an incredible, sweet sound,  then found a late 50's Mullard long plate 12ax7 with very strong and tightly matched sections for the PI.  I rolled 5 different vintage tubes for that spot alone, listening to each twice for ten minutes apiece to allow for full warmup. The  gloriously, breathtaking results from times long gone were worth it!!  But it took all day to get there, no way I could charge for all those hours on the bench.   

Then I let Poirot out for a look with the magnifying glass to see what the story was with all the tone cap replacements.  That amp got harvested of fourteen treble caps, some of the most difficult to locate high dollar ones.  The replacements sound fine, but they ain't the mama and are worth maybe a fifth to a tenth of the replacement costs of NOS Mullard Mustard originals.  That's another way that a tech can make money working on amps...grrrrrr.  Lots of pots, resistors, and tone caps in a tube PA amp, way more than a guitar amp.