Bringing the glory out of a Biacrown Era Hiwatt Custom 50

I recently picked up a Biacrown Era Hiwatt Custom 50 and set about fixing it up (it has a factory quality check sticker dated 8/24/1984). I replaced the electrolytic caps per my normal practice with amps over 20 years old. The Biacrown era refers to about a year after Dave Reeves, owner of Hiwatt, died. Folks were taking existing stock, and whatever they could cobble together or buy, and getting it out the door. While these amps are considered ‘real’ Hiwatts, part of the official cannon, they don’t have the collector value of late 60s, early 70s, Hiwatts that Jimmy Page or Pete Townsend played in the golden age of hard rock.

They were sold under the company name of “Hiwatt Biacrown Limited’. After a year, Biacrown went under, and various pretenders began making ‘Hiwatts’ in a sordid tale of poor quality imitations and trademark violation. Under Dave Reeves, Hiwatt used premium parts and were considered a step above the ubiquitous Marshalls in terms of quality. Not the least of these parts were the expensive Partridge brand transformers.

An amp tech who looked at the amp noted it was both noisy, in terms of 60 cycle hum, and broke up pretty early in a marshally fashion. The ‘Hiwatt’ sound is an amp putting out tons of clean, and when it finally does break up at full volume, you get the sort of growl you can hear in the first few seconds of Magic Bus from Live at Leeds.

At first I thought some sort of JCM 800 sounding Hiwatt might be nice, but I did miss the huge clean sound I got from a 70s Hiwatt I used to own and foolishly let go of. First thing, I noted that the preamp circuit had a high gain mod. I decided to restore the circuit to a lower gain circuit from the late 70s. When removing the mod, I could see, due to some circuit board traces having no solder, that the mod was installed at the factory, though the ‘OL’ designation that went with that circuit was not on the model plate.

With the mod removed the 60 cycle hum was lowered, and it did have a bit more headroom before it broke up. I still thought it sounded marshally and broke up too soon.

I tried selling the amp on Craigslist, advertising it as a dead stock Hiwatt. Seeing no interest in the unit, I got to thinking about upgrading the output transformer. This amp did not have Partridge transformers in it, but rather some of unknown origin. There is a company, Mercury Magnetics that builds premium guitar amp transformers. They got my notice some years earlier when I heard an amazing sounding class A amp that had a ‘Mercury Upgrade Kit’ installed. So, I gave them a call and told Patrick there that I was interested in getting the clean and headroom into my Biacrown. Patrick recalled that a Mercury customer had just had a hiwatt/mercury transformer shootout and one model stood above the rest in terms of headroom. I ordered one for $265 in red, and decided I would make this Hiwatt part of my permanent collection.

I got the transformer Friday and had a chance to install it today. The only delicate part of that process is that the amp has negative feedback from the output of the transformer to the driver circuitry. Two wires to to the plates of the two power tubes, and if hooked up the wrong way, the amp can feed back and destroy itself. I powered the unit up, ready to shut it off if it showed signs of feedback, but I guessed correctly and there was no further drama. While I expected some improvement in headroom, I was amazed at the transformation, so to speak, of the amp. In addition to lots of large clean, for reasons I can only speculate about, it cleaned up the 60 cycle hum to the point that I was not sure the amp was working until I plugged a guitar into it.

So, very pleased with the outcome, I left the amp on for a few hours just to make sure all was well electrically. When I checked it, I noticed that the power transformer was too hot to touch even though the amp had not been putting out any signal. A current check showed it as consuming 77 watts. I added up all of the power usage inside the amp and could only find 57 watts of power usage. Power transformers are normally very efficient, so the extra 20 watts seemed odd. An internet search revealed no good guidelines for determining whether a transformer is too hot or not. I did get a suggestion to try unplugging the tubes and seeing if it still got hot–perhaps then being a problem with the filter caps.

Well, I did that, and even disconnected the filter caps from the amp, and it still drew 45 watts just sitting there. I started thinking about the power transformer as damaged by previous abuse, and perhaps the output transformer was as well. While I can understand the scientific basis for a premium quality output transformer, passing the sound as it does, I am not quite there regarding power transformers, and rather than get another $265 transformer from Mercury, I ordered a Hammond 290GX, recommended by Hiwatt expert Mark Huss, for $108. So, in another 5 days or so, I will see how it sounds with a new power tranny.

5/27/2013–There was an error in my credit card number and the Hammond set at Mouser for a bit until we cured it. The woman there corrected my pronunciation–it is pronounced ‘mauzer’ like the german gun.

Got the new power tran installed. Lots of stuff had to be taken out of the amp to re-lay the wiring, but all went well. Had a bit of a scare. I got the primary wired up and went to measure the voltage on the output with my Fluke bench meter. The fuse blows, and then I blow another one. Really bumming, and then I realized I had the fluke test leads plugged into the ammeter and was shorting the output winding. The dc resistances of the tran are as specified, so don’t think I burned it out.

I also replace the rectifiers with uf4007–a diode that doesn’t ring quite as much when transitioning–they are only like 50 cents apiece. Amp is up and running. Sounds the same as before, with all the mercury magnetic output tran tonal improvement. The power tran runs warm, not hot like the old one did. It draws 70 watts at idle. I still can’t believe that the 60 cycle hum in this is so low that I have to turn the master almost all the way up just to hear that it is in fact hooked up. Its got a lot of clean, but it does break up when really pushed. I like the early breakup growl, but when I turn the gain up even more, it loses that agressive tone that I like. This is one for the books–took an undesirable amp and turned it into a keeper.

Well, on to the next project: Putting uf4007 diodes in and some better hardware in my jtm 100 clone. I don’t expect a tone change, just getting it tip top. It has some nos plastic diodes in it now that I don’t completely trust.

Passing the Bar Exam

One Saturday morning in perhaps April or May of 1986, I walked down the stairs from my apartment to the foyer that contained the mailboxes. The sun shone brightly, belying the bitter spring cold outside. Pulling out my mail, I noticed the return address entitled  Minnesota Board of Law Examiners. My hands started shaking, and I began gulping air in deep breaths. I tore open the letter and my eyes looked for the first sentence. I saw the words “We are pleased…” YES! I had passed the Minnesota Bar Exam.

I wasn’t expecting the letter until Monday, and it struck me that the Board of Law Examiners, in an act of mercy, had saved about 300 of us from a sleepless Sunday night by sending the notifications a day early. It was a bittersweet moment, nonetheless. Since I had decided some time ago that I would not actually practice law, it represented the end of three intense years that, to paraphrase Jimmy Breslin, I loved and hated in equal measure: My legal education.

About the Bar Exam: It was a two day examination that was required of those holding Juris Doctor degrees prior to receiving a license to practice law. The first day was an 8 hour session of multiple choice questions called the Multi-State exam, as it was used by several states. The second day was 8 hours of essay questions–my last adventure with a stack of blank blue books, blurry eyes, cramped hands, and a pen–which had been such an important part of the last three years. Or maybe it was a half day of multi state and half day of essay both days–I can’t remember. We law students thought we were pretty tough with a two day exam. Now the CPAs had a three day exam, but we heard it was divided into subjects, and they could re-take simply those subjects they failed. For us it was all or nothing.

Now many of us wondered why, after three years of legal education and holding a Juris Doctor degree, we needed yet another exam. One of the reasons was that in law school we were taught the principles of law, not the specifics of Minnesota law. After all, there were 50 state forums and one federal one, all with their own laws. And in fact, many of my classmates did return to Wisconsin to practice law and presumably continue proving their oft-stated assertion that they could out-drink any of us from Minnesota!

In any case, when faced with this question in my presence, one of our professors, in a stern and aristocratic tone, informed us that “law school is not a Trade School!”  And to think we were presumptuous enough to sully our righteous quest by concerning ourselves with trivial matters such as earning the filthy lucre…

Due to the high stakes involved in the bar exam, there was a cottage industry of companies that prepared Minnesota bar exam study materials and presented a week or two of evening lectures. BRI (Bar Review Incorporated) was quite prominent, and I ponied up my $450 for their program.

During my first BRI lectures, I noticed students entering the wonderful College of St. Thomas lecture hall just after the lights went down and the lecture started. Somebody explained that they had failed the November Bar and were engaged in a futile and embarrassing effort to conceal that fact. My view was that there is no shame in failing (at least the first time), and it was best to belly up to the group, confess your sins, and enjoy the company of your friends during the lectures.

During this generally unremarkable course of study, I unexpectedly gained full comprehension of the law of Commercial Paper–a frustrating class for me in law school. This was the law of negotiable instruments such as checks, and was as worthless and obscure an area of law for 99% of lawyers as I could imagine. I heard that it is no longer a bar exam subject.

The other thing I recall was that the Evidence lecturer, a rock-climbing, caffeine free, law professor from Utah explaining the ‘Best Evidence’ rule. He explained that it meant “One must present the original document in court…” Then he leapt on a table jumping and shouting “UNLESS!, UNLESS!, UNLESS!.” And quietly concluded: “…you can’t find the original document.”

On the morning of February 25, 1987, I entered a cement floored auditorium somewhere in downtown St. Paul, showed my driver’s license, was designated Examinee 00122, and was given an assigned seat at one of the long tables that seated the perhaps 300 of us who were taking what was known as the February Bar.

It was a smaller group than the one given in the Fall (I will call that the November Bar, but I can’t remember the exact month) which most law students took immediately upon graduation. I gave myself a few months off, since I knew I wasn’t going to practice law. Another feature of the February Bar was that it contained those classmates of mine who had failed the November Bar.

The exam was carefully proctored, that is closely monitored to prevent cheating. The rules were explained to us: If you needed more blue books or writing instrument, raise your hand and a proctor will attend to you. If you want to go to the bathroom, raise your hand and a proctor would note your request. Once your turn came up, they would scan the bathroom for stray copies of Blackstone’s Commentaries or the like, and once inspected, give the all clear. For obvious reasons, they didn’t want two people in the bathroom at the same time, sharing their knowledge, or passing each other notes hidden in the stalls.

The proctors put the tests before us, instructing us not to break the seal and read them until they gave the signal. With a “You may open your examinations…” it began. Now I had plenty of 4 hour exams in Law School, so 8 hours didn’t seem inconceivable to complete, but it did make me nervous.

The only thing I remember of interest during the exam itself was that during the Con Law (constitutional) essay question, we were given perhaps an hour. I got about 45 minutes into it and decided my analysis was wrong, and that I had a better one. I began crossing out pages in my blue books, and the woman seated across from me noted this with a surprised glance before she resumed her frantic scribbling. I completed my revised analysis in the remaining 15 minutes.

For lunch, a couple of my classmates, who had failed the November Bar, and I dined at a nearby McDonalds. Against the most strongly expressed wisdom of our bar review instructors, we discussed our analyses of the essay questions and multi state questions. The three of us had three entirely different approaches to the con law question.

Those of us who had passed the February Bar were invited to a swearing in ceremony a few weeks later in that same auditorium. Entering the auditorium for the second time, I was pleased to see my two friends who had failed the November Bar and had entirely different analyses of the con law question my own. I remarked “Certainly a lot more pleasant circumstances than the last time we were here.” I also saw the woman who sat across from me while I re-did my own con law essay.