The Disposable Amp

I get quite a few questions that usually take the form of something below:

Why would I buy a Headstrong over a re-issue or hand-wired version?

What is the difference between your amp and “Company X”?

Over the years I have made it a policy to not talk bad about any amp company, regardless of what quality they put out or level of service they may or may not provide. I also do not compare my work any other company other than the one I am trying to emulate, mid 50’s-Mid 60’s era Fender amplifiers, that is the bar!

But if pressed for an answer, one of the main differences, is that the amps I make are built to last a lifetime and if you decide to come back and buy another amp from me, it is because you loved the last one so much and want another or you need something else I build to fill a gap in your amp line and you appreciate the level of customer service I provide.

NOT because of this:

Maybe it is the 5th or 6th time to the repair shop one year and you have to make a decision on to pour more money into the same problems, or in most cases, just buy another. I call this the disposable amp model. That is what MANY companies do, more common on the import and mass production level, but also in some other boutique type models as well. I am sure you are familiar with Fender’s re-issue lines and the Hot Rod line, or the Pro Jr. line. These amps, when dialed in can sound really nice and there is a reason most guys request them for back line set ups when on the road without band gear…You can dial in a sound that “works” for the gig, you know what you’re getting, and they do provide the essence of that vintage tone.

The real problems fall to the owners and come in the form consistency, reliability, and long term life span. This is probably not a mistake or oversight, this is a business model. You will inevitably go right back to that amp on the same sales floor multiple times over the life of your guitar playing career…You know the amp, it sounds pretty good, you know how to get your sound out of it…And you dumped a bunch of money into the last one, so really that’s all you either want to or can afford spending on “another” amp. My Dad used to tell me, “pay me now or pay me later” is how life works. You can spend it all on something of quality, or you can buy something decent that probably won't last and you will be spending the same amount (or more) than just buying the one built right the first time. This is not exclusive to amps or gear…I have found this with everyday purchases as well. Just buy the right tool for the job at the requisite quality level to get the job done!

If you have read my other blogs, you know that I am not trying to sell you an amp, but rather, build you an amp you want or need. After we have established that I build something you can use. I am stating the above so that if you are in a position to buy quality over quantity, this is something to seriously consider. Some of us are in no position to spend the money on a new $2000-$4000 dollar hand-wired blah blah blah…And for you, the Re-issue or similar is a KILLER way to go! If you get a good one, they are actually damn nice! I worked with a backline company near Greensboro NC that had all the familiar characters set up on stage, but the speakers in the Re-issue’s had been changed to AlNico Weber’s! The guy playing it was a monster so that helped, but the guys working for the backline company said the owner buys the amps and sends them all to his tech to go through them and upgrade the speakers and tubes….It made a noticeable difference to my ears!

So there are ways to make marked improvements…If you don’t want to learn how to do basic (and a bit more in most cases) maintenance on these amps, make sure you develop a friendly relationship with a tech in your area…They are not always adversarial…In fact, you may want to consider them your lifeline to decent reliable tone…This may improve the dynamic between you and your tech. Regardless of what you buy at this level of quality, just remember that the idea is to get you to buy several of these over the life span of your hobby, or career! This is obviously a viable way to go based on the fact that most people go this route!

I am positive that $4000 Custom Shop guitar with the $1000 pedal board and high end cables will sound great through that $1500 Re-issue…

The other option is to buy something on the higher end market…First figure out what it is you need: wattage, speakers (size and number), what gigs you need it for and more importantly, don’t need it for. Also, do you need just one amp? Is that even possible for one amp to do all of that. My belief is the one amp that sounds like many is a bit of a “jack of all trades, master of none” situation. I will save that for another blog…It is important to know what you can afford, but also what you actually need for your gig. There is the element of what you deserve as well, that gig could be sitting in your music room alone, or with some friends, if you work hard and have the means, you probably deserve to treat yourself! Also this may be for relaxation and fun…It is not very fun taking your not that old “disposable amp” to the tech again!

It is all something to think about and if at some point you call me to ask about a build or just some advice in general, you can rest assured, I will do what I can to get you what you need or point you in the best direction if it is not something I build!

Hope this made some sense and thanks again for reading!

Wayne

1977 Princeton Reverb Repair Part 2

Part 2

The missing bypass cap may have been intentional. The work was not subpar, it may have been a “fix” for the washed out reverb that happens on Fender amps above 4, generally speaking. I had never thought of that one, so there again, someone knew what they were doing, electronically speaking. I brought the entire pre amp section of the amp back to vintage specs.

I then moved on to the power supply cap which was in proper working order, so on to the power and rectifier tubes:

The Rectifier tube was an old Chinese made tube, that honestly, I was shocked it still functioned…The power tubes were generic Russian made and were WAY out of range from each other, like one was reading 28mA and the other was over 50mA…This would explain the “after it is on for an hour, it loses power and dynamics” issue. Fortunately, I had just received a new order of TAD 6V6 tubes…a box of 50, all matched within 3mA! The new Red Base TAD products are really impressive…The quality control going on over there is top shelf, and the tones are very vintage to my ears. Once those new tube were installed, everything came back to life on the old ’77.

Most of the pre amp tubes were older Sovtek short plates tubes, not the best tones I’ve heard from a new pre amp, but very reliable and they all tested good and were quiet, so no changes there. The fiberboard was warped (they all are basically) and had a big hump in it and only one screw “holding” it in the chassis, so I added a screw and locking nut to the other end of the board to secure it better.

After some de-oxit on the jacks and tube sockets, I hit all the pots with lubricant to assure a nice quiet sweep in those. She was just about ready to fire up, but I always use my current limiter to fire amps up, new, used or recently repaired, just in case there is an issue, it is at half voltage. This is also how I “form” the caps of a new amp, bringing up the voltage slowly so as not to hit a new unloaded cap with 400VDC right off the bat. All checked out in that department as well!

Once at full voltage, I checked the bias…I had swapped out the resistor in the bias supply as the old PR’s did not come with a Bias adjustment pot. This is one small change I made with the Lil King Amp, added a bias pot so it is much easier to dial in where you want to be on current, while not changing the tone or dynamics of the original design. Having noticed the current and DC voltage was so much higher on this amp when I fired it up originally, I changed the bias supply resistor from what is usually a 22k resistor to a 27k…I knew that the bias would be way too hot with a 22k. I was also hoping the DC voltage would come down a tad as well with the new rectifier, and it did. It was originally reading 440 VDC, which is what Deluxe Reverb amps usually read, whereas a Princeton Reverb is usually in the 400-425 VDC range. Bias is always a sticky talking point for many techs. If you go by the old manuals a set of 6V6 tubes in this amp should be set in the low 20’s…I prefer the upper 20’s and closer to 30mA per tube. This amp was pulling 32mA per tube at 420 volts so the change of the bias resistor and rectifier tube helped! Definitely on the hot side of things, but these TAD tubes can take a beating, almost the same way a JJ can. The JJ tubes are like tanks and you can basically run them at 440 VDC with few issues…I would say the TAD tubes are close to that, minus the filament rattle. I love the JJ tubes, but they rattle pretty badly on low notes. I use dampening rings to help with this on the JJ GZ34 rectifier I used. The TAD 6V6 were dead quiet and no rattle at all. I burned in the amp on the bench for a solid 24 hours to assure all was stable. When I do this, I will randomly plug in a guitar throughout the day to test the amp a few times, I also measured voltage and current several times.

The next day when I sat down at the bench, I found the amp to be set exactly where it was the evening before! All was ready to load back into the cabinet.

A word about these late 70’s Fender amps…the cabs are not great! In the old days you had the baffles made from higher quality plywood and you could remove them aka “floating baffles” These later versions still had pine shells in most cases, but the baffles and back panels where made from plain old particle board and the grill cloth was mounted on a thin frame and held to the baffled by Velcro. NOT my favorite design, but it works. They are also heavier…And honestly, a little stiff as the baffle doesn’t seem to have the same throw as an older plywood baffle. We use void free baltic birch for the Lil King and all other cabinets, in the period correct floating baffle style. To me this is a BIG part of the old tones, cab size and material plays a big role in the tone of an amp, and the weight!

Once I loaded it all in, I had a chance to try the amp out next to a recently completed Lil King with the stock 12” Alessandro Eminence speaker I use. I ran a speaker cable to both amps so I could run the ’77 into the Lil King’s speaker and the LK into the ’77’s vintage 10” speaker. I put some video below for you to discern the differences. I am pleased with how the LK sounded and very pleased with how much better the ’77 sounded.

This is NOT a competition, tone to me, is as subjective as looking at a painting or a sunset. It is what speaks to you as a player or listener. To my ears the PR is a little bright for my taste, but to others, that is what they love about a Silver-face! What do you think?

I met the customer to drop off the amp, and this rare repair job was complete! All reports back are that the amp sounded better than he had heard it and it was ready for some work on a new PBS soundtrack!

Thanks for reading this and please tell your friends about the blog if you think this will be of interest!

Wayne

The 1977 Princeton Reverb Repair Part 1

Part 1

A couple weeks back a local customer emailed me regarding a Lil King S he had acquired on the used market in the Asheville area. It was an easy fix, but it had a changed cab and a few other things done to it. NO matter, I got that thing fixed right up for his next session! I will cover that one in a future post. He mentioned that he had a 1977 Princeton Reverb that had been acting up and when I met him to pick up his S he brought the PR with, so I could have a look. I was hoping from the description, it would be an easy tube swap or solder joint touch up, “Sounds great for an hour then drops volume and or reverb fades”, you know, boilerplate, my old amp isn’t working right stuff.

I don’t normally do repairs, but if it is a vintage Fender, especially a Princeton Reverb (PR), I will do the work…mainly because I have all the parts on hand to build a new one, so a repair is usually pretty straight forward. Also, I love to hear the old ones as they are usually all a bit different. Some of this is obviously based on the work that has been done to them over the decades, and also, the production process back then was not the most consistent, supplies could change, multiple people building the amps, etc.

I was also thinking I could test this amp out against Lil King (LK) #700 that I had just finished up for Deke Dickerson. Once I got it in the shop, I turned it on to burn it in and see if I could replicate the issues. Sometimes these intermittent issues can be the hardest things to track down. I’d rather have an amp that won’t turn on or has a smoked resistor…Intermittent usually means you’ll hear something along the lines of “it’s working fine here on my bench” back from your amp guy…Then maybe a bench fee, and you take it home, with a emotional cocktail of hope and skepticism…To turn that damn thing on, and then almost immediately, it does the thing again!!!

Back to the tech, repeat and so on…it is NO fun for anyone involved. I know what both sides feel like…in my other posts I have referenced this, take it to a tech and not know what it will sound like when it comes back…Even when it is just some new tubes…it’s agonizing as a player…and as a consumer!

I, of course didn’t hear any of the volume drop or cutting in and out. Jacks seemed fine, tubes seemed fine…I had not even opened the amp up yet, just plugged in and listened. I always try to approach it as a player first…Play the thing and LISTEN. Well I a/b’d it briefly with #700, using a long speaker cable from my bench, I plugged the LK into the PR cab with the (seemingly) original 10” speaker as well as into the bench LK Cab that has a well broken in Alessandro GA-SC64 speaker. First thing I noticed…man the PR was really bright and edgy on the top end and upper-mids…through both speakers. The reverb was also way off…cranked to 6 it wasn’t as present as the LK on 3…There was definitely something off. The LK was way warmer and more responsive…I am confident in the job I do replicating these old Fender’s and that the 70s ones are generally considered “close” to “ok but a little bright” but this was a ways off…This was not a fair way to compare…and Deke was ready for his amp. I decided the a/b test at least in terms of playing would need to wait so I could inspect the 77 and ship Lil King #700 out west.

Opening up the chassis really filled me in on what was going on

There was obvious work done inside, some good, some not so good, the reverb issue was because someone omitted the bypass cap on the reverb driver tube (v2 12AT7)…this was why it didn’t have the lush wash out of a normal Fender reverb. Also, there were quite a few metal film resistors (very stable voltage wise) in key spots, and honestly, in completely random spots as well

The Plate resistors on the pre-amp tubes are the ones you may have heard or heard about, the term, popping, cracking, sizzling or a combination of any of those when they go bad…seeing these replaced is pretty common. I have my beliefs on this, and there are MANY more, most, by guys that probably know more than me about electronics and very likely, everything else…But I do know that in the pre-amp plates, that is where this carbon composition resistors shine for tone, you want the voltages to drift…that is what the old amps did…SO that was the first order.

I assume they didn’t have some of the common values for Fender amps…btw, if a tech tells you he doesn’t stock say a 100k 1/2 watt resistor, he probably doesn’t work on many Fender amps. You may need to seek a second opinion for the repair. To remedy not having the a few 100k’s, and a couple 56K’s he just wired two resistors together to attain the value needed. I replaced all of that with the 1/2 Carbon Composition type to get it as close as I could back to stock

Stay tuned for part 2 and maybe 3 if it is needed…Next we get to the power tubes, rectifier tube and check out the differences between the 64-67 and this 1977 Princeton Reverb

NEXT WEEK:

“The missing bypass cap may have been intentional. The work was not subpar, it may have been a “fix” for the washed out reverb that happens on Fender amps above 4, generally speaking. I had never thought of that one, so there again, someone knew what they were doing, electronically speaking…. “

What are the differences between the Lil King and Lil King S?

…and what’s this I hear about a Lil King X?

First let’s start with the Lil King…first built in 2004, at that time, there were NO Princeton Reverb Chassis available in the boutique amp supply chain, and I know this because the few big companies that were around back then did not have one yet…I am sure someone, some where probably had a few made or bent and welded one themselves, but for someone looking to produce a replica on the fledgling boutique amp market like myself, there was nothing out there. I had an old silver face PR and had a company blueprint the metal work and produce them for me. Several LONG months later it was done and by late 2004 I had the FIRST Lil King built and ready to send to David Wilson (RIP) of The Tonequest Report for review. Back then I had to build and sell these things so I could pay for the parts to build more. (I have a story about how I got the very first Lil King back…YES, I sold the first one to buy the parts for more!!) One of the great things about replicating after years of playing these old Fenders was that prototyping was not nearly as important as when you build something that is tweaked or completely NEW in design. That, as you know, is not something I do, I build replicas, “flaws” and all! I did not borrow ANY money to start Headstrong, it was literally amp to amp back then.

The Lil King is a faithful reproduction of the AA1164 Black Panel Princeton Reverb, and at that time, trust me there was NO ONE building these for the commercial market. I did not tweak anything in the circuit to change the bass response or clean it up etc. Just built this thing as close as I could to an old one. Side note, I did side by side tests of a few GOOD vintage examples that I had access to, as you know there can be a huge variance in these old amps…Some sound good or great while others are just off for a variety of reasons.

The Lil King Reverb is built around one of the GOOD vintage examples and after nearly 20 years and 700 ( I am building chassis no. 700 this week for Deke Dickerson) of the stock Lil King amps of which I have personally wired EVERY ONE, I am confident that its as close as it gets…Not saying it is better than anyone else’s take, just as close as it gets!

The idea for the Lil King-S (the S stands for “Souped up” or “Stage” ) came in 2009 after several years of building the Lil King and people asking me about beefing the amp up or tightening the bottom end. There are a few popular Princeton Reverb Mods out there as you know, but I wanted to take it further…This is one of the few times in the 20 years I have been building amps that I even considered doing this. To me one of the main reasons Princeton Reverb’s sound the way they do is the Phase Inverter (read the Blog, “why do the Princeton Reverb and Deluxe Reverb amps sound so different” for more on this) I wanted to keep that, otherwise I am building a single channel Deluxe Reverb basically. I wanted all that sag to happen like a Princeton, but much louder and cleaner on the way to that point. I boosted the PI voltages by using the untapped leg of the Filter cap can, bumped some voltages in other places, but mainly…I had a HUGE Princeton Sized Power transformer built AND a 35 watt Output transformer built with a special primary impedance so that it would handle a variety of power tubes. It was my thought that is I beefed up all of this, but kept the PI the same, the amp would land at about 25 watts with 6L6 tubes. SO the main difference in the stock Lil King (black panel Princeton reverb AA1164) and the Lil King S is the transformer set and higher voltages across the board…The effect of this has also been explained in previous Blog posts, so please check those out if you are so inclined!

Lil King S (left) and stock Lil King (right) power transformers built to my spec by Heyboer

The Lil King-X…Well that is what I call a “flex” model between the two amps. There is a significant amount of room between the Lil King and at the Lil King-S, so over the years I have talked to so many people about what they wanted out of the amp I was building for them, that the X took shape. Charlie Hunter was one of the first to have one built. He had several Lil King and Lil King S amps, but sometimes there was too big of a gap between them for certain rooms. The X can be many things…The one I just built for JD Simo, is Lil King S power transformer, Deluxe reverb output transformer, it will run 6V6 or 6L6s, for 18-22 watts. PI voltages were raised, but pre amp voltages were kept close to the stock AA1164 readings. I have done so many different versions of this to achieve what someone wants…stock LK power transformer with a Deluxe reverb output to juice it just a little, Lil King S power transformer with stock Princeton Output and 6V6s…a ton of voltage mods to clean or brighten…It is virtually endless.

I personally prefer the stock versions of both, but there have been some cool variations. Rest assured, this is not nearly as complex or vast as it seems, these are finite incremental changes, some of which are so subtle, only guys like JD and Charlie Hunter can really tell the difference…subtle changes to mids, volume, headroom, and compression…these are guys that are TRUE MASTERS of what they do and have done it for so long, they can hear these little 1-5% changes….Not to discourage anyone from exploring this, but lets not over think this thing…Call me and I can walk you through some of this…it is not something that you should obsess over, I can get you where you need to be based on the information you provide.

Lil King-S (left) and Lil King (right) Output transformers built to my specs by Heyboer

Between the Lil King, the Lil King-X and the Lil King-S, I have built almost 1000 chassis, so I have heard most if not all of it at this point…There is a reason guys call me about this circuit…And I am not one to brag, but I do think I have earned the right to consider myself a bit of an authority on the Princeton Reverb and what makes them sound so good!

I hope you enjoyed this latest 5 AM rant! Time to get to work on Lil King No.700!!

Thanks for reading!!

As always, you can call or email me ANY time with questions and feel free to comment below!

Wayne

Why do the Princeton Reverb and Deluxe Reverb amps sound so different?

Did you ever think to yourself, “why do the Princeton Reverb and Deluxe Reverb seem to sound so different?” They are technically both “Blackface Fender” amps, they both have reverb in the circuit…but why is the Deluxe always a bit brighter, cleaner and louder?

The obvious differences between the Princeton and Deluxe reverb amps are wattage, transformers, cabinet size, 10” speaker vs 12” speaker, 1 channel vs 2 channels etc…This article is a bit more granular and nuanced than that.

I will try to keep this on guitar player level tech talk, that is, I will use terms that guitar players use rather than a bunch of terms that amp techs and electronic guys tend to use. I feel that is a strength that I developed early on in my 20 year building career. Not alienating guitar players with a bunch of technical talk…Sometimes guys with a more electronic based background, who lack knowledge of the tone terms (as well as dealing with an eccentric group of people) we like to use a players, can get a little defensive and throw a bunch of big words at you…I prefer to use the vernacular that the players use and bridge the gap between the two sides of the fence so to speak.

I started as a player who knew NOTHING about why tube amps sounded so good other than, every time I played one, I knew that was the tone! Communicating with amp techs (if you could find one) could be dicey and uncomfortable at best. Leaving us wrought with anxiety over how our amp was going to sound when they finished the “work”. Not wanting to offend anyone, was NOT my forte in those days…and I remember a few times the “old guy in the back” gave me that look! How could “I” be wrong I thought, that guy is Full of it I thought to myself!..Yeah man, it was all him!

Fortunately times have changed and there are of course many great options now, but in the 90’s, no internet, no forums etc, you were shooting in the dark with techs.

Now, back to the topic at hand

To me the Princeton reverb still has a foot in the Tweed and Brown era tone. I feel this is due in large part to the Phase inverter section of the amp. In the old days, Fender used what is referred to as a “split load Phase Inverter” meaning that the phase inversion is accomplished by using only half of the 12AX7. The 12AX7 is known as a dual triode…two sides, 3 pins on each side (plate, grid, cathode). Make sense? By only using half of the tube to do the job, like using 3 of the 6 cylinders in your car, it is inherently less efficient than the Long Tail pair type found in other blackface amps, such as the Deluxe reverb and all other BF amps above it. The Tweed Deluxe, had the split load as well. Basically this means the signal is less powerful heading to the power tubes so the sag and break up happens much earlier. Also, to my ear, it is a bit darker and lacks a little of the scooped mid sound of the rest of the Blackface Fender amps above it. The other difference in the Princeton Reverb from other Blackface amps is in the tremolo…The PR has the Bias Vary/Wiggle circuit. This uses the power tubes to modulate the bias to create what I think is one of the most swampy, bluesy tremolo sounds they ever did. This type of tremolo is also found in the Brown Vibroverb, Princeton and Deluxe. (NOTE: It is not to be confused with the only true “Vibrato” Fender did in the Brown Concert, Super, Pro and Bandmaster…That is a completely different beast and I will go over that in a future article. FYI, I will be building that Brown Super this year!) In closing, the Princeton Reverb, to me is still a Brown Princeton, but with the Blackface reverb circuit added. Fender kept the Princeton Reverb virtually the same until the early 70’s barring a few adjustments and general butchering.

The Deluxe Reverb is VERY different from a Brown Deluxe, thus different from a Princeton reverb as well. This is where I feel the real blackface tone people are referencing comes from. Cleaner, brighter, scooped mids etc. The tremolo circuit is also different, Fender moved to the Opto-coupler based tremolo that basically modulates the volume to create the tremolo effect, and to my ears is a little less organic sounding. Still a cool sound, and obviously, used by many legends over the years. They stuck with that circuit on all the other Blackface amps from that era as well. The other difference is the “Long Tail Pair” phase Inverter (both sides of a 12AT7 powered this) making it more efficient, brighter, slightly higher voltages across the amp. The first stage filter caps were also higher than a Princeton so it is a bit tighter. The voltages on the power tubes are significantly higher in Deluxe Reverb amps as well. Some are as high as 470V (JD Simo’s DR is that high at 120v!!!) You often see, “will handle the high plate voltages of a Deluxe Reverb” in some 6V6 power tube descriptions. This is what they mean!

For reference, The Royal Reverb, the Headstrong Deluxe Reverb replica comes in at about 425-435 VDC (Volts DC) @120 volts (AC from the wall). By contrast the Princeton Reverb came in at 400-415 VDC…The Lil King is usually 400-410 VDC range.

Pre-amp gain stage (V1 and V2) voltages are a bit higher in the Deluxe Reverb amps. 170-180 VDC on the plates of the 12AX7 tubes (vs. the Princeton reverb pre-amp plates at 150-160vdc). I think this may be an under discussed topic…The higher the plate voltage on those pre-amp tubes, the cleaner and brighter the sound. The lower voltages, like in a Tweed amp, you get a darker tone…less spike in the notes. Finding a balance between the two is what I try and do when someone wants to tweak the amp a little to their liking. Rather than make these big changes to the circuit, sometimes a small resistor change will get you what you need without drastically changing the tonal character of the amp that you loved. Thus avoiding a case of diminishing returns.

So in closing, the main differences electronically between these two amps is why you may have noticed a big difference in these two amps. Some people may feel, the Princeton Reverb is just a lower watt Deluxe Reverb and that is just not the case. The Princeton will always be darker, softer on the bottom end, less spiky on the top end as well as much easier to carry around to the gig!

I could keep rambling on this topic for days, but I also have to actually build these things! As always, thanks for reading and thank you ALL for the 20 years of support! I still can’t believe this is what I get to do all day!!

Talk soon,

Wayne

The Main Differences between the Brown and Black Fender Vibroverb Amps

In this blog post, I will discuss the main differences between the different Vibroverb amps that fender offered in the mid 60s as well as the options I offer as an alternative to the originals.

Side note: If you haven’t read my first blog about why you would buy a replica or clone of a Fender vs the original, please do as it will help you understand where my thought process stems from on these matters. Yes I want to sell amps, but I don’t want to sell you an amp you don’t need or won’t do what you need for the gig.

Let’s start first with the 6G16 brown Vibroverb that was built for one year in 1963.  This amp came in at about 35 watts. I call it a soft 35 Watts due to the fact that it is not overly bright, overly stiff or in any way harsh. First introduced in 1963 and made for just over a year by all reports, it was the first Fender amp to have onboard reverb, came with 2-10 inch oxford speakers at about 25 Watts apiece, the app came in at 35 watts with 5881/6L6WGB/6L6GC power tubes it had a GZ34 rectifier and all pre-amp tubes, including the phase inverter and reverb driver were 12AX7  

The component, layout in the pre-amp circuit, while laid out differently on the fiberboard is essentially the same pre-amp as a later blackface vibroverb. Like many Blonde and Brown era amps the treble control was Tapped at 70k which drastically changes the mid structure of the amp.


The reverb circuit was unique, which was considered a coupling circuit, and was never used in any other fender amp

And one final thing that really sets this amp apart from his blackface brother is the bias vary tremolo. This, of course is when the power tube bias is modulated to create the tremolo effect. This is the same tremolo essentially found in the Princeton Reverb and my personal favorite of all the Fender tremolo circuits.

Across-the-board, the brown Vibroverb had much lower plate voltages than later, blackface Vibroverbs, which I also think changes the tone of the amp to a little bit less high-end and clean headroom

The blackface Vibroverb (AA and AB763 changed, of course to blackface cosmetics in 1964 and also sported a larger cabinet with a single 8 ohm 15 inch speaker (Usually a JBL D-130) instead of the 2X10 layout in the 6G16

Power tube plate voltage was about 25 volts higher. They both basically share the same output transformer, but of course the brown vibroverb was 4 ohms and the black  AB763 was 8 ohms 

The tremolo in the later Vibroverb is like all other blackface tremolos where they simply ground out the signal right before the phase inverter to create the tremolo effect, also known as a opto-coupler circuit. 

There are very subtle differences between the AA and AB763 Vibroverb are in the inverter plates and the bypass resistor in the tremolo. These are very minor differences, so they are essentially the same amp.

The blackface Vibroverb is the amp that most people associate with the “SRV tone”, not saying that Stevie never played a brown Vibroverb, but generally speaking, he played blackface Super Reverb and blackface Vibroverb amps

I build and love both versions, and from all reports they are really close to the few good vintage examples left out there.

If I had to chose, I would take the Brown 6G16 as it is a nice bridge between Tweed and Blackface! I started offering the “Verbrovibe” aka 6G16 in early 2007 when prices were in the $4000 range. Those prices are now, of course higher. (just saw one yesterday on reverb for $20K!!) The other issue is they only built 500 and there are large number of those in private collections from what I hear. Some are used sparingly and others not at all…i.e they are sitting in a vault or display case due to the rare nature. So you can avoid all of that and a second mortgage on your home and get a replica or “clone”. There are a few options out there, but I am confident in the abilities I have accrued in the last 20 years, that the Headstrong Verbrovibe is about as close as you can get to an old one.

I've had a chance to play one years ago, and also hear a few goods ones in person, and it was glorious.

A fun story that is kind of about that amp (kind of) is when I was in my early 20’s, rent was cheap and I was supporting myself solely on blues gigs (a tough feat then and especially now) I wanted one of the re-issues and figured I would try and find someone to tweak the amp for me. This was of course before I had any real understanding of these things…and that the re-issue, while not a bad sounding amp (they actually came close on some features) was a ways off from the original…mainly the solid state rectifier…In any case, my band leader had a friend with 2 old brown amps, he said “I think they are Vibroverbs", one is pristine and the other is beat down with an unoriginal speaker. Turns out the pristine one was once owned by a blues legend who shall remain nameless (for a future story), and he wanted to sell that one. I did not have the $300(???!!!) to spare all at once…times were and always have been tight, fortunately my rent was cheap and my roommate (and band mate) had a regular job if I ever had a bad month (hey, we guitar players have our priorities) so I was gonna get that amp!…But fortunately the band leader knew I needed a stage amp…I had a small set up then that was kind of cool (another story soon), but not what I needed for this new 4 pc Harmonica band…so he offered to buy it and let me pay him back over a few months worth of gigs. I couldn’t believe my luck! I was going to get a Vibroverb, for $300, on PAYMENTS???

Well it turned out not to be a Vibroverb, but a 1962 Fender Vibrolux (with a 12” grey/blue powder coated Jensen Vibranto speaker)…I will tell that story in another post soon, we will call those blogs:

“Headstrong Origin Stories”

I had that amp for years and it is what I based the Sultan off of…

Now, on to the AB763 version

The blackface Vibroverb version that I build is called the King Reverb and it comes as a 1X15 but also as a 2x10 (Vibrolux Reverb) a 2x12 (Pro Reverb) and of course the classic 4x10 Super reverb set up. I will dig deeper in the differences between all of the king reverb versions in another blog, but the 1X15 version, I get asked about all the time so let me explain that here in a bit more detail. The 35-45 watt AB763 circuit are essentially all the same amps when it comes to the circuit itself other than some minor capacitance and resistance changes to compensate for bass response etc. In other words, a 4X10 won’t need the same bass signal as a 1X12 or 2X10. Then of course the output transformers came in different sizes and secondaries to match with the speaker loads. The 1X15 was an 8 ohm output and the transformer itself is the same size and the Pro and Vibrolux Reverb, while the Super Reverb OT was significantly larger than those models.

Generally you would find the famous JBL D130 ceramic speaker in the amp, but some had Jensen, Utah or CTS speakers in them as well. I have had a few of all of those speakers before, and I generally use the Weber California Ceramic for the JBL sound in the King Reverb 1X15 and it is so close it is startling.

Personally, I prefer the sound of a good P15N or Weber’s equivalent.

I had a client, who I trust has the ear as he owned 2 originals, he said “if I didn’t know that your amp was a clone with a clone speaker, I don’t think I could tell the difference form my old ones.” He called me last year, probably 10 years after that comment to tell me he still has the amp, and it is really the only thing he uses to this day. This is not to say I build something anyone else can’t, but to say that if you want to get those tones, and get as close as anyone else is, but couple it with a level of customer service or experience that I stand behind, The Headstrong King Reverb is worthy of consideration.

If you are familiar with Headstrong and my attention to detail across the board, you know what I am referencing, if not, please feel free to call me ANYTIME to discuss some of the options I offer. Or if there is something I cannot help with, I will point you in the right direction. And remember, I Love Fender Amps! I made a living as a player using them, and I make a great living as a builder, copying them! Even if they have missed the mark over the years, I am a loyal guy who will always speak highly of the legacy!

Thanks for reading and my goal is to put one of these more technical blogs up with some old stories about how I got here, or how I managed to deal with some of the people you’ve seen or heard play Headstrong Amps.

And as always, thanks for your support and interest for these last 20 years!

Wayne