1948 Regal / Oahu / Bronson – Style 50K Squareneck Hawaiian

This guitar was given to me by a very good friend. I really didn’t get around to playing it because the intonation was a bit off… but this turned out the be only caused by the nut raiser.  There are no brand indications whatsoever, but the might have worn off or may have been painted over.

It was imported straight from the US together with its little sister:

Hawaiian music hype

It is not a blues-guitar. It is an Hawaiian guitar and a response to early 20th century hype of Hawaiian music. It was the very same hype that put the ukulele in our collective memory. Remember that during depression days of the late 30s, even the Martin guitar factory only survived thanks to ukes.

Following the 1915 Panama Pacific International Exposition in San Francisco, Hawaiian music became very fashionable in the United States, leading to two predominant Hawaiian-music correspondence schools in the ’20s and ’30s: Oahu and Bronson. Oahu was headquartered in Cleveland, Ohio, while Bronson’s office was in Detroit, Michigan. (It is unlikely that either city was a hotbed of Hawaiian culture at the time.) Each of these outfits sold lessons by mail (often attempting to enlist advanced students as teachers and representatives) and featured its own line of guitars.

Oahu-labeled guitars were made for the Oahu Publishing Co. of Cleveland, which called itself “The World’s Largest Guitar Dealer” in 1935.

The Honolulu Conservatory of Music was established in Flint, Michigan in the late ’20s by Harry Stanley and his half-brother, George Bronson. Stanley founded Oahu in 1933; Bronson started the Bronson Music & Sales Co. in Detroit about the same time.

Harry Stanley around 1938.

Oahu offered a variety of squareneck and roundneck acoustic guitars — most were made in Chicago by Kay and Harmony. The most common are inexpensive ($22.50 in 1935) birch guitars with a dark brown finish. More expensive models were available; I used to own an all-mahogany small-bodied squareneck with black-and-white “rope” style binding ($65 in 1935). The top of the line was a rosewood/spruce jumbo with “pearl” inlay, soundhole ring and top trim. These were $158 in 1935 — more than $2100 in 2004 dollars.

But is it an Oahu guitar?

Oahu did not manufacture these guitars themselves. In fact they were mainly a publishing company focusing on sheet music and instruction books. They branched out into instruments, but had them build by other companies.

In the 30’s the company name was consistently stamped inside the sound hole. Our guitar does not have that however, although it looks very similar. As stated earlier, Oahu did not build guitars, they were built by either Kay or Harmony.

The Harmony company, founded at the end of the 19th century, was bought by mail order company Sears-Roebuck & Co in 1916, simply to corner the ukulele market. In the late 1930s, Harmony “also bought brand names from the bankrupt Oscar Schmidt Co.—La Scala, Stella, and Sovereign. They sold not only Harmony products, but instruments under the Sears name, Silvertone, and a variety of trade names—Vogue, Valencia, Johnny Marvin, Monterey, Stella, and others.”

Note the rounded off headstock, which is almost never found on Oahu-branded guitars:

1948 Oahu slotted headstock

But then again, have a look at this one:










And here’s a headstock from the Bronson Guitar Company: not very different, but note the upside-down tuners. Which are actually the correct way around when playing lap slide.

There seem to be Oahu’s without the brand stamped in the soundhole. On Jake Wildwood’s blog I found this very similar 50k model without the Oahu brand stamp. It does have the logo on the headstock:

It has the fake binding painted on the soundhole like mine, but also around the edges of the guitar. The most surprising thing, which is why it caught my eye, is that this guitar has the exact same bridge as mine. Jake writes:






The standard metal bridge is very recognizable because it has pyramid ornamentation. I was suprised to find this Youtube video of another squareneck Oahu with that same Regal/Oscar Schmidt bridge:

But it has more:

  • painted binding only around the soundhole
  • only light in the sunburst is around the bridge

Oahu guitars usually came with a very strange metal molded bridge, which was bolted down as you cannot glue metal to wood. So maybe the bridge was replaced. The original looks like this:

Original Oahu metal casted bolt-on bridge — source: youtube

Most distinctive feature of our guitar are the diamond fret markers:

All the material I could find is pointing to the the 1940s:

Stamp on the back

There is no manufacturer or company referenced inside the guitar. There is only this:

Then I found this Oahu for sale: http://www.thunderroadguitars.com/1948-oahu-square-neck/

Inside the guitar, there is this:

If this is really a ’48 Oahu, then the quest has ended. By 1948, they seem to have give up stamping the name inside the guitar.

1967 120W Geloso G.1/1110 Tube Amp

img_5793img_5803 img_5794 img_5796 img_5797 img_5798 img_5800 img_5801img_5810

There are fuses taped all over this +100W beast…. looks like professional artists: Animations & Spectacles. Here’s the story on the original owners of the amp.

I cut out the two yellow death capacitors: img_5816

The power chord was cut and should be replaced by a modern 3 prong cord.img_5815

New 3-prong grounded power cord installed. After removing the death capacitors, the grounding point is free to connect the common wire from the three prong cord.


1969 Geloso G.1/1040 40W EL34 Tube Amp

Here’s another nice vintage Geloso tube amp, though already dating from 1969.  With two EL34 tubes, it sports a nice 40W of output power.







Unfortunately, it’s not working, and the reason is clear from these voltages: there’s only coming 245-260V off the solid state rectifier.


With the tubes removed, the voltages are up to scratch: 360V

img_5663img_5712 img_5672 img_5667


1966 Geloso 3215 Tube Amp

It may be due to Flanders irrevocable ties to the Holy See or just because of the numerous musical Italian immigrants, but there are a lot of Italian Geloso amps for sale in the low countries.

Giovanni (John) Geloso (1901 – 1969) was an Argentinian immigrant who established one of the most important electronics factories in pre and postwar Italy.  More information on the Geloso company can be found here.

This is a 17W 1967 Geloso G3215:

img_5308An 1967 handwired, all tube 17W amp running a set of tubes very familiar to the guitar player and hence affordable!  ECC83 or 12AX7 for the preamp, EL84 power tubes and a EZ81 rectifier. In fact, this is the exact tube complement of an earlier incarnation of the Vox AC15.

Filaments of the preamp tubes are run off negative DC, which assures absolutely noiseless operation. And there is the extra filter coil often omitted in guitar amps.



This amp still had all the original Geloso branded tubes:



The amp was sold to me in working condition. In the context of tube celexa 20 mg technology, this often means, the tubes glow up.  So it was in this case, tubes glowed, but no sound.  Things only changed when I changed the mains power switch from 240V to 220V – then this little Italian beast came to live.  It is loud, noiseless and has absolutely cheap buy generic nexium online without rx acceptable guitar tone.  I decided to install an input jack and keep the amp stock for now.  The big yellow capacitors are not Geloso, but Sprague, date coded 1966, 26th week.


Input jacks are shielded from the rest of the circuit.  The wiring is to a very high standard as are the components, who are holding up perfectly, even after half a century.


An additional advantage of these Geloso amps is that they allow you to drive any speaker from 1.5 ohms up to a 1000 ohms.


For now, I installed speaker jack in such a way that you can switch the ends to different poles on the output transformer.


Cleaned up, input jack and chicken heads installed:



Tube Radio Guitar Amp: Part 4 Pacemaker tagboard layout

There are few interesting videos of tube radio guitar amps conversions on the web.  All of them however, are single-ended amplifiers, i.e. using only one power tube (like the Fender Champ).  As far as real conversions go, this is about the only video that’s relevant:

Just using the phono input to plug in your guitar is easy, here’s an instructional video if you need that:

The silly dilemma in the second video sums up the reason why there is so little information on the web about conversions:

  • If you want, you can play guitar on any tube radio with a phone input, you just need a connector cord.
  • To make an optimum guitar amp out of the tube radio components, you will have to completely rebuild it, so you can win some of the power the previously went to the RF section tubes for your amp. If the radio was a stereo unit, you want to use the power available for a mono channel.

So it’s either use as is or rebuild completely, there is no middle road or easy guide. In fact, when cheap generic strattera online no rx buying a tube radio set, keep the following pointer in mind:

  • the more tubes, the better
  • more channels is better (stereo is twice the power)
  • the bigger the power transformer, the better
  • look for radios with ECC83 (preamp) EL84 (power) and EZ81 (rectifier)
  • avoid radios from the 40’s
  • bigger speakers is better, better change that the output transformer(s) can be used

On the other hand, I have not seen a tube radio that does not contain all elements of a 5W Champ head: often tubes, sockets, chassis, mains transformer, terminal strips and components can be salvaged.  This leaves you only with the cost of a very good output transformer for 5W single ended amp (40 euro max), some jacks, a pilot light and pots, just to build your own 5W monster (with vintage power transformer :-p)

So, there was work at the drawing board…


And the vibrato section:


Looking for the right components:


The bloodsucker from the amp parts store charge 25 euros for a Tweed Deluxe tagboard, which is just a stupid piece of cardboard.  In the GAMMA store I found this riveting set for 11 euros.  The rings are a bit larger than normal tagboards, but work just fine.


Laying out the board:


Tremelo board and main circuit board wired up:

Tube Radio Guitar Amp: Part 3 Making Plans – Vox Pacemaker 1965

Yes, there is a very nice and decent guitar amp hidden inside this scruffy old Philips radio, all the components except a suitable output transformer and speaker are present to solder up this nice gem:

Huh? Why? How?

Power rectifier EZ81 — If you are in Europe and hunting for tube radio with any value in the guitar amp field, check for this rectifier tube. If you see it, buy the radio!  This tube is used is the early Vox amp, up to the AC15 as power rectifier.  Most vintage American amp you will be looking at require at least 3 different voltage from the transformers: a high voltage, 6.3V for the tube filaments and 5V for the rectifier. The EZ81 does not require the special 5V, just feeds off the high voltage.

phillipspowersectionIn this way, it is just like a Vox Pacemaker — although below schematic is from a Cambridge Reverb (the same amp + reverb):cambridgereverbpower

Or an AC-15, also using an EZ81:


And all of these are unlike any 50’s Fender amp, which require three voltages on the transformer 6.3V, HV and 5V especially for the rectifier:

Transformer and rectifier tube in a Fender 5E3 Tweed Deluxe amplifier.

2 Power tubes EL84 & 1 Preamp tube ECC83 — if the transformer can power this in our radio, we need only one extra ECC83 tube to make a Vox Pacemaker. It uses 2 x EL84, 2 x ECC83 and an EZ81.  The Philips radio powers and additional 5 tubes for RF purposes, so it is certain that this transformer from a piece of €10 junk can function as the heart of a Vox Pacemaker, Vox AC-15 or Marshall 18W…. value: $75. My calculation seems to indicate this transformer could pull 5.4A on the high voltage.  I don’t believe you could find one that would feed anything more than a 25W amp.


The only thing that is missing, is the output transformer, which will cost around €50. Chassis, resistors (after measuring), 6.3V pilot light and mounting screw can all be salvage from the zombie corpse.

I really think you could use a lot of the power transformers in old radios, but the output transformers from household radio sets will never be strong enough.

Tube Radio Guitar Amp: Part 2 Plugging in…

After thoroughly checking the internet ressources and mostly figuring out which buttons do what, it was time to fire it up.  First I had to dig out some speakers to at least have some load connected to the output transformers to avoid them burning up.  IMG_5065

Well, incredible enough: the zombie came alive…. and it’s name is Steve Tyler.

Not all bands are working, but that’s not the part we care about anyway: we want to plug in our guitar.  For that we use the PU/phone/GRAM input on the radio.  In my case is was a sort of three prong plug: left signal, ground, right signal.  I salvage a two prong from another radio, had to snap it in two, then soldered one to the tip, another to the lug of an input jack.  Guitar is mono, this radio is from 1965 and a stereo unit, so we only use either left or right channel. You always have to connect to the middle, that’s ground.

IMG_5066Of course, you will also have to switch the radio to activate the phone channel.


Well, the sound when playing through a Epiphone Les Paul is mostly a kind of dog fart like fuzz tone that makes the cat up and hit for the garage, the real buy celexa prices lofi dirty gritty overdriven sound. And the volume is also lacking…

Speakers: I think these are 4 ohm speaker, while the output transformers like to see 8 ohm on each speaker. I am overdriving the speaker and overheating the output transfo’s.  I need to address that issue tomorrow.

Settings: The best tone and most volume is with all tone button disengaged. Mono turned on, but even in that mode, the Stereo Exp. function seems to do something (good).

Power Filter capacitors

These suckers are dead as Zed, after 55 years…no doubt about it.  I didn’t have immediate replacements for the big canned 50uF caps, but a third 8uF cap was much more in reach and obviously in need of replacement:

IMG_5076Here it is located in the schematic as C3:

powersectionI rolled up a home made 8µF/900V cap made up of two 4µF 450V’s in parallel:

IMG_5077And mounted them like this:


This gave me a tad more volume.

Input Resistance

The factory schematic shows 100k resistance in series with the phone jack on both channels. Decreasing the value to 68k (standard input resistance on most Fender amps) also will increase the volume a bit.  You may jumper it altogether, but if you start picking up Russian RF signals, it’s not the radio.




Tube Radio Guitar Amp: Part 1 Exploring

I bought another tube radio, it’s a Philips B5X42A.  This is getting seriously addictive, but it’s better to be fixed on €10 junk nobody really wants than getting hooked on buying every Vox amp around, even that silly little white one.  So I spotted a guy selling several tube radios on a classifieds website, contacted him and went over there. He opened up his garage and there was a plethora of tube radio and bakelite goodness. I could only be honest:

‘That’s a stunning collection you have there. I am really looking for a tube radio to convert into a guitar amp. So anything you have lying around of which the radio part isn’t properly functioning, but the main amp is, I am interested in. The higher the wattage, the better.’

‘But then you are better off buying a guitar amp, that’s better suited than this. I don’t have any real throwaways, I repair everything myself.’

‘I have several great tube amps at home, a sixties Fender and an original 65 WEM Watkins. I also have two 5W single ended amps and am currently building a 50’s design guitar amp. But have you ever bought a new power transformer for a tube amp? Do you know what they cost?’

‘I just throw them away, had a box of them around here until last week.’

‘Well, if you want to build a guitar amp, the cheapest transformers you can buy are around €50, this is for 5W amps’


‘I tell you, if I buy a €15 non working tube radio that isn’t burnt out, I can probably salvage all power transformers (+€50/piece), output transformers (+€30/piece).  I knows it’s junk and the real reason tube technology went down the drain, but if you have to buy them in specialized shops nowadays, you pay for being in a niche market’

‘What kind of tube do these guitar amp generally use?’

‘In European denomination mostly EL84 as power tubes and ECC83 for preamps…’

‘Well, then I think I might have some chassis lying around for you…’

We made a deal for €10 for a Philips B5X42B from about 1964:







That’s how it looked back in the day, celexa 40 mg what I bought looked more like something the cat dragged in last night, and the reaction of the wife was accordingly.


Mine doesn’t look at snazzy anymore, the enclosure is not included, but more importantly the looks, is finding the phono input, which may require googling the back panel of the unit in question:






The pickup (PU) jack has three contacts, one for the left mono channel, one for ground and one for the right mono channel… because this is a stereo amp. It has two distinct signal paths: here is only the stereo amp part of the schematic.

deatilEach of the signal paths uses half of a ECC83 (=12AX7) for preamp and one EL84 as power tube. If you consider that the rectifier in this radio is EZ81, it become clear that you have everything to here to build an Vox AC-15 (minus the tremolo).

The reason so many questions about converting radio’s to guitar amps remain unanswered is clear to me now: using it as a guitar amp requires no work at all, just connecting to the phone input. But converting it means getting rid of everything that is in the red square:






That is like 2/3 of the circuit.  This may seem like a difficult job, but it really isn’t because these parts of the circuit are switched in and out.  In fact, we should also get rid of the double stereo part. In fact, we can make one hell of guitar amp using this chassis, power transformer, tube sockets, even tubes… we may have to buy a new output transformer, BECAUSE: if the power transformer is powering the amp section (= one AC15) plus a whole bunch of other tubes, it may become the heart of a serious amp. I dare not believe what the label promises:


That the cabinet is not included, is a shame, it would need almost no work to be converted into a nice guitar amp head:



Not exactly the same model, only the cabinet is different. Very helpful if you want to know which controls do what.

Stay tuned (haha!) for part 2 where we will be plugging in…

1963 WEM Watkins Control ER15 & Pick-A-Bass cabinet

wem01wem02 wem03


This nice little 15 watt all tube amp head was built by the British WEM Watkins company in 1963/4.  At this time, bands played in clubs and used at max 30W amps and the Beatles were still playing their Vox AC-30’s through the stadion PA when they called it quits after Shea Stadion.  The equipment simply was not holding up to the task in 1965, but by 1967 Jimi Hendrix was shredding away: what had changed?

Charlie and Reg Watkins had started their record shop in 1948 and switch to selling guitars and accordeons some two year later. Charlie is mainly interested in electronics:

In 1949, my fascination with the guitar, its mechanics and now its electronic reproduction paved the way to the first Watkins "Westminster" Guitar amplifiers and later the "Copicat" Echo and the "V" Fronted Dominator amplifier. 

The breakthrough which really put WEM on the map happened in 1966:

Invention of the "Slave" P.A. System. Possibly the most rewarding and personally satisfying development. In a world bristling with the likes of Alvin Lee and his Ten Years After, The Faces, Jethro Tull, Rod Stewart, Hendrix and indeed the Rolling Stones with so many brilliant groups waiting to emerge but who were unable to do so for the lack of a powerful and competent sound system. This limited the exposure of groups to small venues and pubs or whatever size a couple of lashed up Marshall 100 or Hi Watt ordering celexa Guitar stacks could handle. 
Charlie Watkins
Charlie Watkins

It’s hard to determine how many amps they put out per year and there is also hardly no information on the Watkins serials. I do have the impression that in the early 60s they were not product bound: the cabinet I own has a similar tag with a different number. I might have to take it apart and check the date codes on the potentiometers if they haven’t been replaced, but on the basis of the serial, this unit will be 1964/1965.

Serial #00951
Serial #00951















I had the cabinet for some years, but it was missing a speaker. Could have gone overboard and spent load of money trying to source the original speaker, but as the thing is meant to be played, I opted for something that’s an affordable solid alternative: Jensen C12Q-16 Ceramic Vintage 12″ Guitarspeaker 35 Watt
RMS, 16 Ohms, 1,25″ voice coil used by Fender Bandmaster, Deluxe
Reverb, Pro and Vibrolux.

WEM Watkins Pick-A-Bass cabinet with new 12" Jensen speaker. Cabinet serial #1150
WEM Watkins Pick-A-Bass cabinet with new 12″ Jensen speaker. Cabinet serial #1150

Around the late 60’s Marshall cloned this exact amp and issues the Marshall 18W Combo. It’s basically running the same configuration a little hotter.

1965/6 Marshall 18W Combo (James Stevensons Collection)
Comparison between WEM ER15 and Marshall 18W by tonegeek.com

instruct er15