OAHU Project - Thank you @Powdog :)

hcsterg

Friend of Fred
Silver Member
Feb 13, 2012
7,455
France
OK - for the moment, I will opt for the Blue Stripes grillcloth, given that it's an easy swap :

cnTDPb-P1170679.jpg


cnTDPb-P1170678.jpg


Next step : chassis / circuit / logos / faceplates.

Wait and See ! 😁😉

A+!
 

hcsterg

Friend of Fred
Silver Member
Feb 13, 2012
7,455
France
You didn’t like the original Bakelite handle?

Aw, my bad ! I really thought it was a missing / broken part :confused:... And reading you, now I reopen the carton and... Wot ? :oops:

1679239833948.png

She was there with the knob... :rolleyes: :rolleyes: :rolleyes: :rolleyes: :rolleyes: :rolleyes: :rolleyes:

Looks great now you need a double platinum Gretsch to go with it! Oh wait you’re a lefty so how about this!


Thanks @Bertotti ! Unfortunately, the double-cut Jets are not my fave : I much prefer single-cut Jets... 😉

A+!
 

Powdog

Gretschie
Mar 15, 2012
405
Cool,CA
Aw, my bad ! I really thought it was a missing / broken part :confused:... And reading you, now I reopen the carton and... Wot ? :oops:
View attachment 204328

She was there with the knob... :rolleyes: :rolleyes: :rolleyes: :rolleyes: :rolleyes: :rolleyes: :rolleyes:



Thanks @Bertotti ! Unfortunately, the double-cut Jets are not my fave : I much prefer single-cut Jets... 😉

A+!
Oh man. If I didn’t mention that I had tucked it away safely inside before shipping I’m REALLY sorry. I removed it to prevent breakage during the trip across the pond.
 

hcsterg

Friend of Fred
Silver Member
Feb 13, 2012
7,455
France
Aw, my bad ! I really thought it was a missing / broken part :confused:... And reading you, now I reopen the carton and... Wot ? :oops:

Oh man. If I didn’t mention that I had tucked it away safely inside before shipping I’m REALLY sorry. I removed it to prevent breakage during the trip across the pond.

No worry @Powdog ! It's me too : if I had looked more closely, I would have found it... :rolleyes:

I found pictures of that little amp fitted with metallic handle but curiously no Bakelite one, and some with strip handle, so I simply went for that last easy solution. I wanted to find a Blue one, but those I found were clumsy and big... This one in Brown is classic and discrete, at least !

1679246747296.png

I took the time today to design the logos that I will put on the Blue Stripes grillcloth : Magnatone at upper left and Oahu at lower right.

1679246930085.png

And the back "Art-Deco" style control panel - along with the logos, this will be silver back-engraved in black :

1679246979522.png

A+!
 

hcsterg

Friend of Fred
Silver Member
Feb 13, 2012
7,455
France
Work is on progress - slowly but surely, as usual par la force des choses...

I tried to do my best to repair the poc, the pète (French term for bump, scuff, scratch, nick...) in the MOTS covering, by cutting in an hidden place some fragments (no possibility for a one-piece pad) - I'll try to complement by using a color matched nail polish (to be find !) for touch-ups :

Before / After :

1681433871183.png

Well, it's already acceptable... Ne soyons pas plus Royaliste que le Roi !

1681434871840.png

The cab, close to be finished :

1681434074591.png

With its custom-engraved "tribute" logos :

1681434381806.png 1681434443858.png 1681434582153.png

The back, awaiting exact placement of the parts :

1681434722294.png

Wait and See ! ;)

A+!
 

hcsterg

Friend of Fred
Silver Member
Feb 13, 2012
7,455
France
Finally finished... :cool:

Basic issues, as usual, at comissioning :rolleyes: :

- Idiot GND routing that gave hum at volume zeroed. I did not followed the logical GND scheme I use for years : GND to chassis accross the inputs at one one side, GND isolated and at center of power transformer HV at the other side... Corrected by displacing a wrong GND point.

- Tendency to oscillate when fully cranked. The EL84 tend to show this problem on some circuits... Corrected with a 10K taming serial grid resistor (could probably be diminshed to 1K - we'll see later).

- Too much throb/thump when tremolo intensity and speed are maxed. This is a very simple tremolo design, modulating the grid of the EL84 in a bias vary mode, and this noise is inherent to that extreme simplicity... Corrected at the best (I mean : acceptably) by adding a 0.1µF accross the intensity pot wiper and GND.

1684273442271.png

1684273490129.png

1684273525880.png

1684273563064.png

1684273608452.png

1684273713967.png

1684273781075.png

1684273840797.png

1684273864729.png

The tone is surprisingly good, with regard to the means used :cool:... You go from clean to a gentle crunch à la Soul Rhythm or Old Rock'n'Roll, and the tremolo is fine, from sublte to dramatic, even if there's remains of throb/thump when Speed and Intensity maxed.

For those who may be interested, I'll redraw the schematic and record some samples, that I'll post ASAP... Well, ASAP ! ;)

A+!
 

DougWheeler74

Synchromatic
Silver Member
Jul 10, 2019
879
NE Wisconsin, US
Finally finished... :cool:

Basic issues, as usual, at comissioning :rolleyes: :

- Idiot GND routing that gave hum at volume zeroed. I did not followed the logical GND scheme I use for years : GND to chassis accross the inputs at one one side, GND isolated and at center of power transformer HV at the other side... Corrected by displacing a wrong GND point.

- Tendency to oscillate when fully cranked. The EL84 tend to show this problem on some circuits... Corrected with a 10K taming serial grid resistor (could probably be diminshed to 1K - we'll see later).

- Too much throb/thump when tremolo intensity and speed are maxed. This is a very simple tremolo design, modulating the grid of the EL84 in a bias vary mode, and this noise is inherent to that extreme simplicity... Corrected at the best (I mean : acceptably) by adding a 0.1µF accross the intensity pot wiper and GND.

View attachment 208170

View attachment 208171

View attachment 208172

View attachment 208173

View attachment 208174

View attachment 208175

View attachment 208176

View attachment 208177

View attachment 208178

The tone is surprisingly good, with regard to the means used :cool:... You go from clean to a gentle crunch à la Soul Rhythm or Old Rock'n'Roll, and the tremolo is fine, from sublte to dramatic, even if there's remains of throb/thump when Speed and Intensity maxed.

For those who may be interested, I'll redraw the schematic and record some samples, that I'll post ASAP... Well, ASAP ! ;)

A+!
That is some excellent work! Nicely done.
 

Powdog

Gretschie
Mar 15, 2012
405
Cool,CA
As always, very clever work. Did you say that the plastic details are done with a laser?

Looks like a few missing resistor values in your schematic, in the oscillator circuit. I’m guessing 1Meg and 1.5Meg?
 


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