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DIY "Retro" Blue Hawaii Build Thread


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Since I discovered electrostatic headphones two years ago, I have been wanting to build a Blue Hawaii.

Thanks to the generosity of Head-Casers Nattonrice and Wink, I've got my chance.

They supplied the board sets FOR FREE! I am so stoked, I cant thank you guys enough.

For whatever reason, I enjoy doing quirky builds. Aesthetics have never been my thing. (prolly because I'm a cheap bastard)

I like to instill some sentimental value in my creations along the way. This KGBH isnt going to win any "best of show" awards.

It will fulfill three of my objectives:

1) Be totally encased / covered.

My listening space, the living room is also shared by two rowdy teenagers who have come close to decimating my other exposed tube amps in the past.

2) Show off the inner workings - pcbs, components and tubes in all their glory. No front panel "on" indicator is needed.

3) Pay homage to audio electronics of years gone by.

The case resembles a 1959 Dynaco ST-70 amplifier that also employed four EL-34 output tubes.

Most of the parts have been received, I will be posting pics and commentary as things progress.

Still waiting for a new soldering station to get here. My three Radio Shack el-cheapo soldering irons are worn out.

Below are a few ebay pics for starters.

FWIW - the transformers will be encased inside of the lower chassis "drawer" section.

The amp and psu boards will be mounted on top of the white deck plate. (I may paint it blue tho)

Heatsinks will flank the sides of the amp boards, all will be enclosed in the upper "cage".

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post-2625-0-01977500-1345068336_thumb.jp

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I've got a couple sets of heat sinks Justin did up for blue hawaiis that I could sell you for what he sold them to me for. I'd just have to dig up what he charged me. 1 set comes with rails, and both are tapped.

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you might want to design your own PCBs for that build. good luck!

Luck? Thanks, I'll need it.

Wanting this one to go seamlessly..... must keep my klutzy tendencies at bay.

The amp & psu boards are 2004 JW design with the comp caps added.

I believe these have worked well in recent builds.

Since you have been down this road a lot longer than I have, I'm all ears to any wisdom you can impart!smile.png

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Since the current source boards I gave you need to be air wired you can put them most anywhere within reason.

For memory Kerry put a pair of 1kv wima caps on them too (HT decoupling like the t2, kgsshv, etc).

I'm looking forward to what you do!

I'll be mounting them like you did on your BH.biggrin.png

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Interesting project! I'm a fellow S. Californian. I've got wood and metal working capabilities as well as a garage full of tube related parts. Let me know if I can be of assistance. I have a quad of EL156 if you're interested in doing something really different.

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Hi Frank!

Thanks, originally I was thinking about doing something similar to the outline of the Sennheiser Orpheus amp.

I dont have any decent woodworking tools or access to a machine shop, although I am competent at doing both, including bending pipe.

Just have my handy Milwaukee battery drill, it should suffice for this build.

I have admired your various masterpieces posted here and elsewhere. You have quite a talent for the "Art Decco Look".

Gotta love them blue mercury toobz. Maybe try some Steampunk next?

As far as the EL156 variant goes, you got me there. Me thinks the homework is more than I could handle.

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I wondered where those BH boards went, they disappeared after a visit from wink.

..ok now I have to say this, Erwin (wink) is one of a kind. I think he's one of the most generous people I know, who happens to have one of the biggest headphone collections... And he lives close by, need I say more, just don't serve him instant coffee.

Looks like a great project livewire, looking forward to seeing the updates.

Edited by johnwmclean
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The only problem I see is heat with something like this. The BH runs hot, very hot and I've seen enough of them burnt up to know there is no such thing as enough ventilation. That means over spec everything, transformers, heatsinks and ventilation slots.

Those PCB's also have some known issues so take care with the standoffs you use and where you use them as some high voltage lines are a bit too close for comfort. The mosfet heatsinks have to be grounded and use the thick pads on them. The amp gets rather hot there so you might want to look into some larger sinks there as well.

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Hi Frank!

Thanks, originally I was thinking about doing something similar to the outline of the Sennheiser Orpheus amp.

I dont have any decent woodworking tools or access to a machine shop, although I am competent at doing both, including bending pipe.

Just have my handy Milwaukee battery drill, it should suffice for this build.

I have admired your various masterpieces posted here and elsewhere. You have quite a talent for the "Art Decco Look".

Gotta love them blue mercury toobz. Maybe try some Steampunk next?

As far as the EL156 variant goes, you got me there. Me thinks the homework is more than I could handle.

Orpheus style with the rounded front and top panel mounted volume knob would be cool, then implement a tube cage that goes on after the amp is off and cooled off. You could externally mount the heatsinks on the top panel like on that one "hot rodded not quite BH, but it's a BH" amp angel.gif

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How much clearance is in the bottom chamber, i.e. height?

The seller quoted 2.5 inches top to bottom on the outside. Inside? - dont know, have not received the enclosure yet. My toroids should fit, barely.

The only problem I see is heat with something like this. The BH runs hot, very hot and I've seen enough of them burnt up to know there is no such thing as enough ventilation. That means over spec everything, transformers, heatsinks and ventilation slots.

Those PCB's also have some known issues so take care with the standoffs you use and where you use them as some high voltage lines are a bit too close for comfort. The mosfet heatsinks have to be grounded and use the thick pads on them. The amp gets rather hot there so you might want to look into some larger sinks there as well.

Thanks for the tips Birgir. The trafos are way over-spec.

For standoffs, I plan on using nylon tubes. Will be using alumina oxide ceramic pads on all heatsinks.

Learned that lesson well on the KGSSHV, it was blowing through them Thermasil pansy-assed pads like a torch through paper.

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Why not use soft-start?

it doesn't help this problem. Just going to be more heat in the PSU than usual, or he will need to run it at higher rails (which would cause more heat to be in the amp, unless adjusted), etc.

Edited by luvdunhill
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Yeah, inrush current is a concern but even the simple tricks used in the Firstwatt amps will make it much easier to deal with. The problem we are talking about is the insufficient current draw from that huge core so the output voltage will rise. The PSU has only a single prereg cap so 500V is the max operating voltage and the transformer could easily reach 340-345VAC which is right on the limit. This also makes it harder for the PSU to regulate to the correct voltage and excess voltage will just lead to more heat.

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