The Bravo / Indeed 6DJ8 Headphone Amp, Revisited

Back in February, I posted some thoughts on a tube headphone amplifier that was – and still is – somewhat popular, and sold online by a variety of merchants under numerous names, including “Bravo Audio” and “Indeed Audio”.

The basic lowdown, if you don’t want to read that: A (very) good design, let down by some pretty questionable component choices.

I’ve been using the amp daily since then – actually, daily since late last year, when I got it – and I still feel pretty much the same way. In fact, I feel even more strongly about this since I partially dismantled mine earlier this week…

I’ve been meaning to replace the electrolytic capacitors on my amp for a long time now. The output capacitors were unspectacular 1000uf, 25V items means for power-supply use, and the main reservoir capacitor is a 6800uf, 25V piece of crap branded Rubycon, which is not a name that inspires confidence.

I ordered some higher-quality replacements, and decided to finally swap these out, since there are signs the big reservoir cap is leaking electrolyte. Fun!

Well, the capacitor I bought to replace it had the wrong lead spacing – doh! – but I still replaced the output caps with some pretty 1000uf, 35V devices from Vishay/BC that are rated to 105 degrees C, woo-hoo.

When I desoldered the old caps, imagine my surprise to see the following marking on the PCB:

Yep, the original design even called for a 35V part here. Bravo Audio saved a penny or two by using a 25V part. On these parts, this isn’t necessarily a bad thing, as I cannot imagine a circumstance under which they’d see anywhere 24V.

When I get the new replacement for the main reservoir capacitor – which does see the full 24V (or more!) from the power supply, and is only rated at 25V – I wonder what the marking underneath will be. 35V? That’s what I’m betting on.

Like I said, the output capacitors were ill-suited for audio use, but otherwise not really out-of-spec. The fact that my reservoir capacitor is leaking electrolyte after about eight months of use pretty clearly indicates the kind of corners that “Bravo Audio” and their fellows are cutting, and the dangers therein…

Published in: 'D' for 'Dumb', Geekiness, General | on June 25th, 2010| 7 Comments »

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7 Comments Leave a comment.

  1. On 6/29/2010 at 11:50 am Robert Said:

    I’ve just been having a look at my new Bravo, which is a slightly altered version with an ECC82 instead of 6DJ8. however the capacitors are exactly as you describe. if you have found a replacement for the Rubycon power supply cap with the right lead spacing, which fits through the hole in the top plate, I’d be grateful to know what type it was. I’ve been looking but unable to find anything yet that quite fits!

    Cheers

    Robert

  2. On 10/28/2011 at 11:02 am Guitar Headphone Amp Said:

    Brings back old memories, my old ECC82 is still rocking. I only use it once every month or when i feel young. rock on dudes

  3. On 12/9/2011 at 3:46 am Genesis Youth Bows Said:

    Had that kind of headphone amp once but my cousin liked it and borrowed it and never came back =(

  4. On 3/27/2012 at 10:33 am truckfighter Said:

    I found some schematics of the Bravo on the internet. I was surprised to see an IRF630 in what seems to be a second ampification stage. Isn’t it claimed to be all tube?
    what is the IRF needed for?

    cheers

  5. On 3/27/2012 at 11:32 am Nemo Said:

    Truckfighter, the FET is a current amplifier – a buffer, essentially. Most tubes have trouble driving low-impedence loads, and a solid-state buffer is orders of magnitude less expensive than an output transformer. The FET can also source much, much more current than the tube alone can, which is useful in this instance if you want to use the amp to drive, say, bookshelf speakers.

  6. On 4/2/2012 at 4:31 am Ralf Busch Said:

    changed capacitors to panasonic ones, changed tube to NOS Telefunken…. bang, bang bang… This old design rocks!

  7. On 1/5/2014 at 4:13 am includemeout Said:

    Care telling us which 35v 10,000uF capacitor in particular you bought (if possible, its part nr) as I’ve been having a hard time finding something which is as small as the original crappy 6800uF one (mine’s already leaked!)

    I couldn’t even find 35v 8200uF for that size!

    Thanks in advance.

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