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Everything to gain... or not.

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As with all  things valve audio, the theory gets you so far, then the tweaking takes over. ;-) I've been messing with the values of the anode resistors on the ECC82, and the cathode resistor on the triode-strapped EF86H. Mainly just to see what effect the changes would have on the tone and "responsiveness" of the amp with my own selection of bass guitars. I also tried various cathode bypass capacitors on the EF86H, but found I prefer the tone with this valve's cathode left unbypassed. Less gain on that stage because of the omission, but not really a hassle because the pre-amp is feeding 340 watts RMS of power amps. More than enough to upset the neighbours. This morning I was looking through my collection of valves and found an old Mullard ECC83. Given that it's pin-compatible with the ECC82, I threw it in there just to have a listen. And that's when I knew I'd found the sound I was looking for! The gain was a bit fierce until I swapped out the 220K
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...but sometimes more is better

It had to happen. I couldn't resist running the single triode (ECC82) box into the quad pentode (EF86) box just to hear what it sounded like. And I liked what I heard. A lot. While building Thunderpump 2, I added a spare valve base to the chassis, just in case. It now has a single EF86 plugged in, being fed from the output of the two stages of gain from the ECC82. And it suits my ears. I'll post a circuit diagram shortly. And some pictures. And maybe a sound clip.
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... or back to bass(ics)

A kind of chicken and egg situation. I'd been playing bass for around 40 years when the urge to learn how to play a six-string guitar (I know, I was a traitor to my calling) overtook me as my mid-life crisis. As my skill on the six-string increased, I found myself hunting for "that" sound. The sound that I could call my own. And this resulted in me designing and building the first of the now infamous Dragondreams T'Watt series of high-gain, low-output valve amplifiers. The first of these was a basic lump: a simple two bottle affair with two stages of gain and a self-split, push-pull output. The controls were minimal too: a single gain, a treble-cut tone control, and a master volume. The triode valves were AC heated from a very basic power supply, and the HT had the bare minimum of smoothing and filtering. And I thought it sounded wonderful. As my playing developed, I tweaked the design. As the amp developed, I improved my playing. This cycle continued for around a
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