Bottlehead Single-Ended Experimenters Amp: The Last Mod
A new stepped attenuator is in-house. I expect this to be the final mod for my Bottlehead Single-Ended Experimenters amp.
I got the part for $50 on Ebay, pre-assembled. I just couldn’t get excited about soldering so many resistors (Dale-Vishay).
This is a 23 step attenuator (100k), and it’s replacing an Alps blue (100k) pot. Mounting and wiring was straightforward, though it took me about an hour to finish the work. Cleaned up some of my prior work – I got sloppy.
OK. First, I didn’t expect this sort of marked improvement. This keeps happening to me, and I am loving it. Each upgrade I have made has resulted in a substantial improvement to sound quality. The Jupiter HT caps were a huge shift in quality – no surprise – just natural tone and timbre, and yet nice air.
Today, resolution has increased, and in general I am hearing more detail and texture. I’ve more play in volume levels, and combined with the perceived lowering of distortion I am now using more of the amps power. Even with the Nighthawks I am able to push the volume farther, which results in more quality low frequencies too. With my Tekton Lore (98db), I am pushing the volume to 1:30 or 2:00, and it sounds better than ever in my space.
The hum remains, of course, though it now seems to be more prominent in the left channel. Probably a tube. I’ll test it later. This brings me to the only downside to the whole deal – the amp is being retired by Bottlehead, because the 6DN7 tubes are getting tougher to find, especially in batches large enough for their business. I need to stock up on as many as I can, to extend the life of the amp. I only wish you could get more consistent quality, but these are not new production tubes.
So, going from an $18 Alps potentiometer to a $50 stepped attenuator is most certainly worth it – a material impact to SQ. Again, I can’t say enough about Bottlehead – both the product and the community are excellent. I think I’ve squeezed as much as I can out of this thing. Finally, on to the next project.