Thanks Sunil! It sounds really good to me, much better than driving the power amp directly from the source.
I'm currently driving an Amp Camp Amp power amp and a pair of FAST/WAW monitors with it. I built the speakers from xrk971's design:
https://www.diyaudio.com/community/threads/10f-8424-rs225-8-fast-waw-ref-monitor.273524/
I am intending to build a new power amp, those speakers are pretty power hungry. Too many designs to choose from though! 😆
I doubt they'll get it soon...people realized at some point that building or buying output transformers for el34 and 6as7 is not in their reach so they're happy to waste tons of electricity on 50mW headphones...
Looks good! I use mine with a KT88 SE amp. I've found that it does something nice with the top end, it just "warms it up" a little.
Be warned, the 6AS7 tube-rolling rabbit hole can be an expensive place to get lost 😀
Be warned, the 6AS7 tube-rolling rabbit hole can be an expensive place to get lost 😀
This is not a headphone amp. And if you're concerned about wasting electricity, a tube forum is NOT the right place to be.
Indeed, you're right, it's not even a headphone's preamp, it's barely driving a 1mW line output by using 50Watts tubes ...Smart!
Thanks showdown! I've got a Russian 6H13C in it right now, but might try others if I can find them.
I don't know what's wrong with using big tubes in a preamp, tube circuits are all about impracticality. Also, this preamp circuit can provide a small amount of voltage gain and a low output impedance with only a single common cathode stage. Any preamp using 6SN7's or 12AU7's is going to need two stages to do that.
The FAST/WAW monitors look really interesting. Too bad I can't get the Scanspeak drivers here. Great to hear they sound good. I've built a Glassware Aikido but the gain with a Tubelab SSE is a little too much and I was looking at a lower gain preamp.
Agree, Hasn't yet explained how using a low mu, low Rp tube with high drive capability is low-fi.
yes more it is like to be tube headphon amp. some high end preamp use power pentod like ecl86 or 6v6 in output .cathode follower for impedanc.very very nice sound .pre amp should use good metal chasis and not connect simply all the ground wires to each others..all tube diyers says sound is good.
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its not like youre talking with a guy who never built such silly things unfortunately...but never considered wasting el34 for headphones or line amplification...With a transformer and some 6n1p tubes you can drive any headphones on earth...except maybe some hungry Hifiman ...
Using small power tubes for line level output stages is more common than you might think. Back in the days before transistors, a lot of professional audio equipment was required to be able to drive up to +26dBm into into a 600 ohm load (that is 400mW in today's money). Quite often small power tubes like the 6V6 or EL84 were used in single ended output stages.
Cheers
Ian
I cant argue with you about that...I still consider it useless for our times and access to way more tubes than we actually had in the 60s...I remember seeing an el84 driving a relay in some 50s 250KV Siemens gamma radiation equipment too...so EL84 can drive a relay too! Should we all make standby circuits based on El84 for the sake of the past?
I don't disagree. As always its horses for courses but sometimes hi-fi buffs will take any old horse just for the sake of it.
Cheers
Ian
