Pretty simple, easy and cheap build. Easy to reconfigure with a few resistors snd caps if you don’t like it. I highly encourage everyone to try it as designed (not the JCM 300B) before dismissing it. Probably beef up the power supply a little bit and compare it to your favorite. put the Analyzer suite aside and enjoy.
These mono blocks have kept me up until sunrise, something my Mark Levinson mono blocks with 802 D3 speakers has never done.
Maybe my brain is just wired different, but I love this thing. I’ve had and still have plenty of equipment from entry level Chinese crap to very high-end SS to compare. Each their own, I suppose.
These mono blocks have kept me up until sunrise, something my Mark Levinson mono blocks with 802 D3 speakers has never done.
Maybe my brain is just wired different, but I love this thing. I’ve had and still have plenty of equipment from entry level Chinese crap to very high-end SS to compare. Each their own, I suppose.
Last edited:
There is a very good technical reason for people to like SETs - their flaws are monotonic, like the real world. As signal levels get lower, the amplifier's flaws get smaller. We mistakenly assume this to always be true, but it's really not. The worst example is conventional semi-con amplifiers biased to idle cold - work fine at high levels but flaws increase at lower levels. Presumably we have the ability to hear this as something un-natural.
All good fortune,
Chris
All good fortune,
Chris
I love the tech side of the stuff, and absolutely love your posts. Maybe just put your inner tech geek aside for a little while and build one of these. Probably with a beefy power supply. Pretty straightforward. Give it a go and if you really think it sucks no one can argue that! Maybe, I am being influenced by the Tamura OTs or the EML tubes. Quite possibly, it could sound even better with a different design. I am open to all possibilities, but this thing, as built, has cost me countless hours of sleep! Either way, Might be a fun experiment! Listening only… No cheating with audio analyzers! All the best!
Last edited:
My building partner itishifi.com built a type 45 amplifier with his friend Dave Slagle's iron, and recently has new, even more sensitive (108dB SPL/1W/1M) speakers, so some new experimentation with very low noise versions of this amp is in progress. Fun!
I would argue that audio analyzers are grounding, and help keep us honest, and that the fault is not in our stars Horatio, but in our assumptions and interpretations. We are a modelling species (and maybe all species are); we don't live in a "real" world, we live in our internal model of the external world. Keeping our models honest is a lifelong pursuit.
All good fortune,
Chris
I would argue that audio analyzers are grounding, and help keep us honest, and that the fault is not in our stars Horatio, but in our assumptions and interpretations. We are a modelling species (and maybe all species are); we don't live in a "real" world, we live in our internal model of the external world. Keeping our models honest is a lifelong pursuit.
All good fortune,
Chris
Very cool! Let me know when/if available. I would love to buy and make a subjective but honest comparison. Quite serious—I can sell off my Levinson system that is gathering dust anyhow. Been meaning to put it up for sale for sometime.
A cursory look at the websites linked—some serious minded heavy hitters! I imagine their equipment is sublime.
Almost 1 AM here and I’ve been glued to this system (45 monos) since 8 PM. Looks like another sleepless night! Ha!
A cursory look at the websites linked—some serious minded heavy hitters! I imagine their equipment is sublime.
Almost 1 AM here and I’ve been glued to this system (45 monos) since 8 PM. Looks like another sleepless night! Ha!
Last edited:
I'm sorry to have given a wrong impression. Iain's project is purely DIY and for exploration. Of course if anything unexpected or at least surprising or interesting appears, one of us will post something about it.
The new speakers have presented new challenges, but have also encouraged new approaches - they have (only!) their own dedicated line level crossover, so are making us lean towards dedicated HF and LF amplifiers designed to do their best at their own end of the frequency range. Vacuum valve amplifiers are fundamentally constrained by their OPTs, with their conflicting requirements at HF and LF, and being forced into separating these conflicting goals, like the prospect of the gallows, tends to sharpen the mind.
All good fortune,
Chris
The new speakers have presented new challenges, but have also encouraged new approaches - they have (only!) their own dedicated line level crossover, so are making us lean towards dedicated HF and LF amplifiers designed to do their best at their own end of the frequency range. Vacuum valve amplifiers are fundamentally constrained by their OPTs, with their conflicting requirements at HF and LF, and being forced into separating these conflicting goals, like the prospect of the gallows, tends to sharpen the mind.
All good fortune,
Chris
Fun project! I am jealous. I would love to have such resources skills and knowledge!
Possibly you should slap one of these together. Even if just to prove, or possibly disprove, your premise. Likely not much intellectual satisfaction… But might satisfy an intellectual curiosity.
I totally agree that analyzers are necessity to keep us honest and amazing tools. On the other hand, they may lead one to a negative bias. There’s a right time and place for every tool. In the end, tube amplifiers are for listening—not analyzing. The greatest analyzer in the world is capable of over trillion floating operation points per second using only 20 W. The human brain. Of course it is subject to bias, but it is ultimately how we choose between one system and another—listening. I have a variety of systems from which to choose and this is the one my brain likes best. For now! Ha!
Possibly you should slap one of these together. Even if just to prove, or possibly disprove, your premise. Likely not much intellectual satisfaction… But might satisfy an intellectual curiosity.
I totally agree that analyzers are necessity to keep us honest and amazing tools. On the other hand, they may lead one to a negative bias. There’s a right time and place for every tool. In the end, tube amplifiers are for listening—not analyzing. The greatest analyzer in the world is capable of over trillion floating operation points per second using only 20 W. The human brain. Of course it is subject to bias, but it is ultimately how we choose between one system and another—listening. I have a variety of systems from which to choose and this is the one my brain likes best. For now! Ha!
Last edited:
After installing 60uF motor run cap B+ dropped 6V. I know there’s no free ride, but this seems excessive.
I then paralleled the motor run cap with a 56uF electrolytic. B+ held steady…No measurable gain or loss. (Ripple at the speaker did drop another 0.2 mV)
I enjoyed the tinkering, however, would not likely do the motor run cap again. (May have been OK if PS voltage weren’t right on the edge already) However, I now have a one and three-quarter inch hole in the top of the chassis and seems stuck with it!
Wondering if going to a smaller value motor run cap, say 10-20 uF, and a larger electrolytic might help bring B+ back up?
Not an easy swap out, have to do a fair amount of disassembly to get to the motor run cap so hoping somebody here might offer some insight.
In the big scheme of things, B+ is still slightly up from where I started after swapping to a lower resistance choke, but would be willing to put a smaller motor run cap in if it is worth the effort.
Any thoughts?
I then paralleled the motor run cap with a 56uF electrolytic. B+ held steady…No measurable gain or loss. (Ripple at the speaker did drop another 0.2 mV)
I enjoyed the tinkering, however, would not likely do the motor run cap again. (May have been OK if PS voltage weren’t right on the edge already) However, I now have a one and three-quarter inch hole in the top of the chassis and seems stuck with it!
Wondering if going to a smaller value motor run cap, say 10-20 uF, and a larger electrolytic might help bring B+ back up?
Not an easy swap out, have to do a fair amount of disassembly to get to the motor run cap so hoping somebody here might offer some insight.
In the big scheme of things, B+ is still slightly up from where I started after swapping to a lower resistance choke, but would be willing to put a smaller motor run cap in if it is worth the effort.
Any thoughts?
Last edited:
My best advice: DON’T do this..unless…
First off, I guess I’m a traditionalist when it comes to tube amplifiers. My preference is black in flat or hammered.
I went down the YouTube “auto paint” rabbit hole and wanted to test my DIY chops with something I had never attempted before…
Candy apple red with a 2K clearcoat… All from a rattle can.
I would advise against doing this unless you already have the tools, equipment and experience (or you just want the experience like me).
I probably spent more than it would’ve cost me to take this to a professional auto or motorcycle paint shop.
Still, not too bad for a rattle can and some buffing:
Some very minor flaws in direct sunlight, not perceptible at all inside. I still have one final stage of buffing to do which should clear even that up. (There are a couple of lint bits here and there in the photo. Those are on the paint… Not in it.)
First off, I guess I’m a traditionalist when it comes to tube amplifiers. My preference is black in flat or hammered.
I went down the YouTube “auto paint” rabbit hole and wanted to test my DIY chops with something I had never attempted before…
Candy apple red with a 2K clearcoat… All from a rattle can.
I would advise against doing this unless you already have the tools, equipment and experience (or you just want the experience like me).
I probably spent more than it would’ve cost me to take this to a professional auto or motorcycle paint shop.
Still, not too bad for a rattle can and some buffing:
Some very minor flaws in direct sunlight, not perceptible at all inside. I still have one final stage of buffing to do which should clear even that up. (There are a couple of lint bits here and there in the photo. Those are on the paint… Not in it.)
Last edited:
Nice to see a fellow 45 tube enthusiast! I am just rekindling my tube audio journey - first order of business is building a set of speakers over the summer then trying some different driver tubes I have stashed away...some DHTs in particular -10Y, 26, and 101D. My last latest and greatest rendition - (a test mule of sorts built quite some time ago) is an EC8020 interstage to a 45...also a Yamamoto A-08S does workshop duty using those very nice EML 45 tubes you have. Like you (Rob7) I am still in the learning phase and eager to try stuff out for myself. Looking forward to the journey!
The heater voltage reference is a derivation of the other way to elevate the filaments above DC ground. It is a different version that the old radio manufactures would use. It lowers the over all Noise Floor of the amp that way.