My goal is to (one way or another) have a tube amp with the sound quality of a commercially designed $2-3k amp. Right now I have a S5 K12G (stock) and after hearing some older McIntosh, Rogue Audio, Primaluna, older VTLs I desire to have that level of clarity and detail in my system. Before hearing those higher end amps, I was just going to upgrade the K12 with new OPT, caps, B+, etc., but now I am thinking it won't be enough because the circuit design and the tubes themselves are not going to be good enough.
So, I was wondering if there were some opinions on what would be a DIY tube amp design (or kit) that would compete with a Primaluna or an older VTL amp. As mentioned above, I am looking for clarity/detail mostly. Not worried about bass as I have a sub. I am not looking for high power because I listen 5ft from the speakers and all of mine are simple two way designs.
In the kit direction, I see the Elekit TU-8200 from Tube Depot or a Dynakit ST35 in the $600 price range, but from research I don't think the ST35 has the level of clarity I am looking for.
So, I was wondering if there were some opinions on what would be a DIY tube amp design (or kit) that would compete with a Primaluna or an older VTL amp. As mentioned above, I am looking for clarity/detail mostly. Not worried about bass as I have a sub. I am not looking for high power because I listen 5ft from the speakers and all of mine are simple two way designs.
In the kit direction, I see the Elekit TU-8200 from Tube Depot or a Dynakit ST35 in the $600 price range, but from research I don't think the ST35 has the level of clarity I am looking for.
Just my opinion, but you could spend $2-3k in DIY parts and supplies while you hunt for the right combination of schematics and components to satisfy your desires, or you could spend $2-3k on the amp that you want, hook it up, and be done with it.
It depends if you have the patience to spend the time to build what you want. It's not simple, and to do it right, it's not quick.
It depends if you have the patience to spend the time to build what you want. It's not simple, and to do it right, it's not quick.
Hi,
I recoommend you to build amplifier A75 by Nelson Pass. It is not all tube amplifier, but performance and sonics are with the best out there (be it tube or ss). Check it out, as tube lover you will be very satisfied!
https://www.passdiy.com/project/amplifiers/a75-part-1
https://www.passdiy.com/project/amplifiers/a75-part-2
I recoommend you to build amplifier A75 by Nelson Pass. It is not all tube amplifier, but performance and sonics are with the best out there (be it tube or ss). Check it out, as tube lover you will be very satisfied!
https://www.passdiy.com/project/amplifiers/a75-part-1
https://www.passdiy.com/project/amplifiers/a75-part-2
If you're an experienced designer/constructor, you can do far, far better than most commercial efforts (don't think for a minute that there's any price/performance correlation). If you're not, you'll have to sort through a lot of bad designs confidently published by the clueless to try to find something good- and you won't be able to tell them apart. 
Worse, because layout and construction are critical, you'll have a frustrating time getting it working properly. Even worse, you won't have the proper tools to make it work correctly (e.g., scopes, generators).
Tube amps as a hobby are very, very rewarding IF you're not looking for a one-off build, but are more interested in a learning journey through several builds of increasing complexity.
Worse, because layout and construction are critical, you'll have a frustrating time getting it working properly. Even worse, you won't have the proper tools to make it work correctly (e.g., scopes, generators).Tube amps as a hobby are very, very rewarding IF you're not looking for a one-off build, but are more interested in a learning journey through several builds of increasing complexity.
I definitely don't want to spend $3-4k at this time, I am pretty set on wanting a project to build. I built the S5 which was super easy, and I built the Akitika GT101 SS amp which was also super easy to build. Having one of each, I'm certainly hooked lol. I am pretty set on building Pass' F5 Turbo as my next SS amp, but I have no tube amp to match it. I was hoping for a new tube project that at least included circuit boards and some sort of instructions to follow as I am definitely not experienced, but have lots of patience and want to learn along the way. If I can't find what I am looking for, plan B is to build up the S5, learning how to use a 'scope along the way. At least I would learn how each modification changes the sound and in the end it will be better than I started with...
One tried and well-liked design that you can get a PCB for, is Pete Millett's Distortion-canceling "Big Red Board".
That one uses easily available parts, and produces good performance.
It is also scalable to much higher powers than its nominal 20wpc.
Plus the bonus that Pete is often to be found on this forum, and there is a HUGE thread that chronicles the development and build of the original design.
That one uses easily available parts, and produces good performance.
It is also scalable to much higher powers than its nominal 20wpc.
Plus the bonus that Pete is often to be found on this forum, and there is a HUGE thread that chronicles the development and build of the original design.
I built one too.....just a wee bit more powerful than SY's.
I didn't stop at one either, I built three. One was just for experimenting to see how far I could squeeze the design. I stopped squeezing at 250 WPC, or 525 watts paralleled mono block.
I built the other two at 125 WPC. I loaned one to my boss at work, but didn't get it back before I left Florida, so I finished its twin. Very nice sounding amps at full crank, or idling along at a couple of watts feeding high efficiency horn speakers. The buildup of all different power levels are scattered throughout the long thread.
I'd also recommend a PCB project to get started.
Tubelab has some great options as well, with excellent documentation.
Pete has more than just the 'engineers amplifier' everyone's talking about. But it's probably the most popular, and has the most info available on the forums. I built something w/ his 'universal push pull driver' pcb, and like it very much.
An st35 rebuild was one of my first projects, and I've never been happy with it.
Tubelab has some great options as well, with excellent documentation.
Pete has more than just the 'engineers amplifier' everyone's talking about. But it's probably the most popular, and has the most info available on the forums. I built something w/ his 'universal push pull driver' pcb, and like it very much.
An st35 rebuild was one of my first projects, and I've never been happy with it.
Consider that the BIG problem for home builders is not the "electronics" but the "mechanicals" , specially chassis and iron.
Not only strong enough to hold parts weight but also nice enough to show others.
No need at all for chassis/cabinets CNC machined from a solid 25Kg aluminum billet and wrapped in exotic woods (although that doesn't exactly hurt ) but you'll probably want better than a spray can painted chassis with hand filed holes and little PC printed stickers for labels.
What's the point?
I'd suggest you go for a kit, unless you're mechanically inclined and have some machines available, either at home, work, or know somebody who does.
FWIW I started making tube amps in 1969 and became very friendly with metallurgical shops, which cut and folded my first aluminum chassis, also anodizers who didn't charge me, also met this old guy who knew how to wind incredible transformers (specially output ones) , etc.
Otherwise, it would have been impossible or so hard as to take all fun out of it.
Not only strong enough to hold parts weight but also nice enough to show others.
No need at all for chassis/cabinets CNC machined from a solid 25Kg aluminum billet and wrapped in exotic woods (although that doesn't exactly hurt
) but you'll probably want better than a spray can painted chassis with hand filed holes and little PC printed stickers for labels.What's the point?
I'd suggest you go for a kit, unless you're mechanically inclined and have some machines available, either at home, work, or know somebody who does.
FWIW I started making tube amps in 1969 and became very friendly with metallurgical shops, which cut and folded my first aluminum chassis, also anodizers who didn't charge me, also met this old guy who knew how to wind incredible transformers (specially output ones) , etc.
Otherwise, it would have been impossible or so hard as to take all fun out of it.
I've built a few amplifiers in my time, and, as stated above, it is the chassis and iron cost that eats into the budget. For example, even using Edcor iron, Front Panel Express top plate, an Allied Electronic power transformer, and a Triad choke, it was real easy to hit over $750 in parts - all for a simple single-ended pentode amplfier.
The last unit I built, a fixed-bias single-ended pentode amplifier with regulated screen, cost me ~$1000 in parts. The James 6123HS output transformers were a big chunk of the build cost.
Another budget method is to go the Dynaco route - buy, for example, a Dynaco 70 and upgrade away. It's a good learning experience with plenty of different routes to go.
The last unit I built, a fixed-bias single-ended pentode amplifier with regulated screen, cost me ~$1000 in parts. The James 6123HS output transformers were a big chunk of the build cost.
Another budget method is to go the Dynaco route - buy, for example, a Dynaco 70 and upgrade away. It's a good learning experience with plenty of different routes to go.
Given the price limitations and limited experience, I would suggest buying a set of used EICO monoblocks and updating them as you see fit. The EICO HF-22, HF-35, HF-50 and HF-60 all use a good sounding, reliable circuit with tube rectifier, point-to-point wiring and good iron. Starting with a working amp simplifies your project considerably.
I am considering the dynaco route still....plus there is the dynakit options as well and they are within my budget. I was just worried that an upgraded dynaco/dynakit isn't as good as a newer design. Although it certainly must be better than my K12G....
I am not that concerned with making a chassis...I am not looking for anything fancy, although I do have access to machine shop services for free since I am their IT guy lol.
The 300B is out of my price range at the moment.....though out of curiosity, what makes it $1500? Not including the case, since that's mostly free for me, as stated above Does the design work nearly as well with cheaper transformers?
I have never heard of EICO, but a quick search on eBay brings up several options all inexpensive....so I will check that out some more.
So Multi....are you saying buy a chinese amp just for the case basically? With my limited experience how would I know if a particular amp has a good circuit design?
I am not that concerned with making a chassis...I am not looking for anything fancy, although I do have access to machine shop services for free since I am their IT guy lol.
The 300B is out of my price range at the moment.....though out of curiosity, what makes it $1500? Not including the case, since that's mostly free for me, as stated above
Does the design work nearly as well with cheaper transformers?I have never heard of EICO, but a quick search on eBay brings up several options all inexpensive....so I will check that out some more.
So Multi....are you saying buy a chinese amp just for the case basically? With my limited experience how would I know if a particular amp has a good circuit design?
Yes Chinese amp can be a good source of chassis and (probably) powder transformer. Circuit is first thing that should be changed, output transformers likely too. Still cheaper than order custom mechanical parts. If you are lucky, output transformers won't be bad, and you will need to buy only $200 or less worth new parts.
The 300B is out of my price range at the moment.....though out of curiosity, what makes it $1500? Not including the case, since that's mostly free for me, as stated above
You could probably do it for a bit less, but he's being realistic. (I think most of us here lie to ourselves about how much our projects end up costing
)Power TX can be a couple hundred. Output TX's can be 4 or 600. 300b tubes will cost a couple hundred. His 300b has a few components that need heatsinks, so add those (although if you're in IT, you probably have an endless supply of old heat sinks of various sizes). Then caps are probably next most expensive..
Anyway.. it adds up fast!
And if you spend less on budget transformers and things now, that's fine and you'll probably be happy for a while... But you will most likely be buying better ones at some point. (I did.. Bought some $300 for the pair output tx's for my first 300b amp.. few years later upgraded them to $700 per pair output tx's) But, I don't regret it, and used the lesser tx's in other projects...
Another plug for Pete's DCPP amp, as the top plate and chassis are more work than the rest of the amp. If you can farm this work out to someone else, then the build would be very easy.
jeff
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