Sun Valley vs Sun Audio 300b

Fremer was very impressed with the SV with Hashimoto transformers at a recent show visit on his channel. Output iron is very important. That's all I got!

I heard hashimoto are great, but the circuit is a lot more complicated and has NFB. Anyone can look at these two schematics and get a feeling for what would sound different? (Assuming similar components)

Sometimes simpler is better, and sometimes regulated, constant current source configurations, for example sound better. I wish I could help you more. Best of luck. 

@clustrocasual I am also interested in these 2 amps. Did you manage to find any more information which would help compare the two ?. 

@kdogsy I found a few things.

- YouTuber and DIYAudio poster Skunkie built the Sun Audio and found a lot of things she considered problems. Paraphrasing here - the input stage of how the twin triodes are wired is very very high gain and increases noise and distortion. She wired them in a different way for a much better and cleaner sound. It’s possible the original design was done this way intentionally, and I know OJAS is selling the "history" of the amp, but she questioned the original 6SN7 schematic and did not agree it sounds best. The design was thought to be from JC Morrison but someone else claimed it was a Japanese guy. I was interested in trying Skunkies schematic if I build it.

-I asked Brent Jesse and he considers both the 12AU7 and 6SN7 to be the best twin triodes for different reasons, and he said 12AU7 is lower noise and FAR more available. (Telefunken smoothplates, etc). A great 6SN7 is really hard to find right now and collectors bought them all up. If you plan on maxing out the amps, it’s something to consider.

- One think Skunkie did not like about the Sun Audio design is the 300b plate voltage is strangely low, around 300V. Her mod puts it near 400 which is the modern day common use.

- I asked Victor about removing the negative feedback on Sun Valley and he did not give a clear answer. It seems Sun Valley is designed for a "modern" 300b sound, more stable, a bit more circuitry. The Sun Audio with Skunkie’s mods may compete with it, but it also has a double starting price for the kit and you need to find good 6SN7’s.

- From what I read, Hashimoto transformers may give me the sound I prefer, which is a bit of Japanese Furutech sound, kind of OCC copper sound, very realistic and intimate.

I will likely buy the Sun Valley from Victor and try it with and without the GNF. I plan to upgrade all components to the best Audio Note, VCap and internal wiring, so I don’t think I will be disappointed. It’s impossible to know for sure, but gotta start somewhere. :)

@clustrocasual amazing thanks for the detailed reply. I will try and learn some from Skunkie’s work on the Sun Audio. 
There seems to be more awareness about the Sun Audio amp I guess maybe because it’s been around for longer in its current form. 
I get the feeling the Sun Valley may not have had the Hashimoto as standard for as long. 
 

Out of curiosity what is wrong with GNF?. Is it considered a less pure design as in if it was a better circuit it shouldn’t need it ? 
 

I've gone back and forth on the Sun Audio. It is true that simpler circuits are _not always_ better and I think it came from the hazy days of japanese jazz kissas. think NOS speaker cabling, WE , Beldon etc. Those are all fine, but not really what I've been building in my own systems. I prefer things a bit more modern. 

I looked at AN's 300B's going back a couple decades. I couldn't see all the schematics but they are not as simple as the Sun Audio and they moved away from 6Sn7. But AN and everyone else says, why bother running 300b in NF... I agree, makes no sense in single ended design. Rather, put higher quality components in. Before I buy I may as the question on Victor's DIYAudio thread.

Also, I have an idea to sandblast and paint the SV chassis, so I'm a bit up to the challenge. 

Also, I agree SV maybe new to Hashimoto - and it might mean this is a good opportunity! I did ask Devon on his OJAS instagram which transformers he preferred (Tamura versus Hashimoto) and he gave a waffling answer :). Hmmm he has to support SV, after all.

@clustrocasual I am also interested in your quest. Seems like one day I will have to build a 300B and have followed Skunkie and others on the topic. The thing about Vikto Kung is that it is not clear how you buy from him, at least from what I have read on DIYaudio. Please continue to relate your experiences on this thread.

just a FYI......i had two Don Garber Fi integrated 2a3 amps, one with Hashimoto and the other with Magnequest.....the difference in sound was substantial, Magnequest was much better, and more focused.

That was the second amp i had with Hashimoto, the other a Triode Labs integrated and again in that circuit they sounded lean and flat (maybe I mean more linear less passion) that the Fi.

Any new developments to report? Did any of the above participants (or others) try either the Sun Audio or Sun Valley 300B amp? 

Hey O, 

I just completed the Sunvalley 300b and had a great time doing it. Granted I did it twice since I misinterpreted a couple of basic instructions and my first attempt started to smoke after about 10 minutes of play. That said I'm not a pro, so chalk it up to rookie mistakes. I'd done probably six solid state FirstWatt amps prior to this, plus one SPUD tube amp, but this one was a little more complicated. 

The instructions, especially the illustrations, are very good, but the brief text explanations are aren't always the clearest (translation issues). Suffice to say you should pay close attention to the schematic and the images, particularly the icons in the process steps. Example: the lack of a red dot means "insert the component leads but don't solder yet", while a red dot means "insert component leads and solder now". Also there's a little red arrow that means "even though there are multiple leads soldered to this one lug, don't let the leads touch each other". 

Anyway, after my initial failure I realized I'd rushed at some important points, so I decided to desolder the whole thing and start over. I kept the caps, ordered some higher quality resistors, and got better wire since the hookup wire supplied with the kit is pretty cheap and you don't get a lot of it (though I'm sure it works fine). The silicone-covered 22awg I bought is not only a little thicker, it's more elastic and holds shape/position better. Also as I'm sure you know it's nice to have an abundance of wire just in case!

One important piece of advice: if you go the Suvalley route, make sure to use the diode rectifier (parts included) and not the supplied tube, which can barely handle the voltage. 

In summary, I've been running the Sunvalley for a couple of weeks now and absolutely love it. My initial intention was to buy a Sun Audio from Devin T, maybe even go to New York and build it in one of his workshops, but I got tired of waiting for the next drop. The man is clearly in demand (good for him!). I've rolled some different 300b's in the Sunvalley, and currently have some Shuguang black treasures in there...simply luscious sounding. Also using a pair of RCA clear top 12AU7s and a Mullard 10M gold pin 12AT7. I'm happy as a clam, even though there's a lot of tube burn-in yet to go.

Overall I'd say that the project isn't as complicated as it's made out to be. Especially if you take your time and get fussy with it, it's a pleasure to build (even twice). Victor is also extremely helpful and friendly. I recommend the experience. 

@beattyomatic Great post. Thank you. 

@beattyomatic Sorry for the delayed response and thanks for the very informative post.

What speakers are you using with the Sunvalley?

My pleasure! Regarding speakers, I’m using open baffles made by Caintuck Audio. I chose the Lii Audio F12 full-range drivers, which are about 96dB sensitive. I also have two Caintuck subwoofers with Eminence Alpha 15’s in them.  

One thing I should add about these amplifiers. The Sunvalley, and I presume the Sun Audio, are Japanese appliances that are not grounded in the same way that that US appliances are grounded. They use 2-prong power inlets and power cords instead of our standard 3-prong power inlets and cords. So I understand it, it's because Japanese engineers approach safety measures differently, focusing more on preventing short circuits than ground issues.

However you feel about the relative safety of floating grounds, they can be noisy, susceptible to electromagnetic interference. And indeed my unit was, probably  because I set it in a spot in the house near all our wifi/router gear. Because the soft, static noise I was hearing didn't go away completely when I turned the volume all the way down, it was clear I had a grounding problem. After checking all my ground connections for cold solders and bad connections, I decided to earth-ground the unit, which was quite easy to do. 

Anyone who decides to build the Sunvalley will see in the build guide that all the ground wires connect to a central ground which is, not surprisingly, a through-the-case screw by the rectifier that holds down one of the terminal strips (it's marked "ground point" on page 8 of the illustrated wiring guide). That screw simply needs to be connected by wire to the third prong of a replacement US-style power inlet. Happily, those inlets very easy to acquire, indeed the product linked below is an exact duplicate of the two-prong inlet that comes with the Sunvalley. The screw holes even match up.

All you need to do is install the inlet, connect the internal power leads to the usual spots, then connect the inlet's third-prong ground to the ground point (the US version even includes wire and spades if you want.) The process takes about five minutes.

Anyway, earth-grounding the unit solved my noise problem, and I expect it would solve similar problems for other Japanese amplifiers. Plus in the end you have, at least IMO, a safer amp. Here is the product I mentioned:

Hi all. I am new to this group.

I've been addicted to DIY audio for many many years, but just recently decided to give tubes a try. I wanted to start out with a single-ended kit that could be modded rather than going full-on scratch-built as my first experience. I spent considerable time researching and I found myself in a similar situation that was the catalyst of this discussion thread - torn between the Sun Valley, Sun Audio, Elekit, and Audio Note. Not a lot of comparison reviews out there for these contenders. Buying an amp without hearing it or touching it can be stressful. I eventually decided on the Sun Valley 300B (SV-S1616D) with the Hashimotos. My decision factors were point-to-point construction, price, and footprint (aesthetics). I just ordered it from Victor last week and it should arrive this week. I will say Victor is great to work with and passionate about this stuff. In our numerous email exchanges he always responded quickly, never more than a couple hours. He gave me a great deal, with a combo discount for buying a tube set with the amp, and he threw in the silver solder for free. I have a few upgrades in mind as I build - better hookup wire, better capacitors and resistors, possibly upgrade the tube sockets, maybe repaint the chassis, etc. I bought the GZ34 rectifier tube so I can experiment with tube vs SS rectification.

@beattyomatic Thanks for your write ups, they are helpful as I get started on this project. Great point about using a grounded IEC. I am curious about your mention that the rectifier tube can barely handle the voltage. From the 5AR4 type tube spec sheets I have seen the plate voltage can go up to 550V, and as far as I know the SV 300B is running the B+ at around 400V. I would love more detail on this if you don't mind. I was feeling like I wanted to be all tubes and use the tube reification for that "sound" but not if it introduces reliability risks.

I will keep you all updated with my build.

Hey clustrocasual, can you msg me please?

Great thread, stoking my DYI fires.  Hopefully someday when I have more available time.  I have taken a PC board soldering class, so feel fairly confident I can construct an amp kit, but I really want to understand how it works and how to upgrade components.  Maybe someday I’ll try to design simple amps for personal enjoyment.

Why not take a look at the Audio Note Kit????

Johnny

I strongly considered the AN Kit1, Kit1-10, and Kit1-15. Honestly for all the upgraded parts that are included with the Kit1-15 you can't really beat the price. In the end I was stuck on my own requirement of 100% point-to-point wiring (no circuit boards) and so I went with the SV. Probably nothing wrong with circuit boards and it was more a matter of personal preference than any sort of pragmatic choice. I also preferred the 12AT7 & 12AU7 tubes used by the SV as opposed to the 6NS7 & 5687 tubes used by the AN because of availability and cost when considering tube rolling. I haven't completed my SV kit yet so can't comment on its sound. Who knows, maybe in the future I will purchase the AN Kit1-15 to do a little comparison listening (if/when I have a $5K of mad money available).

Hello all to who are still following this thread. I bought a used Sun Audio SV-300BE recently from a very nice gentleman in Nova Scotia where we both live.

I like the fact that it is a simple design and there is no global negative feedback, and I upgraded all the tubes to new or new old stock. I also upgraded the two single coupling capacitors with Solen teflon caps from France. I hear they need to be burned in longer than other variations but I am patient.

This is the first time I moved to a single ended amp and I am very much a fan now of SET. The sound of the 300B amp is very sweet, and it sounds so much better than anything I have had. Voice and instruments are so articulate. The high frequencies are very clean and clear. The bass isn't profound but I could eventually get a subwoofer to handle that for me. I have no desire to go back to push/pull or Class A/B.

FYI, I can only afford to buy used but I have had some great used Conrad Johnson amps that are beautiful to look at and are built like tanks...and they sound wonderful as well. Conrad Johnson uses polypropylene and teflon capacitors in their amps. Very well regarded brand and they last a very very long time....but I am loving this 300B Sun Audio amp!

Bill in Nova Scotia

PS. I changed out the 300B tubes to PSVANE Cossor, the rectifier tube to a NOS Svetlana black plate and the two 6SN7’s are new Northern Electrics. I have some serious sound happening here now. I have two sets of speakers...Yamaha NS-1000M’s and Belle Klipsch which are out for new veneer and haven’t been listened to with the 300B amp yet. Hopefully for Christmas.

@wgs57 thanks for the info:)