Hi I came across this Japanese blog detailing the amp's measured performance when I was looking for more info regarding the amp prior to acquiring one
https://blogtag.ameba.jp/news/SV-S1628D
And here's a couple of videos of the SV1628 recorded on youtube to give an idea
https://blogtag.ameba.jp/news/SV-S1628D
And here's a couple of videos of the SV1628 recorded on youtube to give an idea
Interesting to see the graph of measured distortion. It looks to be the performance with the 211 tubes..
Another comment by a seller..
https://www.usaudiomart.com/details/649589205-sun-valley-sv-s1628d-845211-set-amp/
Quote "This is a Sun Valley 845/211 amp purchased as a kit from Victor at VKMusic. The amp is from Japan It is a much higher level amp than the Elekits that he also sells. I am a fairly experienced DIYer and I assembled the kit and then had Blacky Pagano of stereophile fame(search on youtube) go through it and test it on his oscilloscope. He reported that the amp produced15 WPC with less than 2 pct distortion at full output. He was very impressed with the numbers. This amp is dead quiet and sounds amazing. It is an excellent very affordable way to get into the SET world without having a flea watt amp that needs super efficient speakers. This amp can drive almost any speaker with finesse. I have 3500.00 invested in the amp as follows: -Amp 1850.00 -Vcap and resistor upgrade 680.00 -Upgrade of coaxial wire to Mogami and volume pot to Alps blue velvet 100.00 -Blacky Paganos fee to go through amp and test 250.00 -Tube set including Psane 845 370.00 TOTAl 3500.00 The amp looks great and the work was done very neatly(see pics) This amp is guaranteed to be flawless upon arrival. See Vkmusic and the audio asylum page for info and more pics. This amp can also run 211's with a flick of a switch. If you are looking t this you know how expensive 845/211 amps are so this is a great opportunity to get into one at a good price. Thanks for looking and let me know if you have any more questions."
Another comment by a seller..
https://www.usaudiomart.com/details/649589205-sun-valley-sv-s1628d-845211-set-amp/
Quote "This is a Sun Valley 845/211 amp purchased as a kit from Victor at VKMusic. The amp is from Japan It is a much higher level amp than the Elekits that he also sells. I am a fairly experienced DIYer and I assembled the kit and then had Blacky Pagano of stereophile fame(search on youtube) go through it and test it on his oscilloscope. He reported that the amp produced15 WPC with less than 2 pct distortion at full output. He was very impressed with the numbers. This amp is dead quiet and sounds amazing. It is an excellent very affordable way to get into the SET world without having a flea watt amp that needs super efficient speakers. This amp can drive almost any speaker with finesse. I have 3500.00 invested in the amp as follows: -Amp 1850.00 -Vcap and resistor upgrade 680.00 -Upgrade of coaxial wire to Mogami and volume pot to Alps blue velvet 100.00 -Blacky Paganos fee to go through amp and test 250.00 -Tube set including Psane 845 370.00 TOTAl 3500.00 The amp looks great and the work was done very neatly(see pics) This amp is guaranteed to be flawless upon arrival. See Vkmusic and the audio asylum page for info and more pics. This amp can also run 211's with a flick of a switch. If you are looking t this you know how expensive 845/211 amps are so this is a great opportunity to get into one at a good price. Thanks for looking and let me know if you have any more questions."
Hi all. I have been following this thread and really like the look of this amp as well as others that Victor sells. I understand this project is more complicated than some of the others and is dealing with a more dangerous amount of current (900v+). ME- I have built 1 kit before from Bottlehead that went smoothly. I have previous soldering experience on smaller electronics and feel pretty confident with my soldering ability. My knowledge of electronic design and how to stay safe is basic but I am able to follow instructions and safety instructions well I think.
From what I have written are you able to advise if this project is a good idea for me to attempt?.
From what I have written are you able to advise if this project is a good idea for me to attempt?.
Victor – I received the Hashimoto H-30-5S output transformers from you this past Wednesday. Thank you for promptly filling my order – DHL delivered from Vancouver to Houston in a little over one day. Remarkable!!
I replaced the stock OPTs with the Hashimoto and completed the job this past Friday evening. The chassis did have to be punched out to accommodate the center terminals as you’ll see in the accompanying photo. Also, the 211 filament power supply chassis had to be lowered by about 5/8 inch (using spacers) to provide clearance for the OPT terminals. Silver wire now connects the OPT to the speaker terminals. I added two more terminals for the 16 ohm taps as I plan to run the left and right sections in parallel, so the amp can function as a monoblock. A switch can combine the inputs. As I have two of these amps, the second one will be modified in the same fashion. The Hashimoto faceplate fits perfectly inside the chassis, but it does get covered over by the 211 filament power supplies. This amp can be called a Sun Valley only to the extent that the power transformer, the chassis and most of the power supply remains. Along with the new OPTs, the front end has been redesigned and now uses a 6072 operating in SRPP mode, which then directly drives (no coupling cap) the grid of a 7119 operating as a (non-inverting) cathode follower. The 7119 is unitary gain and drives the grid of the 211 via a .15uf coupling cap (I use the Miflex KPCU-01). The 7119 provides ample current to the 211 which it needs to function properly. Needless to say, this is now a 211 only amp – no more 845s. What you will see in the pictures are a pair of GE VT-4-C 211 tubes manufactured in 1942.
Okay – so how does it sound? Is it different, or is it better? It is both. The immediately noticeable difference is that the stock OPTs were bright on the top-end, not harsh, but they could be penetrating at times. Detail was good. Bass was good (better than my Audio Note 300B Interstage amps). And the Hashimotos? Better in virtually every respect. The highs are all there, but without any harshness – lots of very fine detail – hearing things not heard before (and I have a very revealing system). Mid and lower bass are noticeably better – lower and more dynamic throughout. A better sense of depth. Singers are almost in the room with you. One friend observed how they sound very clean. Was it worth the cost and the time? A definite yes – it is now a much better amp. You don’t want to stop listening. Let’s play one more – and another – and another. You get the idea.
By the way, these suckers are heavy. I estimate at 9 pounds each they’re about twice the weight of the originals.
Overall, highly recommended – but not a project for just anyone. If one has already built a Sun Valley, then there should be no problems.
Regards,
Joe F Houston, TX
I replaced the stock OPTs with the Hashimoto and completed the job this past Friday evening. The chassis did have to be punched out to accommodate the center terminals as you’ll see in the accompanying photo. Also, the 211 filament power supply chassis had to be lowered by about 5/8 inch (using spacers) to provide clearance for the OPT terminals. Silver wire now connects the OPT to the speaker terminals. I added two more terminals for the 16 ohm taps as I plan to run the left and right sections in parallel, so the amp can function as a monoblock. A switch can combine the inputs. As I have two of these amps, the second one will be modified in the same fashion. The Hashimoto faceplate fits perfectly inside the chassis, but it does get covered over by the 211 filament power supplies. This amp can be called a Sun Valley only to the extent that the power transformer, the chassis and most of the power supply remains. Along with the new OPTs, the front end has been redesigned and now uses a 6072 operating in SRPP mode, which then directly drives (no coupling cap) the grid of a 7119 operating as a (non-inverting) cathode follower. The 7119 is unitary gain and drives the grid of the 211 via a .15uf coupling cap (I use the Miflex KPCU-01). The 7119 provides ample current to the 211 which it needs to function properly. Needless to say, this is now a 211 only amp – no more 845s. What you will see in the pictures are a pair of GE VT-4-C 211 tubes manufactured in 1942.
Okay – so how does it sound? Is it different, or is it better? It is both. The immediately noticeable difference is that the stock OPTs were bright on the top-end, not harsh, but they could be penetrating at times. Detail was good. Bass was good (better than my Audio Note 300B Interstage amps). And the Hashimotos? Better in virtually every respect. The highs are all there, but without any harshness – lots of very fine detail – hearing things not heard before (and I have a very revealing system). Mid and lower bass are noticeably better – lower and more dynamic throughout. A better sense of depth. Singers are almost in the room with you. One friend observed how they sound very clean. Was it worth the cost and the time? A definite yes – it is now a much better amp. You don’t want to stop listening. Let’s play one more – and another – and another. You get the idea.
By the way, these suckers are heavy. I estimate at 9 pounds each they’re about twice the weight of the originals.
Overall, highly recommended – but not a project for just anyone. If one has already built a Sun Valley, then there should be no problems.
Regards,
Joe F Houston, TX
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Victor – thought you might get a kick out of this. Attached pic shows a pair of 211 (only) amps. Though they are built on a Sun Valley chassis and use most of the original power supply, the amp circuitry is not at all related to the Sun Valley. Each amp can operate in stereo mode or as a monoblock – which is how I use them. In this mode they put out about 18 or so watts from a pair of 211s on each chassis that operate in parallel. They are fully in class A1, no feedback. Tube configuration: input is a 6072/12AY7 operating in SRPP mode, directly connected to the grid of a 7119 (no coupling caps). The 7119 has unity gain. One half of the 7119 functions as a constant current source, and the other half is a cathode follower. The primary function of the 7119 is to deliver lots of current to the grid of the 211 (via a quality coupling cap) which it needs to operate optimally. The circuit was designed by a brilliant friend of mine and it is mostly the same as the famous Ongaku. Construction details: all silver wiring throughout, particularly the grounds, film caps in the audio path, all tantalum and Z-Foil resistors. The unit on the right has the Hashimoto OPTs while the unit on the left still has the original Sun Valley OPTs and awaits the Hashimotos from you. Yes, the Hashimotos are better than the stock (more body, depth, mid and low bass), but the stock OPT is still quite good and most people would be satisfied with it. Sound? Mind blowing. A note on the stock vs. Hashimoto OPTs: I had the unique opportunity to directly compare two identical amps but with different OPTs along with a fellow audiophile: we can confirm that the Hashimotos are sonically better than the stock OPTs in virtually all aspects of sound reproduction. Is it huge? In my system (very revealing) it was noticeable and preferred – but it may not be worth it to some – a matter of individual tastes and budgets.
Tube configuration: 211 – GE VT-4C; 12AY7 are GE black plates; 7119 are the Holland Amperex PQ.
Hello Drippinsound in Austin. Would be pleased to have you stop by here in Houston for a listen. The SV1628 are now 211 only amps operating as a pair of monoblocks with the Hashimoto OPTs. Contact Jfenninger@comcast.net to arrange date and time. Regards.