What's the greatest bargain in SET these days?

Nice read Rebbi, I look forward to seeing the transformers. You're on your way with this fun project.

Thanks, Charles. The transformers should be fun to unpack; the box itself weighs close to 40 pounds! They are scheduled to arrive today.

Hello Rebbi,
Happy Chanukah! The Audio Note packing looks super. I' glad you noted how well thought out the various bags and sub-bags of parts were labeled according to build order. I' looking forward to the build (by you) and reading your thoughts as you go along. All the best.

Mikirob,

Thank you! Transformers come today! :-D

Started the build last night. Transformer unpack photos posted and initial chassis build pics to follow soon.

Rebbi are you a true Rabbi as Rebbi is yiddish for Rabbi. I assume you are not Orthodox. I have never met an Orthodox Rabbi that was into high end audio.

Jwm,
You have outed me, yes. :-)
I am a (Reform) Rabbi, it's true. I've been into music forever and fascinated with audio gear since my college days.
And building (and taking apart) things is my play therapy. :-)

Wonderful if you are a rabbi in a Temple or Shull, maybe you can get others involved in this crazy hobby. I have a friend who ate Pork and Shrimp and was heavy into the high end. He went to NY and met the head Lubavitcher Rabbi at the time and then became extremely Orthodox. His interest in the high end was gone. He moved to Cleveland and is now a plastic surgeon at the Cleveland Clinic. Great stories

Rebbi, Reading your blog today and seeing your installation of the tube sockets. Its a ton of fun building gear, right?
regards Jet.

Jetexpro:
Yes, a TON of fun! :-)

And when it is completed and sounding great while listening/enjoying you have the extra satisfaction that you built it and understand how it works.

I may have mentioned this before, but if you find something about the sound of the amp that bothers you or you feel could be improved, now that you have a working knowledge of the circuit, it is very simple to try a different cap or resistor and this will alter the sound. Much less expensive than buying a different set of interconnects or speaker cables.

Jetrexpro,
Exactly. Right now I will have the better capacitors (Mundorf Gold/Silver/Oil rather than the stock Mundorf Supreme) and the addition of the three-input switch. That tapped out my budget this time around, but I do envision more upgrades down the road.

Reb, nice blog. You are the Lewis and Clark of set amp builders from where I stand. :-) If only they had a web blog back in their day.

Map,
:-)

Rebbi,
Really enjoy following the blog, even my wife has joined with great interest. She is now thinking, hey, maybe I can build one also. Michal, my wife has been smitten by AN ever since an audio meeting around 2000 in New Jersey, most of the big names in audio reviewers were there, highlighting the 300B, featuring the Komuro, amongst others.

Mikirob,
Thanks a bunch for the nice words. The IEC power section is built, as is the hardwired part of the 300 B section. I am just now, at this very moment, sitting here about to embark on populating the PCB for the driver section -- currently scratching my head over reading resistor values (colored stripes... argh!)
Onward! :-)

Rebbi, One thing I do before soldering any part be it a resistor or capacitor into the circuit, I measure it with my DMV to make sure it measures what it is supposed. That will give you added peace of mind. Some parts will not measure correctly once they are installed. This will also sus out any parts that are defective before they are installed.

Jetrexpro,
I haven't taken it to that level but I have been very, very careful to read the instructions several times before making anything permanent.
In some ways, this is - so far, anyway - an easier kit to build than my Bottlehead Seduction phono preamp, which I built 4 or 5 years ago. I seem to remember having to solder teeny little components on to the leads of valve bases in a rather cramped space that was very challenging. So far, the nice, clean layout of the 300 B driver PCB, which is what I'm currently working on, is making this an easier process.
The only thing that's been at all frustrating is that there have been a few design changes to this 2014 edition and I'm working with a combination of the 2010 edition of the manual and a beta of the 2014 manual. Sometimes it's been a little confusing but Brian is very accessible to his customers so I've never gotten stuck for too terribly long.

Lots of new posts on the Audionote Kit 1 build blog. Enjoy!

Reb. How many more steps?

Definitely reminds me of my electronic kit building days as a kid except this one costs way more and will sound much better than anything I've ever done. Still have all the tools though so with those and your journal one would be armed and dangerous. 😉

Map,
At this point, with the 3 PCB's all built up, most of what's left is "inter-wiring," that is, doing the wiring between the various PCB's themselves and between the driver PCB and the 300 B hard-wired "tag strip." There's also a little wiring and connecting to be done at some of the valve bases. The last step is to solder in the big Mundorf caps and install the RCA connectors, speaker posts and volume pot.
Then, I'll take various measurements to see if all looks well. After that, it's add in the tubes and power up.
So I'd say I'm more than 2/3 of the way into the build, but there's still a good deal more to do. And I'm a slow worker! ;-)

So TAS has finally come out with Dick Olsher's review of the Coincident Dynamo 34 SE. I find it an odd read... one of those reviews where the conclusion doesn't quite seem to match the body of the review.
He describes his dismay that his rectifier tube kept arcing on startup, which he said Coincident describes as "a normal event."
His review unit then kept blowing fuses and had to be shipped back to Coincident. The problem turned out to be a failed filter cap.
He lauds the unit for its exceptionally dimensional sound stage, but says that the lows and mids fell short of his Primaluna DiaLogue Premium. He then starts tube rolling, and after replacing the Chinese EL 34's and the 6SL7 with Tung Sol's, he feels the amp starts to show what it can do, although he cautions that because of the amp's 10.2 ohm source impedance off the 8 ohm taps, speaker matching is crucial. On his Basszilla DIY speakers (odd choice for a review!) he found the tonal balance "distinctly lightweight."
In the end, after a digression on the psychology of perceived value vs. price in the field of wine connoisseurship, he concludes that the Dynamo "may not always yield the most accurate tonal balance, but the crux of the matter is foot-tapping musical bliss."
Your thoughts?

So much depends on the speaker when judging an amplifier, particularly SET/SEP types. It seems Tim Smith of 6 Moons may have use more compatible speakers as he notes numerous fine matches. System synergy is such a key factor for success .

Rebbi, I haven't yet read the review, but based on your synopsis, it does seem to be a bit perplexing. As you may recall, I also had the problem with the arcing rectifier, and in due course pitched it into the trash can. Arcing may be "normal" but it so what? There was a time when the plague was normal in Europe. Small comfort. I don't quite get why Israel thinks his customers will think this is a non issue. Its not like the stock rectifier is a stellar performer. Perhaps a cheap 5AR4 that doesn't arc would be a better choice. It is unfortunate that Olsher's experience was also marred by a bad cap. Could be he was soured a bit by these events.

Mikirob's tube rolling adventures validate Olsher's observations that tube rolling is a productive exercise. This is not exactly a startling revelation.

I found the tonal balance to be neutral. The dynamo is a very cost effective product, in my estimation. It is not a destination piece, but it is a good choice for someone getting started or building a 2nd system.

I am eager to experience 2nd hand your thoughts on your current project.

Brownsfan,
Thanks for the reply. Yes, Tim Smith's review was much more thorough. Israel points out in his manufacturer's reply that Olsher never even mentions that the amp has a headphone section...
And I agree that if the stock rectifier is a turkey, then supply your customers with a better one. Heck, charge an extra $50 and supply a better one. $1299 may be a bargain for this kind of product, but it's still not small change.
As for the Kit 1, it's getting there. My backordered tubes shipped today. A few more hours of wiring and I should be ready to test.

Charles,
I agree with your point about system synergy, which is why using some one-off, DIY speaker for evaluation purposes makes so little sense. We know almost nothing of this speaker. Or, my goodness, if you suspect a mismatch, borrow a different set to try.

Oddly, Israel Blume expresses gratitude and appreciation in his manufacturer response. I mean, in the end it's a positive review but the middle section's pretty mixed.

My advice for people interested in tube amps and specifically the Dynamo is to spend the money required to obtain high quality tubes. I've seen enough feedback regarding this amplifier to belive it is very good and an exceptional value.It has a good simple circuit,good transformers and is well built.If It comes with average quality stock tubes, upgrade them. A well designed tube amp certainly responds to better tubes. The entire point is to achieve good sound that enhances music listening enjoyment. I understand why most manufactuers use cheap tubes as stock. Consumers can easily improve this variable and tailor the sound to their preference. It begins with a solid foundation(good quality amplifier) then the use of superior tubes to take it further.

I followed this principle with each tube amp I've owned over a span 20 years. With my current SET amplifier it's near amazing how it reflects the different 300b tubes I've owned and borrowed(generous loans). You can very easily hear the subtle and not so subtle characteristics of every single one of them. This is one of the great attributes of tube amps and makes owning them such a joy and rewarding experience. After well over 5 years of pure satisfaction with SETs I can't imagine using any other type of amplifier. Rebbi, I hope you have the same thrilling outcome with your Audio Note Kit 300b SET.

Charles,
Thanks for the good wishes and for being such a gentleman.

The 10.2 ohm source impedance is the thing to REALLY pay attention to when matching this amp to the appropriate speakers as Charles notes. That is a VERY high source impedance and would seriously limit the speakers it might be used with optimally. I can certainly imagine some compromises in performance when used with the wrong speaker. It seems designed with Coincident speakers in mind with their very high output impedance. I also totally agree with Charles that the quality of tubes used can make a HUGE difference in performance beyond the critical amp/speaker interface. One can't expect the best tubes in a 1.2K integrated amplifier. I would expect this amp could sound exceptional with the right speaker and some tube rolling. Dick Olsher is very technically oriented but could have been a bit more through in the why of what he heard. I agree that using a DIY speaker is not useful to most folks reading the review. He should have requested a pair of Coincident speakers or had on hand a speaker with a high enough output impedance to offer a fairer idea of what is possible with the Dynamo. What the reader is left with after the review is more questions than answers, at least I was. Dick has been at this long enough, he should have known better going into the review.

Maybe Al might chime in here with more technical insight.

Rebbi, thanks for calling attention to the Dynamo review. I haven't received my copy of that issue yet, but I'm particularly struck by the mention of the amp's high output impedance. A 10.2 ohm output impedance/source impedance on the 8 ohm tap will cause the resulting sonics to vary DRAMATICALLY as a function of the impedance vs. frequency characteristics of the particular speaker that is being used. The most neutral behavior being likely to occur with speakers having impedances that are both relatively flat as a function of frequency and relatively high. That is true of most SETs, but to a considerably greater degree than usual in this case due to the uncommonly high output impedance.

The 4 ohm tap will have a lower output impedance, most likely around half of that value, or 5.1 ohms, which is still quite high.

I assume, btw, that since those numbers aren't specified at the Coincident website that they were told to him by Mr. Blume, as TAS (in contrast to Stereophile) doesn't usually perform such measurements.

On another note, like the others I am very much enjoying following your extremely well done blog.

Best regards,
-- Al

P.S: My post just above went up within a few seconds of the one just above it by Tubegroover, and was composed and submitted before seeing his. Great minds think alike!

Best regards,
-- Al

10.2 ohm output caught my eye as well. That would make for some varied and possibly interesting results. Hard to see how that would perform well with most speakers, but again optimal performance and what one considers to be good sound are often not the same.

I wonder what accounts for such a high output impedance of the Dynamo. The Frankenstein has an output impedance of 1.8 ohms, quite a difference. Tim Smith found good speaker matches in his review despite this seemingly obvious limitation of the Dynamo.

Ok, I'm sick in bed today, reading, listening to my Dynamo right now, playing Capitol's Great Gentelmen of Song, Nat King Cole, Louis Armstrong, Dick Haymes, Sinatra, Martin, Bennett, well you get the idea.

I usually enjoy Dick Osher; but he is way off base here. Something was definitely out of kilter with his set-up. I have the Primaluna and the Coincident beats it out in nearly ever parameter. Consolidating what Charles stated from Olsher, the review is wacky. Believe Tim Smith from 6 Moons and the Enjoy the Music, reviews you can trust that were thorough and used better mached speakers. And I am not impugning Dick Olsher something was wrong.

Remember my comments: the Dynamo was used. It had Gold Lion KT77s, a Phillips 5R4GYS rectifier (not recommended for use by Blume) stock Shuguang 6SL7. The sound was ok with that set-up, my wife did not like the bass, nor did I.

So, being the tube roller that I am since experience has taught me that you
can almost always improve the sound with different tubes, especially NOS (part of the fun of tubes), I rolled. This is what I did: the first thing I did was replace the rectifier tube with a NOS Mullard 5AR4 from 1960s. Wow! Significant improvement. I also had in my tube stash some NOS Military Sylvania 6SL7s. Boom! Another leap forward. Then, I purchased NOS RFT Siemens (Tim Smith, 6 Moons liked these best of EL34s, 6CA7s), "fatter, fuller, better bass". I prefer the Shuguang Black Treasure 6CA7s.

I still have some experimenting to do (going to try the RCA Red Base, a couple of of other rectifiers).

My system as currently constituted sounds remarkable. Purity of tone, natural and organic, the music flows with ease, great textures, big, well defined soundstage (wall-to-wall), deep, coherent, lovely midrange, bass tight and fast, PRat, highs that are never fatiguing (Tekton speakers), rich, full, smooth, neither Yin or Yang, just right to me in my room. This amp will play anything, rock, classical, chamber, Jazz, Louis, Ella, in the room,duke's piano never sounded better.

I'll mention that I was a professional musician and have listened to all types of systems from great to small. This is an amp that most everything tight. Must have sensitive speakers, you will enjoy the music.

P.S. I used Tekton 4.5s, mostly M-Lore, Lore. No problems. Also used my Infinity Prelude Compositions, 6ohm, 96db. No problem.

01-06-15: Charles1dad
I wonder what accounts for such a high output impedance of the Dynamo. The Frankenstein has an output impedance of 1.8 ohms, quite a difference.

Good question, Charles. I don't know the answer, of course, but if I were to hazard a guess, and assuming that the 10.2 ohm figure is correct, I would say that the need to minimize the size and cost of the output transformers probably has something to do with it.

Best regards,
-- Al

It's always about the amp/speaker synergy...always. That is why, for example, the Inspire amp may not sound as good on a particular set of speakers. All about the synergy. Dennis uses good trannys on his Inspire amps as an FYI.

I love this thread as I read the whole thing last night! My speakers are 90db efficient and 8 ohm. They to not dip below 6 ohms and are pretty easy to drive. I have tried several 7 - 12 watt SET amps and find I get enough volume....with the right music. The type of music played is a factor we need to add to the amp/speaker synergy equation.

If one listens to jazz, small ensembles etc, then I found 8 watts was plenty with my moderately efficient speakers. This type of music is not as demanding on a system. Now play some music that is dynamically challenging, then the lack of watts and lack of headroom is readily apparent.

So in addition to the room size and prefered volume level, one needs to take into account what type of music is played most of the time.

Rebbi, I think you made a wonderful choice with your AN kit and view your blog almost daily. Someday I will build a nice SET amp and actually looked at yours pretty seriously. I wish AN offered the same essential amp with no electrolytics and no circuit boards as a kit. It would most likely require a larger chassis to fit the ASC or GE oil caps etc...

Are any of you aware of a SET kit that uses all point to point wiring and no electrolytic caps? I would also like to try transformer coupling or direct coupling in this SET amp.Not sure such a beast exists in KIT form?

Interesting spec on the Coincident EL34 amp. I think Al is spot on with his answer as to why. It is cost related and gives the builder an opportunity to make the best quality output tranny within a smaller range of ideal operation.

A typical SET amp has an output impedance of some 3 ohms (no feedback) with many under that. Speaker matching is especially critical with this amp. I think Dick O. got it right in his review warning folks to be careful and clearly showing the sonic results of mating this amp with a "typical" speaker. Not sure it is his responsibilty to hunt for a particular speaker for the review? Maybe it is?

Hi Al,
Yes the output transformer is a logical culprit. Except in this case two things counter that assumption to some degree.
1) Israel places much emphasis on the importance of transformer quality and is consistent in that stance.

2)6 Moons and Enjoy The Music reviewers as well as Mikirob and Brownsfan attest to the very high quality sound from the Dynamo. These different users cover a variety of speakers as well.

These factors would suggest that the output transformers must be pretty darn good at a minimum. I suppose it's possible to have good quality transformers that suffer unusually high output impedance.

I believe it is Dick Olsher's responsibility to utilize different speakers that have a chance to mate well with a given amplifier. Most reviewers would not mate a low-watt SET with grossly incompatible speakers except to note, for example, that one must be careful in speaker matching. Then he, the reviewer, would generally base the review on compatible rigs to let us, the reader compare and contrast.

Yes, Dick should avoid a gross mismatch for sure. Should he hunt for a 10-16 ohm speaker for the review? No, not so much.

I will read the other reviews to see the speakers that were used.

Grannyring,
Yes we all here would agree on the importance of synergy/compatibility. For this reason a reviewer should rationally use an appropriate speaker for the amplifier under review. Otherwise what good is the reviewer's results if the match isn't properly sorted out? SETs need easy to drive speakers with reasonable efficiency. As Mikirob pointed out, he has no limitation of music genres with his Tekton speakers. An excellent 300b SET will sound woeful if asked to drive a Magical or a Thiel. Get the match "right" and the amp will shine.

01-06-15: Charles1dad
I suppose it's possible to have good quality transformers that suffer unusually high output impedance.

Agreed, Charles. My comment should not be taken as implying that the output transformers are not "good," or are not capable of providing fine performance when paired with suitable speakers. My comment was speculation as to the reason, or one of the reasons, for the high output impedance. Nothing more, nothing less.

Best regards,
-- Al

The interesting thing seemingly about SET amp is that one has to understand the unique limitations of each unique design and match gear accordingly. Not so much different than the norm, but the rules and players are different. I would expect in the end that teh best implementations of any robust paradigm will tend to sound more or less similar. However the variations one might achieve along the way could vary widely. But in the end, reproducing music well is always a team sport. :-) You can build a playoff caliber team around Tom Brady or Joe Flacco and the end results might be very similar but teh rest will vary.

Yes, my statement also said they were high quality trannys made to play within their limited range of greatness. My goodness an amp priced this well, point to point wired, and that is beautiful to look at, has to save $$ somewhere.

I would guess just about any 8ohm spesker with above 92-3db would be optimal. Not hard for a reviewer to do. Lot's of fine choices in this category. Even Dick himself, has mentioned this type of compatibility in many other reviews if my memory serves...

Rebbi,
Now you've done it! My wife very much wants to build the AN Kit. She desires to do it by herself. Then, in our new home (late spring), she wants her own private room also. Thank God we'll have the space. I thought I was downsizing somewhat. Oh boy!

Hi Mikirob,
What a wife you have. Not only does she appreciate SET sound, she wants to build one. She obviously is a music lover with superb taste. You must feel fortunate. She is attracted to a natural sound it seems.

...and attracted to a soldering gun and ohm meter! A rare woman indeed! We should all be that lucky!:) Jet

Charles, yes, she is something else. Always handy around the house and she doesn't look like Annie the Riveter. SET gal, who has always loved the 300B. I am lucky Jet.

I wonder if Brownsfan has gotten any listening in on the Dynamo. I would love to get his further opinion. I hope Brownsfan is having luck with move. We can all appreciate how tough that usually is.