[HiGHFLYiN9]

Great news for the headphone DIY community; Pete Millett has released his Sengaku design as a DIY friendly offering on his site: http://www.pmillett.com/sangakuDIY.html

The original was a TTVJ offering in 2016 for $2K. Changes include swapping SMD for through-hole components and ditching the fancy selector switches on the front.

You can snag the bare bones kit on ebay for $170 + shipping which includes the board, two Nutubes, two flexible mount systems (NuTubes are fussy about vibration), and two JFETS, which I assume are matched.

Below is the populated board.

Well-documented DIY balanced tube amp projects are like hens teeth. Other than the Bottlehead Mainline I can't think of any others. It would be nice to see Elekit start offering balanced headphone outputs as their latest 300B / 2A3 amps are very well designed.

This should be a high performing design. I'd imagine swapping out the coupling caps, potentiometer and using discrete op-amps will take it to the next level if you wallet can handle it. If not it will still be a tremendous value.

I have my kit ordered. Let me know if you plan to build one as well. Gotta keep this forum on life support

For anyone wondering I believe the output should be about 1 to 1.4W in 32 ohms.

 

[Beefy]

Well-documented DIY balanced tube amp projects are like hens teeth. Other than the Bottlehead Mainline I can't think of any others.

I mean, maybe? This isn't really balanced. The balanced and SE input signal both go through a THAT buffer to create a single-ended signal for the gain stage (the two sections of the tube are paralleled) and the balanced output signal is generated by a second output buffer with reversed polarity. That will give you a more voltage swing, but not much else.

using discrete op-amps

I asked this question in a different forum, but is worth asking again here...... The OPAMPs are working as unity gain high current buffers. Are there any discrete OPAMPs suitable for this sort of application? Most discrete OPAMPs still seem best suited to replacing voltage gain stages, although I haven't really looked that closely.

Gotta keep this forum on life support

I've been away for years, but I'm shocked there doesn't seem to be a simple 'Post pics of your build thread' anymore. Seems a huge loss to not just be able to post one-off builds, without having to start an entire new thread.

 

[HiGHFLYiN9]

I mean, maybe? This isn't really balanced.

You're correct, and no 4-gang pot, etc., but I'll take what I can get.

Are there any discrete OPAMPs suitable for this sort of application?

On cursory glance the Nuhybrid appears to be a similar config and there were several builds with Bursons, though I don't know the significance of the improvement (if any).

I'm shocked there doesn't seem to be a simple 'Post pics of your build thread' anymore. Seems a huge loss to not just be able to post one-off builds, without having to start an entire new thread.

Here's ye olde build thread: https://www.head-fi.org/threads/post-pics-of-your-builds.85561/page-654
...it could probably stand to be stickied.

 

[Beefy]

On cursory glance the Nuhybrid appears to be a similar config and there were several builds with Bursons, though I don't know the significance of the improvement (if any).

Here's ye olde build thread: https://www.head-fi.org/threads/post-pics-of-your-builds.85561/page-654
...it could probably stand to be stickied.

I mean, people will just seemingly put Bursons anywhere, whether it is appropriate or not. Maybe I should have a closer look at their actual capabilities.

As for the build thread.... yeah, still there I suppose, I actually updated a couple of my very old posts several months back. But since it hasn't been posted to in the last two years I didn't see it when looking more recently. I guess that's a good analogy for the current state of DIY.

 

[HiGHFLYiN9]

I guess that's a good analogy for the current state of DIY.

Well... I wouldn't go that far. DIY is alive and well, just not here

The folks that run kit businesses have told me the demand spiked from people being cooped up at home. DIYAudio has a lot of nice kits available now, and their forum remains quite active.

 

[Whitigir]

If I do any DIY desktop amp, then it have to be True balanced with classic vacuum tubes. Is there such a thing ?

 

[HiGHFLYiN9]

If I do any DIY desktop amp, then it have to be True balanced with classic vacuum tubes. Is there such a thing ?

Check this one out: https://www.head-fi.org/threads/modern-balanced-tube-amp-build.852879/

 

[Whitigir]

Check this one out: https://www.head-fi.org/threads/modern-balanced-tube-amp-build.852879/

Nice ? But can’t find any BOM and schematic and such

 

[Beefy]

If I do any DIY desktop amp, then it have to be True balanced with classic vacuum tubes. Is there such a thing ?

I really don't understand the point of going 'true' balanced with a tube amp. It just doubles up the number of tube sections that you have to try and match/balance.

The most desirable approach with a tube amp would surely just be to have something with output transformers wired for balanced connection (I'm sure this is what the mainline does....?). And if your source is balanced, just put line-level transformers on the input as well.

 

[Whitigir]

I really don't understand the point of going 'true' balanced with a tube amp. It just doubles up the number of tube sections that you have to try and match/balance.

The most desirable approach with a tube amp would surely just be to have something with output transformers wired for balanced connection (I'm sure this is what the mainline does....?). And if your source is balanced, just put line-level transformers on the input as well.

Points taken, and I just need to find a good recommended design for DIY to tackles

 

[HiGHFLYiN9]

I got the BOM order in today. A lot of items are OOS given the state of things right now so count on a handful of substitutions. The long pole in the tent is the Schurter DD21.0111.1111 which can't be found anywhere. It looks like it will return to stock in 3 months or so.

Also FYI Landfall systems is making the front and rear panels for these and they fit on a standard hammond, so you get a nice looking chassis for under $100.

 

[jh4db536]

Here is my Sangaku Amp that i've had for a month, i have deviated from the original BOM a bit due to personal preferences and parts availability
Still unfinished due to parts being OOS but it functions. I just dont want to make another order for a $5 part so it's going to wait.

 

[Whitigir]

Here is my Sangaku Amp that i've had for a month, i have deviated from the original BOM a bit due to personal preferences and parts availability
Still unfinished due to parts being OOS but it functions. I just dont want to make another order for a $5 part so it's going to wait.

I love that TU8900 there

 

[HiGHFLYiN9]

I'd love to get your impressions on the jupiters vs the Vcaps in there. Glad to see you used the Vishay Dale resistors, the leads are non-magnetic which is important.

I got a bronze powdercoated chassis from Landfall this week for mine. Their prices are very reasonable and the turn around is super fast. Now to play the waiting game...

 

[jh4db536]

I love that TU8900 there

shipped it to the owner last week after the build. Got my taste of Elekit and to see how the automatic tube detection works
Ultimately too complex of an amp for my taste. I like to mod and tinker with point to point amp.

I'd love to get your impressions on the jupiters vs the Vcaps in there. Glad to see you used the Vishay Dale resistors, the leads are non-magnetic which is important.

I got a bronze powdercoated chassis from Landfall this week for mine. Their prices are very reasonable and the turn around is super fast. Now to play the waiting game...

I cut my own plates to save $50 and put it into jupiters instead.

I do not like how the stock default bom amp sounds at all. For my chain, this amp sounds best with my HD580; HD800 imo sounds terribad.
Ultimately this amp has more bad bloom (i like good bloom) than i like and it cannot be controlled even by removing the bypass caps (100% local feedback on triode cathode). I even tried playing with the input buffers and removing them to see what happens but it made it worst. The only thing left really is to roll the OPA551s with some other unity gain stable chip or do some discrete riggin. Currently running with no bypass caps (C33 34 not populated)

IMO, right now, i want an Ideal cap that is both vcap and jupiter. Likely this is impossible and i will have to pick and choose. Jupiter is a much better bargain

I'm going to put a hundred or so hours on my Vcaps, but my experience with them in the 8900 amp says they Might work in my chain depending on what i want to sacrifice. I think vcap might pair well with my philips dac if the Macro performance gets back up to an acceptable level (because my custom dac is highly aggressive organic and thicc already). Jupiter should synergize very well with Rockna dacs which are more neutral, super clear, and very aggressive (esp wavelight).

Jupiter imbues this amp with the rich wet warm Organic Tonality that it is missing (cause it sounds grossly inorganic and sahara dry with the default BOM). Bass bloom is big both good and bad bloom, clarity lower than i prefer. Jupiter is also more fluid dubya and aggrofi/ big ridiculus punch and slam which i like. Ugh. I pulled these off one of my other amps so they are well burned in. For $45 a piece, the enjoyment i get from the amp are worth it for me over the Vishay couplers

Vcap provides more bass control (less bad bloom, more good bloom) and is clearer, but a lowly SW51 still beats the *** outta this amp in clarity. It has a cold straight line neutral tonality which doesnt help the sangaku already lacking tone. vcaps cost a huge % of the amp cost too and it's likely not worth it for most people. This sounds more technical but boring to me. Macro performance took a huge hit compared to jupiter and i'm not into this boring hifi stuff. LARGE CAVEAT **This might come back with burn in time, because i didnt find Vcap lacking macro in the 8900 amp so i dunno i just to keep running it cause i only got about 24 hours on em **