[docentore]

Hey folks and happy New Year.

I'm thinking of building this amp as my small desktop amp. Just wondering if it would be enough to drive the T50rp MK2 (Argons)?
Anyone tried the combination?
My apologies if the question was asked and answered before.

 

[ilikepooters]

OPA551's drive the output to the headphones and rated at 380 mA, 2 of them so 380 mA per channel theoretically, no idea what that is in watts.

 

[pukkita]

Been a while since last time...

First of all, THANKS Pete for sharing this project and making it easy and basically giving away the PCB!

Been following you since early 20's (pukka, but can't seem to recover the pass, went on to Senns 6xx and ditched the K701).

I built it yesterday, took about 3 hours (been out of DIY some years) and worked perfect right out of the bat.

Assembled it stock, only modification from stock BOM: changed the WIMAs for MKP (fit perfectly, 505-MKP2D031001F00KF) and got the TKD pot.

I did the pot grounding mod, set bias to 11V.

Used one of the zillion switched 24V adapters for PoE I have around (network admin).

Zero noise. I can hear the high microphonic pitch for about a couple seconds at turn on, that's all.

Really impressed with the sound of this amp. Euphonic, great freq balance, great dynamics,sweet highs and incredible detail... so far have tested it only from an iPhone Xs out (superb!!!).

I see myself building this amp as gifts for my relatives!

Definitely, the best project for someone looking to delve into tubes/DIY safely, with killer price/performance.

Sorry but the forum screws my attempts at posting pictures.

 

[SchwarzeWolke]

Finished the build last evening. It just looks phenomenal!!!
Thanks Pete for the opportunity and also sharing everything from assembly manual to BOM.
There is one thing I've stumbled upon: In the BOM on your website, there are 35V/470uF Nichicon large caps mentioned. In the BOM on the Mouser website, which I also used, they have been switched to 50V/470uF caps. After searching this thread, I've just found some pictures from recent builds where also the 50V versions were installed. Am I right that this is no problem? I thought that given how caps work, this should be any problem at all.
Sound is really good, I ordered an A/B-switcher to be able to listen to my Massdrop THX AAA 789 in comparison to the Nutube Hybride. Will post my impressions maybe next week.
Microphonics are there with really sensitive In-Ears. With my HD-6xx I didn't have any problems. Might also be that the Nutube needs some time switched on, right now I've left it on for about ten minutes and will try it maybe in an hour or so again.
Assembly was fairly easy and you were right with the statement, that this might be a good beginners project! Maybe the O2Objective will be my next project, had a lot fun soldering this amp to a working unit.

 

[pukkita]

Loving this amp! really diggin the nutube sound signature and of course, your implementation! Awesome sinergy with HD6XX. Huge sound, incredible microdetail... but the thing I like most is how it brings the texture or timbre from instruments... not only acoustic, i.e. electric guitar/bass sounds how it would on stage next to an amp!

Lovin it so much that wondered how using nutube(s) for I/V DAC output stage would sound...

 

[ilikepooters]

Finished building mine. No pics because looks basically the same as everyone elses except for my amateurish soldering Took 90 minutes to build roughly. Used cardas quad, this is my first ever proper soldering roject.

Powers HE-500's really well, cranked the volume way up to more than i'm comfortable with and no sign of any bass clipping, wonderfully tight and controlled.

It makes me feel like buying Lyr 3 was wasted money, this little DIY project punches way over it's price bracket and is definitely on a par.

 

[ilikepooters]

OK so op-amp rolling...

Ordered up a couple of AD8397's and a couple of DIP-8 adaptors. Unity Gain stable and 24v.

But is there any danger of it oscillating in this circuit? Heard they can be quite fussy op-amps.

 

[pmillett]

OK so op-amp rolling...

Ordered up a couple of AD8397's and a couple of DIP-8 adaptors. Unity Gain stable and 24v.

But is there any danger of it oscillating in this circuit? Heard they can be quite fussy op-amps.

There is always a little chance that an opamp will oscillate driving some headphones. Headphones are complex impedances, and if they present too much capacitance, the circuit can become unstable. I've not heard of it happening on this amp, but have seen a couple of cases with other opamp-based amps.

That's largely why the series resistors R8 and R9 are there, they make the circuit more forgiving. If you do have oscillation you can make them larger to mitigate it. But the resistor will probably change the sound more than the opamp swap...

Pete

 

[SchwarzeWolke]

In its natural habitat.


Have tried my new A/B switcher and it is really hard to hear some differences between the Massdrop and the Nutube. The Massdrop is one hell of a machine, so kudos to the Nutube that it can step up to it!
Only question for me now is if I should keep both amps. I'm more the "just keep what you are using" guy and I just have one pair of ears...

 

[pukkita]

Couldn't agree more... I found the nuhybrid to be extremelly transparent, to put an analogy with graphics, I find it kind of "unsharp mask" the sound, enhancing it, keeping details but enhancing "contrast", while remaining incredibly transparent.

It really reflects the the source quality, and makes it more lush and enjoyable.

It doesn't make the sound "slow", or compress/shift the dynamics like other tube amps, truly all-terrain and enjoyable with all kinds of music, be it Rock, EDM, metal or Vocal/Jazz.

Sounded beautifully straight out of the macbook line out, but what incredible change after switching to a DDDAC mkII! need more listening hours though.

Have A/B'd it vs a Loxjie P20, both from same DAC source (Audirvana-> HiFimeDIY Sabre USB DAC 2 (ES9023) SPDIF -> Stock Ultramatch Pro in Upsampling mode, feeding SE to NuHybrid and Balanced to the Loxjie P20, HD6XX used in both cases.

Main difference is in soundstage presentation, the NuHybrid being more "in your head" and "perpendicular to your ears", while the Loxjie P20 (what an amp too!) creates a wider, more centered and slightly laid back soundstage.

I know I'm comparing apples to oranges, the point is I'm curious how a Balanced Amp Nutube implementation will sound, @pmillett: have you by chance tested it? Really curious about a I/V Nutube DAC too...

As main critical component affecting the sound on the NuHybrid is the volume pot, thought about using a similar implementation as the Loxjie (NJW1195) will be of great benefit for the NuHybrid....

Using Switched PSUs in both. I've tested linear PSUs and found I actually prefer (quality) switched ones, kind of more "energetic" or livelier sound presentation.

 

[docentore]

OK so op-amp rolling...

Ordered up a couple of AD8397's and a couple of DIP-8 adaptors. Unity Gain stable and 24v.

But is there any danger of it oscillating in this circuit? Heard they can be quite fussy op-amps.

Interested to hear your opinion on the AD8397

 

[silverfishla]

Any of us here that have built the Nutube headphone amp thinking about building Pete’s new stereo Nutube amp? I just saw it on his pages. Looks really interesting, I want to go for it.

 

[ThermalAlchemy]

Any of us here that have built the Nutube headphone amp thinking about building Pete’s new stereo Nutube amp? I just saw it on his pages. Looks really interesting, I want to go for it.

Does it have XLR capabilities is it running Dual mono inside with two separate power supplies ? I would be up for that especially if I could run optional exterior power supply . Especially if it had out to be used as a preamp . I could use it with my Nelson pass mono blocks that have been converted to XRL as a preamp itself . Or use some of Nelson Passes preamp like the BA-1 or the BA-3 with XLR . Sounds like an excellent marriage made by the Audio Gods

 

[AddiDub]

I finished my build of the NuHybrid amp few days ago and i am very happy with it until now. The PCB and tube arrived fast and save and i ordered the components at mouser using the ready made BOM - very convient! It was my first "tube" project and thats why i choose the NuHybrid. After i finished the build the amp worked straight away - lucky me..

I use the NuHybrid amp together with my DIY jFet phono preamp to listen to my records. It really sounds better then using the headphone output of my integrated amplifier. Maybe it is because it has more capabilities to drive my DT770 Pro 250 Ohm headphones compared to the other amp. I have some favourite records that i use for subjective listening tests like Fat Freddys Drop - BOATS or Absolute Beginner - Blast Action Heroes. This might sound awful to some audiophiles ears but i really like them for testing stuff, because both records have loads of deep but well defined basslines. With headphones you only get a CLEAN bass if amp and headphone match very well. On my integrated amplifier the bass of both records sounds muddy and boomy. But with the NuHybrid amp and my DT770s the bass is much cleaner and well defined.

I would like to know what NwAvGuy would say about the NuHybrid amp. Clearly not the "objective" approach but very good sounding and it looks well engineered. Fun Fact: I missed that there is a portable version of the NuHybrid amp now and got me a DIY kit for the "objective2" amp at Head'nHiFi. It is also good in driving my bigger cans and thats why i like it as much as PMillets NuHybrid amp. And the O2 costs only 95 Euro including shipping for a really complete kit including the optional lower power version.

Thanks PMillet for all your works and for making nice NuTube circuits available to the public

 

[cgnman59]

I finished the NuHybrid Headphone amplast week. I made no modifications at all, just made it the way Pete specified. I should note my soldering skills are average at best and I struggle to understand and read a schematic. So I approach any project like this with a certain amount of trepidation. Pete though, made this project as easy as possible. You can just link to the project on Mouser and add the parts listed to the cart. He was quick to send the PCB and Nutube. It went together with no trouble at all. So following his directions I powered it up. The Nutube lit up with a cool light blue glow and the green led lit up. So that's good news. I adjust the bias to the 11 volts recommended by Pete. Plugged in my headphones, turned up the volume, started the CD player and...silence?? So check everything again and discovered I had not soldered two pins of the K1 relay. Okay, solder those and try again. This time music. How does it sound? Well I think it sounds very good. I use a pair of Sony MDR-V6 headphones I have owned since they first came out in the early 90's. I played Boston, the Berlin Philharmonic, "The Planets" Alison Krauss and The Dave Brubeck Quartet. The NuHybrid handled them all easily and made listening enjoyable. It is also quiet, no hiss evident. I have to admit I don't listen often at home with headphones. A couple of years ago I built Pete's DCPP Engineer Amplifier. This is my main rig. So I put the NuHybrid between my DAC and the DCPP to find out how it sounded through my Klipsch KG3.5 speakers. I was amazed at how good the two sound together. A great song to test with is The Dave Brubeck Quartet song, "Three To Get Ready" This is a very dynamic piece from his landmark LP, "Take Five." It features each member of the group. With the NuHybrid and DCPP I am hearing more detail than I thought possible right down to the slight rasp of the reed as Paul Desmond plays the sax. Best of all this little amp is inexpensive and easy to put together.