Does op-amp swap affect overall sound quality in ADV? I see from your photo that you have Burson opamps? Does these apamps affect quality of overall sound and how much is that effect heard? I'm confused which one of these portable amps to choose 🤔🤔🤔 I use only my full-size headphones: HD650...

Also, what opamp did u modified for the little bear? If u have to choose between little bear VS ADV, how would that be? It would be kind of u to describe whats the pros and cons for all three too. Thanks a million

Thanks for your explanation, korg looks interesting but is however 4 times the price of ADV. Does balanced output in ADV gives less noise?

...ear/headphones. There's are no gain levels and there is significant channel imbalance up to about 8 o'clock knob mark. Right now I also own b4-x and korg ha-s with nutube in terms of portable tube amps. Korg is the most refined and cleanest sounding one out of the three and it has been...

Welding? Soldering, actually. Triodes and pentodes require different support, therefore are incompatible. Nickel-cadmium and nickel-metal hydride cells are 1.2 VDC, whereas carbon-zinc, alkaline, and lithium cells are 1.5 VDC, excepting rechargeable lithium-ion cells which are 3.7 VDC.

...damaging the cable/iem? 2. this product uses china made tube, i was wondering if there is difference to product that uses USA tube such as B4-X or tap2, is it worth to swap it to other tubes? 3. I know there are 3 modes in ADV, 1) single 2) single parallel 3) balanced. May I ask whats the...

...charging circuitry in it? I've probably seen AliExpress pages for the other small tube hybrid amp - but I haven't heard one. I have 3 tube hybrid amps - 1 desktop (Loxjie P20), and 2 portables (Little Bear B4-X, and KAEI TAP-1S) - all of which I have modified, mechanically and electronically.

Other than that do u know anything about the adv portable tube? It gives balanced output while doesn't break the bank like kaei tap 1.

Thanks for your amazing detailed explanation, I'm very grateful and impressed. So between b4 x and tap2: 1. B4 X I manage to speak to the shop and they can modify it where it can be used while charging at the same time. The only concern is noise. Does tap2 have noise when in use? (during...

...and wanted a small tube hybrid Amp - for convenience of use, I would select the TAP-2 - since it uses a standard USB-C for charging, and the B4-X uses a special 12.6V Lithium-Ion charger. The B4-X can not be used while it's charging - when the 12.6V input is connected, a relay disconnects...

Hi all, I am considering little bear b4-x VS kaei tap2 1. B4-x: What's the characteristics of 5899 VS 5784 tube? 2. Kaei tap 1 is much much expensive than tap2, how much of a difference except it's a balanced output? 3. There are two types of Op amp to be chosen for tap2, opa2132 VS muses02...

I mean live your life, but even the best faraday cage will not block 100% of the noise if you're stacking this with the source of the noise. Shielding is about attenuation, not elimination. The tubes are sensitive, so even if you stacked them with a gap between you're going to get significantly...

Just be careful with that foil - I cut one of my fingers right away working with it, and did the rest of the work with gloves on. That stuff is really sharp!

Cool, glad that works for you. I want to stack my DAP and B4-X together so will do a different solution.

Honestly, it doesn't take much physical distance to stop the interference. I got the same thing from the radio on my cell phone, and all it took was putting it in a pocket on the other side of my jacket from my phone to stop the noise. Maybe a foot and a half / half a meter or so is plenty.

B4-X tubes are picking up wifi interference. In some of the earliest posts some guys were lining the case with copper foil to block wifi interference. When I stack the B4-X with Shanling M3X and turn on the wifi I can hear the noise caused by the tubes. Noise goes away after turning off the...

The problem most likely isn't the cable, it's the tubes. Any longer cable will be useful for keeping your phone away from the amp, because it's tube microphonics that are the issue.

https://www.amazon.com/Boaacoustic-3-5mm-Audio-Auxiliary-Stereo/dp/B07XG1PL1R/ref=sr_1_15?crid=1XUG1VZJ20TNN&keywords=HQ+OFC+Shielded+3.5+mm+cable&qid=1665472410&qu=eyJxc2MiOiIxLjQxIiwicXNhIjoiMC4wMCIsInFzcCI6IjAuMDAifQ%3D%3D&sprefix=hq+ofc+shielded+3.5+mm+cable+%2Caps%2C264&sr=8-15...

Are there good quality shielded aux cable for the b4-x, preferably a bit longer, the supplied cable I feel is bit noisy as it picks interference from things like mob phones etc.

Thank you for the detailed specs and the photos. Very helpful indeed. I'll give the SS3602 a try as they are slightly smaller.

Thanks. mt877 has the new B4-X which is the one I have. Looks like there is just enough room for the Sparkos.

...SS3602 will be about the same as the OP8802. The electronic spec for both SS3602 and OP8802 are very similar. I have the newer version of the B4-X. The OP8802 is slightly wider, but not touching the tubes. Edit: Right channel clearance Left channel clearance Top clearance For top...

Yes - they fit, but one side was tight. . I do not know whether the current B4-X has the same amount of space between the tubes and the sockets.

NOTE: I have the first generation of the B4-X, which does not have the relay near the "front" of the circuit board. . Since I built new tube carrier boards (for my B4-X), that move the tubes closer to the edges of the case - there's plenty of space for wider devices, like the Sparkos, or...

Could've find any reviews of the op8802. But there are several glowing reviews of the Sparkos ss3602. Does anyone know if the Sparkos will fit inside the B4-X?