DBaldock9
Headphoneus Supremus
Saw this mentioned on the "Portable tube amp from china?" thread.
Turns out to be basically what I was wanting to do, with mods to the Little Bear B4-X.
The B4-X has a Single-Ended Input, a pair of small Raytheon RF tubes in the preamp section, with a pair of dual channel op-amps driving the Single-Ended and Balanced Outputs.
I had an idea of modifying it to have a Balanced Input, two additional tubes, and more battery life & stronger power supply - that can operate while connected to external power to charge. (The B4-X can operate for ~4 - 4.5 hours, and then has to charge for ~2 - 2.5 hours, before being used again.)
Enter - the KAEI TAP-1S - Fully Balanced Tube Hybrid Portable Amp & Desktop Power Supply - 4x tubes in preamp, 2x socketed op-amps in driver stage, discrete transistor output stage - Input (3.5mm TRS & 4.4mm TRRRS); Output (3.5mm TRS & 4.4mm TRRRS) (portable = 1.5-W/Ch ; desktop = 2.45-W/Ch)
https://www.aliexpress.com/item/1005002983396935.html
I really do like the sound of this Tube Hybrid Amp.
For those of you have have tried mods on the Zishan DSD and DSDs - the TAP-1S unfortunately shares the same sort case, with end-caps that come off, and a pair of circuit boards that slide into the case from the end. This limits the height of replacement op-amps to possibly using a Burson V5i. It would be much easier to do op-amp rolling, if the case was like the Zishan Z1/Z2/Z3 - where the top of the case can be removed, allowing easy access to the op-amp sockets, while the circuit boards are protected by the case bottom. So, now I'm thinking of ways to cut the sides (but still keep things securely attached together) - to allow the top to be removed.
Turns out to be basically what I was wanting to do, with mods to the Little Bear B4-X.
The B4-X has a Single-Ended Input, a pair of small Raytheon RF tubes in the preamp section, with a pair of dual channel op-amps driving the Single-Ended and Balanced Outputs.
I had an idea of modifying it to have a Balanced Input, two additional tubes, and more battery life & stronger power supply - that can operate while connected to external power to charge. (The B4-X can operate for ~4 - 4.5 hours, and then has to charge for ~2 - 2.5 hours, before being used again.)
Enter - the KAEI TAP-1S - Fully Balanced Tube Hybrid Portable Amp & Desktop Power Supply - 4x tubes in preamp, 2x socketed op-amps in driver stage, discrete transistor output stage - Input (3.5mm TRS & 4.4mm TRRRS); Output (3.5mm TRS & 4.4mm TRRRS) (portable = 1.5-W/Ch ; desktop = 2.45-W/Ch)
https://www.aliexpress.com/item/1005002983396935.html
I really do like the sound of this Tube Hybrid Amp.
For those of you have have tried mods on the Zishan DSD and DSDs - the TAP-1S unfortunately shares the same sort case, with end-caps that come off, and a pair of circuit boards that slide into the case from the end. This limits the height of replacement op-amps to possibly using a Burson V5i. It would be much easier to do op-amp rolling, if the case was like the Zishan Z1/Z2/Z3 - where the top of the case can be removed, allowing easy access to the op-amp sockets, while the circuit boards are protected by the case bottom. So, now I'm thinking of ways to cut the sides (but still keep things securely attached together) - to allow the top to be removed.