[alvaroenoht]

Thanks for letting me know! This was the first I've heard of that amp, having been out of the hobby for a couple of years.

So I just put in an order for one on Aliexpress, they're on special for AU$460. (roughly US$337)
https://www.aliexpress.com/item/330...earchweb0_0,searchweb201602_,searchweb201603_

I'll compare it with the B4-X once it arrives and let you guys know my findings.

The BA300s seems to be an otl tube amp.. the little bear is a hybrid one. I dont know what the output impedance of the Oriolus could be, but seems to be designed for high impedance headphones..

 

[seamon]

The BA300s seems to be an otl tube amp.. the little bear is a hybrid one. I dont know what the output impedance of the Oriolus could be, but seems to be designed for high impedance headphones..

The BA300s is not OTL. mki has 4xLMH6643MA(+3dB Gain + Buffer) on the output stage and mkii has 2xLMH6643MA(Buffer) on the output stage.

Edit:
LMH6643MA Output Impedance is actually very very low.

I have used it to drive my 42Ohm Diana V2.

 

[alvaroenoht]

The BA300s is not OTL. mki has 4xLMH6643MA(+3dB Gain + Buffer) on the output stage and mkii has 2xLMH6643MA(Buffer) on the output stage.

Edit:
LMH6643MA Output Impedance is actually very very low.


I have used it to drive my 42Ohm Diana V2.

nice!. is any of the opamps swappable?

 

[seamon]

nice!. is any of the opamps swappable?

In the mkii, since the opamps are just acting as Buffers with around 150mA of current, there's really no need to swap them. Most audiophile opamps can't do more than 50mA. In the mki, you can't swap out the gain stage.

 

[Bosk]

Also, you can connect an Unbalanced Output from a phone (3.5mm) to the Balanced Input on the BA300s(4.4mm). You need a custom cable for that.
Source: Have a custom cable for exactly this purpose.

Great to know - I wasn't sure if this could be done safely. That will allow me to use the BA300s with my iPad for movies as well.

Hopefully the V5i-D's I ordered for the B4-X will be here before the BA300s arrives, so I'll be able to duplicate the comparison in that video. Not sure if he was using the BA300s 2020 version which is what I'll be comparing it to.

 

[seamon]

Great to know - I wasn't sure if this could be done safely. That will allow me to use the BA300s with my iPad for movies as well.

Hopefully the V5i-D's I ordered for the B4-X will be here before the BA300s arrives, so I'll be able to duplicate the comparison in that video. Not sure if he was using the BA300s 2020 version which is what I'll be comparing it to.

He's using the old BA300s

 

[alvaroenoht]

Has anyone already tried the power supply mod?.

 

[alvaroenoht]

Just realized that I forgot one critical component, that every fully balanced amp requires - a 4-gang Potentiometer, to control the L+, L-, R+, R- signals.

For #2, It will need to be a 4-gang stepped attenuator.

For #3, The trimpots probably need to remain, since every tube is different, and may also need adjusting as it ages.

For #5, I did add a GND wire around the Volume Control shaft, so that when the nut is tightened, the "front" panel is solidly grounded.

For #6, I recently looked, but haven't been able to find the chassis mount Pentaconn jacks for sale on AliExpress or in Google Searches - and only the one VERY EXPENSIVE ($66.75 each) listing on eBay. A number of vendors sell the cable mount Plugs, and some have the cable mount Jacks - but the chassis mount jacks aren't readily available to the general public.

https://a.aliexpress.com/_msDFN1X could this work?

 

[DBaldock9]

https://a.aliexpress.com/_msDFN1X could this work?

You'd need to verify that the metal shell is isolated from all 4 signal pins - so that none of the signals get shorted to the case, which is GND.

 

[Bosk]

Allow me to report on my recent portable amp developments.

A few days ago the Oriolus BA300S arrived and I've been burning it in ever since. After conducting a final listening test today I arrived at the conclusion it is not the answer. I don't know if its because I'm using it with A&K DAPs rather than Sony which I assume its been tuned to match, but the sound is too dark and the soundstage too narrow to match either of my DAPs satisfactorily. The Little Bear B4-X is a far better match and it isn't even close. As a result Operation Little Bear Transformation has been launced, and to that end no time or expense will be spared making it all it can be.

So about two hours ago I retrieved my old soldering iron and brushed off the dust that been collecting for the better part of three years since last using it. As luck would have it I'd built up a small collection of audiophile caps, resistors and such from those DIY days and so was lucky enough to find a number of Elna Silmic II electrolytic capacitors ready to use. For those not versed in DIY, in those days (and perhaps still today?) Silmic II's were commonly regarded as the highest quality electroytic caps available now that Black gates are no longer being made.
The largest caps with through hole leads small enough to fit the B4-X's existing board was a quad of Silmic II 220uF 16v, more than double the capcitance of the Rubycon branded 100uF 25v power supply caps they replaced. Yes they're too large to fit inside the existing case properly and are only in there temporararily because I was eager to hear if they'd make any difference.

Well. Without knowing how much difference is due to the larger values providing a greater reservoir of power storage and how much can be attributed to them being higher-grade components, the change in sound is of a similar magnitude to what I experienced replacing the stock OPAMPs with Burson V5is.
Pardon me for gushing a little but there have been across the board changes. Deeper bass -especially sub bass- was immediately the most notable thing, but the soundstage has also widened and deepend, there is better articulation, and the dynamics are better. I would liken the overall effect to the feeling of upgrading to a significantly more expensive amp, and whereas before I was somewhat on the fence about using the B4-X with my SP1000 & Lunas, feeling like as much was taken away as was added, now there's no question I'm more satisfied with the amp in the chain.

Next I plan to upgrade the resistors, and would also LOVE to upgrade the battery but have not found a good replacement - does anyone know where I can source a 12v (or is it 12.6V?) 2-4000 mAh battery to replace the rather wimpy existing 1000 mAh one? Four hours of playback just isn't enough for an entire evening.



Pardon the quick & dirty photo!

 

[Bosk]

Quick question please, would anyone happen to know if the Burson V6 discrete OPAMP's have enough room to fit the B4-X?

 

[Mouseman]

Quick question please, would anyone happen to know if the Burson V6 discrete OPAMP's have enough room to fit the B4-X?

They are way too tall. I think there's a picture in the thread where someone installed them, with the window popped out.

 

[DBaldock9]

Quick question please, would anyone happen to know if the Burson V6 discrete OPAMP's have enough room to fit the B4-X?

I increased the size of the opening in the top of my B4-X, and the V6 op-amps fit.
.

 

[Bosk]

I increased the size of the opening in the top of my B4-X, and the V6 op-amps fit.
.

Excellent! I've just ordered a pair and look forward to comparing them with the V5i's. Might need to remove the plastic cases though as I don't plan on moving my tubes.

Speaking of tubes do we know of any substitues that might offer a different sonic flavor?

 

[DBaldock9]

Excellent! I've just ordered a pair and look forward to comparing them with the V5i's. Might need to remove the plastic cases though as I don't plan on moving my tubes.

Speaking of tubes do we know of any substitues that might offer a different sonic flavor?

I don't think there's a cross reference / replacement tube for the JAN5899.
But, there are some eBay vendors who sell "matched" sets of JAN5899 tubes.