[tourmaline]

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Originally Posted by Roam /img/forum/go_quote.gif I honestly don't have the time nor inclination to read through every single shoot-out and comparison along with trying to determine the viewpoints & biases of those writing the reviews. I'll just have to take your word that people have indeed rated the Bada PH12 over the other amps and that their opinions are honest and pure as fresh fallen snow. However, I do have the schematics for the Singlepower, Doge, and many other amps, and frankly they're nothing to write home about, and in the case of the Doge it's even more incompetant than the Bada. It does not take a world class designer to see the faults in the Bada & other amps, all of the design flaws are basic level fundamental screw-ups which even a neophyte can recognize after reading the first few chapters of Valve Amplifiers by Morgan Jones. It's not rocket science, it's basic tube theory. MOSFETs sound best when they're run wide open, which of course creates a lot of heat. To me it's not a concern, there's only one of them per channel so if & when it fails, replacement is simple & cheap. If the life of the power supply capacitors is a concern, then simple use caps rated for 105°C. The suggestion to re-use the Solen cap was made with interest towards keeping costs down while improving sound, a freebie if you will. If cost isn't a concern then chuck it and use whatever fancy capacitor pleases you. With regards to drastically changing cap values, I suggest familiarizing yourself with the simple formula F = 1/(2Pi * R * C) which determines the -3dB point of the bass roll-off. In the cascode stage, the -3dB point moves from 1.6Hz to 2.4Hz. This will have no effect on the circuit's performance, besides getting rid of the problems inherent with using an overly large cap, that being increased inductance, poorer overload recovery, greater leakage current, etc. The same applies to the coupling cap leading to the MOSFET, -3dB goes from about 1.5Hz to 3Hz, it's an inconsequential changes except for the superior properties of a smaller capacitor. This is all basic circuit design. Actually, I have. The fact that I didn't kick it across the room in disgust is a testament to how forgiving tubes are of epic design failures. All you've done is make blind parts swaps with boutique brands in the hope that it'll improve the sound. You've failed to look at the circuit, understand the circuit, know what it does and what's going wrong, and then addressed the root cause of the problems. One of my designs is in the DIY forum. As for my real name, past experience with insecure deranged audio nuts has led to a policy of keeping it to myself. My wife does not care to find another envelope in the mail containing rambling incoherent threats against me.

one more thing; did it cross your mind that they "intentionally" screw up basic designs to make it sound the way it does?! Like some really high end cables do?!

Thank god there's only one smart guy in town.

Again, i've heard alot, also amps of 50.000 and more but some don't sound that good at all! superieur design doesn't mean it's good at every aspect of sound, tonality is one of em and most fail, even very expensive amps!With the new couplers, the bada is much faster, has more drive and sounds much more detailed allready. With the other mod going on, it will take it even further! A world class high end amp should have correct tonality, speed, drive, stage, air and extended top and bottom with controlled bass! With the mods, the bada is creaping very close towards this ideal!The solens sound closed in with a very small soundstage!I urge everybody with a bada amp to get rid of the coupler and the signal solens as soon as possible and you'll know what the bada can do!(much more then roam is capable of thinking of!)

 

[Roam]

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Originally Posted by a-LeXx /img/forum/go_quote.gif My issue - to much gain for 40-Ohm HPs. What would be your idea to lower gain? Some local feedback? Global feedback? An attenuator at the output of SRPP to MOSFETs?

Without a full schematic I can't really suggest a proper fix. My suggestion for now would be to build an attenuator for the MOSFET outputs, the headphone plugs into the attenuator which then plugs into the amp.

 

[Roam]

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Originally Posted by tourmaline /img/forum/go_quote.gif Sorry roam,but i agree with stuart on this one.Design doesn't tell you anything. it's all in the sound.

If design tells you nothing, then you might as well throw parts together at random and hope for good sound. Oh, wait, that IS what some "designers" do in audio, nevermind...

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It's all too often that on paper something impressed and just sound bad! Happenend before!

Of course it happens. The good designers will then go back and try to figure out why. Hacks, and the unwashed masses repeat the above saying as some sort of platitude to make up for their lack of knowledge.

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I am the one that is turning the bada inside out and and when i am finished it's in another ballpark all together. Even the professional modders stated to me that they were pretty impressed by the sound and that says alot since they mod the most expensive amps on a daily bases with the most exotic components!

That's great. So you've turned it inside out and made it a million times better. Would you care to share your modifications with the rest of us? I've done a search of your posts and come up with some vague mentions of capacitor & power supply upgrades. If they're so wonderful, why don't you share them so the rest of us can benefit from it? Surely you wouldn't want to deprive the rest of us of good sound?

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Again, people don't like the designs of say audio note in general, but they all love the sound and musicallity. Now what does that tell you?!

It tells me you are overly fond of sweeping generalizations.

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You can like the sound of an map or not, but please don't tell me it's a piece of crap. I had much more expensive pieces of crap. Not always the car with the biggest engine wins the race! The bada won out of 20; this means it beats also more expensive american designs!

Fine, the amp's design resembles mung, happy? When an amp sounds like it has serious design errors, and upon examination of the schematic, turns out to actually have a half dozen design flaws, it is indeed mung. I have almost every 6SN7 known to man, the Bada, and yes, I have heard it, is in my opinion a waste of anything better than a GE or RCA 6SN7GTA. Sure it sounds a bit better with a Round Plate or Metal Base, but frankly you're just burning up good tubes for marginal gains.

 

[tourmaline]

Quote:

Originally Posted by Roam /img/forum/go_quote.gif If design tells you nothing, then you might as well throw parts together at random and hope for good sound. Oh, wait, that IS what some "designers" do in audio, nevermind... Of course it happens. The good designers will then go back and try to figure out why. Hacks, and the unwashed masses repeat the above saying as some sort of platitude to make up for their lack of knowledge. That's great. So you've turned it inside out and made it a million times better. Would you care to share your modifications with the rest of us? I've done a search of your posts and come up with some vague mentions of capacitor & power supply upgrades. If they're so wonderful, why don't you share them so the rest of us can benefit from it? Surely you wouldn't want to deprive the rest of us of good sound? It tells me you are overly fond of sweeping generalizations. Fine, the amp's design resembles mung, happy? When an amp sounds like it has serious design errors, and upon examination of the schematic, turns out to actually have a half dozen design flaws, it is indeed mung. I have almost every 6SN7 known to man, the Bada, and yes, I have heard it, is in my opinion a waste of anything better than a GE or RCA 6SN7GTA. Sure it sounds a bit better with a Round Plate or Metal Base, but frankly you're just burning up good tubes for marginal gains.

I thought you knew it all, why should i care to enlighten somebody that is obviously full of himself.

Quote:

The good designers will then go back and try to figure out why. Hacks, and the unwashed masses repeat the above saying as some sort of platitude to make up for their lack of knowledge.

That's why i take care of some problems of the bada and take it to the next level. And it's professionally done, so, i don't have the problem of not having "enough" knowledge.

Changing tubes have been anything but subtle. So, i am still not convinced you "really" listened to the bada.

Just tell the people you don't like the bada and move on to another thread.

He won out of 20, so there are obviously 19 even worse designs, also american more expensive designs. I see alot of work for you to "enlighten" people.

 

[Black Stuart]

Roam,
the only one making 'sweeping generalisations' sorry that should be 'arrogant sweeping generalisations' is you pal.

You ask Tourmaline to provide info on his mods which he will do and that's for sure - but when asked by myself to provide precise info and part nos. and supply cos. - you don't offer any kind of reply at all - do you understand what the word hypocrite means?

Kicking an amp across the floor - was your expression, very revealing that.Your so absolutely certain of everything you say - also very revealing.

Like Tourmaline said - don't thread crap just go away or grow up.

 

[tbonner1]

Thanks Stuart.

Let's keep this thread on topic.

I have the Bada rated very highly in my 21 home amp comparison. As time goes on I am more confident in my review. With many other components (along with cars and motorcycles I own) flaws become magnified as time goes by, but not with the Bada FWIW.

 

[pftrvlr]

I posted the schematic of Bada.

If I were to design the amp myself, I'd have done it differently. But, I have to admit that Bada sounds pretty good - I mean that Bada I have right now, which has no MOSFET in the output. It can only drive my DT880, not the 701. However I am listening to the Bada more than my other amp now.

I guess I really the sound the 6sn7 tubes. I am now gethering parts to rebuild the Bada completely, using point to point wiring. Then I can experiment different component values, even diffetent circuit topologies.

 

[Black Stuart]

pftrvlr,
that's what I call contributing to a thread in a really meaningful way.

I too think that the 6SN7 valve is a damn fine valve, that different versions sound so different - lean or full is only part of it.

Tourmaline has decided to go to town on the original Bada but I feel that your approach will be cheaper in parts costs but will have the costs of new/different chassis to bear as well.

Hard wiring has one huge advantage over a PCB - if you want to tweek an amp, changing out caps or Rs - it is easy, try that with a PCB and it ai'nt enjoyable - track lifting, snapping solid core wires, the effect on components being constantly de and re-soldered. If your not into tweeking then maybe PCBs are fine.

pftvlr - would you consider seperating the delicate signal section from the PSU, which is itself sheilded from mosfets. Tourmaline tells me that the mosfets used in the Bada are capable of pumping out 120W. I was thinking of a two section/box build.

Have you also thought about creating a power amp, given the o/put of the mosfets. As a die hard valve/tube man, what so surprised me was the hybrid sound - which I personally cannot fault.

Would there be some way to create a switchable o/put - one for power circuit and one for h/amp use.

I would like to continue with these questions but have to visit the 'big city' today - will continue when I get back tonight.

This thread now has the potential to really get creative - excellant

 

[pftrvlr]

Black Stuart,

My goal is to re-use the transformer and case of Bada to create an all tube headphone amp. I will take the minimalist approach.

The bada MOSFETs draw power from separate transformer winding and rectifier than the tube section. As it is running in class A mode, it is generatig lots of heat. The cooling fan helps to some extend, but I doubt 120W class A output per channel is possible from a single MOSGET.

 

[Black Stuart]

pftrvlr,
there's no way to get 120W of class A from a single mosfet. I was looking to get about 15/20W per channel using maybe two per channel. But then there is the power consumption to think of as well.

A great idea but is'nt the very small chassis part of the problem for the mosfets not being able to dissipate the heat they create.

What kind of volume control will you use. I keep hearing conflicting views (as always) on digital volume controls. Some describe them as noisy or grainy but when I look at the S/N figures they are outstanding.

Would you not remove the mains Tx from it's stupid place on top of the mosfets and drill out the top plate?

Tourmaline has dumped the puny little fan fitted by Bada and is going to be using 2 Papst fans from a seperate 12V source. He has said that they are nearly silent and far far more effective than the original.

It is'nt only the design of an amp that is important but also it's layout - that is my big criticism of the Bada, they knew the mosfets would generate an awful lot of heat but stuck them inside a traditional chassis. I believe that with hybrid amps need a different style/shape of chassis - indeed why not keep the signal section 'virtually' seperate from the PSU/output.

 

[pftrvlr]

The stock volume pot is pretty decent, I am planning to keep it.

My DAC has digital volume control. I don't hear much noise, though I have really compare it to a pot.

 

[Black Stuart]

pftrvlr,
your handle is a difficult one, do you have an abbreviation which I could use?

The Alps blue will colour the sound in a warm way - why not shunt it. Try resistors of your choice until you find what you like. You will have to turn the volume control a little more but that's all.

As you will not be using the mosfets when you hardwire, will you be using o/put Txs and won't they need to be very good quality so as not to degrade the sound.

 

[tourmaline]

Quote:

Originally Posted by pftrvlr /img/forum/go_quote.gif I posted the schematic of Bada. If I were to design the amp myself, I'd have done it differently. But, I have to admit that Bada sounds pretty good - I mean that Bada I have right now, which has no MOSFET in the output. It can only drive my DT880, not the 701. However I am listening to the Bada more than my other amp now. I guess I really the sound the 6sn7 tubes. I am now gethering parts to rebuild the Bada completely, using point to point wiring. Then I can experiment different component values, even diffetent circuit topologies.

The problem with the tube amp is that the 6sn7 is only capable of low wattage! Hence the problem to drive another headphone. That's one of the reasons the 6sn7 is used as a driver for other tubes, say 300b; it suppose to be one of the best 300b driver tubes.

My modding is done! I got it back, working like a dream, constructed active cooling myself and it is totally cool tot the touch after 3 hours of play!

This way you ensure that the mosfets are working most efficient(not too hot) and a long tube life!

Pictures will be posted soon!

I can assure you, picture extravaganza!( stuart had the premiere).

 

[tourmaline]

Quote:

Originally Posted by pftrvlr /img/forum/go_quote.gif The stock volume pot is pretty decent, I am planning to keep it. My DAC has digital volume control. I don't hear much noise, though I have really compare it to a pot.

I use a custom made linear pot, expensive, yes, but it's like the pot isn't even there in the signal path. I use alot of custom made components in the modded bada!

As i said before, the pics will be posted this week.

 

[pataburd]

The Bada lost its right channel yesterday, but it was not due to a premature tube roll. (Could it have been due to a headphone change while powered up, w/volume up?) The right channel does not pass music, but will emit bursts of static-y sound when the volume level is increased.

(1) Do the symptoms described indicate a blown MosFET?
(2) If so, where can I buy a replacement or two?
(3) Can a mod be implemented to make the Bada less susceptible to this sort of thing.
(4) What sorts of things can blow a MosFET, besides premature tube-rolling?
(4) Does anyone out there want to replace the blown MosFET and possibly do some mods to my Bada? : )

Help!