Good VFM? The PANDA headphone amp. I'll say so!

[PinkFloyd]

Music with the stock or modded SCHA has a very different presentation to the stock Panda

Agreed. Lighter, airier and less dynamic (IMO) a lovely sound but, to my ears, the Panda has a lot more GRUNT and takes a better grip of the drivers. Leo, you may prefer the presentation of the SCHA? I can't remember if you were a basshead or not?

[PinkFloyd]

What I find interesting, is that the main references to Panda , when you "Google", are from Rock Grotto, and a few online sellers.

So, what are you saying? This is a relatively new "find" to builders in the Western world.... if you look at the HiFiDIYnet forums you'll see that the Panda is a VERY highly respected head amp in China....

Just because it's not plastered all over Head-Fi / DIYaudio means nothing Alex and it "not" being plastered all over the internet also means nothing....

I don't "need" a flock of sheep to tell me what sounds good. We have a very highly regarded musician here who rates it as the "best" he has heard, we have a few prolific members who also regard it as the "best" they have heard and you have me who also regards it as the best he has heard (bar NONE).

Of course it is all down to personal taste. Thing is, I have actually "listened" to a LOT of amplifiers (so have quite a few of the other guys here) and am basing my comments on my experience of all these different amps.... IMO, to date, the Panda absolutely wipes the floor with most of them.

I have offered to send you a kit to get you up to speed but you seem to be convinced that the SCHA is the way to go.... how will you ever know unless you try a few different amps mate?

[leo]

Nov 15, 2010 20:27:44 GMT PinkFloyd said:

Music with the stock or modded SCHA has a very different presentation to the stock Panda

Agreed. Lighter, airier and less dynamic (IMO) a lovely sound but, to my ears, the Panda has a lot more GRUNT and takes a better grip of the drivers. Leo, you may prefer the presentation of the SCHA? I can't remember if you were a basshead or not?

It is nice to have that power when required When your used to listening to speakers some music can sound sort of weedy with some HA's, miss parts from tracks you know well, if possible it is good being able to get some of those bass notes with cans
The stock Panda isn't bloaty, just a bit of tightening up would be good. Maybe when you bypassed the caps it help lower the ESR a little making it sound a little more tighter ? either that or your mains is dirty and the schaffner helps filter out the crap? It'll be interesting to read your update if you decide to try it without the Schaffner in a few days

[leo]

With all the different amps out there you certainly do have to try as much as you can, its also good fun comparing these things

[Deleted]

Nov 15, 2010 20:23:06 GMT PinkFloyd said:

That's Panda three up and running and initial impressions are that the cap bypassing has added a certain "airiness" to the sound. The bass, whilst still teeth low enough to rattle your teeth, has become more swift of foot. I think it was Leo who mentioned that the bass was a bit "tubby" with the stock amp... well, yes, now that I hear this version I can see where he was coming from.... I don't "why" but the cap bypassing has certainly tightened things up in that dept.

I've also fitted one of those "schaffner" thingways as I couldn't be bothered stitching my own together, let's just say this.... the insight and detail is now a touch clearer so whether this is partly down to the schaffner and partly down to the cap bypassing I don't know so I will remove the schaffner in a few days and have a listen without it.... I used my old ratchet crimp tool to connect the 6.3mm females so no desoldering required, the mains connections are all push on (insulated) on this one.

Light quality is crap here today so I'll take some good pics of the completed Panda Three tomorrow.... here are a couple of pretty dire ones:

That`s a lovely looking job Mike, i see they also do a nice wood sided enclosure, given that some thought for my third, with my own s/steel knob, feet etc, should look nice.

Ian will receive his on Wednesday, i think he is in denial at the moment, do hope he is happy with its performance, sounded damn fine to me.

Mick.

PS.

I have been SHPONGLED

[Deleted]

I have offered to send you a kit to get you up to speed but you seem to be convinced that the SCHA is the way to go.... how will you ever know unless you try a few different amps mate?

I have never said that the SC HA is the way to go. It was however, far better than average at the time, and more than 120 modified units were constructed worldwide.
In fact, the more recent Class A HA eats the SC HA for breakfast,
and that isn't just my opinion.
It also has dual power supplies, and a JLH for each channel.
It also has a bias of >100mA per channel for better Class A performance.
You obviously have a heavy preference for overblown low end, as evidenced by your many recent comments about headphone performance too. What you personally prefer tonally, isn't necessarily what everybody else prefers.

[Chris53]

I thought that one of Mike's headphones was the HD600's. I certainly wouldn't describe the bass of those "overblown" or does this comment put me in the cloth ears category too?

[PinkFloyd]

either that or your mains is dirty

As clean as a whistle up here leo which makes me think the bypassing has paid dividends and may sound even BETTER with the schaffner removed

[Deleted]

Nov 15, 2010 21:27:21 GMT Chris53 said:

I thought that one of Mike's headphones was the HD600's. I certainly wouldn't describe the bass of those "overblown" or does this comment put me in the cloth ears category too?

Unless I am mistaken , they haven't been Mike's favoured headphones for quite some time !
I was referring to Mike's current preoccupation with extracting more, and more from the low end, in preference to accuracy.

[mrarroyo]

"I've also fitted one of those "schaffner" thingways ..."

What does the "schaffner" do?

[xerxes]

What does the "schaffner" do?

It's an electromagnetic interferance (EMI) filter. It's supposed to filter out noise from the mains, which ideally should be a clean 50Hz sine wave (in the UK). However, machinery, motors etc. connected to the mains can add other noise frequencies to the mains 50Hz frequency and filtering these out should make sensitive electronics bahave better.

I think mains filters are a bit of a suck it and see thing, some people like the effect on audio equipment, some don't. Personally I like it, too my ears my system sounds better connected to a mains filter than directly to the mains and I have one of those Schaffner doo-hickeys in all three of my headphone amps.

I also made some parallel filters, which I plugged in around the house: www.tdsf.co.uk/Audio/Mains2.shtml. I'm not so convinced about these though.

[Deleted]

Nov 16, 2010 0:31:40 GMT mrarroyo said:

"I've also fitted one of those "schaffner" thingways ..."

What does the "schaffner" do?

These kind of filters (Schaffner is a brand) are intended for usage at a generating source (the equipment that emits/generates all kinds of unwanted electrical 'garbage').
You can see this by looking at the schematics of it (which is printed on the part) on page 72 and notice the parts on the 'load' part of the filter all have capacitors to gound which conduct these produced RF/IF EMI signals to ground.
That's why they are not seen on the input of the filter (line) as this is supposed to be the clean mains already.
they ONLY work OPTIMAL when mounted on metal casings where everything is mounted in and ONLY when this device is grounded or at least is connected to a grounded mains socket (which often is not the case in audio)

For this reason these type of filters (the ones with the capacitors to ground on one side) work better if fitted 'the other way around' when used as an input filter to filter out nasties on the mains.
So the mains connected to the 'load' of the filter and the 'line' of the filter connected to the amplifier (the transformer).
2 TVS connected, One from L to N and one from N to ground at the cable entry will complete the filter.

Input filters, those that are designed for filtering noise coming from the mains, should be connected the right way around (line on mains, amplifier on the load)

I should note:.... Isolate properly and use a fused mains entry or insert a fuse between the mains inlet (L wire) and the filter parts behind it.

The wiring from the mains entry MUST be as short as possible and NEVER come near the filtered wires physically nor near other parts so it to has proper functionality.
The mains must have a grounded wall socket for it to work as intended.

These kind of filters are normally used to prevent garbage that is produced by machinery or switching power parts in power supplies to enter the mains.
They are really needed there in these cases as without these filters the equipment simply wouldn't pass EMC tests and could(may) not be marketed.

Like all other parts in audio:

These parts are often not used as intended and certain qualities are given to them based on subjective listening, reviews or assumptions.

Some like it.. some don't.
Some hear huge differences, others don't.
They do filter HF energy, even if not applied correctly (ungrounded mains wiring or not mounted on plastic casings), but in a much lesser degree as they could.

It is a bit 'anal' in case of a headphone amplifier but won't hurt in any case under the motto better safe then sorry which HiFi often is all about...

I hope this is not too much info or confusing...

[mrarroyo]

"These kind of filters are normally used to prevent garbage that is produced ..." Interesting, maybe wifes should ...

[Deleted]

I believe that's why they sell closed headphones.

[PinkFloyd]

A close up of Mr. Schaffner:



Fully grounded (bolted direct to the chassis / continuity check across entire cabinet = OK) fuse fitted (below it).... Happened to have it kicking about so why not use it..... belt and braces, belt and braces

Datasheet: www.schaffner.com/components/en/_pdf/Datasheet%20FN2090%20e%2091.pdf

[PinkFloyd]

Whenever I think of the Schaffner this image appears in my mind.......



Oh no, wait a moment.... he's Mr. "Shatner"

"there's bass Jim, but not as we know it"

[Deleted]

For Bass-9 and above all 'Scotty' needs to do is connect the load to the 'line' and connect the mains entry to the 'load'.

Then Scotty can truly say... She can't give anymore capt'n ... or she's gonna blow !

[PinkFloyd]

Will try that when I get home Frans. On a bus at the moment and don't have the Panda with me.

[mrslim]

Mr Floyd, or Can I call you Pink?

Do you have a link to the HifiDiY forum? I'd love to see what they are doing with the Panda.. I tried uncle google, without success.

A message posted on headfi about the Panda rang with something I was thinking about, that the Tip41/42 transistors on the output stage are quite old and perhaps upgrading them to newer/faster/cleaner replacements might be an interesting exercise. (wondering if this has been discussed on HifiDIY.. )

[Deleted]

Changing the output transistors for faster ones is a pointless excercise.
These transistors easily reach 3 MHz (they are emitter followers) while the bandwith of the amp is limited to about 100kHz so the transistors are WAY faster then any signal that could ever be applied to them from driving stage of the amp.
If the TIP41/42 were used as an amplifying device things might be different.
You are free to put in every fast transistor you can find as long as they are complementary, can handle 3A, >20W, have an hfe>30x, Vce>60V

forum: forum.hifidiy.net/
website: en.hifidiy.net/

[toad]

Well I've been listening to the Panda for a few hours now and I must say I'm very impressed. It's a cracking amp with mids to die for. It warms up the K701s nicely and has cracking bass and good resolution to boot.

Mick many thanks for this it's a definate keeper. I love it.

It blows the little Bravo away. It betters the Aune and my GS Novo.

It's a great listen and very musical. It portrays music in an effortless way. It has bags of power.

However, sorry to buck the trend here but I personally prefer my GS Solo by a small margin. The reason being the Solo with LM4562 onboard has a greater detail, better imaging and soundstage and believe it or not IMHO better bass. The Panda has great bass and lovely mid range warmth. The Solo has less warmth and a little less bass but more extension on the bass. As low as the Panda goes the Solo goes lower and has greater control across the bass and lower mids. At least on my gear.

I think Leo summed things up in his comment "The stock Panda isn't bloaty, just a bit of tightening up would be good."

I will reiterate here though the Panda is an awesome listen and I love it. It will definately get plenty of use. It's the sort of amp you can just listen to and enjoy from the word go. My Solo on the other hand can be harder to get into. I even prefer my Aune to my Solo when I'm at work because the Aune is similar to the Panda in that it sounds good from the second you start listening to it, whereas if I want to enjoy my Solo I need to have set aside dedicated listening time to get into the music. Something I don't have to do with the likes of the Aune and Panda.

It's difficult to explain, the Panda is just very easy to enjoy and very musical, more musical in some ways than the Solo.

I may even take the Panda to work and sell my Aune as I listen to far more music at work than at home.

So overall the Panda represents awesome bang for the buck.

Thanks very much for building it for me Mick and please don't think I'm not grateful as I am.

[Deleted]

That's interesting Ian. I love the depth of the Panda and feel that it really enhances the K701 enormously. In fact, it's changed my feeling on the AKG quite a lot.

I never heard my old solo with the AKG's so I don't know. I think the Aune is a good match as well though. (Don't sell it!!!!) Although it has a very low output impedance, it seems to be tailored to suit the K701 quite well. (Less detailed but nice sound)

I'm addicted to the Panda sound. Especially after going from other amps - the difference is quite large.

How many hours has the Panda been going? It may need some time to settle as well?

[toad]

Well I know Mick had it on for a week or so and it's been on here for a good few hours. It's been warm to the touch for about 3 hours so I believe it's had time to warm up. I will post any changes if it does tighten up a bit with use.

I do like it very very much though and I can understand your being addicted to the sound. It's like a beefed up Aune. A nice musical sound that gets the foot tapping. I am pretty sure I'll replace my work Aune with it as I am forever having to answer the phone and visit PCs etc there so an amp with that immediate get up and go fun sound is just what I need at work. Some of my best listening moments have been at work during the odd hour or two where I get no calls LOL.

As for the Solo Ian, the LM4562 transformed mine into a totally different beast.

EDIT: typos... finger trouble today

[Deleted]

Oh, I see, you changed the op amp in the Solo.

I enjoyed the Solo at first until I started moving to other things and then felt it wasn't quite as good as I first thought. The one I sold was an early one and I think there was a drastic revamp; especially after the lead free business went through the EU.

I'd like to hear the Novo one day and perhaps a new build solo to see if things have changed. I never changed the op amp in it.

You sure you're not just accustomed to the Solo sound?

[Deleted]

I have 68 ohm output resistors in mine soon to be replaced with 75 ohm ones, would lowering the resistors value in Ians(100 ohm) give him the SQ he is looking for do you think Mike,Frans or anybody else in the know.

I could detect a difference when i A-B them, but not sure now where the differences were

Mick.