Zigisg Portable Amp

[Deleted]

IMO, the gain is spot on for the K601. I don't what you set the new one at Zigis but it is really comfortable where it is.

I can't stand amps with the gain set too high. Poor tracking at the bottom becomes a real problem. It was a bit of a problem with the Neco, but I had mine lowered and it got rid of it.

Also lowers the noise level doesn't it?

I rather like the simplicity of the amp as well, not having too much in there to interfere with a pure signal.

[Deleted]

Feb 24, 2012 20:58:35 GMT @iancraig10 said:

Also lowers the noise level doesn't it?

I rather like the simplicity of the amp as well, not having too much in there to interfere with a pure signal.

yes it certainly does, but only it's own noise which in case of a OPA2134 is already very low.

Funny thing is the Zigis only has 1 opamp in it and 'appears' as there are very little components in it.
BUT.... the total amount of parts used is actually quite big (much more parts than in a Panda or AK A-HA) and the circuit itself is also way more complex.

Inside each opamp there is a pile of transistors, resistors, compensation networks, capacitors, current sources, diodes e.t.c. perfectly matched and combined on a very small surface.
2 of those circuits are on 1 chip and in one small housing.
Add to that the extra parts in the TLE (where the audio signal passes through as well) and the 'minimalistic' approach suddenly isn't very minimalistic anymore.

[Deleted]

The amp itself is the most basic C'Moy there is.

Come on Frans - simple or complex?

Are you talking about the fact that the chips incorporate more 'bits' so in fact it's not so simple?

[Deleted]

Yep exactly,

There are more parts (transistors mainly) inside the opamp than there are in the Panda or most other discrete amps.
They are just much smaller and appear to be one part when looking at it's case.
It's a reason why Chong feels opamps can never sound as good as discrete amps I guess.

Inside a small plastic DIP or metal case package (and also those tiny SMD opamps) there are more parts than in the Panda.
Only capacitors above a few pF cannot be stuffed in the silicon chip.
Only resistors, semiconductors, tiny value inductors and capacitors can be made 'on chip' but the number of parts and complexity can be incredibly higher.

The circuit itself (schematic) inside the chip also is much more complex (much more gain stages and elaborate circuitry) and the audio signal passes through lots more parts.

So in essence the Zigis amp has more parts and is a more complex design as a discrete amp is COMPONENT COUNT wise at basic component level.

The Zigis does have very little parts surrounding the chip and is the standard application of an opamp in the most basic form.

www.ibiblio.org/kuphaldt/electricCircuits/Semi/03323.png
Above is a picture of the schematic INSIDE of the well known, and not so well performing, uA741 chip.
The more modern designs use more transistors and even more complicated architecture so although an opamp seems to be a single part it consists of a whole bunch of them.
The real schematics and architecture of opamps is 'secret' although sometimes a principle schematic is given. This appears not to have many parts inside but only 'basics' are given.
The reality is much more complex.

[funk1969]

Cool...

[Deleted]

Hi Zigis,

Here are the schematics of both amps in pdf Format.
first version: www.mediafire.com/?82c6qlwc2x6wb6b
upcoming version: www.mediafire.com/?az1idbz9l7wh15f
You can download them and host/publish them yourself if you want.

[Deleted]

Mar 2, 2012 19:16:33 GMT @solderdude said:

Hi Zigis,

Here are the schematics of both amps in pdf Format.
first version: www.mediafire.com/?kaque3dw8eaqgq9
upcoming version: www.mediafire.com/?o1y1zdfr0n31ij3
You can download them and host/publish them yourself if you want.
The newer version has some parts that are not yet verified.

Very interesting Frans, lots more going on than the average electronically challenged person like me, would envisage.

I would like just 10% of your knowledge regarding electronics.

Mick.

[Deleted]

I would like just 10% of your mechanical skills / knowledge

and your headphone collection ;D

[Deleted]

Aaaah. What sweeties!!!

You know, I was thinking today, I'd like to put a decent 30v supply on this amp but the pricing works out kind of mad!! £36 for the amp plus £200 for a supply.

The cheap little 24v supply I use puts noise into the amp which is detectable on low impedance headphones which is a pity.

That means when plugging it in, it would be way better to put something half decent on it but that means putting a lot more money into it, or sticking with just 9v batteries.

[Deleted]

Ian,

You don't need power as current is restricted by the virtual ground.
All you need is voltage.
So you can stack 3 of those 9V batteries (in series) and have a clean 24V available.
It will even be portable and you can drive HD650 near it's limits !

Batteries will last equally long as a single 9V in this case (even longer actually)

low impedance headphones cannot be driven well from this amp AND do not need a high voltage (a high voltage can never be reached because of the current that is limited) so a single 9V will already be enough.

[Deleted]

I'm driving the K601 and the HD650 from it Frans, so I was wondering about whacking the full 30v into it.

It seems to have more impact with the 24v supply (with added noise)

I'm not using low impedance cans with it. In actual fact, I don't think they improve with it that much. I'm not sure, but it seems as though low impedance lose a little top end. (Or gain more bottom end)

So just make a box for 3 batteries?

[Deleted]

Yes, that seems a good idea.

You can give it a try already using the 9V clip.
Since + and - of the batteries 'fit' (and if you have 3 of those lying around) you can connect 1 pole of 1 battery to the clip.
The next battery you press on the open pole of the first battery.
The third battery you connect to the open pole of the 3rd battery.
The open pole of the third battery you connect to the clip.
can't do much wrong and to test you don't need to solder or have 3 battery clips.
???If it works for you make a nice external case with a plug.

[Deleted]

Just a wild thought, apart from trying the 3 x pp3 batteries in series.

As you are a Naim owner, you'll have some incarnation of at least one HiCap in your system. With an adapted lead you could take 24vdc from one o/p of a Hicap to the Zigis, just to see if a decent mains supply has the desired effect

[Deleted]

Just mind the + and - when connecting an external power supply.

If reversed it's bye bye opamp, capacitors and maybe even the rail splitter.

[Deleted]

Mar 10, 2012 19:10:38 GMT @cjarchez said:

Just a wild thought, apart from trying the 3 x pp3 batteries in series.

As you are a Naim owner, you'll have some incarnation of at least one HiCap in your system. With an adapted lead you could take 24vdc from one o/p of a Hicap to the Zigis, just to see if a decent mains supply has the desired effect

Aha .......... Bang!!!!!

I'm think more for those hotels I visit on a regular basis Chris!!

[Deleted]

Naughty boy!

I was coming from an experiment angle, just to see if the good quality mains supply was worthwhile.

I now have a picture of you checking in with a case cart full of Naim gear.....

[Deleted]

Mar 10, 2012 19:58:28 GMT @cjarchez said:

Naughty boy!

I was coming from an experiment angle, just to see if the good quality mains supply was worthwhile.

I now have a picture of you checking in with a case cart full of Naim gear.....

I can see it,

'Err, hello. Have you got a nice rectangular shaped room for me and my Naim with lots of sound damping 'cos I don't want the neighbours to hear. I'd like a nice filtered mains so I don't get any buzzin' cos my female socket is just waiting for that 1/8th inch jack to play that t'umpin' music man!!! Yeah baby!!!!'

I'd better stop, I'm starting to sound like Mike.

[Zigis]

Hi, long time have not been here.
Solderdude, both schematics are correct, thanks.
In both diode position now I use Shottkys, I find in Farnel for good price.
On board is place for C3, like in datasheet, however I don't use it. I cant hear any noise or osicillation.

Rabbit, I use amp with 3 x 9V rechargable in series too, with 300 ohm HD580. I like it little more than with my 24V PS. However at the moment in my amp are 2 x OPA627 on adapter and I like to listen at low volume.

[Deleted]

Hi again, Zigis. I connected it to a very posh24v power supply and there is absolutely no noise at all.

It really seems quite funny to have a Cmoy running from a £200 supply though!!

I guess I need to collect some decent supplies!!

[Deleted]

Solderdude, both schematics are correct, thanks.In both diode position now I use Shottkys, I find in Farnel for good price.On board is place for C3, like in datasheet, however I don't use it. I cant hear any noise or osicillation.

The schematics have been updated accordingly (reply #105)

[toad]

Mar 19, 2012 18:41:02 GMT @iancraig10 said:

Hi again, Zigis. I connected it to a very posh24v power supply and there is absolutely no noise at all.

It really seems quite funny to have a Cmoy running from a £200 supply though!!

I guess I need to collect some decent supplies!!

Get one of these Ian www.ebay.co.uk/itm/BATTERY-HOLDER-10-x-AA-R6-HR6-R6P-1-5V-BATTERIES-PP3-OUTPUT-CONNECTOR-/230760690724?pt=UK_ConsumerElectronics_Batteries_SM&hash=item35ba68b424


Chuck in 10 duracells and you've got 15v with a 9v connector and they last ages.

Ian

[Zigis]

Someone, who long time use my Desktop LM4562 amp with high quality 30V PS, ask me to build him portable amp with the same sound quality, powered with high voltage.
After some discussion, we come to conclusion, "compromise" could be Hammond 1455J1202 enclosure with amp and 3 x 9V battery inside.

27V for chip and 120x78x27mm box for portable, not bad!

Attachments:

[Zigis]

Amp have 6.3mm phone socket, one 3.5mm input at front for portable use and extra RCAs input for home use.

So, amp is dedicated to two types of music lovers;
a) maniacs, who be willing carry in pocket 120x78xx27mm brick for uncompromising sound,
b) who just want to enjoying music with high voltage powered amp and extra clean battery power

Sorry, I made photo in building process, wen I notice I miss few screws (at home)

Attachments:

[mrarroyo]

A few years ago that would have been considered an average size amp! I like the 6.3 mm socket specially when used at home or office.

[Deleted]

Zigis, are you going to start making these for real or was this a one off?

I still rate the little Cmoy very highly. Nice, simple little circuit that does the job well.

I'm one of the nutters Who is perfectly at ease jumping amps around.