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Chameleon DAC listening and modifications - Page 46

post #676 of 1144
Quote:
Originally Posted by Wood View Post
Hi driguy, thanks for those points for consideration!

Bill was saying earlier that you are using 2 pairs of duelands in the dac and pre-amp http://www.head-fi.org/forums/f7/cha...ml#post6489984

I was wondering why you chose to double the caps up, and not just use caps in one or the other. The reason I am asking I because I am considering trying the duelands myself after all the good vibes from your good self and others about them, but it gets pricey and I am wondering if I can get away with having no caps in say the amp, and rely on the just the one pair between the dac and amp?
Wood, I am not sure what you mean when you say "double up". Each component of course requires them in order to work. All of my gear is tubed after the DAC. The caps in each perform slightly different duties but they are needed as I do not use transformers in my preamp nor my amp except as outputs for the 300b's of course.
I would recommend putting them in the smallest value spot first (in the signal path of course) to get a taste with the smallest up front cost. They do jump in cost pretty fast as the values go up. Parts Connection has fairly frequent sales so I would wait for one if the values are large. Also consider that they are low voltage unless you order a high voltage version (more $$) so the larger value at a lower voltage may be the best choice. Almost anything in a tube amp will require high voltage. As far as I know they have the value Bill Allen used (fits inside the DAC) available and potentially on sale as I believe they are return items. Worth a call if you are interested.
post #677 of 1144
To clarify, I mean, if you are using 2 caps as dc blockers, on the input of the pre, and 2 caps, as dc blockers, on the ouput of the Dac, then because the 2 pairs of caps essentialy feed each other and are both doing the same job, then possibly you could remove one pair, and rely on one pair of caps to to the dc blocking for both dac and pre.

The Diypardise Charlize2 amps don't have input caps and depend on upstream gear having them, such as your dac, or pre. You have to have dc blockers somewhere but why double up?
post #678 of 1144
Thread Starter 

Impedance

Wood,

I think you also have to think about matching impedance as well.
post #679 of 1144
Uh oh, impedance matching, now that really makes my head sore! Not sure how caps are related to impedance, thing is my new intergrated is coming on nicely. You need a decent amp to get the most out of the Chameleon, but there is little point imo of sticking duelands in the dac and then something less than that in the amp. I will give it a try with no input caps in the amp, with another dac (with caps), to check there is no DC problems. And then keep the fingers crossed over impedance. Thanks!

(is it possible these duelands sound better then - no caps -, I mean the descriptions I'm hearing..... surely just, not having caps, cannot be as good as that, are they enhancing the sound in some way, makes yeah wonder?)
post #680 of 1144

Clarification

Quote:
Originally Posted by Wood View Post
To clarify, I mean, if you are using 2 caps as dc blockers, on the input of the pre, and 2 caps, as dc blockers, on the ouput of the Dac, then because the 2 pairs of caps essentialy feed each other and are both doing the same job, then possibly you could remove one pair, and rely on one pair of caps to to the dc blocking for both dac and pre.

The Diypardise Charlize2 amps don't have input caps and depend on upstream gear having them, such as your dac, or pre. You have to have dc blockers somewhere but why double up?
The caps in the preamp are on the output, not the input. The input goes through the attenuator, a grid resistor and then to the grid of the 26. The caps are on the output from the plate of the 26 which is at about 170 volts. Very simple and direct circuit path.
On my amp there is also no input cap. The caps there are between the driver tube and the 300b. The input goes straight to the grid of the driver tube.
post #681 of 1144
Thanks driguy, will give it a try, anything to reduce unnecessary components in the audio path is the way to go (and in the case of super caps, have some budget left to spend elsewhere).
post #682 of 1144

Amplifier 101 ... It's and Adventure

Amplification stages are either current or voltage gain devices. With tubes we are talking voltage gain, with the solid state (Chameleon Amp) we are talking current. (In general) In either case we are using DC voltage to do the heavy lifting, the musical signal is always AC and is just along for the "ride".

After any amplification stage we need to block the DC voltage and pass just the AC music signal. With the Chameleon "Amp" we are converting the current output from 16 DAC chips to voltage with a single resistor and then block the leftover DC with a cap. That's as simple as an amp gets, and you want it as clean as possible. (I.E. excellent caps & I/V resistors required). The very last thing you want to do is pass this pristine A/C signal into a cheap input cap on the next stage of amplification.

Preamp and power amps with caps on the inputs tend to be corporate driven products with little sonic merit. (At least in my book). The quality of the input caps and the whole circuit layout in general is seriously suspect with these designs.

So yes, direct "input" coupling as Tony describes above is a must be it tube or solid state. In fact if you've read this far you have to seriously consider what's inside your next gain stages. You will be shocked how cheap the parts are inside any production amp, I dare you to open yours up and take a look ... "the horror!" The past 70 years of amplification has really been a corporate nightmare. Where airplanes and cars have steadily advanced, amps for the most part have gone steadily backwards in sound quality.

One interesting fact is that back in the 70's the average Joe had no problem spending $400 for a good receiver. Problem is that same Joe 30 years later still want to spend just $400 on a new receiver. What kind of twisted thinking is that! Imagine what kind of "new" car you could buy today for the 70's new car pricing of $4000!

So yes the Chameleon DAC sells for $400 and can be made to sound like $4000 with an additional $400 worth of parts. That's a modern bargain and a real world learning experience all wrapped up in one. The next logical step is to move on to building your very own power amp. Keep it simple and build it yourself ... or mod and amp that has potential with quality parts.

That my friends is not a job ... it's an adventure!
post #683 of 1144
Bill exactly my arguments I use to get people to DIY their Audio gear, any item in a shop is produced with 30% profit for the factory, anything between 20 and 50% for the importer/wholesaler and then 100% for the shop.....just calculate what sort of hardware you buy for a 1000....
post #684 of 1144
Very interesting Bill, now come on hurry up with your blog please, we need it now!!!

Yes I think there is a paradox/irony with this little lizard. It truly is high end, at low end prices (specially with a few simple mods). But, if you stick it in a typical system in the same price range; well it will be good, but your never gonna hear what it can really do (the valab is less demanding in this respect, but deserves the best nonetheless). Like you say, (and as I have to do), to keep prices commensurate with the Chameleon, you have to find the Chameleon version of amps/speakers and mod them, which is ok, because its great fun.

Now Ive' got a Radford STA35 amp and Audionote J speakers (and a pair of Quad ELS63's) etc, stuck in the Cellar of my house in London and they are not to shakey, but.... I'm out of the UK for now, with severely restricted listening space so Ive had all the fun of modding up chinese amps and whatever I can get my hands on for speakers.

The Chameleon is part of my challenge, to put together a compact cheapish truly hi end system. The Dac part is more or less solved, (Ongaku dac clone anyone?) the rest is not so easy.
post #685 of 1144

Decoupling caps

Quote:
Originally Posted by Wood View Post
Great looking caps there Bill, thanks for your update, lets us know about the Cu flat Jupiter as well, lots of choices here.

I see you did the 74hc04 MOD. Or did that come stock?

Those of us who did added a couple of resistors to avoid reflections between the USB, Spidf receiver and the XO.

There should be two 47R resistors between the XO and the S/PDIF and USB receiver.

The possible reflections will introduce jitter.
Easiest thing to do is to remove the connections between pins 3&4 and 10&11 and put the two resistors there.

Here is Rhodes54 diagram, Picasa Web Albums - therealrhodes54

I did the resistor update though I did not myself hear any problems without it. Oh and you can remove and bypass those 3 resistors on the top right as you can see from my pic.

Though if this is Teradaks new stock version then perhaps nothing needs doing.

And some pics of the implementaion on my dac, and the Visay-Rodenstein. I used 0.01 and there was just enough space, the 0.1 size you can see on the input board, much bigger still.
Hey Wood, can you describe the audible benefits of the V-R .01 cap install? Bill Allen told me it is worth doing but maybe the rest of the guys would like to know. Perhaps I just missed your description somewhere along the line. I have ordered them already.
Regarding installation; am I mistaken in my reading of the naked circuit card that these and the 10uF caps are simply in parallel? My reading of it is that they are just "bypass" caps for the 10uF caps which are way larger than the 100pF caps on the datasheet. If that is the case then why try to solder to the old SMD spot? Just solder them to the legs of the replacement caps (you have replaced these already,right guys?) before or after install. If you have not replaced the SMD 10uF caps then you can just solder them into the nice tabs provided by Teradak for the purpose of modding the larger caps. Again, this is not technically on the digital side (not the digital signal path) so a slightly longer path is not as big of a deal. This may help the less experienced or those who hate micro-soldering (count me in here). I think that it would increase the number of guys willing to try it if it were really this easy and we would stop trying to find SMD devices to fit when we don't have to.
The purpose of the "decoupling" caps is to act as a VERY local temporary current supply for the chips during load changes. Sound familiar? Yup, that is the Reservoir Mod in a nutshell only more local. Yes, that does mean that we are modifying the power supply AGAIN.
Of course this is all moot if I have it wrong. Let me know. I would simply measure it for continuity but it is a pain to get to my unit. I will make sure when I take it out to do this in the next few days after delivery of the new caps.
post #686 of 1144
Yes Woody please elaborate on what you heard with the Vref decoupling mod.

Steve Nugent says that ideally we use .1uf caps at this position. The only way the .1uf Vishay-Roderstiens are fitting with the blackgates is with long legs. "I ain't afraid of no Ghosts."
post #687 of 1144
On my new blog I plan to explore low cost DIY speaker solutions and yes even amps that can be modded to deliver real music in real rooms.

The biggest issue with amplifiers is moving from one gain stage to the next. This is not unlike passing a baton in a relay race, be it running, skating, or Nordic skiing, the key is a fast smooth transfer. Easy concept to understand yet in most gain transfers the handoffs are slow and awkward, with slow being the biggest problem. With that thought in mind you would think an integrated amp would have the clear advantage, as any competent audio engineer should be able to implement this gain transfer properly. Obviously this is not the case with any known integrated amp … including the Ongaku. What does that say about the present stage of audio engineering? Let me help you out … Piss Poor!!!

Last night my wife and I went to see Alice in Wonderland 3D at the Imax theatre. Like Avatar, this new 3D movie experience is some next level stuff, very amazing technology. Made me think where is our next level stuff in audio reproduction.

Alice in Wonderland;
"Alice laughed: "There's no use trying," she said; "one can't believe impossible things."
"I daresay you haven't had much practice," said the Queen. "When I was younger, I always did it for half an hour a day. Why, sometimes I've believed as many as six impossible things before breakfast."
Alice in Wonderland.

Here are my Six:

1.Microphone’s that effortlessly record from 20Hz to 20kHz cycles.
2.A/D converter that automatically transfers a live music feed to the internet with no loss in resolution.
3.Sound Engineer’s that can leave the above alone and simply capture the moment & Musicians that get paid!
4.D/A converter that plays back the live music feeds from the internet with no loss in resolution.
5.Amplifiers that are just straight wires with gain.
6.Single driver loudspeaker that can play from 20Hz to 20kHz … in any room.

These are 6 impossible audio things that I believe in, breakfast starts at billallenmods.com in the very near future.
post #688 of 1144
Quote:
Originally Posted by Bill Allen View Post
Yes Woody please elaborate on what you heard with the Vref decoupling mod.

Steve Nugent says that ideally we use .1uf caps at this position. The only way the .1uf Vishay-Roderstiens are fitting with the blackgates is with long legs. "I ain't afraid of no Ghosts."
Planning is the key with this mod, removing the existing smd caps is quick enough going backward and forward with the iron, another trick I learnt is to put a blob of hot solder enough to cover both end of the smd, pops of very easy. I had to take out 2 rows of BG to get enough elbow room.

With the 0.1 you might be able to fit them between the rows of BG or use all the legs to lift them above the BG, either way long legs. I can't compare 0.1 to 0.01 but there is nothing lacking as far as I can tell.

Tony I didnt tie the caps directly to the BG because It gets fiddly for my clumsey fingers.

The difference in SQ is immediately obvious when you plug the dac back in, the midrange and above really shines, and bass instrument, contact sounds, are faster and tighter and gain their distinct textures and character, so that the contribution of bass becomes more then just providing rhythm.

With some burn in the expressive touches of a performer on a drumkit come through, no less, then say a singer did, before the mod, I can tell you that is stunning. All the performers individual talents start emerging.

Everything that is supposed to sound fast, sounds faster, more immediate and so is more breathtaking.

The existing smd don't colour the sound or do anything bad, but the replacement caps let much more through, a lot more! Its as if this upgrade, is a part in the puzzle that allows one to see more of the whole picture, rather then just the individual parts.

I think the Vishay-Rodenstein, are allowing all that effort of doing the other mods and installing better caps, payoff much more, cos there is no way they can be doing all this just by themselves.
post #689 of 1144
Bill, I'm with you yet I'd vote to add 1 item; an acousticly perfect listening room at no extra cost.....
Solve that and your Mike item is also solved (a Blümlein Pair of great mikes goes a long way)

I've heard some original studio master tapes on a high endish system and was amazed how much detail is recorded, I am firmly convinced that item #3 is important too (many audio engineers start at concerts and it is usually only once they have firmly established hearing damage that they are promoted to studio engineer allowing them to screw up perfectly fine recordings.
post #690 of 1144

Chip Cap Mod

Quote:
Originally Posted by Wood View Post
Planning is the key with this mod, removing the existing smd caps is quick enough going backward and forward with the iron, another trick I learnt is to put a blob of hot solder enough to cover both end of the smd, pops of very easy. I had to take out 2 rows of BG to get enough elbow room.

With the 0.1 you might be able to fit them between the rows of BG or use all the legs to lift them above the BG, either way long legs. I can't compare 0.1 to 0.01 but there is nothing lacking as far as I can tell.

Tony I didnt tie the caps directly to the BG because It gets fiddly for my clumsey fingers.

The difference in SQ is immediately obvious when you plug the dac back in, the midrange and above really shines, and bass instrument, contact sounds, are faster and tighter and gain their distinct textures and character, so that the contribution of bass becomes more then just providing rhythm.

With some burn in the expressive touches of a performer on a drumkit come through, no less, then say a singer did, before the mod, I can tell you that is stunning. All the performers individual talents start emerging.

Everything that is supposed to sound fast, sounds faster, more immediate and so is more breathtaking.

The existing smd don't colour the sound or do anything bad, but the replacement caps let much more through, a lot more! Its as if this upgrade, is a part in the puzzle that allows one to see more of the whole picture, rather then just the individual parts.

I think the Vishay-Rodenstein, are allowing all that effort of doing the other mods and installing better caps, payoff much more, cos there is no way they can be doing all this just by themselves.
I don't know what we can label this mod that sounds good and gets across that it is slightly different than the other cap mods (slightly). I will leave it to Wood since he is the first to do it (I think).
I will agree with his description of the improvements to be had here and that they may not be as apparent to those who have not done some of the other mods. Very much worth doing and not too expensive especially if one has already paid for the BlackGate caps for the DAC chips.
Also agreed that a bit of planning is necessary to get the job done in the easiest manner possible. I will give a few tips here to help out those who may be doing both DAC chips at once. This is by far the easiest way to do the mod as you do not have to remove previously installed parts.
First off for Wood and others who may be having trouble holding on to the parts and soldering them. This probably includes anyone without 3 hands. Use a rubber band to clamp the caps to something that is nice and solid or that can be put in a vise. Not too tight, just enough to hold the caps down. Much better than trying to use a vise to clamp them directly. Tin the leads of the larger cap close to the top of the leads. Then tin the leads of the smaller cap. Now you can just solder the two together with the soldering iron without having to hold any solder with the third hand that you don't have. If you feel more solder is needed you can apply it one leg at a time without the need to hold on to anything but the solder and the iron. Do not solder down lower on the larger cap leads as they may not fit into the holes provided. If you do not have one, a spring loaded pair of tweezers is recommended to hold the smaller parts. A regular pair of tweezers with a rubber band holding them closed will work as well. These tweezers are good to use as heatsinks when soldering close to heat sensitive parts as well.
Now you can install the assembled caps into the holes provided (thanks Teradak). Leave enough length on the cap legs to get clearance for the smaller cap over the other stuff on the board.
Another way to do it if you have caps installed already is to just solder the smaller caps where the old SMD 10uF tabs are. Like Wood mentioned, you will probably have to remove the previously installed caps to get this done.
This is just like the Reservoir Cap Mod only even closer to the current sink (load). If you have the time look up the ESR of even a BlackGate electrolytic vs. almost any film cap you will see that it has about 2-3 times the resistance. That is why this little film cap gets the job done. Please see one of my previous posts for a recommendation for a nice film cap to use in lieu of the BlackGates if you have not purchased them already.
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