OK - thank“s
now I will start !!!!!!!
greets
vid
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OK - thank“s
now I will start !!!!!!!
greets
vid
Hi Guys - Just a bit of final advice please.
Have been running a 7520 with a 4526 and ML5/6 removed into a pre-amp with a 33k input impedence.
Today I carried out Stans suggested initial passive mod
http://theartofsound.net/forum/showp...&postcount=207
Well that was definately a step closer to audio nirvana; but I guess I now need to fit the capacitors.
I've read all 101 posts on this thread and have come to the conclusion that I should be considering a cap' with a value of 2.2uf. In fact Martin has been so impressed with the 2.2uf 200v Auricap that I'm thinking I'll try these.
I just looking for confirmation from the experts out there that even with a standard 7520 this is the way to go
Great site guys - keep up the good work
Regards
Tony
Tony I would go a little bigger than 2.2uf say 3uf.
I use 3.9uf Claritycap ESA into 24k for a Linn Kairn. I prefered these to the 4uf Auricaps I tried, 250V version of Clatiycap also allow the case to close.
The Claritycaps are good but I preferred the Auricaps. The value is not too important as long as your preamp has a decent input impedance of, say, 50k ohm or greater.
Thanks for you input guys (no pun intended)Quote:
Originally Posted by LittleTone
Pre-amp has two switchable settings. i.e.input impedence is 33k on 150mV setting (currently using )
OR an input impedence of 50k on 775mV
Also have a switchable subsonic filter engaged 12db/octave Butterworth, -3db at 17Hz
Please advise if ok to go ahead...............
Tony
You definitely want the 50k 775mV otherwise the input circuit will be saturated into distortion.
Hi Martin,
Thank you for your assistance; I'm getting there
Yes, OK I'll switch it over to the 50k impedence setting. I had wondered about this; considering the output from the DAC was probably quite high.Needs a bit more stick on the volume control control though.
The Cap' calculator would suggest a value of around 1.6 uf now. Do you think that would be OK.
Curious - As I have no caps' in place at the moment does that mean my optimal
low frequency response is infinity. The sound is better; vocals have really come alive; more detail and the difference between good and bad recordings seems more noticeble. but does sound less controlled, especially at the bottom end. Hence the caps I guess.
TIA
Tony
Hi Tony, what do you mean by this? Are you still using the op-amp board output? If so, then the lo frequency cut-off will not be DC but it will be very low.Quote:
Originally Posted by LittleTone
With coupling caps, as you have calculated 1.6uF upwards will be fine, making 2.2uF the obvious choice unless you have a size restriction with certain brands of cap.
P.S. there is no need for the subsonic filter unless your speakers have very limited power handling.
I'd get some capacitors in the respective positions as soon as possible if i was you ;) If i'm right the output of the DAC is sitting at about 2.5V for zero volts output as it's only powered by a single 5V rail. This means you are putting 2.5V DC down the audio cables to your amplifier & it'll probably be dropping this accross the input resistor which will result in an increase in Johnson noise.
I think you are lucky that it's not a DC coupled amplifier & must have capacitors on the input or you'd experience some serious problems :doh:
Eek, I was hoping that Tony is not doing that!
Wired it like this post by Stan
http://theartofsound.net/forum/showp...&postcount=207
Regards
Tony
Ah, ok that's fine :)
i have been reading this post since beginning,stay with 47uf caps(nichicon zk's) very nuetral,bypass with polystyrene .06 to .1,better than any polypropelene.you can pick them up on the net surplus.I've been using them since the 80's,also use small values on power supply electrolitics,silver mica or polyester-pass.try listening comparisons.polypropelene's are good but the prices have sky rocketed.
Hi Nick,
Welcome to AoS :)
Could you please pop into the Welcome area and introduce yourself to our community?
This is required by all new members, so use the existing threads there as a guidline to see what info is required (system details and music tastes).
Cheers! :cool:
Marco.
has anybody though of buying another one and running them as mono pair?
Not really, but do explain what you would expect to hear?
no cross talk between channels,everything is separated,power supplies,etc.getting back to caps-conrad-johnson has been using polystyrene coupling caps since the late 70's.
I still like the sound quality I'm getting from 2.2uF AuriCaps. I like dual-mono construction in general, but doubling up on Caimans is probably egging the pudding too far and there may be better ways to do things.
I can see problems straight away. You only have a single 75 ohm coaxial cable or Toslink. Splitting that into two without buggering up the 75 ohm impedance would be a game in itself :eyebrows: Likewise with the Toslink me thinks.
Of course after that the problems just keep mounting up. What you need to do is make seperate PSUs for the left & right output ICs or Gator if fitted. Would save a shed load of hassle at the end of the day ;) However still not the easiest if you don't know precisely what you are doing :eyebrows:
Very much so. But I am getting fed up of the ever increasing pile of abandoned expensive prototypes. I need a breakthrough.. Maybe pure DC (i.e. no caps in the signal path ) might be the solution to those caps.Quote:
Originally Posted by MartinT
...which leads to fully balanced design with XLR outputs, yay!
Please? :)
How about using two DAC chips in differential mode to do this? Surely a better idea than converting single ended to balanced :scratch:Quote:
Originally Posted by MartinT
Yes, was thinking that, cancels out the distortions rather nicely too.
Indeed :)
Balanced leaves me hot and cold... I don't even own a balanced amp. I am not running a studio set up after all.
:lolsign: You don't know what you are missing Stan, get up to date :spank:Quote:
Originally Posted by StanleyB
I much prefer a balanced system & i'm sure Martin will totally agree :) The difference between balanced & single ended isn't subtle, it's quite noticeable ;)
Agreed! Stan, balanced is not just for studios. It inherently has lower noise floor and better noise rejection but the thing I find is that balanced connection always sounds more dynamic and tighter in the bass, too - especially when the whole system is connected that way.
Try the em8740,balanced out and you can tap the + signal from each channel for single ended.
I ment the wm8740.
All well and true for a more expensive system, but the average punter is more into a T-amp, Grado SR80, and some bookshelf speakers. For him/her a balanced DAC is a waste of money. What that person is looking for is something with high satisfaction level at no more than £99.99 to £149.99. There isn't much out there that currently satisfies those buyers and their budget. The TC-7510 sold by the lorry full each year because it mainly catered for those kind of users. But few DACs in that price range have shown up lately with the same giant killer instinct. High tech designs with prices starting at £299.99 are now the norm rather than the exception. They can afford to be XLR.
But the budget conscious have been cast aside and left to take a punt on unknown quantities found on eBay. In the mean time only the expensive high- end solutions to each problem are being served up by many newcomers to the DAC market. It's economic overload for the financially hard pressed. We need a new revolution that will take us back to financial reality and serve us up with cuisine at take away prices.
The TC-7510 was one of those DACs that set a new trend with its features, performance and price. Even a two or more year old version can still sell on eBay for more than 80% of its original purchase prise. How many DACs can boast of the same value holding ability, let alone a budget DAC? If it had been balanced I doubt it would have been so cheap, and so popular at its price point. Maybe that explains why there was never a MK7 version :eyebrows:.
You did ask for ideas! The budget market is very much me-too. Surely you've built up a following on the forums with the taste for a little more performance? Maybe it's just me.
I can only speak for myself, but what I call budget can be a difficult feat to repeat by even the Chinese DAC builders :eyebrows:. As I was playing with the prototype of the Caiman RC I put it aside and asked myself why I spent two years improving on the Caiman, instead of improving on the technology? I happen to read a review of a recent DAC that mentioned it introduced the technology of upsampling to 384KHz. It struck me that the TC-7510 was oversampling at 352.8KHz and 384KHz all those years ago, but little was ever made of it by me as far as marketing was concerned. There was only a brief mention in the product write up.
I suspect that my next budget DAC will be an equally impressive giant killer, and give me a bit more time to come up with something more spectacular for the well healed.
stan has done an excellent job regading the mod,work with what you have,upgrad to the best parts you can afford and improving the power supply is the heart of any audio gear.sad to say cost constrants to build in a certan price range limits some part quality.
Just a note, I have both balanced systems (have worked with them for years) and non-balanced. After lots of experimenting, I do not believe that balanced is any panacea or that it has any inherent sound quality advantage. What it can do is to provide common mode noise rejection, and if implemented properly it can provide immunity to ground/earth current fluctuations (which unbalanced can overcome with good grounding practice). This may be useful for you in a specific case (I've seen this once domestically with high RFI problems), and it is useful for professional applications where cable runs of many 10s of meters are common. Balanced is of course mostly required for professional microphones as they have noise problems from long cable runs - that's a whole other story.
However, this comes at a cost of typically double the component count (which means double the distortion and noise generating bits), and added complexity. Balanced does give you an extra 6dB of gain (that's quite a bit), which can give the illusion of sounding better. Depending on how it is implemented (ICs etc), a balanced audio circuit can sound worse than its unbalanced counterpart due to poor implementation and added component count. I have experienced this with some balanced input power amps, which were essentially unbalanced but ran the balanced input through extra op-amps and sounded worse through the balanced input.
Stan is right, for typical home listening, unbalanced is fine and provides a more cost effective solution. With properly controlled listening tests, and well designed equipment, I've never heard a significant difference. Don't forget that such audio design gurus as Nelson Pass (and Scott Wurcer etc) have produced many unbalanced designs when they could have produces balanced versions if they thought it sounded better (yeah, OK, NP used balanced too with the later Zen-like designs, but for the extra gain...).
I wasn't arguing for pseudo-balanced designs. I only use components with fully balanced internal design, where balanced connections are the natural continuity between components. There is no additional component count in this case, it's the natural way of connecting them up together.Quote:
Originally Posted by tdog
Been there, done that :)Quote:
Originally Posted by nickbojko
There's not really a lot more I can do to my Caiman. And lest anyone thinks I'm criticising Stan, nothing could be further from the truth. I applaud his great designs, his openness and willingness to be present on a forum to answer so many questions from the likes of us. He is a model to other manufacturers as to how to generate a large and loyal following.
I just use my Caiman (and Gator board) as Stan sent them to me.
I can't be doing will all this fussing.
Any significant improvements would come in the speaker area, and that can get expensive.
Note that I am very happy with my Caiman now that I have an updated Gator board from Stan and I don't think I have any need for XLRs.
That said I do remember reading that my Rotel Class-D amp, which uses standard ICE Class-D modules, is actually a balanced design but there is a simple phono to balanced board on the inputs and people have converted these back to a balanced input. Let me go google...
Ah, here is a discussion: http://www.avsforum.com/avs-vb/showt...1109794&page=3 with a pointer to the original work on a French language forum: http://www.homecinema-fr.com/forum/v...056&t=29914113
I have had my caiman a few weeks now and im enjoying it very much but would like to try this passive mod.
When i had the 7520 i also had the gator board fitted which again was very good.I don't have the money to get the gator board for the caiman atm so for now can someone reccomend some caps to try.
My croft amp has an input impedance of 100 kΩ
With an amp input impedance of 100K you have a lot of options. Firstly I would recommend that you browse back through this thread and find the diagram that shows how to insert the caps into the opamp board sockets. Basically you remove the opamp board and insert the cap legs into the left hand socket. Doing the mod this way makes it easily reversible.
Next I would recommend that you familiarise your self with the cap value calculators HERE. Looking at the calculator on the right, you need to enter your input impedance in ohms (100000) and then decide how low you want your bass to go. I'd recommend that the highest value you enter in the Hz box is 10Hz. You can go all the way down below 1Hz if you like but there's not much point. There's more info on all that earlier in the thread. So if you put in 100000 ohms and 10Hz you get a cap value of 0.16uF. That means you need to look for caps that are 0.16 or higher. However there's not much point going above 22uF as that will give you a bass roll-off frequency of 0.72Hz. Don't worry if you can't find the exact value of cap recommended by the calculator. A close value will be fine.
Now that you know the cap value you need to decide the cap type. You mainly want to concentrate on non-polar caps, sometimes called bi-polar. Electrolytic caps are the worst type for this application but they're the smallest and cheapest and some do sound pretty darn good. There aren't many non-polar electrolytic's. Seen as you are able to use low value caps I'd recommend you look at film caps like polypropylene, polyester, teflon etc. They all sound a bit different. The only downsides are that they're bigger and more expensive. Teflon's are some of the most expensive but arguably the best. Some people like oil impregnated caps. These can be good but pricey. You would not believe how expensive some teflon and oil caps get. I'm talking £1000+ for some crazy ones. :eek:
On the subject of voltage ratings; anything from about 6V upwards is fine. Some film caps have ratings over 1000V which is also fine. Just remember that the bigger the cap, the bigger the cap leads. Leads above about 0.8-1mm probably won't fit in the sockets.
The choice of caps is mainly down to the price you want to pay and whether you want to be able to replace the cover or not.
THESE are some of the best electrolytic caps and are a great entry point to see if you like the passive sound. THESE film caps are highly regarded and are good value.
ClarityCap's are also good value, as are the Mundorf Supreme. Elna electrolytic's don't seem to work well in this application, so avoid them.
Another tip is to avoid branded caps from foreign countries on eBay. There are lots of fakes around.
Happy cap rolling. :cool:
Wow,cheers dave,that's exactly the type of info needed.I have now had a browse through the thread and now have a better understanding,please don't test me though :lol:.Quote:
Originally Posted by HighFidelityGuy
I tried the calculator but it doesn't seem to want to calculate,so i'll go with the calculation you did at 10Hz for now.
I don't think i'll be spending £1000+ on crazy caps,I've spent a little over that on my whole system :lol:
I might leave it a week or two,as the caiman has just finished burning in fully so want to get used to the stock sound before i go changing things around.
Good advice from Dave there. I'd add a vote for ClarityCaps, they are great for the money.
No probs. :)Quote:
Originally Posted by kininigin
If your Caiman is brand new then I definitely recommend that you let it run in for at least 200 hours before you start trying mods. The Caiman takes an unusually long time to run in and the sound quality can fluctuate quite a bit during the run in period. :)
I had been leaning towards them or the mundorf's as they are not wallet busting and appear small enough to close the lid on.Quote:
Originally Posted by Ali Tait
Well,it's second hand and the guy i bought it off used the usb input but assured me it was well run-in on the coaxial input but clearly it wasn't(unless he meant input 2).It's been sounding good the last week or so.Quote:
Originally Posted by HighFidelityGuy
Probaly will leave it a couple more weeks,but knowing how good the gator board was in my last dac,it's tempting just to do it straight away.
well my impatience got the better of me and i ordered some claritycap's from the SA range with values of 0.47uF,630V.
They turned up today,so i decided to fit them but the lead out wires seem to be too big and i didn't want to force too much.
I take it others have used these caps,so how did you fit them?
I tried one pair (nit these though) that were a little too big, so just filed them down a little with a flat needle file - worked for me.
Or you could scrape the leads with a stanley knife or solder thinner wire to the end.
Make sure you insulate the leads too so they don't short on anything. :)
Makes sense,not sure i have a file about the house though.Quote:
Originally Posted by Alex_UK
So let the search begin.
I do have a solder iron,what sort of wire would be suitable?Quote:
Originally Posted by HighFidelityGuy
If you've got a Missus, nick one of her nail files or emery boards! ;) Any bit of old abrasive paper will work, but take a bit longer. Last resort, go outside and rub them on a brick or concrete paving slab - anything abrasive will do, and you're not too worried about a perfect finish for this... :)Quote:
Originally Posted by kininigin
So decided to scrape the wire with some wire cutters i've got.
Started to push it in to see if i'd scraped enough,was a little tight still so pulled it out along with the black plastic housing which has now split in half :doh: :(
Not sure what to do now :scratch: