Mod your Caiman

[StanleyB]

Since nobody has yet started off a thread in The Drawing Board for modding the Caiman, I guess the honour is left to me..

Going back to when people started experimenting with opamps, the LM4562NA came up as the most favoured one. However, many continued in their search for more bass. The overall feeling was that the LM4562NA pulled up a bit too early in the bass delivery department. But it has not been an easy search for a practical and cheap solution. Initially I settled on the LM4562HA. But I could hear, through A/B testing, that the HA offered a bit less detail. So I went about looking for my own cost effective solution, which is as indicated in the following pic.

http://www.homehifi.co.uk/images/b1.jpg

The mod has only been designed and tested on the LM4562NA!!! I don't know how it will sound with other opamps. What I can say is that you could use a larger resistor for less bass ( up to 68K in fact). I am using 27K for the LM4562NA. The cap is 100nF.

Please make sure that you:
1. Trim the ends of the components,
2. Bend the parts back so that they don't touch the case when you close it!!!!!
3. Only attempt this mod if you are technically capable of removing the top PCB without breaking it.
4. Got access to the right parts and tools.

The bass will be on the same level as the HA, or maybe even the THS4032. However, it is far more solid and controlled.

Stan

[lovejoy]

...and there was me planning a quiet Sunday morning.

Thanks Stan, fantastic work as per. Off to check what I've got in the bits box.

Of course you know that more bass = rematch with the CDS2 coming up ;-).

[lovejoy]

Bingo! A couple of X7R 100nf caps left over from my TeddyReg build. Time to get the iron out...

[StanleyB]

Don't jump straight for the 27K resistor. Try 27K to 68K first. i.e: INCREASE the resistor for less bass.

I got 12" bass units, and the floor vibrations are,..well... dynamite. I can feel notes that I can't even hear:scratch:.

[lovejoy]

Cor, you weren't kidding!

Only 8" bass units in my Arcs, albeit with 10" passive radiators at the back, but the 27K resistors made the bass way too prominent. 18K is much more like it, but I may ease off a little further. But not before I've played all my Dub albums ;-).

That is some serious bass :smoking:

[StanleyB]

The resistor value does appear to be a difficult one to decide upon. Try MORE than 27K for LESS bass... I think:scratch:.

I am going to fit a 50K preset instead so that I can play about with the settings.

[lovejoy]

Yes, it's a strange one. I switched to 12K and that seems to have more bass than the 18K, which in turn had less than the 27K, although the 12K doesn't seem to swamp the sound like the 27K did.

I am rather liking what the 12K does at the moment though, so I shall stick with that for a bit and see how it goes.

[StanleyB]

This looks more and more like a preset job just to find the optimum value. I'll give that a go after F1.

[leo]

Come on guys, give this a go :lolsign:

I tried 16k and then 68k, certainly seems more bass with 16k , 68k seems brighter and more forward

What I did was use a cut up 8pin DIL socket (middle pin cut) soldered where the original ceramics was and then soldered a few different R+ 100nf as seen bellow allowing quick comparisons

Will need to compare a few more


http://i273.photobucket.com/albums/jj220/kingbusoms/DSCF3900.jpg


http://i273.photobucket.com/albums/jj220/kingbusoms/DSCF3901.jpg

[Adrian B]

Hi all

I've just received my Caiman and won't be modding it till I have a sense of the basic sound. And this will take time as I have no digital interconnect yet! But, a descriptioon of the circuit changes would be helpful to avoid mistakes made by simply copying the photo.

Stan, the DAC arrived safely on Fri - thanks

Ta

Adrian

[StanleyB]

I've just received my Caiman and won't be modding it till I have a sense of the basic sound. And this will take time as I have no digital interconnect yet!
Well I guess you'll have to use it as a mantel piece for the time being:lol:.

Stan

[Gazjam]

just use any old phono cable in the meantime..

some would say it makes no difference anyway (but WE know better) :)

[leo]

Length of low loss CT100 Sat cable (Air cell dialectric) terminated with phono plugs will do you for now, a bit stiff to use though

[Adrian B]

Thanks LEo, in fact I have a number of home-brew I/cs of that description. Will post impressions in a day or 2

Adrian

[ZebuTheOxen]

Is this modification appropriate for WM8716 + 4562NA modded 7520s?

I was just about to put the MCL 5/6 caps back before I read this thread.

[StanleyB]

Is this modification appropriate for WM8716 + 4562NA modded 7520s?
Yep. I am even using it on a TC-7520 with LM4562NA.

[HighFidelityGuy]

Hi Stan,

Is there likely to be any benefit from swapping one of the SPDIF phono inputs on the Caiman for a BNC socket? The digital cable connected to this would be a BNC to BNC design.

Thanks.

[StanleyB]

None that I can think of. The TC-7520/7520SE take the incoming signal and recreates a perfect square wave version of it instead. That square wave is sent to the DAC chip. So even if the incoming digital signal is ragged or the cabble impedance is way out, the actual data sent to the DAC chip is a tidied up version of the dodgy one.

[leo]

I added a 75R BNC socket to replace one of the phono inputs, mainly because my co-ax leads are terminated with BNC's anyway

[HighFidelityGuy]

None that I can think of. The TC-7520/7520SE take the incoming signal and recreates a perfect square wave version of it instead. That square wave is sent to the DAC chip. So even if the incoming digital signal is ragged or the cable impedance is way out, the actual data sent to the DAC chip is a tidied up version of the dodgy one.

Thanks Stan, that's very interesting and clever stuff. In that case I'll probably not bother. I'll give it some thought. :)


I added a 75R BNC socket to replace one of the phono inputs, mainly because my co-ax leads are terminated with BNC's anyway

Thanks Leo. Did you notice any difference in quality at all? I guess it will be difficult to tell if you used an entirely different cable before and after.

[ZebuTheOxen]

I've got a nice Cambridge Audio SPDIF cable (Fully shielded, about £30 iirc?) I could compare to Stan's 1m optical cable.
Will report back in this post :]

Reporting back:
Practically no difference.
With the Coaxial, there is a slight softening at the very top end, but I imagine with a silver-coated cable that would disappear also.

If you listened to either, you would still experience the fullness of the music.

[StanleyB]

I would like to say that the following has nothing to do with me. However, it should serve as a warning to those who have been in any sort of doubts as to what the Caiman stands for, and who would find a suitable use for it.

Caiman (http://www.guardian.co.uk/world/2009/sep/24/mafia-boss-caiman-naples-police).

[Gazjam]

What a croc of..... :)


(Tips hat out of respect to Stan "the Don" Beresford)

[HighFidelityGuy]

Nice, that reminds me, I need to collect some money from my neighbours....

[StanleyB]

You missed the important bit:
"Camorra boss used reptile to extort money from businesses.."

[Gazjam]

Ah-Ha!
Gotcha ;)

in the words of Bazza Norman.......and why not?

[StanleyB]

Anyone knows where in the UK I can buy a Murata 7812SR and 7805SR? The only places I can find that stocks them is in the US.

[Gazjam]

Any use Stan?

http://www.applegate.co.uk/listings/stock/euro-tech-export-ltd/murata-power-solutions-7812sr/7812SR-C-25539.html


http://www.eurotech.co.uk/dynamic/detail.php?part1=7805SR&man=DATEL

[StanleyB]

Cheers Gary. It's a starting point for a mod on the horizon;).

[Gazjam]

And with THAT comment Stan, a hundred pairs of ears just got pricked up.
(including mine :))

[trailer]

I've just bought 50,000 shares in them :cool:

[Johnboy]

And with THAT comment Stan, a hundred pairs of ears just got pricked up.
(including mine :))

Hi guys

Lets say 101 pairs , just to say hello ,
I have installed the Caiman in my system this morning , and started playing CD's something that I have not done for years ,because I listen to records I'am turntable crazy, but man I can't stop this Caiman is unreal I find some added bass but thats what I love about it, Stan this is the best upgrade I've done for years , very very happy guy. Caiman just Fantastic.
thanks to this forum I got my hands on a Caiman ,
Wait till my wog mates hear it here in Tuscany , big ups .

John

[DaveK]

Hi guys
Wait till my wog mates hear it here in Tuscany , big ups .
John

Hi John,
What is your understanding of a "wog mate" - you wouldn't get away with using that term here in the UK as it is considered to be very derogatory here.
Just interested.
Cheers,

[Johnboy]

Hi John,
What is your understanding of a "wog mate" - you wouldn't get away with using that term here in the UK as it is considered to be very derogatory here.
Just interested.
Cheers,

Hi Dave

not if I'am a wog ,like I'am and I live in tuscany , plus since the film came out , THE WOG BOY this is not considered derogatory much any more,

we are proud to be wogs ,

Johnboy or should I say Wogboy

[Johnboy]

Hi Dave

not if I'am a wog ,like I'am and I live in tuscany , plus since the film came out , THE WOG BOY this is not considered derogatory much any more,

we are proud to be wogs ,

Johnboy or should I say Wogboy

Hi Dave

I'am sorry the wog stood out, this was to praise the Fantastic Caiman DAC ,
cheers
John

[Clive]

I'm not sure that you definition of "wog" is that same as the derogatory term but either way it's totally unacceptable language in the UK which in some circumstances would lead to you being prosecuted or loosing your job. It doesn't do any favours for this forum either.

I know that Italy (like Spain) is not as PC as the UK - I have a lot of Italian family - but the use of that word is so far over the line......

[Johnboy]

I'm not sure that you definition of "wog" is that same as the derogatory term but either way it's totally unacceptable language in the UK which in some circumstances would lead to you being prosecuted or loosing your job. It doesn't do any favours for this forum either.

I know that Italy (like Spain) is not as PC as the UK - I have a lot of Italian family - but the use of that word is so far over the line......

Ok Clive I see you guy's take it to much on the hursh side I mean I didn't refer to anyone on the forum or esle for that matter , In any case I guess it's time to move on,

ciao
John

[Clive]

John, the Oz use of the word is somewhat strange and those three letters actually have a meaning that for sure never included Italians. Wily Oriental Gentleman - then it spread to include other non-white races.

There is another similar derogatory word used for Italians (just one letter different). The word you used is taken by most people to be immensely racist. I can see the meaning you intended and it is different from the normal meaning. You've for sure not insulted anyone here, I'm not saying that. It just that those sorts of words could get this forum shut down, these things are monitored by the authorities.

I know you didn't intend anything unpleasant, as you say let's move on.

[Johnboy]

John, the Oz use of the word is somewhat strange and those three letters actually have a meaning that for sure never included Italians. Wily Oriental Gentleman - then it spread to include other non-white races.

There is another similar derogatory word used for Italians (just one letter different). The word you used is taken by most people to be immensely racist. I can see the meaning you intended and it is different from the normal meaning. You've for sure not insulted anyone here, I'm not saying that. It just that those sorts of words could get this forum shut down, these things are monitored by the authorities.

I know you didn't intend anything unpleasant, as you say let's move on.

Hi Clive ,,

I would like to ask anyone in the UK after seening the film of the The wog boy , if they had many laughs , in this film they refer to greek guy's but it's the same for Italian's. I had lived in Australia for 20 years I was born in Queensland , today it's not a racist word , also in the 80s on TV in Australia
every week a comedy show called Kingswood country and they said wog min 30times in half an hour, Sorry I don't have the feel of how it's in the UK , but the BBC has passed these shows in the UK,

lets move on , or mabye better I find another forum don't want to cause any hassles it's not my nature ,

Ps I think Stans Caiman dac is number 1 that was the reason of my first post,,

Bye
John

[Clive]

BTW I also have family in Oz and I've just spent a very enjoyable month there, indeed half of our time was in FNQ. Oz is kinda weird, great but weird. Some aspects are very modern (mainly Sydney) other aspects are surprisingly colonial and 60's or 70's based, in some some respect it's like going back in time. OMO soap powder being one very trivial example. I think that views of what happens in the UK are really quite dated. Sounds like a negative but I love Oz!

[DaveK]

Hi Clive ,,
lets move on , or mabye better I find another forum don't want to cause any hassles it's not my nature.
Hi Johnboy,
No need to pick up your bat and ball and go home - nobody's accusing you of doing/saying anything derogatory - it's just that what may be common parlance in Italy ain't always so in UK these days. Our only interest is to avoid any criticism about sanctioning what some may perceive as racism on the forum. It could have severe consequences in this day and age for the forum, that's all. Stick around and enjoy yourself, it's a great place.

Ps I think Stans Caiman dac is number 1 that was the reason of my first post. So do most of us - Stan is definitely the man as far as many of this forum are concerned, and he's a nice guy to boot, not that I know anybody who's booted him :lolsign: .


Bye surely not - I thought Aussies (even Italian ones ;) ) could take it as well as hand it out ;) ?
John

Cheers,

[ZebuTheOxen]

In my quest for getting better sound out of my K701s, I have reverted temporarily to 5532 in the line socket, 4562 in the HA socket.
Reponse is better across the range, but I can definitely tell I'm missing some details.

I've got a few more opamps lined up, we'll see how they go :)

Edit: I've popped the 4562 back into the line, I dropped the source volume and cranked up the Caiman itself. This produced a more desirable sound, but it still struggles to feed the headphones at points.

[NRG]

I've now tried this mod with 18K/27K/33K and I don't like it! The bass became just too 'Phat' and rounded...it lost the articulation of the standard setup and I found the midrange lost a touch of clarity. Going back to standard was a relief! Maybe its because I use a 300B PP amp that has v.good low down grunt and a clean detailed but rich mid that this mod did not work for me....maybe its also the reason I don't get on with the 2132...anyhow its fun and I await Stans new PSU with anticipation....

[Marco]

Hi Clive ,,

I would like to ask anyone in the UK after seening the film of the The wog boy , if they had many laughs , in this film they refer to greek guy's but it's the same for Italian's. I had lived in Australia for 20 years I was born in Queensland , today it's not a racist word , also in the 80s on TV in Australia
every week a comedy show called Kingswood country and they said wog min 30times in half an hour, Sorry I don't have the feel of how it's in the UK , but the BBC has passed these shows in the UK,

lets move on , or mabye better I find another forum don't want to cause any hassles it's not my nature ,

Ps I think Stans Caiman dac is number 1 that was the reason of my first post,,


Guys,

Before we get any more deeply-entrenched in our respective cultural differences, and the ensuing misunderstandings this has caused, I think we should all draw a line under this episode and move on.

John, I know you didn't mean to cause offence (this is obvious), however, you must appreciate that the word "wog", used in any context, is inappropriate in the UK and also on this forum, therefore I'm sure I can rely on your discretion not to refer to it again in future.

Anyway, don't worry, everything is fine here so I'm sure you'll be back again soon! :cool:

Ciao,
Marco.

[Peter Galbavy]

OK, not a sound quality mod question but one of power.

I have chosen to use a master/slave power block with the pre-amp being the master. The only unit not to auto power on is the Caiman.

Stan, or anyone, is there any way to mod the unit to auto power on ?

If so, the next step is to select the "default" input too ?

[HighFidelityGuy]

OK, not a sound quality mod question but one of power.

I have chosen to use a master/slave power block with the pre-amp being the master. The only unit not to auto power on is the Caiman.

Stan, or anyone, is there any way to mod the unit to auto power on ?

If so, the next step is to select the "default" input too ?

You beat me to it Peter, I was going to ask the same questions today. :)
It would be nice if we could make the Caiman or standard 7520 turn on automatically when power was applied and select the default input. On the subject of selecting the default input; it would be good if the mod included a switch or something to allow any of the inputs to be set as default at any time, that way if people swap from using coax to optical (for example) as their main input they wouldn't have to break out the soldering iron again to do the mod for a 2nd time.

Is this possible to achieve Stan? :)

[StanleyB]

Anything is possible, but mods like that are personal requirements and therefore left to the specialist to implement and put a price on accordingly for the work done.

To give an idea: someone wanted two opticla inputs instead of one optical and one USB. I quoted £100 for the mod, but that was considered too high. Exactly how much does two hours of mod and testing cost? A fiver? That's less than the minimum wage limit.

[DaveK]

Hi Guys,
Correct me if I'm wrong but have I not read on this forum: -
1) constant on/off cycling of electronic components is not good for their longevity, and ......
2) StanDACs draw so little power and run relatively coolly that they can be left on permanently without the need to build another power station.

That being the case (if undeed it is), the need to auto-power the StanDAC disappears, doesn't it?
Cheers,

[Peter Galbavy]

In general I agree and I am not an eco greewash freak (it's 80% b****** IMHO) but I like having one button and I don't like leaving most electrics on when the house is empty ... just in case :)

If modern electronics can't cope with being turned on and off regularly then there is a real problem anyway. I can understand old fogey technology like valves, but... :lol:

[chrism]

Apparantly, switching on and off speeds up burn in time as the capacitor's charge up then dissipate. On this basis it probably shortens the useful life span as well (I suspect).

I leave the Squeezebox and DAC on all the time but switch off my power amp and computer.

Regards

Chris

[Themis]

I bet Caiman is less than 10w... (my Northstar 192 is at 15w).

But I understand the (absolute) need.

[Peter Galbavy]

Not sure I am brave enough to try to yet mod my week-old Caiman, since I am *still* playing with speaker positioning and room acoustics. However, I feel the need for more bass. Before I embark on this I will compare the overall response with DAC and without on both SB3 and CD player - just for some reference. I am not happy with the low bass yet, but this could well be room acoustics. My "test track" is IC19 by Buraka Som Sistema which opens with stupidly low freq. and in my 5.1 setup the sub pushes me back into the sofa, quite literaly.

Given the mod Stan posted would it be a good or bad idea to fit a minature pot instead of a fixed value resistor, something like a 100K one of these: http://www.maplin.co.uk/Module.aspx?ModuleNo=6499 ?

I have really not been near a circuit board for decades, so I am wary...

[StanleyB]

Instead of the cap/resistor mod, try a THS4032 or LM4562HA in the line output. It's better and does not require dismantling of the audio PCB.

[Peter Galbavy]

Thanks Stan - I will go insane if I have to read the 1,300+ post in the 7250 modding thread - what's the real difference between the HA and the NA ? The Caiman uses the NA, right ? The HA is a drop in replacement but your first post in this thread mentions "less detail" - can you elaborate ? i.e. which foot am I shooting myself in or should I just buy a couple and try them for myself ?

Is the HA the metal canister one ? Off to google I go.

I would leave the headphone amp side alone, as I don't use it - is that OK or should that side's opamp be changed too ?

[roscoeiii]

Hi Peter,

I'd say there's a lot of consensus here that the Caiman needs some time to break in. I'd give it some time before switiching things in or out, especially since you are messing with speaker arangements etc. I'd suggest listening to your new arrangement with other sources if possible and seeing if you hear the same bass characteristics from them that you are hearing from the Caiman. Room arrangement and speaker placement can have drastic effects on these things. Hope this helps. For myself, I'm going to wait until the warranty ends before I jump into the op-amp/mod end of things. Won't be easy to wait that long, but in the meantime I'll work on other aspects of my system (dampening vibrations, finding a great transport, etc.)

[StanleyB]

Hi Peter, see the mod page on my site first. It shows some pics of the LM4562HA in action and also describes the wiring.

[technobear]

There's a chap on the Wigwam selling a pair or THS4032 op amps for free plus postage.

http://www.hifiwigwam.com/view_topic.php?id=25437&forum_id=5&jump_to=728282

Scroll down to the post by HectorHughMunro (#693)

[lemon]

How many Volts are:
a) the main internal PSU Capacitor/10000uF
b) the last one electrolytic capacitor of fixed output

at the Caiman?

[chrism]

The big input cap is rated as 10,000uf/16v. Not sure about the last one you have asked about though.

Regards

Chris

[leo]

presume he means the output signal coupling caps on the line out? if so 25v I think

[lemon]

Thanks for your answers.

It seems to be identical to 7520.

Due to more Vac between old PSU (12.07Vrms) and the new Caiman PSU (15.57Vrms), maybe needs a higher voltage cap (25V).

[chrism]

Any updates on the current preferred Caiman Opamp?

Does the LME49720HA offer any improvement over the standard? It's gone a bit quiet and I was interested in the current thoughts of those who have had ago.

Regards

[StanleyB]

The 4562NA has more detail in it as long as you burn it in for a week or so.