Chameleon DAC listening and modifications
Apr 1, 2010 at 5:04 PM Post #722 of 1,158
Quote:

Originally Posted by PatOMalley /img/forum/go_quote.gif
The transformers do add isolation and the sound really benefited from that as well as chaning the output impedance - which again made a nice improvement. But once you know how to rid yorself of the the caps why wait?

I won't be moving off of the steel core soon. I like the sound. I do not crave hifi. Bit it nags at me anyway ....



..... would something like this 2 Channel unbal Line Isolation Transformer for PC Audio on eBay (end time 01-May-10 14:03:37 BST)

do the same job but at lower quality then the cinemags? If so it might be an alternative to cheaper couplings caps, and a lot easier to set up.
 
Apr 1, 2010 at 5:24 PM Post #724 of 1,158
So any transformer that was 1:1 600ohm would work with your circuit? I'm so curious to know what you are hearing Pat, do you have any more impressions, compared to your previous cap setup to share?
 
Apr 1, 2010 at 5:48 PM Post #725 of 1,158
I think 1:1 is the thing. You go higher or lower in impedance. And if you found one that was 180ohms you would need no resistors.

The differrence between the caps is like apples and oranges. The caps do something desireable. They add smooth flowing detail.

But the transformer just let's the signal through withoy any zing, or extra detail, and with a far higher level of presence.

Puit it this way. I like the the
Denon DL103 cartrdge vs the Benz ACE. The caps are like the ACE. More hyper and cooler. Tran is full as phat can get in the mids and sense a nice extended topend that has a little weight vs tons of airm the CineMag steel is denser but the midrange is more populated ... And none of this constitutes and comprerssion either.

There is a nice sense of ease when a big band just takes off or masses strings spread out. Also nice image placement on orchestral.

If you like NOS I can't see how you won't like what the transformers do.

Maybe you might want a better tranformer but once you hear one at output you will go see.
 
Apr 1, 2010 at 6:03 PM Post #726 of 1,158
Pat,
Very nice alternative instead of using output caps and I like to try this.
How about DC level with cinemag? did you happen to measure the DC at the RCA outputs of the chameleon with load (i.e: connected to pre-amp)?
The reason I asked, in my case, I already got rid of my input caps in my pre-amp. Is there a solution for this?
Thanks.
 
Apr 1, 2010 at 6:08 PM Post #727 of 1,158
Nice description, thank you Pat, I can kinda understand a bit more more what happening now, midrange is important for me, guess I'm gonna have to go for this. I like the look of those cinemags too.

Another one of those ready-mades FGA-102 stereo line transformer - connevans.co.uk

But, whats the point if they price is catching up with your trannies?

Anyway, who uses caps these days, pah, old school!
 
Apr 1, 2010 at 6:47 PM Post #729 of 1,158
Quote:

Originally Posted by sinrouge88 /img/forum/go_quote.gif
Pat,
Very nice alternative instead of using output caps and I like to try this.
How about DC level with cinemag? did you happen to measure the DC at the RCA outputs of the chameleon with load (i.e: connected to pre-amp)?
The reason I asked, in my case, I already got rid of my input caps in my pre-amp. Is there a solution for this?
Thanks.



I did not measure but was assured there is small chance of DC so I risked it. If there was DC it would have saturated my trasnformers and I would get distortion. No distorion = no DC so all good. And I am using the yellow wire mod.

I'm like the kid who jumps off the rock into the cave pool with his friends behind him saying, "Yeah, it's cool. Jump. You're OK." :wink:
 
Apr 1, 2010 at 7:19 PM Post #730 of 1,158
Quote:

Originally Posted by PatOMalley /img/forum/go_quote.gif
The TXs are old school, Wood. Back in the day everything was transformer coupled. Not a cap in sight.
Cinemag used to be Altec and these transformers ahve the same DNA has all the old cinema stuff, Westinghouse stuff, etc.



Yes of course. I suppose when everything went solid state caps where the cheap compact alternative, but ironicaly, now with demand for higher sq, there is recent proliferation of expensive non-compact boutique caps when in many situations TX is better.

Can you give us a hint of the price range of these cinemags pat? Can't find anything on the site.
 
Apr 1, 2010 at 7:38 PM Post #732 of 1,158
Is size an issue here? I noticed looking at the datasheets the CMOB- 3-4 range are smaller then the CMOB-2 range, no doubt the nickel are more pricey too.

$60, very tempting.
 
Apr 1, 2010 at 9:09 PM Post #733 of 1,158
I've been curious for quite a while if the Chameleon would benefit from a better clock.
The Chameleon has 2 XO's on board: 1) a 12 Mhz XO for the S/PDIF and USB input and 2) a 24.576 Mhz XO for the upsampling board.
I decided to go for the upsampling board first and I've replaced the XO by the Tentlabs XO 2.2 tonight.

Connecting the clock is easy:
1) Remove the 47uH choke
2) Remove the 100R resistor located in the middle at the top of the upsampling board.
3) solder the XO output of the tentlabs to the upsampling board as shown in picture 3 and you're done :)

It has been on for 30 minutes only so I can't give a detailed description on the sound yet. One thing that was obvious right away: No more grainy highs coming from the upsampling board! ahhhh!

As usual some pics for you:
 
Apr 2, 2010 at 3:16 AM Post #734 of 1,158
Quote:

Originally Posted by PatOMalley /img/forum/go_quote.gif
The transformers do add isolation and the sound really benefited from that as well as chaning the output impedance - which again made a nice improvement. But once you know how to rid yorself of the the caps why wait?

I won't be moving off of the steel core soon. I like the sound. I do not crave hifi. Bit it nags at me anyway ....




Okay. My arm is twisted. Now I have to find a set of 330r carbon resistors PDQ to mirror the Texas Components I have in the Valab. I'm on vacation for a week after next and I'll spend what I need out of it on the trannies, etc. I needed to spend some time cleaning it up anyway. Most of the mods I've done were left messy.

What watt spec should I seek on the carbon resistors?

If I somehow manage to kill my March 09 Valab in the process you guys will hear a gut-wrenching, blood-curdling scream from the heavens.
 
Apr 2, 2010 at 3:29 AM Post #735 of 1,158
Newk, You need four resistors. Two for each transformer.
The schematic shows one transformer's wiring:

OPT.jpg
 

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