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I went about modifying my CD player - in a manner much different from what most people do.
Basically changed three things:
(1) Paralleled power transformers till it got good. ( It took three.)
(2) Optimized the 120 VAC feed / path to the power transformer primaries.
(3) Rewired Conrad-Johnson's audio FET board, with Kimber Kable TCSS, to minimize the negative effects of the ( not-good-wire) PC traces.
Now, thankfully, this player is improved - more dynamic, displays better diction on voice, and is more mentally engaging to listen through.
This was a rewarding project.
Jeff Medwin
Follow Ups:
Very cool, Jeff.
now, how does it sound?
Thanks for asking.
Its getting exciting and very promising.
Lived with three power transformers in parallel for a while, liked it ...... 'till I experimentally tried FOUR and parallel and 'dems the bees knees in inner resolution, DYNAMICS, and stability.
Four really is GOOD.
Next, I am in touch with a top-notch DIY Romanian CD-modder, and we are going to identify how to divide digital and analogue supplies, so that they don't "talk" to each other through the common single power transformer. This is always a "no loss" / good thing to do.
Two days ago, I experimentally took the four in parallel, and split them, two driving one bi-polar full wave bridge, and the other two separate power transformers driving another full wave bi-polar bridge. I HEARD what my Romanian friend was telling me...yeah !!
But honestly, it needs to be split AND ALSO ULTRA-low in DCR.
In a certain way, four in parallel was better overall than two plus two splitting functions.
BUT, BUT, BUT......The ideal will be SPLIT plus new low DCR ( highest current ) power trannies. We need to combine the best of "my" experiments with my Romanian friend's splitting. Best of both worlds !!
I am going to likely go to a single 3.6 A. rated secondary power transformer, and use multiple 130 VA power transformers for different CD functions, divided-up as precisely suggested by my nice expert Romanian friend.
It should really kick A** is my guess.
I am ALSO planning to do a NON - C input filter to the supply that does my audio, and, maybe apply that type of filter to other CD player power supply functions.
Something like :
a 3.6 A. power trannie, solid state bridge, L1 400 mHY @ 10 Ohms, 20 uF, L2 900 mHY at 8 Ohms, and 50 uF...
ie: L1/C1/L2/C2, then the regulators. What I call a "modern supply".
Definitely the way to go if you like to hear resolution, inner detail, and maximum ( REALLY fun ) dynamics !!!
Now, I am fairly hopeful and even am "thinking" I am on the best, most EFFECTIVE modding track possible here.
The PSUD simulations above shows a roughly estimated stock "C" input filter, into 330 uF, and the second PSUD shows a proposed L1/C1/L2/C2 filter ( doing a 15% current step at 4.1 seconds, and recovering within 50 mS. )
It was AMAZING to me to hear what four PTs in parallel did for the music. Absolutely amazing. I had to HEAR it to understand and believe it !! Ultra low DCR "overpowered" all the other numerous power supply compromises in the stock circuit. GREAT to experience!!
Jeff Medwin
Again Jeff,
What about a single power transformer with all the parameters of the four in parallel? Shouldn't be hard to get accomplished. it would seem that no matter how close the tolerances are for each one there has to be some differences that make it sound a bit off. It sounds like you lowered the DCR by a quarter and got four times higher current.
I know a few years back when I was totally into DIYing(will get back to it someday but for now I like to read what all you guys are saying) I built two pairs of amps. One pair was two totally separate monoblocks using separate power transformers and then I built the same feeding off one huge power transformer. I liked the results of the single power tranny feeding both channels more. Both ways had huge power supplies but it was the single one that was best to my ears. More coherency. Just a nicer sound.
Very sweet! Jeff.
what goal(s) are you trying to achieve by modding this player?
Good question. I have several concurrent design goals:(1) Since I don't have a lot of CDs versus LPs, I want to avoid spending $1200 on a new OPPO 105, or $850 on a used 33 pound Pioneer Elite BDP-09FD player.
Maybe I can "run" with either, or maybe perhaps exceed them. Hard to say just now. I don't know !!
(2) I want to have a CD player that will be good enough to help me select Rk film cap bypassing ( by ear ) for my present prototype amp, a SE DC triode-connected 6AQ5 amp, with a good low DCR power supply.
(3) Sonically: I am trying to maintain maximum dynamic contrasting, because music is not dynamic range limited, while also maintaining good frequency extension, bottom to top, and good INNER DETAILING. I wanna UNDERSTAND all the words on my Gilbert and Sullivan opera CDs. I wanna have the diction totally precise, and I wanna have the proper tonal colors of the orchestra and singers. I want the music to be mentally involving and very engaging for me, not ho-hum and boring.
(4) I also want to be able to show my audio friends the importance of optimized power supplies, and how it can improve audio gear, beyond any other modification path that is typically taken. In the end, we all listen to a modulated supply.
I would say, generally, I am equally motivated, by (1) through (4) above.
The first 130 VA power transformer I am going to use is $35.00 shipped from a popular auction site !! It alone will eliminate three of my multiple stacked Philips trannies.
Jeff Medwin
Edits: 04/28/13
Right On! Jeff. I,too, enjoy extended highs & lows. Resolution and inner detail (air) around all instruments on a recording are important to me as well. Keep up the outstanding project work.
Very cool idea with the 3 transformers.
One of the best mods to do on any gear is run the 120VAC right to the transformer primary bypassing switch, board and other stuff. I've had such good luck with this on both CD players and even an amplifier. The amp, an NAD 2200, improved dynamics so much I could now light the peak light on occasion (usually on midrange peaks, not bass) which I had never done previously.
Thanks for the post.
ET
Are you still using a fuse, or did you bypass this as well?
Certainly w/o a fuse is risk taking. In the case of a CDP I used with my PS Audio P-300 o fuse since a dead short would cause the P-300 to shut off with only a two and a half amp draw.
On the NAD it was connected to an older Monster power conditioner through a switched outlet which in turn acted as its power switch. The first week or so no fuse but then I added one when I got the parts. I used a YBA sand filled fuse a good fuse holder and added only three inches of wire.
ET
Thanks for the post.
It is a risk with the fuse out, but I have heard the benefits of this in Ribbon tweeters I have. I think if you run the same gear for a while and there is no problems, one can experiment, like I did with my Ribbons.
My system is still in storage, but when I do get it set back up, I will try it on my CDP.
Thanks for the tip.
I rewired my CJ MF2100 amp that had a hard wired AC cable that was 18 gauge and it went right under the board to a side mounted IEC and twelve gauge solid wire, no fuse. A risk but quite nice. It is my HF amp in a passive bi-amp. I'm going to get either another MF2500A or a 2250A and retire the older MF2100.
ET
Very true. I use a medium powered tube amp. I bypassed the length of wire from the rear panel up to the power switch (as well as the power switch) and simply eliminated it. To turn the amp on and off, I plug-in and unplug the power cord. Due to the soft start nature of the ps, there has never been a sparking problem or deterioration of the contacts.
Sonically, the results were outstanding -- an even bigger improvement than using a top notch cord. The dynamics and transparency are extraordinary. Dynamics are incredible, actually.
This type of mod is best not considered by beginners -- you first want to make sure you're safe!
Hi !!
Nice post.
If you view the left hand corner of the above chassis, I have installed a AC switch, where I can, at will, bypass ( short out) the CD player's AC fuse. Also, I am running triple paralleled Kimber TCSS ( clear) to and from the short-out switch. This CD player's AC cord has been upgraded from 18 gauge to 12 AWG Carrol wire, that helped too.
I always do my serious listening with the AC fuse shorted out.
This can't be done on a commercial product. My SE DC amp uses the same technique. It is thrilling to hear, more mentally involving.
Thank you very much - for posting your like-experience !!
Jeff Medwin
Jeff, if you can live with that transformer tower great. Have you considered going to a larger core outboard transformer? Or leave a single tx onboard and separating the analog pwr to a separate tx? I don't use any fancy wire but my CDP analog DC uses a over spec. Tx and fast diodes. Fun stuff at any rate....JH
Hi hennfarm,You state:
"Jeff, if you can live with that transformer tower great."
Yes JH, once I mod the top cover, I can live with that. I think it is a great "DIY visual", and people who see it understand right away what was done.
"Have you considered going to a larger core outboard transformer? Or leave a single tx onboard and separating the analog pwr to a separate tx?"
Yes, I have considered that. Need to get a shop manual for that. This was just an EASY basic substitution and a "proof of concept" project, .....worked out well.
"I don't use any fancy wire but my CDP analog DC uses a over spec. Tx and fast diodes."
I've find wiring, ( type and amount in parallel) to transfer instantaneous PEAK energy, is important. I found ( on this CD player ), I had to redo ALL the wiring from the power cord through the secondary lead outs, to the plug into the CD player's circuit board, to get the full benefit.
I had to even "wire-out" the AC fuse, with a user-selectable "in-out" switch, as the AC fuse was impeding the dynamics that the triple trannies and good wiring was capable of bringing to the music playback.
My work-in-progress two stage SE prototype amp ( 12AY7 direct coupled to a triode-connected 6AQ5 ) is similarly wired. The overall result of both pieces together - is good.
"Fun stuff at any rate....JH"
Agree with you fully....thanks for commenting and posting. ... Jeff
Edits: 04/15/13
Excuse my ingnorance Jeff, how do you parallel the trafos and what do you gain in terms of power?
Great project!
How is that amp coming along?
Cheers
Jorge
Jorge,I didn't answer "how to parallel power transformers."
First of all, I had FOUR exactly-the-same Philips model number power transformers from circa 1986 CD players. I just paralleled with TWO Kimber Kable TCSS runs, the terminals of the trannies, one to the other, on both the primary and secondary sides. "Big loop" ( see photo ) required on the first to second power trannie secondary - first three runs - to clear the drawer mechanism.
I initially Jorge tried two power transformers in parallel by clip leading with 8 clip leads, two trannies together. It became better sounding with two, but clip lead connections and wires sound like doggie - doo. So after TRYING two with clip leads, I double TCSSed the runs, soldering them in place. Cool.
I also used 6/32nd threaded rods, and 6/32nd nuts, to "stack" trannies vertically. It was a trip to the local hardware store.
I also carefully replaced the ultra-thin wire on the stock 9 pin power supply connector with TCSS, single runs.
Eventually, I did this paralleling with three power trannies as shown above, and it was way better than two, and almost perfect with three.
Four in parallel, however, was easily the best result, IF using one trannie to simultaneously do ALL the functions of the CD player.
But I KNOW (now) that it will take low DCR .......and .......SPLITTING up of functions, to get the best result. My Romanian friend, who IMHO is an EXPERT, tells me splitting of power supplies, into different functions, powered by a separate transformer ( so the grounds, etc, do not "talk" to each other ) is THE most effective and important thing to do to modify any old CD player.
My testing over this weekend briefly shows him 100% correct.
BUT, it also needs to be LOW LOW LOW in DCR .... " Jeff's Thing ".
I will use Signal Transformer Company's A41 power trannies, to replace all this stacking, and I believe the A41s models that are VA-rated at 130 VA will do nicely.
Obtain a SERVICE manual on your CD player before doing this work to confirm what you visually can see.
Jeff Medwin
Edits: 04/28/13
Hi Jorge,
Need to get digital source squared away, before I can FINE TUNE Rk bypassing on my SE DC amp Jorge.
Patience I am sorry to say !! I had other ( quicker ) hopes originally, didn't I ? !!
Jeff Medwin
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