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Don Allen modded Philips changer

91.77.96.166
Posted on June 29, 2013 at 03:24:01
Tubers


 
Dear Todd,

I came across some information about Don Allen modded Philips/Magnavox CD changer which now has a tubed output. I am wondering what it looks like - does it look like and works as a changer?
I will apreciate if you give me Don Allen's details. I understand that he does not have a web site.

I have Cary 308T and MHZS 88F CD players each of them is good enough but I am wondering whether Don Allen modded Philips player would be an improvement...

 

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RE: Don Allen modded Philips changer, posted on July 1, 2013 at 02:20:05
Todd Krieger
Audiophile

Posts: 37333
Location: SW United States
Joined: November 2, 2000
 "I came across some information about Don Allen modded Philips/Magnavox CD changer which now has a tubed output. I am wondering what it looks like - does it look like and works as a changer?"

From the exterior, the only differences are the bottom plate (which damps the case and sinks RF interference) and a tube mounted horizontally on the rear of the changer on the right side near the top. (Tube rolling is possible without need to open up the unit.) The interior has the added power supply for the tube stage, which replaces the op-amp output stage of the changer. Ferrites are also present to shield the audio circuitry from RFI from the front display.

The unit functions exactly like the changer in stock form, except the headphone output becomes disabled. The same output jacks are used. The stock tube is a GE 6BQ7A, I use a Philips 6922 or Siemens E188CC, depending on the system.

Don now mods exclusively the Philips CDC-935, which happens to have a D/A section that IMO beats just about anything short of a Wadia 9 or Prism DA-2. (Nobody realized how good the D/A was only because the stock output stage, which Don replaces, masked its qualities.) Other Philips-based changers use different D/A sections, the Marantz CC-45 has a very good one as well.

 

RE: Don Allen modded Philips changer, posted on July 1, 2013 at 02:49:13
Tubers


 
Does he mod Philips or other notable CD players (not changers)?

 

RE: Don Allen modded Philips changer, posted on July 1, 2013 at 18:32:55
Todd Krieger
Audiophile

Posts: 37333
Location: SW United States
Joined: November 2, 2000
 "Does he mod Philips or other notable CD players (not changers)?"

Just the Philips based changers.... Philips, Magnavox, Marantz, or Yamaha 5-disc CD changers.... (Although Don now focuses mainly on the Philips CDC-935, due to its superior D/A section.) Built from the late 1980s through the early 1990s. It's the closest thing to the "Small Block Chevy" for CD playback sources... Where units can be rebuilt and mechanical parts can be interchanged (in most part)..... If one of my units were to croak, a replacement laser/drawer assembly (from another unit, not necessarily the same brand or model) can be swapped out, and the player works fine again.

Unlike the 5-disc changers, there was never a sizable family of single-disc CD players with interchangeable drawer assemblies, to my knowledge.

 

RE: "Don now focuses mainly on the Philips CDC-935" , posted on July 5, 2013 at 06:06:44
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 You've been dangling this carrot for some time now, and I finally bit. I scored a stock (used) CDC-935 from ebay the other day. It will be an interesting "apples to apples" comparison to your previously recommend CDC-925, which I bought a couple of years ago, after my JVC 1050 died.

One thing I noticed while looking at the 935's literature is that it has a digital out jack, which the 925 lacks. I have some old Audio Alchemy equipment mothballed, and the 935 will give me a chance to try that out too.

Once I'm sure the CDC-935 I bought is healthy, then it'll be time to contact Don Allen for a quote.

It's all your fault, TK!


 

RE: "Don now focuses mainly on the Philips CDC-935" , posted on July 6, 2013 at 00:47:51
Todd Krieger
Audiophile

Posts: 37333
Location: SW United States
Joined: November 2, 2000
 "You've been dangling this carrot for some time now, and I finally bit. I scored a stock (used) CDC-935 from ebay the other day. It will be an interesting 'apples to apples' comparison to your previously recommend CDC-925, which I bought a couple of years ago, after my JVC 1050 died."

I don't recall recommending a specific model prior to the Philips '935, aside from maybe the Marantz CC-65SE...... (I like the CC-45 for the solid state mod.) I once thought any of the changers would suffice, but the 935 is the real standout.

"One thing I noticed while looking at the 935's literature is that it has a digital out jack, which the 925 lacks. I have some old Audio Alchemy equipment mothballed, and the 935 will give me a chance to try that out too."

I think the 925 has a headphone jack. (The 915 does not.) But Don's mods of the output stage loses operation of the jack.

"Once I'm sure the CDC-935 I bought is healthy, then it'll be time to contact Don Allen for a quote."

Good luck.

"It's all your fault, TK!"

Blame accepted.... [-;

 

RE: "Blame accepted", posted on July 6, 2013 at 05:03:58
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 I know you know I'm only kidding about the blame. But I do find it interesting that if you hang around the Asylum (any audio forum, really) and read enough posts by someone, you get to know them, in a sense. Their likes, their dislikes, tastes, etc. At least as far as hi-fi is concerned, anyway.

Your generally negative view of many digital products, along with your accolades for the musicality of the JVC XL-Z1050TN player, leads me to believe that we have similar objectives from our digital playback equipment. I've formed a similar kinship (for lack of a better word) with Art Dudley, specifically regarding speakers and analog front ends. It doesn't mean I'm going to like everything he likes. But, to him, the music is more important than to know which way the trains are running under Carnegie Hall, and so it is with me.

You're right about the CDC-925 having a headphone jack, but I've never used it. It won't be any loss to lose it in the CDC-935 if I decide to have Don Allen work his magic on mine.

Below is a link to the post where I got the impression that any of the players listed would be ideal for one of Don's mods. I found the CDC-925 on ebay for like $20 or $25 several years ago, and grabbed it. Which was good, because somewhere around that time my JVC 1050 finally gave up the ghost. The 925 can serve as a parts unit, when the 935 needs them. Or such is my understanding, anyway.


 

I Spoke to Don on Sunday.........., posted on July 8, 2013 at 13:55:19
Todd Krieger
Audiophile

Posts: 37333
Location: SW United States
Joined: November 2, 2000
 I briefed him on your potential call. Good luck!

 

Thank you, sir!, posted on July 9, 2013 at 18:59:17
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 I appreciate you giving him a head's up for me.

The CDC-935 showed up this afternoon, and looked to be in fine shape, at least externally. It's playing music as I type, sounds and functions great so far. Once I'm sure it's not going back to the ebay seller because of malfunctions, then I'll call Don to introduce myself and get some information.

Perhaps you can give me a bit of information in advance. Does Don rework the power supply? Given its age, I'm sure it could use a recapping. I could do that myself, but don't want to solder in a bunch of new caps, just to have Don yank them out because he redesigns the power supply.

Thanks again, Todd


 

You're Welcome..., posted on July 10, 2013 at 13:56:05
Todd Krieger
Audiophile

Posts: 37333
Location: SW United States
Joined: November 2, 2000
 Don can rework the existing power supply..... He's fixed other units whose electrolytic caps have gone bad. Might cost a little more, but should be worth it if that's a concern. (I generally don't do that with my unit, only because if it were to go bad, I just drive the unit up to his house for service.)

Don does not modify the existing power supply. He adds a power supply for the tube output. The only word of caution is if you open the unit after modification, the added filter caps on the right side will have live voltage on them. (The caps provide the tube's "B+".) The unit should be treated no differently than any other component with a tube stage.

 

RE: Power supply, posted on July 11, 2013 at 09:40:52
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 I appreciate knowing Don doesn't (normally) have to touch the existing power supply. That way, if I get a wild hair and go in to recap mine, I'll know he's not going to simply throw the board into the trash as part of his standard upgrade.

I downloaded the service manual for the Philips CDC-935 from the HiFi Engine and took a look at the power supply. It seems fairly basic, using 1N4002 diodes in a full wave bridge. A simple change to the quieter UF4007's (which I have on hand) may or may not offer an improvement, but would be $2 worth of peace of mind. New caps, if nothing else, would be fresh, as opposed to the current 20-year-old caps in place now.

The real key is whether I want to attempt to pop the hood at all. The exploded view is "busy" to put it mildly. I don't want to get it apart, just to have a Rubik's cube puzzle to attempt to reassemble.

Thanks for the head's up on the hot power supply present in Don's version. I have done enough soldering on my own tube equipment to know to unplug and measure prior to touching anything, but a reminder never hurts.

I did a comparison between the 925 and 935 last night, and the 935 was more musically enjoyable. The only thing I'd like to check is the s/pdif digital out jack. I need my male RCA to female BNC adapter, and I haven't used it in years. No telling where it might be. The 935 seems to be working OK, so when I get back from vacation, calling Mr. Allen for pricing will be in order.

Much appreciated!





 

RE: Don Allen modded Philips changer, posted on May 19, 2020 at 08:35:51
Boomer303Sooner
Audiophile

Posts: 1
Joined: May 19, 2020
 Might be able to pic up a 915 for dirt cheap.

Would that still be a candidate for one of these mods?

 

RE: Don Allen modded Philips changer, posted on June 3, 2020 at 05:41:13
jbrianfoto
Audiophile

Posts: 67
Location: Mid Atlantic
Joined: September 12, 2000
 Yes - the 915 can be modified, however the CDC935 or 936 has a better DAC. If you are looking around I'd go for one of those.

 

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