I fancy modding one on these players particularly the NOS mod,
Q/ Is the Alpha Plus as moddable as the Alpha? I note that it has the same mech and DAC
Noting this thread
Thanks
I am not sure of the differences, but I believe they are very much the same. I believe mine is the Alpha Plus, and I have been using the Alpha service manual as my guide. There is a wealth of information in this thread. Symon and Andrew can help you with the main board. I pretty much focused on the DAC section.
Have fun. The results can be pretty spectacular!
Good news / bad news
For about the 10th time I have messed this thing up. It is getting harder to debug it at this stage as there are quite a few weak solder points that could go bad. It really is time to get a scope to see what is really going on.
I had weak solder on the caps on the MSB pins, and had trouble getting one of them soldered. It played, but had lots of distortion in one channel. It is possible that I got too much heat on the 1541a. Anyone following my lead with the surface mount caps, I advise keeping them under the board to keep the heat away from the 1541a. Also possible I just have a bad solder pt somewhere or a small piece across 2 pins.
However there was one observation that I would like to note. As an experiment, I switched the DEM signal from WS to BCK. In the brief period before I pooched it the SQ was very promising. After rereading through pages of posts on the DEM topic it appeared that taking raw BCK at 2.8m is in some cases possible if the decoupling is well done. It is also a very simple experiment as it just means moving one lead from pin 1 to pin 2. Easy to reverse. Of course like me it is also easy to inadvertently kill something in the process.
For about the 10th time I have messed this thing up. It is getting harder to debug it at this stage as there are quite a few weak solder points that could go bad. It really is time to get a scope to see what is really going on.
I had weak solder on the caps on the MSB pins, and had trouble getting one of them soldered. It played, but had lots of distortion in one channel. It is possible that I got too much heat on the 1541a. Anyone following my lead with the surface mount caps, I advise keeping them under the board to keep the heat away from the 1541a. Also possible I just have a bad solder pt somewhere or a small piece across 2 pins.
However there was one observation that I would like to note. As an experiment, I switched the DEM signal from WS to BCK. In the brief period before I pooched it the SQ was very promising. After rereading through pages of posts on the DEM topic it appeared that taking raw BCK at 2.8m is in some cases possible if the decoupling is well done. It is also a very simple experiment as it just means moving one lead from pin 1 to pin 2. Easy to reverse. Of course like me it is also easy to inadvertently kill something in the process.
I fancy modding one on these players particularly the NOS mod,
Q/ Is the Alpha Plus as moddable as the Alpha? I note that it has the same mech and DAC
Noting this thread
Thanks
Hi
From memory the ' Plus ' is exactly the same except for Blackgates in the output stage.
Apart from that all the tips on these threads apply.
Good luck - if you follow the whole thing and do as we've done you'll be very pleasantly surprised with what this old timer can do.
Andrew
For about the 10th time I have messed this thing up. It is getting harder to debug it at this stage as there are quite a few weak solder points that could go bad. It really is time to get a scope to see what is really going on.
I had weak solder on the caps on the MSB pins, and had trouble getting one of them soldered. It played, but had lots of distortion in one channel. It is possible that I got too much heat on the 1541a. Anyone following my lead with the surface mount caps, I advise keeping them under the board to keep the heat away from the 1541a. Also possible I just have a bad solder pt somewhere or a small piece across 2 pins.
Walter Hi
I overheated a DAC chip accidentally about a month ago mucking around as I do.
It didn't distort - it just didn't do anything at all
Lucky for me I had a 1994 TDA spare so I fitted a 28 pin socket pressed the chip into place and it worked.
I think you've got to check your stuff before you write her off.
If you've cooked it I wouldn't expect one channel to be OK and the other one to be distorted - you'll find the bug like you've done before - don't despair
I'm now a bit reluctant to try the decoupling thing as I'm so close to bolting it all down - well.. maybe 2.2uf on the MSB ( hahaha..see ?... can't help myself !! )
I've just changed the 68 ohm resistor trick ( grid to ground ) to a discrete i/v stage and it's mind bogglingly better - don't ask why please...but it's a keeper.
I've just started collecting bits for my new project - a hybrid gainclone using 4P1L Pentode's. Have the valves, caps and resistors and just need the Loctal bases and traff - Donor gainclone is here built already.
It'll sound like 300B's on the cheap allegedly !!
This will distract me from fiddling with the Arcam after the external PS is working - which it isn't yet - not much to do though
After that it's save up for super regs.
I'm really at the end with it now, it sounds sublime and I want to keep it that way if possible.
I might buy another one so I've got a spare transport just in case.
Good luck with the hunt
Andrew
DONE!!
Right you are Andrew! It took me 4 hours, but I went over every inch and found a number of issues that are now corrected. Ultimately, a broken solder joint on one of the super regs did it in.
Now for the good news. It works, and it is sublime. Like Andrew, and I suspect Simon I am off to other things. There may be marginal increases to be had, but the risk of breaking it is now too great, and I value it immensely. If I take it up a notch, it will be a new hand wired TDA1541a using all the learning from here and EC Designs.
The 8.2u organic caps on the pins turned to be a real winner. I would not wish the exercise on anyone. Better to do it on a scratch build. The other key thing that worked out for me was soldering caps right on pins 16 & 17 + and inductor for good power from pin 15. With all of this, I am able to run DEM right off the BCK WITHOUT flip flops / reclockers or anything. That is 64xWS or 2.8mHz. Sound is superb. I am 2x EC Designs rate which is 32xWS. I also finished the board and all components by cleaning up with rubbing alcohol to get rid of dirt and solder flux. This should help minimize leakage.
So how I ended up is decoupling with 8.2u SMT organics on the first 6 pins leaving in place the ARCAM supplied Tantalum and film caps. The 7th pin has just the 220n film cap, no organic. I am leaving the Burson regs on -5 and -15 and the original LM317 on the +5. I figure with lots of OSCON SEP caps how bad can it be. It has its own transformer winding followed by BG CRC filtering bypassed with Russian silver Mica. Its possible it would be better with one more super reg, but I will never know. Again I am done.
With this new level of detail and resolution, I actually had to go back and retune the source. I drive with a CMP2 computer transport. It allows you to tune the algorithms for phase and bandwidth essentially dialing in where inevitable ringing occurs. I think that is a sign of the new level of resolution. Before this, I could barely understand what these settings were for.
Andrew, post details of the IV stage. That is something of interest for both my tube output stages. Thank you
Andrew, the new amp project sounds like a winner. I too am back to building my tube amps.
Right you are Andrew! It took me 4 hours, but I went over every inch and found a number of issues that are now corrected. Ultimately, a broken solder joint on one of the super regs did it in.
Now for the good news. It works, and it is sublime. Like Andrew, and I suspect Simon I am off to other things. There may be marginal increases to be had, but the risk of breaking it is now too great, and I value it immensely. If I take it up a notch, it will be a new hand wired TDA1541a using all the learning from here and EC Designs.
The 8.2u organic caps on the pins turned to be a real winner. I would not wish the exercise on anyone. Better to do it on a scratch build. The other key thing that worked out for me was soldering caps right on pins 16 & 17 + and inductor for good power from pin 15. With all of this, I am able to run DEM right off the BCK WITHOUT flip flops / reclockers or anything. That is 64xWS or 2.8mHz. Sound is superb. I am 2x EC Designs rate which is 32xWS. I also finished the board and all components by cleaning up with rubbing alcohol to get rid of dirt and solder flux. This should help minimize leakage.
So how I ended up is decoupling with 8.2u SMT organics on the first 6 pins leaving in place the ARCAM supplied Tantalum and film caps. The 7th pin has just the 220n film cap, no organic. I am leaving the Burson regs on -5 and -15 and the original LM317 on the +5. I figure with lots of OSCON SEP caps how bad can it be. It has its own transformer winding followed by BG CRC filtering bypassed with Russian silver Mica. Its possible it would be better with one more super reg, but I will never know. Again I am done.
With this new level of detail and resolution, I actually had to go back and retune the source. I drive with a CMP2 computer transport. It allows you to tune the algorithms for phase and bandwidth essentially dialing in where inevitable ringing occurs. I think that is a sign of the new level of resolution. Before this, I could barely understand what these settings were for.
Andrew, post details of the IV stage. That is something of interest for both my tube output stages. Thank you
Andrew, the new amp project sounds like a winner. I too am back to building my tube amps.
Last edited:
Thanks Andrew. I've just got it home, I got a bit of a bargain actually, good condition, box, manual, remote for £40, with local pickup around 15 miles away. It even plays CD-r's and takes alot of effort of prodding the CD to make it skip. It doesn't fare well compared to my modded CD63 KI, but I wouldn't expect it to - there is a distinct veil to the sound and the bass is very ploddy, missing the leading edges. I'm looking forward to getting this player working properly.
With regard to output stages, what do people recommend? I don't like the idea of two op-amps per channel, are there any output PCB's people recommend? Would something like a DC-B1 circuit work well? Where is best to take the audio output from?
With regard to output stages, what do people recommend? I don't like the idea of two op-amps per channel, are there any output PCB's people recommend? Would something like a DC-B1 circuit work well? Where is best to take the audio output from?
Hi df
If you look through the whole thing ( yawn ! ) you'll see that Simon has used a Pass Labs D1 which he swears by and Walter ( Lowes ) and I have gone down the valve output stage route. I took mine directly off the legs of the TDA via passive resistor ( which I didn't like ) and then switched to taking it off the i/v op amp for a while ( LM49710 )
Now using discrete op amp to valve output stage instead which 'm still not entirely happy with. There's another i/v stage option developing here on the forum which I'm keeping my eye on as we speak
The best Alpha is Simon's ( just my opinion ) as he's used a real high end clock, his D1 is about as good as it gets, his capacitors are good brands and outrageously large ( hahaha ) and his player is laden with super regs and many off board power supplies.
I've no doubt your KI is better than the Alpha out of the box - I've seen the massive Marantz 63 / 67 / KI section here and it's clearly a good bit of kit with all those mods done.
However, run through some of the mods mentioned here and you'll be quite shocked at what will happen to your Alpha - I still am.. and I've still a bit to do yet.
It's quite easy to work on once you get used to looking at it and reading the service manual. The separate DAC and it's regulated PS gives you a head start straight away. I worked the DAC board to death before I started the tricky stuff and the rewards for that effort alone were huge. Then quieten the 7220 with it's own supply and relieve it of it's clock duties and it starts getting really serious.
You'll be well pleased !!
Get stuck in !!
Andrew
If you look through the whole thing ( yawn ! ) you'll see that Simon has used a Pass Labs D1 which he swears by and Walter ( Lowes ) and I have gone down the valve output stage route. I took mine directly off the legs of the TDA via passive resistor ( which I didn't like ) and then switched to taking it off the i/v op amp for a while ( LM49710 )
Now using discrete op amp to valve output stage instead which 'm still not entirely happy with. There's another i/v stage option developing here on the forum which I'm keeping my eye on as we speak
The best Alpha is Simon's ( just my opinion ) as he's used a real high end clock, his D1 is about as good as it gets, his capacitors are good brands and outrageously large ( hahaha ) and his player is laden with super regs and many off board power supplies.
I've no doubt your KI is better than the Alpha out of the box - I've seen the massive Marantz 63 / 67 / KI section here and it's clearly a good bit of kit with all those mods done.
However, run through some of the mods mentioned here and you'll be quite shocked at what will happen to your Alpha - I still am.. and I've still a bit to do yet.
It's quite easy to work on once you get used to looking at it and reading the service manual. The separate DAC and it's regulated PS gives you a head start straight away. I worked the DAC board to death before I started the tricky stuff and the rewards for that effort alone were huge. Then quieten the 7220 with it's own supply and relieve it of it's clock duties and it starts getting really serious.
You'll be well pleased !!
Get stuck in !!
Andrew
Thanks Andrew. I've had a search around, and the Zen I/V stage looks very interesting, not sure how I will get a +30/-30 regulated supply in the case and everything else I plan to install as I intend to keep it all in the chassis if I can. I'm not keen on valves personally (I'm sure I would blow myself up!).
I already have a 1ppm TCXO for this player, and a handful of Coffin regulators built already, but I need to have another read through to work out how best to re-clock these players.
I already have a 1ppm TCXO for this player, and a handful of Coffin regulators built already, but I need to have another read through to work out how best to re-clock these players.
I thought I'd blow myself up too - but I didn't and it works VERY well
I followed Simon's clocking route and clocked 7220 with it's own feed, the 7310 with it's own feed and then pin 2 and pin 4 independently on the TDA. Then the DEM after plucking up the courage.
Anyway, it's all here, pictures, diagrams and explanations - there's nothing left out at all
Good luck keeping it all in the box - we all tried.....and failed
Andrew
I followed Simon's clocking route and clocked 7220 with it's own feed, the 7310 with it's own feed and then pin 2 and pin 4 independently on the TDA. Then the DEM after plucking up the courage.
Anyway, it's all here, pictures, diagrams and explanations - there's nothing left out at all
Good luck keeping it all in the box - we all tried.....and failed
Andrew
Good luck keeping it all in the box - we all tried.....and failed
Andrew
Except for me, but I ended up getting rid of everything but the blue audio board
I think you'll be impressed following Simon and Andrew's path.
Smarty pants from Canada !!
Our one box hero !
Forgot about that Walter...ooops sorry
How are you btw - it's been a while.
Hey df...don't listen to him about our stuff - check out what he did to his
Ultra serious - he threw it all out, he didn't even like the transport !!
Black Gates everywhere, Peter Daniels kit and 175 Oscon sepc's in there too !!
Too modest Walter...tell him how good it is
Best Wishes
Andrew
Our one box hero !
Forgot about that Walter...ooops sorry
How are you btw - it's been a while.
Hey df...don't listen to him about our stuff - check out what he did to his
Ultra serious - he threw it all out, he didn't even like the transport !!
Black Gates everywhere, Peter Daniels kit and 175 Oscon sepc's in there too !!
Too modest Walter...tell him how good it is
Best Wishes
Andrew
I am well, thank you. Nice to hear from U2 Andrew!
Actually I bearly qualify to be in this thread because I did start modding a CDP and ended up with a USB DAC. But I did end up learning a bunch, its in the original box and yes I does sound wonderful. Hard to believe how far it has come from stock.
My transport is a pc and it is pretty radical. We are cutting up WinXP like sharks in a feeding frenzy over on the CMP2 posts on audioasylum.com. The sound is following similar path to our DEM reclocking.
Still waiting for the 1u smt film caps to arrive so I can post the SQ comparison of ecdesigns choice vs my 8u organics directly on the decoupling pins.
Cheers
stripping the output stage
One of the things that helped my system was to strip away the output stage. Basically everything from R1/101 to the rca posts can go. Any cap starting with a 200 number likely should stay, and all parts down in the power supply stay R201-r220.
One of the things that helped my system was to strip away the output stage. Basically everything from R1/101 to the rca posts can go. Any cap starting with a 200 number likely should stay, and all parts down in the power supply stay R201-r220.
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.