Early Micromega Duo DAC

[Dowser]

Yay - another audio desire realised - after being impressed with Micromega Stage CD players (I have a modified Stage 3 which will never leave the collection - dual TDA1305 DACs, great implementation, beats a Naim CD3.5...which it should, it only has one TDA1305) I finally lucked upon an early Micromega Duo DAC/pre-amp from Italy;

TDA1541 based DAC Some confusion on internet - Dutch Audio Classics suggests a TDA1541A chip inside, some Japanese sites suggest S1/S2 variants.

I can confirm mine is a plain TDA1541, and I guess I just found somewhere to use my last spare genuine S1 chip I opened it quickly just to see type of chip and check it was safe - it's a bit of a dogs dinner in there - lots of recap work, and all joints have been reflowed...but too heavily...and quality of PCBs (3 layers in that tiny enclosure....it's packed!) is not that great - fair few broken/repaired tags. Has a completely< discrete output stage as far as I can see, with no output caps and trimmers to adjust any offset.

It's actually a preamp - accepts SPDIF & Toslink digi inputs, plus 1 line in. It has fixed and variable out. I'm using SPDIF from my Pi4 streamer, toslink from TV/Xbox (that I have been trying to get to work via the damned RPi4/Digi+ I/O HAT unsuccessfully so far) and just the fixed out into my Croft Mega Micro.

Sounds stunning I've had quite a journey over lastfew years with DACs - and same as with CDPs, I've ended up with vintage as my preferred

I started in 2019 I think with a Pioneer N50 network player - was happy with it with SPDIF for RPi, toslink for TV/XBox/RPi with Kodi. Then I picked up a Rega DAC cheaply - used digitial out from Pioneer into Rega and preferred it. Same as always with Rega though - it did zero wrong, but was just a little limited frequency range wise compared to the Pioneer (but the Rega was more enjoyable to listen to). Tehn I got a Chinese TDA1541 DAC;

https://pinkfishmedia.net/forum/threads/new-tda1541-based-dac-mods.231503/

I sold the Rega pronto - fitted an S1 TDA1541A chip and /B 7220 to it and was happy. Lots of other mods I could have done, but it sounded great....why bother Then I picked up a cheap Camelot Technologies Arthur DAC;

https://pinkfishmedia.net/forum/threads/vintage-camelot-technologies-arthur-dac.248195/

Heavily modified, it sounded good and replaced the Chinese design 1541. It's been in my system 6 months or so now - been happy. Still prefer the sound of the Micromega Duo though - not straight away - sounded a bit ragged at first, and lacking in bass resolution. After 5 hours playing Radio Paradise from my RPi4 I'm impressed - don't think I'll sell the Arthur either, both are great early examples of DAC implementations!

Stay tuned for a thread in DIY or Classics soon when I mod the Duo a bit

Richard

 

[Mike P]

Can we have some pics of the internals please?

 

[Dowser]

Probably weekend Mike - if I can wait that long to try an S1, LOL I did Pop it open quickly, but no photos yet.

Just sat and listened properly rather than from my office - it has that layered and textured 1541 quality in spades, I’m very impressed - it kills the Chinese 1541 with S1 and 7220/B from memory, and is certainly better than the Camelot too.

But I think it retailed at £1500 when new way back when.

 

[a.palfreyman]

Sorry for the aside...
I remember listening to a Micromega Duo BS (Bitstream) and Micromega transport (can't remember which now but it had the thick, bevel-edged clear plastic lid as so many early micromegas had) and sounded wonderful (IIRC of course as this was about 1990/1!) Would have loved this combo, but sadly couldn't afford it. Also auditioned the early Meridian (not sure which, maybe 200, 201 or 203: think it was 2 shoe-boxes) but found this too clinical.
Do you guys find the straight 1541 has a 'bigger' sound (wide, deep image)? Never listened to the 'A' chip or higher (S1 etc). Maybe I need to get a 7220B / 1541A based player (currently have 2 Philips CD160s, a Micromega Drive 3 and Arcam Delta 170 transport optically coupled to Bushmaster ii as the optical seems slightly cleaner sounding). Not sure SWMBO would like me squirreling more gear into the house tho'! Must admit I'd love to hear a really well implemented 1541 or 1541A. Reckon you'd need a good system (and good hearing!) too to be able to 'distinguish' the differences and not sure my waning hearing is up to it nowadays as I struggle to discern much if anything between my standard CD160 and modified CD160 although the later has vastly improved noise floor.
Will look forward to 'More Adventures of Dowser (MAD)'

 

[Dowser]

Sorry for the aside...
I remember listening to a Micromega Duo BS (Bitstream) and Micromega transport (can't remember which now but it had the thick, bevel-edged clear plastic lid as so many early micromegas had) and sounded wonderful (IIRC of course as this was about 1990/1!) Would have loved this combo, but sadly couldn't afford it. Also auditioned the early Meridian (not sure which, maybe 200, 201 or 203: think it was 2 shoe-boxes) but found this too clinical.
Do you guys find the straight 1541 has a 'bigger' sound (wide, deep image)? Never listened to the 'A' chip or higher (S1 etc). Maybe I need to get a 7220B / 1541A based player (currently have 2 Philips CD160s, a Micromega Drive 3 and Arcam Delta 170 transport optically coupled to Bushmaster ii as the optical seems slightly cleaner sounding). Not sure SWMBO would like me squirreling more gear into the house tho'! Must admit I'd love to hear a really well implemented 1541 or 1541A. Reckon you'd need a good system (and good hearing!) too to be able to 'distinguish' the differences and not sure my waning hearing is up to it nowadays as I struggle to discern much if anything between my standard CD160 and modified CD160 although the later has vastly improved noise floor.
Will look forward to 'More Adventures of Dowser (MAD)'

i think, as you identify, the actual chipset plays a part, but so does the implementation.

I‘ve taken a Marantz CD60 (basically 40/60/80 are all the same) and done extreme mods to it...I still prefer my Naim CDI, with only a Flea & replaced caps for smoothing and output. Why? Only transport and output stage differ, along with the implementation of the chipset...oh, and S2 1541a, LOL.

another player I really like is the Micromega Stage 3 - generally when modding players I check chipset datasheets and Internet forums for best implementations. Honestly, outside of the clock that I’ve done, there is very little else that can be improved. After tracing everything out, they already used best in breed implementations - there’s a thread here from me somewhere, comparing Stage 3 and 5.

on the 1541 vs 1541a - I’d just describe the 1541 as slightly blurred in the midrange compared to the 1541a...but honestly, as per my recent shootout thread, I’d be happy with a well implemented 1541 design such as the CD-94.

if you want a bargain tda1541a player, keep your eyes open for a Sony CDP-750 - I’ve got 2 in the cellar for a rainy day - last one I got was chf 25.- in perfect condition with manual, remote and packing. I reckon they can be made pretty good...but still haven’t tried...just used them as cheap donors for later 1541a chips

the Duo 2 continues to be stunning - I feel some work coming on this weekend

 

[Dowser]

Here you go - pictures...did I mention it's a bit of a dogs dinner? Honestly, I'd refuse to take this on as a repair if doing it for someone else...but I really like it, so am going to invest some time on it. First up to simply clean up the board and redo some of the most obvious dodgy joints...

1541 hiding here

The full horror

Under the TDA - I was worried by the wire links when I saw them, but its by design I think - digital at one end, PSU in middle, OP stage at other end with the 3 wires linking them

PSU and OP stages (one fixed, one variable)

Just look at the soldering! I don't consider myself a particularly tidy person, but would never accept this.

To note - the thing is fully functional currently....hope it is when I've finished I've only tested fixed level out (2 output stages, one fixed, one variable) with both SPDIF and Toslink inputs (there's also an AUX line level input I have not tried yet). Toslink is a bit quieter than SPDIF, and one of the fixed output plugs has poor contacts.

Wish me luck - initially I think just a clean up and swap the TDA1541 for a TDA1541A S1, at the same time reviewing their implementation. My view of Micromega is that they started with very good implementations but then dropped quality later in the range to reduce costs (look at differences between Stage 2 & 3 CDPs, versus their later 5 & 6 ones - the 3 was always the one to have). Equally, online there is very little info on this original first gen Duo - but their later ones simplified things considerably, what photos exist of the Duo BS just show a single PCB when in the same form factor model.

Richard

 

[Dowser]

I just cleaned up the PCB today a bit - the quality of the tracks is complete shite, so I forgive whoever did the previous work a bit. All I did apart from clean PCB was replace an 85 degree electro with an 105 degree one, and mounted it better - no after photos (sorry, forgot, next time I open it), but before;

Both tracks broken underneath, with wire links used to repair - I mounted a replacement parallel to PCB as it should have been

For the first time since I was 26 or 27 I actually cleaned fuse and fuse holders...this time maybe necessary
Before;

After;

Even fuse holder was bad - didn't take a before, this was after;

The crud;

I also cleaned the fixed out and SPDIF in sockets - similarly dirty.

Still working I was listening to my original Camelot Arthur while doing the work - it sounded great. The Duo is better, but I could live with either easily - they're both stunning.

Now need to work up courage to strip the boards apart ond replace the TDA - it's complicated, with various between board soldered connections...I smell very many more broken tracks!

Richard

 

[a.palfreyman]

Yes, that soldering looks well dodgy in places and mine isn't all that good! If you replace the non-A 1541 for an A, surely you also have to replace the 7220A for a B as well?
Oh, and you need some hand-cream by the looks of things!

 

[Mike P]

Do you guys find the straight 1541 has a 'bigger' sound (wide, deep image)? Never listened to the 'A' chip or higher (S1 etc).

Mr Lampizator describes the non A as being more 'vigorous' than the A.

I generally find the 'A' to be a bit more refined sounding than the non A, and I do consider the 'A' to be an upgrade but the implementation is far more important. The best single box player I've heard is my own hot-rodded Sony CDP-555esd and that's still running it's original non A chip.

The only version I'd actively avoid is the R1.

 

[Cupuacu]

I have been using my Duo BS version 1 DAC for more than 30 years - sound-wise it is nicer than any modern dac I've heard, but then I am in my 60s and prefer to listen to music as a trained musician, not hifi. The Dac feeds off a Marantz CD75SE from the same period - both are still going strong. No idea what upgrades were made in the BS Mark 2 except for the rotary switch on the front - please enlighten me!

 

[Dowser]

I have been using my Duo BS version 1 DAC for more than 30 years - sound-wise it is nicer than any modern dac I've heard, but then I am in my 60s and prefer to listen to music as a trained musician, not hifi. The Dac feeds off a Marantz CD75SE from the same period - both are still going strong. No idea what upgrades were made in the BS Mark 2 except for the rotary switch on the front - please enlighten me!

The Original Duo was a multibit DAC, the BS a Bitstream one (SAA7321GP) - I’ve never heard one, so cannot comment on sound, but IME Micromega implementations are generally very good. Your CD75 has the same TDA1541 DAC section as my Duo I believe, but as always everything is down to implementation.

I haven’t done any further work on the Duo yet - sounds fantastic as is, so am just listening to it

 

[atcman]

Off topic maybe but just got the Micromega mydac and it is one of the most Human sounding dacs i have heard,not yet had the pleasure of a Duo,poss in the future.

 

[John Cretton]

Old thread I know.

I have just had my Micromega Duo DAC serviced and in my case there was indeed a TDA 1541 S1 chip. Wonderful machine, only bettered for me by Cambridge Audio CD3.

Only thing is the DAC runs so hot that I never dare leave it on, only use for listening sessions - I had the whole unit checked by my superb technician here in Switzerland and he said it's normal due to the design - maybe why so few still seem to be around and why the insides are often a mess? My one was ok thankfully, one cap to replace.

 

[Dowser]

Mine runs warm, but not massively hot - when in use I left it on 24x7 without worry. Nice to know there's another Duo user in Swissieland - I'm close to Zurich

Don't suppose you got any pictures from inside? I can only assume mine, with a non-A chip, must be an early one - be interested to see if they made other changes to later models, or just the DAC chip.

 

[John Cretton]

Mine runs warm, but not massively hot - when in use I left it on 24x7 without worry. Nice to know there's another Duo user in Swissieland - I'm close to Zurich

Don't suppose you got any pictures from inside? I can only assume mine, with a non-A chip, must be an early one - be interested to see if they made other changes to later models, or just the DAC chip.

Sorry for (very) late reply. I think my technician did take some photos. I'll check. Just had the transport (CD F1 Digital) serviced too. First time they run as a proper, working combo on my main system and the Cambridge CD3 and the Micromega are neck and neck.