The layout is the same as all other analog metric boards. I am running cs8414, NOS, an only one op-amp per channel - jumper from input to output of 2nd op-amp. I know the problem with ad797 is oscillation. When I remove them from the circuit the oscillation goes with it.
I have some dual op-amps I'd like to try ie lm4562. Anybody converted the single to dual op-amp with this board?
I have some dual op-amps I'd like to try ie lm4562. Anybody converted the single to dual op-amp with this board?
You could try the LME49710, That is supposed to be the single version of the LM4562 isn't it?
I think I'll try the output section from the Audio Workshop. I could suspend a board over the current output section so I could try dual op-amps.
I am still unclear about the capacitor values for C550 and C515. One post it looked like .1 uF another 1 uF and your at 8 uF.Do you know what Grundig used? I appreciate any comments and thanks for sharing. 😉
Right you are, c500,c515. All I have now is the posted diagram. I suspect if you do some digging around this site you'll find more references to the Grundig design. I think the caps might be much lower value like .1u. I recall that I started with a film cap something recycled at around .1u or less. The next step was the 8Uf smt with better results. I suspect there is a wide range of caps that can be used here. Lots of posters claim low leakage is important.
Hi there,
You can get the Grundig Service Manual from here .
Both caps on the DEM reclock (C500 & C515) are .1uf.
I tried this mod without success, I could never get it to lock, I went back to a Mica cap on the pins instead and this seemed better for me. If you test it with a low level recording it's pretty obvious if this mod has worked or not! (very noisy with no lock).
Hope this helps
You can get the Grundig Service Manual from here .
Both caps on the DEM reclock (C500 & C515) are .1uf.
I tried this mod without success, I could never get it to lock, I went back to a Mica cap on the pins instead and this seemed better for me. If you test it with a low level recording it's pretty obvious if this mod has worked or not! (very noisy with no lock).
Hope this helps
Attachments
Grundig DEM
Hi Josha, Thank you for the information. Much appreciated. Yes, I am aware not all mods work as intended. I'll get some parts together and see if it works with my 1541A. 😉 Dave
Hi Josha, Thank you for the information. Much appreciated. Yes, I am aware not all mods work as intended. I'll get some parts together and see if it works with my 1541A. 😉 Dave
The caps I am now using are soldered right on the pins.
ESRD Series 7.3 x 4.3 mm 16 V 8.2 uF Polymer Aluminum Electrolytic Capacitor
My "Yellow" pins arrived. It's a pity, but what You write is true.
They look good, but after few times push-pull in them, they became loose. The plastic body is very brittle, also. Comparing, my used sockets and pins look everlasting. So..., sorry China🙁
Here I did find the answer about decoupling capacitors and naked pins, which I was looking for.
What do you think about this improvement? It's because capacitor is changed to silver-mica, or because of capacitance decreasing?
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Hi ctef, Get a hold of a CPU socket. Remove the needed pins from that. They are much stronger. As to the naked chip holder, yes that is why I went with the starch plastic holder. You solder it on first then dissolve the starch plastic. It isn't as strong a pin as the ones from the CPU socket. You don't want to add any undue capacitance with the holder. ECDEsigns is right on with his solution. As to the DEM capacitor. We change the free running DEM oscillator frequency so that you get a lock on the bit steering logic. You get a cleaner sound. I am using 120 pF Silver Mica + an air variable trimmer. I believe the DEM oscillator then runs around 705 Khz. The Grundig mod kills the DEM oscillator and lets you synchronize to the WS if I am not mistaken. No samples are lost due to the DEM free running situation. 😀 It is very easy to hear the difference. I use headphones to check low level details. 🙂 The Silver Mica caps are very nice, can't say they have any influence on the sound quality. Dave
decoupling caps
Lampiztor seems to suggests increasing the decoupling capacitance for better performance. Any comments?
Lampiztor seems to suggests increasing the decoupling capacitance for better performance. Any comments?
Here I ask about pins 16,17 capacitor.
A lot of people suggest increasing decouplings. Also and -ecdesigns-. Lampizator explains why they are important. By the way, here our digital gurus, don't respect him. About me, what to say? The first my CD-player's mod was by his scheme. And... was impessed 🙄 But I'm not guru
Pin 16 17
Hi Stefan, Yes. I understood your asking about the pin 16, 17 DEM capacitor. Higher frequency I think is better. 120 pF + small air trimmer is about 705 Khz. There are other values that lock too. 200 pF should work. The Lampizator tube stage is very simple and can work well. I don't feel happy about the high I/V resistor value. Stick with a Gomes type as Thorsten suggest. If you already have Lampizator and like it. No issue here. 🙂 For decoupling caps everyone has a favorite value. 0.1 uF is the smallest value. I may try 0.22 uF with 1 uF at MSB pins. Hope that helps.... Dave
Here I ask about pins 16,17 capacitor.
A lot of people suggest increasing decouplings. Also and -ecdesigns-. Lampizator explains why they are important. By the way, here our digital gurus, don't respect him. About me, what to say? The first my CD-player's mod was by his scheme. And... was impessed 🙄 But I'm not guru
Hi Stefan, Yes. I understood your asking about the pin 16, 17 DEM capacitor. Higher frequency I think is better. 120 pF + small air trimmer is about 705 Khz. There are other values that lock too. 200 pF should work. The Lampizator tube stage is very simple and can work well. I don't feel happy about the high I/V resistor value. Stick with a Gomes type as Thorsten suggest. If you already have Lampizator and like it. No issue here. 🙂 For decoupling caps everyone has a favorite value. 0.1 uF is the smallest value. I may try 0.22 uF with 1 uF at MSB pins. Hope that helps.... Dave
It is true everyone has an opinion, so its good to experiment. In my case, no doubt that increasing from the stock .1uf was an improvement. Many are using the ecdesigns choice, Cornell Dubilier Stacked Metallized Film Capacitors 1µF/16V FCA 1210 caps. I have a Red Baron board with these caps installed but yet to plug it in. Having too much fun listening to my current setup with ESRD Series 7.3 x 4.3 mm 16 V 8.2 uF Polymer Aluminum Electrolytic Capacitor. SMT directly on the pins is the secret sauce. Every mm counts here. Even adding small blackgate soldered right on the pin of the +5 -5 and -15v pins will be very rewarding. That's even with OSCON SEP in the usual position. reducing distance to cap is key.
Hi wlowes, I couldn't agree more. I plan to redo the decoupling on my first 1541A dac build. I will pull pins from a CPU socket. I did prefer Panasonic PPS to the Cornell Dubilier acrylics that ECDesign's used. Not a huge difference. I like the warm musical qualities of the PPS dielectric. 😀 Sad to say still no Red Baron boards so it looks like $40 down the drain. I ordered 2, wish I hadn't. This isn't Oliver's fault, he has no control over the Postal Services. 😡 No one likes to loose the hard earned cash like that. I'll try your tip about the electro's right at the supply pins. Dave
Hi Dave,
I was thinking of trying a 1uf cap near the MSB pin of the TDA1541A. But I'm confused about which pin represents the MSB. My dyslexia doesn't help my lunacy 🙂). Also, it seems the only people complaining about no boards are from the USA. Is it a coincidence or does somebody in Germany not like us?
I was thinking of trying a 1uf cap near the MSB pin of the TDA1541A. But I'm confused about which pin represents the MSB. My dyslexia doesn't help my lunacy 🙂). Also, it seems the only people complaining about no boards are from the USA. Is it a coincidence or does somebody in Germany not like us?
Somebody doesn't like us, Germany etc. Can you blame them considering the lunacy in Washington DC?
I call it the Dacasaurus Rex Mark II. Mark I is just as big. 😉 Future projects will be smaller. 😎