I have made a dem reclock of 174Khz to the dac.
Divided clock signal of 11Mhz in 4 and in 16, this gives a reclock signal to dem pin. It will result in a sound with perfect articulated instruments, "layered" sound, perfect bass (base drum, cello etc)
Search for details in the ultimate 1541 dac topic: (enourmous huge thread)
http://www.diyaudio.com/forums/digi...building-ultimate-nos-dac-using-tda1541a.html
Divided clock signal of 11Mhz in 4 and in 16, this gives a reclock signal to dem pin. It will result in a sound with perfect articulated instruments, "layered" sound, perfect bass (base drum, cello etc)
Search for details in the ultimate 1541 dac topic: (enourmous huge thread)
http://www.diyaudio.com/forums/digi...building-ultimate-nos-dac-using-tda1541a.html
Hi guys, I should really point out that the source of my information is here on the forum. The thread that the DEM information has been extracted from is the EC Designs Ulitimate NOS thread. The document started as a collation of usefull info I've found (my sources are always quoted) but ended up as a more generic how to clock the TDA 
The DEM clock is a worthwhile mod for sure but not possible until you have a clock and a counter (for the /2 or /4 output).
Anyone tried the simple single opamp I/V yet?
The DEM clock is a worthwhile mod for sure but not possible until you have a clock and a counter (for the /2 or /4 output).
Anyone tried the simple single opamp I/V yet?
Will these Heatsinks be enough for the regulator schematic posted below?
What input voltages are acceptable to give 5Vdc out?
What input voltages are acceptable to give 5Vdc out?
An externally hosted image should be here but it was not working when we last tested it.
Depends on where you are using them!! The greediest chip is the 7220. Try it. If it gets too hot, use a bigger one!!!
Cant see the dropout voltage quoted in the datasheet but 7v in should be enough. You can go much higher if you want. I think most of my 5v regs are supplied about 11v. General rule of thumb is that it will run hotter with higher voltages. BTW, be carefull with heatsinks on LM317 as I think the case is the output Again try it. Its all to do with the voltage on the adjust pin
Depends on where you are using them!! The greediest chip is the 7220. Try it. If it gets too hot, use a bigger one!!!
Again try it. Its all to do with the voltage on the adjust pin
Ordered the LED's and isolationkits for TO-220.
Also got 2 EI trafos 1x9Vac 1200mA (10VA).
Resistors and caps for the regulator.
It's intended for use w SAA7220 yes.
EDIT: Just got confirmation that my 122pF less than 1% tolerance Silver Micas are sent and should arrive tomorrow
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Well, I'm running 2 round metal can LME49710's at the moment for i/v ...
Is that what you mean ?
I've bee looking at the new LME49990 too for this.
I've been taking my signal straight off the i/v op amps to a valve buffer because I could not get 68R passive i/v resistor ( off the TDA pins ) to sound OK at all
I also love my Audio GD Sun discrete buffer units ( like Bursons ) so there's a fair bit of indecision on my part with ' output stage ' generally.
I'd love a pass labs unit but hey, there's none available that I can see and they are costly.
Andrew
For the ones who want to dig out the dem issues:
http://www.diyaudio.com/forums/digi...e-nos-dac-using-tda1541a-226.html#post1660547
And: http://www.diyaudio.com/forums/digital-line-level/11949-tda1541-dem-reclocking-11.html#post1708425
http://www.diyaudio.com/forums/digi...e-nos-dac-using-tda1541a-226.html#post1660547
And: http://www.diyaudio.com/forums/digital-line-level/11949-tda1541-dem-reclocking-11.html#post1708425
I think have one at home that is a little bit bigger.
I'll build the regs on veroboard(no conductive surface on the componentside) and to be extra careful I ordered some isolationkits for TO-220
How many volts did you feed your reg? Mine will be fed by either 13,6Vdc (no load) or I'll use a diode(BYV95A) or two(in series) to drop the voltage a bit more directly after the diode bridge.
I used two, the first from 15v to 9v and the second from 9v to 5v, it was the first one that got hot. My player has a big heatsink hanging out of the back so I attached it to that in the end (once I figured out I needed to isolate it!) and that fixed it.
I was going to balance the voltages out a bit but the 7220 died before I got round to it!
I was going to balance the voltages out a bit but the 7220 died before I got round to it!
So if I use a standard lm317 to drop dc from ~16 to ~11V, the "more quiet" reg w led's won't get THAT hot? I could always use the cd players bottomplate as heatsink(w lm317 insulated)...
Personally, I'd not use the diodes to drop the voltage! That reg will be fine on a bigger heatsink.
Now you are starting to understand the many considerations when adding regs. I always use 9v transformer which will give me approx 11-12v DC after rectification. My regs are heavily based on SPowers which need approx 5v drop out so this is fine for 5v rails. The 960 is an all metal chassis which makes things nice and easy. In that CD65 I've just done, its all plastic so you need heatsinks. I also only use encapsulated FETs as the output devices. This means that mounting is one less thing to worry about
With LM317's even if you are using isolators, make sure you insulate the mounting bolt too!!
Now you are starting to understand the many considerations when adding regs. I always use 9v transformer which will give me approx 11-12v DC after rectification. My regs are heavily based on SPowers which need approx 5v drop out so this is fine for 5v rails. The 960 is an all metal chassis which makes things nice and easy. In that CD65 I've just done, its all plastic so you need heatsinks. I also only use encapsulated FETs as the output devices. This means that mounting is one less thing to worry about
With LM317's even if you are using isolators, make sure you insulate the mounting bolt too!!
I know
You're talking about UV101, who's offered to get me the caps I'm having trouble finding?
Just noticed thisreading back through the posts I've missed!!! I'm very keene to point out that I'm not a supplier. I do have a good relationship with Brent (who is also a member here) at "Fidelity Audio"/ "Audio Upgrades" and I have purchased lots of his products. I have no problem recommending him or his products.
I've offered to supply components to a fellow user here, sourced from RS in the UK at cost plus postage, as perticular items are proving difficult to source. I can do this only because I spend too much money on components and as a result have accounts with a couple of component suppliers.
My website is non commercial.....all this is just for fun! I have a pretty stressfull job in IT and this is one way I can switch off without completely switching off!!!
Just to say again, that although I wrote some of that document, it clearly references the sections that were not written by me!!!
Well, I'm running 2 round metal can LME49710's at the moment for i/v ...
Is that what you mean ?
I've bee looking at the new LME49990 too for this.
I've been taking my signal straight off the i/v op amps to a valve buffer because I could not get 68R passive i/v resistor ( off the TDA pins ) to sound OK at all
I also love my Audio GD Sun discrete buffer units ( like Bursons ) so there's a fair bit of indecision on my part with ' output stage ' generally.
I'd love a pass labs unit but hey, there's none available that I can see and they are costly.
Andrew
I've been using a simple opamp (or Burson) as I/V for a couple of years now. Literally just a single inverting opamp with 1k78 in parallel with 2n2 straight into a DC blocking cap (4.7uF MKP). I did have a valve buffer for a while but I'm happy with the less is more approach these days.
I do have a idea based on a slightly modified Meridian TDA1541a output stage thats fully discrete and uses an opamp running as a DC servo to null the DC on the output (no DC blockers are then required!!) I'll build it on vero as some point soon and see what it sounds like
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