Diodes
Hi Mayday, Yeah... the diodes in BOM is really overkill. In my builds I used Schottkey (spelling?) diodes. In that case the board land area comes in handy as they are big. I'm sure someone can recommend some for you. I used 2 Amp 100-200 PIV diodes. They were called high efficiency rectifiers. I see they are no longer available from Digikey. Anyway... use at least 2 Amp 100-200 PIV rectifiers and all should be fine. I'm not sure what diodes are the rage at the moment. Anyone? Feeling better yet? Dave
Hi Mayday, Yeah... the diodes in BOM is really overkill. In my builds I used Schottkey (spelling?) diodes. In that case the board land area comes in handy as they are big. I'm sure someone can recommend some for you. I used 2 Amp 100-200 PIV diodes. They were called high efficiency rectifiers. I see they are no longer available from Digikey. Anyway... use at least 2 Amp 100-200 PIV rectifiers and all should be fine. I'm not sure what diodes are the rage at the moment. Anyone? Feeling better yet? Dave
Diodes
Hi Mayday, Those diodes you mentioned will probably work fine. I'd use 2 Amp diodes feeding the supply for the SAA7220. The 1.5 Amp should work OK everywhere else. On my second build I mounted the diodes above the board for airflow. I didn't do that on the first one. The big difference there is the first build doesn't use a SAA7220 so not as much current draw or heat off the regulator heatsinks. The NPC filter with glue logic doesn't draw that much power. Also sounds different from the SAA7220. I think my second build will use the SAA7220 B revision. It will be interesting to compare them. I'm going to order some caps this weekend to try the DEM clock mod. I'll have to grade a bunch of caps and give it a try. Glad your on the mend. So far I am doing OK. It was almost 50 Degrees F yesterday. I think that's just above 10 Degrees C. Unheard of in Minnesota. Global warming? Dave
Hi Mayday, Those diodes you mentioned will probably work fine. I'd use 2 Amp diodes feeding the supply for the SAA7220. The 1.5 Amp should work OK everywhere else. On my second build I mounted the diodes above the board for airflow. I didn't do that on the first one. The big difference there is the first build doesn't use a SAA7220 so not as much current draw or heat off the regulator heatsinks. The NPC filter with glue logic doesn't draw that much power. Also sounds different from the SAA7220. I think my second build will use the SAA7220 B revision. It will be interesting to compare them. I'm going to order some caps this weekend to try the DEM clock mod. I'll have to grade a bunch of caps and give it a try. Glad your on the mend. So far I am doing OK. It was almost 50 Degrees F yesterday. I think that's just above 10 Degrees C. Unheard of in Minnesota. Global warming? Dave
Oh... Mayday, I forgot to mention that the board is a bear to rework. My best luck desoldering was heating the lead and pulling it out one lead at a time. I had no luck solder sucking the holes and found a small drill bit and pin vise was super easy for removing the solder in the hole. Just a hint that might help you out. Dave
We've had similar weather here in Sweden. A few days of snow in total so far.
Minnesota? That's where a lot of the Swede's who moved to the US a hundred years or so ended up staying.
Yes I'm getter better everyday now thank god, it's been awful.
I'll use the SAA7220P/B, that's the ones I've got a few of. And TDA1541A ofcourse.
Was offered a cd mainboard a while ago that had the single crown TDA on it, but at $50 + shipping I thought it was a bit much. (Don't think it's THAT much better than the A?)
I think I'll go for diodes I know to work well, probably BYV27-200.
I like mur840/860 too, but they won't fit this pcb.
That's a sturdy board alright
My solderstation goes to 450 C(adjustable by 1 degree C between 150 and 450 degrees), and I have a very good solderpump.
I have to be careful not to accidentally suck solder islands(correct word?) on most PCB's.
Hopefully I won't need to re-solder anything(haha, me being naive), but if I do I'll keep your advice in mind
How heatsensitive are the SAA/TDA?
I don't care about the donor board.
Is it best to heat very fast w a hot iron, suck solder(and probably solderpad), move to other chip and repeat?
Reason I'm thinking of going back and forth between IC's is to let them cool a little before hitting them with the hot iron again.
I don't care about the donor board.
Is it best to heat very fast w a hot iron, suck solder(and probably solderpad), move to other chip and repeat?
Reason I'm thinking of going back and forth between IC's is to let them cool a little before hitting them with the hot iron again.
Desoldering
Hi Mayday, Yes, I would do as you suggest. Desolder a pin and go to the other part. Let cool and return. I suspect several pads will lift. I have (2) TDA1541A S1 Crown Dacs, they sound smooth and refined. They also were purchased many years ago before the fakes started to appear. In UV101's paper he indicates that a plain 1541A with DEM locked will negate the difference. So I'd say it makes no sense to pay for the S1 or S2 graded parts. I finally did get a cold. Not to bad, the price I paid to see the Minnesota Orchestra last Friday night. A cold wind waiting for the light rail train. New compositions. Interesting stuff.... Yes, Minnesota is the home to many generations of Swedish people. Myself I am Scottish, German and Noregian not sure of the percentages.
Hi Mayday, Yes, I would do as you suggest. Desolder a pin and go to the other part. Let cool and return. I suspect several pads will lift. I have (2) TDA1541A S1 Crown Dacs, they sound smooth and refined. They also were purchased many years ago before the fakes started to appear. In UV101's paper he indicates that a plain 1541A with DEM locked will negate the difference. So I'd say it makes no sense to pay for the S1 or S2 graded parts. I finally did get a cold. Not to bad, the price I paid to see the Minnesota Orchestra last Friday night. A cold wind waiting for the light rail train. New compositions. Interesting stuff.... Yes, Minnesota is the home to many generations of Swedish people. Myself I am Scottish, German and Noregian not sure of the percentages.
Hope you get well soon!
My mother told me some of her parents siblings moved to the US so apparently I have relatives over there...though she's lost contact with them over the years.
I know my percentages lol! My father did alot of genealogy when he was still alive. Our family has been in sweden atleast since the 17th century, he got stuck there because the church containing archives going further back was destroyed in a fire around that time.
I'll use that method then when desoldering IC's.
I may be able to get some more parts this month, I've probably sold one of our 3 digital kameras.
Take care,
Jonas
My mother told me some of her parents siblings moved to the US so apparently I have relatives over there...though she's lost contact with them over the years.
I know my percentages lol! My father did alot of genealogy when he was still alive. Our family has been in sweden atleast since the 17th century, he got stuck there because the church containing archives going further back was destroyed in a fire around that time.
I'll use that method then when desoldering IC's.
I may be able to get some more parts this month, I've probably sold one of our 3 digital kameras.
Take care,
Jonas
Last edited:
I haven't decided.
Valves are new to me, atleast building with them.
There's also the option of going w output trafos(expensive).
Or a discrete class A output.
I'll do a search for the section about the Pass B1.
Going down the valves route is cheap.
I went nuts and got matched valves and matched PIO's, nice caps and welwn resistors and even with the traffo struggled to get over £60 for the lot !!
The only downside to it was I was completely traumatised by the voltages going on inside and an annoying hum which took me a week to find and then silence.
I have a trick cap discharging weapon now and I'm happy fiddling around with it - still no shocks !!
Must mean I'm learning something.
btw....it sounds very nice.
I went nuts and got matched valves and matched PIO's, nice caps and welwn resistors and even with the traffo struggled to get over £60 for the lot !!
The only downside to it was I was completely traumatised by the voltages going on inside and an annoying hum which took me a week to find and then silence.
I have a trick cap discharging weapon now and I'm happy fiddling around with it - still no shocks !!
Must mean I'm learning something.
btw....it sounds very nice.
Actually just talked to my friend, he said I can have it for free, not even pay shipping
It should arrive the day after tomorrow.
It's completed except for the caps.
From what the guy who helped me with the tpr told me I just take the signal from where the second pair of AD797 should've been.
Also he said that AD797 as a buffer needed a 100R resistor from out to -IN, he refered to the datasheet Fig.36(haven't had a look yet since he just told me)
It should arrive the day after tomorrow.
It's completed except for the caps.
From what the guy who helped me with the tpr told me I just take the signal from where the second pair of AD797 should've been.
Also he said that AD797 as a buffer needed a 100R resistor from out to -IN, he refered to the datasheet Fig.36(haven't had a look yet since he just told me)
Yes, I'll use it.
Just put the first pair of opamps in as I/V and the hook the B1 up the the DIP8 sockets for the second pair(the buffer pair). Couldn't be more to it then connecting opamp in and gnd to B1 in and gnd? And hooking B1 to a PS ofcourse
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.