They are in fact the Parts Express $7.00 transformers. I got three when they were still available. They are nice little transformers for the workbench, but I am using torroids in the finished boxes (someday).
I am actually working with my brother up in VT on designing some cases, which I can hopefully make available. We'll see what happens there.
I am actually working with my brother up in VT on designing some cases, which I can hopefully make available. We'll see what happens there.
BrianDonegan said:
Do a GB thing from Par-Metal. He can make custom cases and his are first rate for the cash.
Thought about that. Still a possibility.
We were talking about a stainless steel case with aluminum front and rear panels. They would definitely be "nicer" cases, maybe aroung $100-$125. We are making at least two (one for me, one for him). Selling is more of an outside possibility at this point.
I like the idea of being able to provide all the parts people need, as a lot of people who buy the kits are new to it, or just back from an extended break. I am thinking of including RCA jacks in the kits, possibly binding posts, but maybe as add-on options. I just remember when I was first getting into it, how much of a pain it was to get standoffs, screws and stuff like that, without buying a bunch. That's why I include those thing now.
We'll see what happens. I'm not expecting (kowing how my brother and I ususally work together) anything to happen really soon. I'll let you know if something happens though.
We were talking about a stainless steel case with aluminum front and rear panels. They would definitely be "nicer" cases, maybe aroung $100-$125. We are making at least two (one for me, one for him). Selling is more of an outside possibility at this point.
I like the idea of being able to provide all the parts people need, as a lot of people who buy the kits are new to it, or just back from an extended break. I am thinking of including RCA jacks in the kits, possibly binding posts, but maybe as add-on options. I just remember when I was first getting into it, how much of a pain it was to get standoffs, screws and stuff like that, without buying a bunch. That's why I include those thing now.
We'll see what happens. I'm not expecting (kowing how my brother and I ususally work together) anything to happen really soon. I'll let you know if something happens though.
Just a question about stainless steel cases. How would they be on the heating front? S/S is not very efficient @ conducting heat. Would an S/S/ case not insulate heat too much?
The only problem with ALU, because it conducts heat so well, is that it take alot longer (Read more expensive) to laser cut.
stainless is only 1/17th as thermally conductive as aluminium so its probably not a great idea unless you have the chip attached to a plate of aluminium or copper and then attach that to the stainless, and the stainless is pretty big. it sure would look nice though 🙂
making a case
Nice metal cases can be made. I like the weight of aluminum and it's easy to drill etc. A case can be vented for cooling. If you have a tablesaw, you can cut aluminum with a carbide blade. It is a dusty affair and you have to protect your eyes well. I believe Peter Daniel is good at this. [making a professional amp case]
This pic. was my 1st lm3875. The case is formed 1/8" aluminum; it's not quite as good as I wanted but live and learn; sanded with a rotary mikita sander; the trim pieces on top are mirror polished stainless-nice stuff.
cheers
doggy🙂
Nice metal cases can be made. I like the weight of aluminum and it's easy to drill etc. A case can be vented for cooling. If you have a tablesaw, you can cut aluminum with a carbide blade. It is a dusty affair and you have to protect your eyes well. I believe Peter Daniel is good at this. [making a professional amp case]
This pic. was my 1st lm3875. The case is formed 1/8" aluminum; it's not quite as good as I wanted but live and learn; sanded with a rotary mikita sander; the trim pieces on top are mirror polished stainless-nice stuff.
cheers
doggy🙂
Attachments
Cap upgrades..?
Hi folks.
Apart from C13 (1uF Wima) are there any other caps worth upgrading? It's purely for the exercise. C15 (22uF Nichicon) perhaps? What have people tried in place of C13 and with what results?
Cheers
Kendal
Hi folks.
Apart from C13 (1uF Wima) are there any other caps worth upgrading? It's purely for the exercise. C15 (22uF Nichicon) perhaps? What have people tried in place of C13 and with what results?
Cheers
Kendal
The stainless would be the top and sides, possible bottom. They would be vented as well, so I don;t thing heat would really be an issue. Heatsinks would protrude from aluminum surfaces, so if we made them come out the sides, the sides would be aluminum.
As far as cap replacement goes, C15 is only there as part of an RC timer for the relay. Not much use in replacing that (that's why it's not a high-q cap in the first place).
For C13, my stock of 1uF Wimas is starting to run low. I was thinking of trying 1uF 400V Jantzen MKP's from PE if they would fit (would definitely take a little pin bending). If they fit and sound good, they may replace the Wimas in future kits. Unless anyone has another suggestion (requirements are reasonable cost and high availability).
As far as cap replacement goes, C15 is only there as part of an RC timer for the relay. Not much use in replacing that (that's why it's not a high-q cap in the first place).
For C13, my stock of 1uF Wimas is starting to run low. I was thinking of trying 1uF 400V Jantzen MKP's from PE if they would fit (would definitely take a little pin bending). If they fit and sound good, they may replace the Wimas in future kits. Unless anyone has another suggestion (requirements are reasonable cost and high availability).
Cast Aluminum Cases
I have mine shoehorned in a Hammond 1590 cast aluminum box. It fits, but requires pulling the binding posts and speakon connector to install and remove. The 7.00 power transformer is mounted in a matching 19.00 chassis.
Going to use a nice Deltron box for my next one. These are a lot larger and run 30.00 from Mouser.
To conduct heat, aluminum plate is mounted behind the board to make the aliuminum thicker at the chip. Using mica and thermal paste. The aluminum is lightly coated with paste also.
Works great! And is very easy to drill.
George
I have mine shoehorned in a Hammond 1590 cast aluminum box. It fits, but requires pulling the binding posts and speakon connector to install and remove. The 7.00 power transformer is mounted in a matching 19.00 chassis.
Going to use a nice Deltron box for my next one. These are a lot larger and run 30.00 from Mouser.
To conduct heat, aluminum plate is mounted behind the board to make the aliuminum thicker at the chip. Using mica and thermal paste. The aluminum is lightly coated with paste also.
Works great! And is very easy to drill.
George
Very sad also if Mauro stays away. Thanks again for a great gift.
I do hope however that this thread doesn't just dissolve into a sales and troubleshooting forum for standard TP kits' as IMO this discussion has been most productive and enjoyable.
I do hope however that this thread doesn't just dissolve into a sales and troubleshooting forum for standard TP kits' as IMO this discussion has been most productive and enjoyable.
Hi guys-
For the record, I don't mind, and I don't think Russ minds (buy I do not speak for him) that Rudi made his own boards. I also don't mind that anyone wants to try and tweak/change/whatever the circuit, be it on our boards, Rudi's boards or their own. That is why we are all here. I try stuff with mine all the time. That is DIY.
My interpretation of Mauro's comments is that he would like to see more technical discussion/description/reasoning behind mods. I personally do not have the technical depth and expertise to always explain things, nor to comment/remark on other people's. This is why I have not said much or tried to "help out" with Rudi's experiments, not that I mind them, I just don't feel comfortable offering advice I can't justify (plus, I don't have much time to keep up with it all 😉 ).
In retrospect (20/20 hindsight), I think we shoudl have broken off the TPA board offering stuff from Mauro's main thread long ago, so that Russ and I could have commented on our stuff without it looking like we were somehow inflexible and hostile to other's ideas. I can only assure you that we are not, though, through the magic of the internet, communication of emotion is generally terrible.
I actually have to run to make some lunch for my son, so I hope this came out okay, as I had to rush it a bit.
I hope we can just get back to playing now ad have some fun!
For the record, I don't mind, and I don't think Russ minds (buy I do not speak for him) that Rudi made his own boards. I also don't mind that anyone wants to try and tweak/change/whatever the circuit, be it on our boards, Rudi's boards or their own. That is why we are all here. I try stuff with mine all the time. That is DIY.
My interpretation of Mauro's comments is that he would like to see more technical discussion/description/reasoning behind mods. I personally do not have the technical depth and expertise to always explain things, nor to comment/remark on other people's. This is why I have not said much or tried to "help out" with Rudi's experiments, not that I mind them, I just don't feel comfortable offering advice I can't justify (plus, I don't have much time to keep up with it all 😉 ).
In retrospect (20/20 hindsight), I think we shoudl have broken off the TPA board offering stuff from Mauro's main thread long ago, so that Russ and I could have commented on our stuff without it looking like we were somehow inflexible and hostile to other's ideas. I can only assure you that we are not, though, through the magic of the internet, communication of emotion is generally terrible.
I actually have to run to make some lunch for my son, so I hope this came out okay, as I had to rush it a bit.
I hope we can just get back to playing now ad have some fun!
Gmorris said:
Thanks guys, they looked so pretty, and I thought they had a copper shielding case.
From this, I would like to know why most DIYers prefer the torroids to trans similar to the Parts Express trans?
Secondly, do you guys think that bring a 240v line to an on/off switch in the front panel of an amp, (due to to high voltage in the enclosure) would this cause strong magnetic fields that can degrade the performance of the amp?
Gmorris, my first completed GC is sitting on a piece of plywood too, waiting for my enclosure to be finished. This was my first lesson in microphony and isolation. 😀
You don't know the anxiety of waiting for a group order that a few of my friends and I are putting together for the TP Mauro's Ref C amp and Kookaburra pre kits. The reason is because if my cheap GC using a China board (2 channels on a single small board) could sound like what I have now, I am damn anxious to build the Ref C and the Kookaburra. 😉
Thanks in advance for any response to my newbie questions.
safetyman posted:
When buying new, cost. Also VA rating relative to size and then availability.
As long as you are careful with the routing of the "mains", which we all should be in any case, there should be no problem. One could spark a debate about the relative benefits of 120 versus 240V, but let's not get into that here.😉
When buying new, cost. Also VA rating relative to size and then availability.
As long as you are careful with the routing of the "mains", which we all should be in any case, there should be no problem. One could spark a debate about the relative benefits of 120 versus 240V, but let's not get into that here.😉
Any pointers on routing of the mains cable?
I simply try to keep it as far away from my inputs as possible. This usually means running it down the middle of the amp over the cap bank & rectifiers. Although in this case the rects & caps are on the boards. This seems to work well enough, there is no nasty hum or anything like that.
Take a look at page 2 of the MyRef Collection in my project gallery if you get lost with my ramblings of the way I have it now.
I simply try to keep it as far away from my inputs as possible. This usually means running it down the middle of the amp over the cap bank & rectifiers. Although in this case the rects & caps are on the boards. This seems to work well enough, there is no nasty hum or anything like that.
Take a look at page 2 of the MyRef Collection in my project gallery if you get lost with my ramblings of the way I have it now.
Ed Lafontaine said:
Ok, so I assume there is either not much or no diff between trans, of course not taken into account, the good stuff and the crap.😀
Ed, any chance of a lesson on "how to be careful routing mains"? Please....give me tips to avoid and best practices....
Thanks
Shehzad
safetyman,
If the transformer is in the same case as the Amp boards, then a Toroidal is a better choice, as there will be less problems with magnetic interference.
When running the 240V mains cable in the Amp case twist the two wires together and try to keep them away from other components.
In my case, I have to run the 240v mains from the back to the Toroidal T/F at the front of the case, and between the two mono boards which are 30mm apart. To be safe, I will use Belden 19364 shielded power cable and tie the shield to the chassis/mains earth point.
Audie.
If the transformer is in the same case as the Amp boards, then a Toroidal is a better choice, as there will be less problems with magnetic interference.
When running the 240V mains cable in the Amp case twist the two wires together and try to keep them away from other components.
In my case, I have to run the 240v mains from the back to the Toroidal T/F at the front of the case, and between the two mono boards which are 30mm apart. To be safe, I will use Belden 19364 shielded power cable and tie the shield to the chassis/mains earth point.
Audie.
In general - toroids apart from having less of an EM field, also run cooler and have less mechanical hum. They are better in terms of providing for the demands of music as they can withstand short overcurrent peaks better than their EI core bretheren.
For what it is worth, getting back to the Mauro design, on post 1500 about a month ago, I reported on my comparisons between the $7 PE transformer and using different toroids. I have not been able to go back and determine why the PE sounded so much worse, but the difference was audible.