There is no law that says you have to mash the resistor FLAT on the board.
If you flubbed the power calcs, part number, or PCB layout, that's fine. I have done it too. But DON'T do that to resistor. Rule one, read and follow the manufacturers specs... no one is more interested in you having a successful experience and buying MORE parts.
Rule two, form resistor leads WITHOUT stressing the resistor body.
Stand those off the board and form the leads correctly...
If you flubbed the power calcs, part number, or PCB layout, that's fine. I have done it too. But DON'T do that to resistor. Rule one, read and follow the manufacturers specs... no one is more interested in you having a successful experience and buying MORE parts.
Rule two, form resistor leads WITHOUT stressing the resistor body.
Stand those off the board and form the leads correctly...
Member
Joined 2002
poobah said:There is no law that says you have to mash the resistor FLAT on the board.
If you flubbed the power calcs, part number, or PCB layout, that's fine. I have done it too. But DON'T do that to resistor. Rule one, read and follow the manufacturers specs... no one is more interested in you having a successful experience and buying MORE parts.
Rule two, form resistor leads WITHOUT stressing the resistor body.
Stand those off the board and form the leads correctly...
I agree. I was once shown and told that bending the leads really tight will cause problems My dad once showed me when you ben them leads really tight like that you can cause the inside of the resistor to crack witch will then change the value of the resistor.. Look how i did mine for my mini a's.
Attachments
Yes, thats the way to mount them. (Cute little board, btw🙂 ) I dont mind mounting the resistors that way.
Steen🙂
Yes. That resistor isn;t soldered. I just did that for illustration of fit. Note the spacing used here on the larger resistors for heat dissipation:
Spacing tips for these boards:
For the PS, U used one of the 0.1uF caps on it's side as a spacing gauge for the 3W resistors. Works very well.
For the pre board, if you mount the faston connectors before the 2w and 3W resistors, they will hold the pcb a perfect distance off your work surface to give the resistors a nice (and even) spacing: bend leads and insert resistors, flip the board, and then gently press them even with the work surface, then solder.
An externally hosted image should be here but it was not working when we last tested it.
Spacing tips for these boards:
For the PS, U used one of the 0.1uF caps on it's side as a spacing gauge for the 3W resistors. Works very well.
For the pre board, if you mount the faston connectors before the 2w and 3W resistors, they will hold the pcb a perfect distance off your work surface to give the resistors a nice (and even) spacing: bend leads and insert resistors, flip the board, and then gently press them even with the work surface, then solder.
That's cool,
I didn't intend to be a jerk about it. The official line form manufactures is that the first 0.04 - 0.06 (1/16") of the component lead should be left undisturbed AND that that portion of the lead should be supported/clamped (needlenose) when forming the the rest of the lead.
Thruth be told, you would be fine to just gently roll the lead over a pencil and mount them vertically on the board... make sure you have 1/8" clearence between the bottom of the component and the board when finished soldering.
If these buggers are actually packing some heat, this will help with cooling too.
😀
I didn't intend to be a jerk about it. The official line form manufactures is that the first 0.04 - 0.06 (1/16") of the component lead should be left undisturbed AND that that portion of the lead should be supported/clamped (needlenose) when forming the the rest of the lead.
Thruth be told, you would be fine to just gently roll the lead over a pencil and mount them vertically on the board... make sure you have 1/8" clearence between the bottom of the component and the board when finished soldering.
If these buggers are actually packing some heat, this will help with cooling too.
😀
Member
Joined 2002
steenoe said:
It Really is a cute board with TONS of power these little mini a's @ 15watts are really nice.. I still think that the smd mini a's sound better.. Ill be connecting my smd version back up tonight to compair.
Dale Resistor Kits
I just added an item to the order page for the Dale resistor kits. It includes Dale RN60 versions of all 42 2/5W resistors in the regular kit. Price is $8. Shipping is covered by the board or kit shipping. Have fun.
BTW: I plan on shipping all the board only orders on Monday, so if you are one of those and want the resistors, now would be a good time... 😉
I just added an item to the order page for the Dale resistor kits. It includes Dale RN60 versions of all 42 2/5W resistors in the regular kit. Price is $8. Shipping is covered by the board or kit shipping. Have fun.
BTW: I plan on shipping all the board only orders on Monday, so if you are one of those and want the resistors, now would be a good time... 😉
Ready to Build
Thanks Brian for the offer on the resistors. PayPal is in the mail. I went the other direction from the mini-A's with the Brian GT boards. Two sets made a nice pair of Aleph 2's, with one board left for a mini-A one of these days. You can see why I am looking forward to building the twisted Bosoz.
Thanks Brian for the offer on the resistors. PayPal is in the mail. I went the other direction from the mini-A's with the Brian GT boards. Two sets made a nice pair of Aleph 2's, with one board left for a mini-A one of these days. You can see why I am looking forward to building the twisted Bosoz.
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Re: Ready to Build
What do you think of your mini a's Do you like them ? I find that they have lots of power for any of my need's..
J
hayenc said:
What do you think of your mini a's Do you like them ? I find that they have lots of power for any of my need's..
J
Mini-A's are still a project for another day. I am very impressed with the Aleph 2's from the BrianGT boards. Needs the pre-amp though, as I am currently just driving them from the DAC1. I will say I am impressed with the flexibility of the boards and the ease of construction.
Member
Joined 2002
hayenc said:
I 2 are only powering my aleph's passivly.. i need a pre thus why i ordered one of these kit's. Hope to hear good sound from them 4 channels now 😀
j'
Correct. If you already paid shipping (or if you were one of the lucky free shipping folks) no need to pay shipping again.
We are waiting for a quote from Avel on a custom trafo. Shoudl be reasonable. Concerns are shipping weight and time frame for delivery, but not really big concerns. When we hear (hopefully early next week) we will post.
They will be a seperate item (not part of the kit). Shipping, well, we will need to wait and see what the weight is and how they fit in the packaging.
Member
Joined 2002
Id like to say that Avel has really nice product's I have 2 of there product's the transformers and they are nice cheap and reliable..Also dealing with them is easy and effortless 🙂
Jason
Jason
Russ White said:Hey you two, your making me cry in my beer. 🙂
Thanks, we are all in this together.
Cheers!
Russ
You wouldn't want to water that down...now would you?
I just stuffed a psu and pre board, went together like glue.
What is this - "Preamps for Dummies"🙂
Error on the BOM
Marc, and anyone else looking at the BOM,
I started building my preamps yesterday too! 🙂
Since its the weekend and he is probably watching football and such I have not been able to raise Brian yet about this, but I wanted everyone to know that D1 on the premp boards is supposed to be a 1N5235(or equivalent) 6.8V Zener, not a 1N4004 as stated on the BOM. So please don't power this thing up until you are sure you have the right part in there. 🙂
The Diode is marked correctly on the Schematic and the Silkscreen, it was just a case of a lot going on at the time when the BOM was being published I think. Don't blame Brian. I should have caught it earlier.
Cheers!
Russ
Marc, and anyone else looking at the BOM,
I started building my preamps yesterday too! 🙂
Since its the weekend and he is probably watching football and such I have not been able to raise Brian yet about this, but I wanted everyone to know that D1 on the premp boards is supposed to be a 1N5235(or equivalent) 6.8V Zener, not a 1N4004 as stated on the BOM. So please don't power this thing up until you are sure you have the right part in there. 🙂
The Diode is marked correctly on the Schematic and the Silkscreen, it was just a case of a lot going on at the time when the BOM was being published I think. Don't blame Brian. I should have caught it earlier.
Cheers!
Russ
DOH!
6.8V zeners are ordered and on the way for the kits.
I will get the online BOMs updated later today. Sorry for the confusion, and good eye Russ. I stuffed my boards so fast I didn't notice!
6.8V zeners are ordered and on the way for the kits.
I will get the online BOMs updated later today. Sorry for the confusion, and good eye Russ. I stuffed my boards so fast I didn't notice!
Trafo and zener questions...
Thanks,
I have a couple of questions to anyone very familiar with the circiut.
I have a transformer from a small old rotel rcvr that I think may work nicely. It has a few secondaries. One secondary is a no-brainer 28-0-28. That will do nicely. However the other 2 secondaries can be series'd (new word?) for a total of 12.2v ac. When I load the series'd secondaries with am 8r power resistor it drops to a little over 11vac. That's well over an amp and is a good acid test for it IMHO.
Now, I'll assume about 11.5vac sec voltage under load from the pre(I think I'm being very conservative). I am looking at ~ -11.6vdc after rect. and fet vgs losses providing my zener stack allowed Max possible voltage.
Should I change my negative zener stack to a 9.1v and a 6.2v? It seems like it will give in excess of the required -9v...am I right?
Also, will a 6.2v zener work as D1 (instead of 6.8) as just mentioned by Russ/Brian? This I have no clue....
Thanks in advance.
Thanks,
I have a couple of questions to anyone very familiar with the circiut.
I have a transformer from a small old rotel rcvr that I think may work nicely. It has a few secondaries. One secondary is a no-brainer 28-0-28. That will do nicely. However the other 2 secondaries can be series'd (new word?) for a total of 12.2v ac. When I load the series'd secondaries with am 8r power resistor it drops to a little over 11vac. That's well over an amp and is a good acid test for it IMHO.
Now, I'll assume about 11.5vac sec voltage under load from the pre(I think I'm being very conservative). I am looking at ~ -11.6vdc after rect. and fet vgs losses providing my zener stack allowed Max possible voltage.
Should I change my negative zener stack to a 9.1v and a 6.2v? It seems like it will give in excess of the required -9v...am I right?
Also, will a 6.2v zener work as D1 (instead of 6.8) as just mentioned by Russ/Brian? This I have no clue....
Thanks in advance.
Please update the IRF9610 in the psu BOM also, I noticed that the wrong type is persisting😉 You list IRF610's for all the fets in the supply. The Negative rail, really needs an IRF9610🙂 Just to avoid mistakes
Marc, if I understand you correctly, you have like 12V AC, Lets say 11V just to be sure. That nets you something like 15,4volts after rectification and before the regulating fet which eats like 3 volts!! You are pretty close to starving the Zenerstring with that voltage!
Variations in the main supply might starve them, and you really do not want that, believe me😉 You could swap out the P-channel fet with a BJT which doesnt throw off so much voltage🙂 You are pretty close to the minimum voltage that I would use!
Steen🙂