No, the amplifier is not connected to the case. The case is connected to the AC Earth/Safety ground using a short piece of 14ga. solid copper wire and a ring terminal. You can find the wire at any home improvement store.
The two 3.5mm phone jacks have a plastic body and are insulated from the case.
Hello,
First of all the PCB arrived and the kit is really helpful, and well explained
I do have some difficulties to make the tin stick to the PCB, but I guess it' because of the tin. Some better is on its way.
I'd like to use this amp to power my HD800 (300 ohms, 102db) and another headphone (40 ohm, 102 db). Would it be Ok to use the following setting ?
R3 : 4.75k (as in the kit)
R3A : 1.5k (as in the kit)
R4 : 11k
With the HD800 switch closed (high gain), and with the other headphone switch open (gain low) ?
Also, regarding the attenuator, would a 10k also be suitable ? do you have any recommanded attenuator ?
Lastly, do you have any recommanded rectifier ? those big that you have seems easy to work with.
Would those be OK : KBPC3502 35A Bridge Rectifier 200V | eBay ?
Thank you
First of all the PCB arrived and the kit is really helpful, and well explained
I do have some difficulties to make the tin stick to the PCB, but I guess it' because of the tin. Some better is on its way.
I'd like to use this amp to power my HD800 (300 ohms, 102db) and another headphone (40 ohm, 102 db). Would it be Ok to use the following setting ?
R3 : 4.75k (as in the kit)
R3A : 1.5k (as in the kit)
R4 : 11k
With the HD800 switch closed (high gain), and with the other headphone switch open (gain low) ?
Also, regarding the attenuator, would a 10k also be suitable ? do you have any recommanded attenuator ?
Lastly, do you have any recommanded rectifier ? those big that you have seems easy to work with.
Would those be OK : KBPC3502 35A Bridge Rectifier 200V | eBay ?
Thank you
Hi, let me try to sort out some of those question,
Probably your iron is too low power. 50W+ is recommended, variable output type is best.
Yes, those values should be fine.
Yes, 10k can be used if you like. There is no recommendation since this part operates independently from the Sapphire circuit and the choice is completely open. I used Goldpoint V24.
Yes. Any of the KBPC35 or KBPC25 series in the big metal case like those you linked to are good as far as I am concerned. Again, its mostly for mounting convenience rather than specs.
/R
Probably your iron is too low power. 50W+ is recommended, variable output type is best.
Yes, those values should be fine.
Yes, 10k can be used if you like. There is no recommendation since this part operates independently from the Sapphire circuit and the choice is completely open. I used Goldpoint V24.
Yes. Any of the KBPC35 or KBPC25 series in the big metal case like those you linked to are good as far as I am concerned. Again, its mostly for mounting convenience rather than specs.
/R
I usually have mine at 350. I should look up what is the recommended temperatures, I just settled on 350 as being fast without scorching.
Triad toroids
Here's the response I received from Triad:
We have two different transformers with similar part numbers. One part number is VPM240-1040 and the other is VPT240-1040.
The VPM240-1040 does have the flux band you are referring, but the VPT240-1040 does not.
The black color band you see on the VPT240-1040 is just a film we use for aesthetics.
PS: Triad responded quickly, but my mailer placed it in junk mail, and I don't check that regularly.
Here's the response I received from Triad:
We have two different transformers with similar part numbers. One part number is VPM240-1040 and the other is VPT240-1040.
The VPM240-1040 does have the flux band you are referring, but the VPT240-1040 does not.
The black color band you see on the VPT240-1040 is just a film we use for aesthetics.
PS: Triad responded quickly, but my mailer placed it in junk mail, and I don't check that regularly.
Hello,
I've nearly finnished the soldering. Indeed it's a lot easier with the correct iron temperature and good solder
I have few other questions :
Is there a way to identify the correct orientation of Q11 and Q12 ? The transistor seems to have a side larger, as in the PCB, but it's difficult to be sure.
Also, I have 0.047uF / 630V caps, can I use them as C1 replacement ? By the way talking about C1, I see in the BOM that there are supposed to be 0.47uF, and I got 1uF. Did the value change and the BOM was not updated, or does it simply doesn't matter ?
I've nearly finnished the soldering. Indeed it's a lot easier with the correct iron temperature and good solder
I have few other questions :
Is there a way to identify the correct orientation of Q11 and Q12 ? The transistor seems to have a side larger, as in the PCB, but it's difficult to be sure.
Also, I have 0.047uF / 630V caps, can I use them as C1 replacement ? By the way talking about C1, I see in the BOM that there are supposed to be 0.47uF, and I got 1uF. Did the value change and the BOM was not updated, or does it simply doesn't matter ?
Q11-12, if you look at the top of the transistors you will see they have the same shape as the shape on the board. there is text on the front of the transistors and the text goes to the front of Q11 looking from C1 and to the back of Q12 looking from C1. Q11 should be ECB and Q12 should be BCE pin orientation looking from the front of the boards (C1). pin E is on the left hand side of the transistor if looking at the text on the front.
C1 can be anything from .22uF upwards, the lower the value the less bass. .047uF wont work but your 1uF will. i have gone as much as 2uF without any problems.
An externally hosted image should be here but it was not working when we last tested it.
C1 can be anything from .22uF upwards, the lower the value the less bass. .047uF wont work but your 1uF will. i have gone as much as 2uF without any problems.
Hello,
Ive wired one board and have an output offset too high I think : 60mV. I used every part from the kit, except for the C1 capacitor which I got from ebay (0.47uF), so it could be a bad one.
Do you think it's related ?
I have every other voltage correct : no input offset, 34.8V between V++ and V-- and 23V between 4 and 7th pin of the opamp. I only wired the power supply, didn't wire the jack, the attenuator nor put the opamp.
Lastly, I have a led on my interruptor. I think I've read somewhere in the thread that I could wire it to V++ and ground, with a 10k ohm resistor. Is that correct ? Is the resistor needed ? I don't have 10K in stock but I do have 12k.
Thank you
I'll post pictures when it's finished (now the wires are too much of a mess
). I think I have the same enclosure as a lot of people here, but I changed the layout a bit.
By the way, could you give me the name of the little attachments you use in your enclosure to keep the wires together ? I don't know the english name to order it.
Ive wired one board and have an output offset too high I think : 60mV. I used every part from the kit, except for the C1 capacitor which I got from ebay (0.47uF), so it could be a bad one.
Do you think it's related ?
I have every other voltage correct : no input offset, 34.8V between V++ and V-- and 23V between 4 and 7th pin of the opamp. I only wired the power supply, didn't wire the jack, the attenuator nor put the opamp.
Lastly, I have a led on my interruptor. I think I've read somewhere in the thread that I could wire it to V++ and ground, with a 10k ohm resistor. Is that correct ? Is the resistor needed ? I don't have 10K in stock but I do have 12k.
Thank you
I'll post pictures when it's finished (now the wires are too much of a mess
). I think I have the same enclosure as a lot of people here, but I changed the layout a bit.By the way, could you give me the name of the little attachments you use in your enclosure to keep the wires together ? I don't know the english name to order it.
60 mV is higher than normal but not dangerously so. I wouldn't worry about it.
It's not a bad capacitor. Once thing you can try is to switch opamps between channels and see if the offset follows it. The offset might be the result of the op amp or it might (more likely) be one of the transistors in the buffer has a unusually high/low Vbe. The kit parts are graded for hfe, but not Vbe.
LED should be between V++ and V-- , with about 10k to 20k series resistance. Depends on how bright you want your LED.
If you mean those stick-on cable management - I'm not sure what they are called either. I just got mine at the local hardware store... a search for "stick on cable tie" seems to bring up the right kinds of thing though.
It's not a bad capacitor. Once thing you can try is to switch opamps between channels and see if the offset follows it. The offset might be the result of the op amp or it might (more likely) be one of the transistors in the buffer has a unusually high/low Vbe. The kit parts are graded for hfe, but not Vbe.
LED should be between V++ and V-- , with about 10k to 20k series resistance. Depends on how bright you want your LED.
If you mean those stick-on cable management - I'm not sure what they are called either. I just got mine at the local hardware store... a search for "stick on cable tie" seems to bring up the right kinds of thing though.
whilst reading one of the TI data sheets it says that opamps settle down at around 10hrs for offset and to take measurements again afterwords.
those cable management square things are called ''adhesive cable tie base''.
.....
i made my nice new cases down the workshop today but i messed up on 1 size so its out with the grinder tomorrow then its a dry run then assembly. should be done completely including painting and such in two weeks
those cable management square things are called ''adhesive cable tie base''.
.....
i made my nice new cases down the workshop today but i messed up on 1 size so its out with the grinder tomorrow then its a dry run then assembly. should be done completely including painting and such in two weeks