• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

Group order of non-inverted LM3875 pc boards? Anyone interested?

Status
Not open for further replies.
Jump to Latest
#102
Given the demand, given the current totals, I am seriously considering not to include the Blackgate capacitors with this group order, and only including the Panasonic capacitors, which are quite cheap in quantity.

It someone wants to take over a group order of Blackgate capacitors, this would be fine for me.

The main issue is, that 4 of these capacitors cost the same amout as the rest of the items in the kit, doubling the cost of a kit.

--
Brian
 

Attachments

  • totals.gif
    totals.gif
    2.5 KB · Views: 1,133
#103
roibm said:
Hi there,

I am also interested in getting 4 complete channels(including ps), but as I live in Europe(Germany) I was wondering about the S&H costs...
Would you like to provide some details?

Thank you 🙂
Click to expand...

As far as the S+H charges, I will look into this before I decide on shipping charges. I do not expect it to be unreasonable. If anyone here has experience of the best way to ship to Europe, let me know. I just used the US post office for mailing to UK last time.

--
Brian
 
#104
this is for up to 2lb (possibly more too), from US to Germany by USPS.

global priority mail, 4-6day delivery, 6"x10" - $5
global priority mail, 4-6day delivery, 9.5"x12.5" - $9
Airmail letter post, 4-7day delivery, max length = 24", max length+height+depth = 36", 13.30
 
#105
Looks like FC's are the will of the people. I didn't realize the price penalty for BG was so much. Heck, they are really easy to swap later. I still kind of prefer the insulated chips. Again, either will work, and I agree that you should settle on one or the other.
Looks like you are down to a choice of just the circuit board or one complete kit!

You are making big progress!
 
#107
Re: Re: Absolutely...

BrianGT said:

I am looking forward to having this amplifier in kit form for myself as well. I have several friends wanting their own gainclone amplifiers. I love an amplifier that you can build in several hours.
Click to expand...

PCB's will be newest gainclone fashion... 😀
It's true, you can build a gainclone now in an evening. In my opinion (and in my amp), PCB's even seem to sound better... (though I also interchanged a few parts)

Fedde
 
#108
Bas Horneman said:
Just checking if I'm right on this..

2 * 4,7uF FC caps per channel?
4 * 1000uF FK caps per channel?

Cheers,
Bas
Click to expand...

This is incorrect. The FC and FK capacitors are 1000uF capacitors, of which one pair is needed per board. The FK is the newer version of the FC, but only available in SMD package.

On the sheet, the capacitors go by channel, meaning one channel = 2 FC capacitors. It appears like it also would make more sense to just stick to FC capacitors to avoid confusion and lower the component count.

Now, on the power supply, I was planning on using 2*4.7uF FC capacitors also, which are not on the sheet, but will be included with the kit.

--
Brian
 
#109
Variac said:
Looks like FC's are the will of the people. I didn't realize the price penalty for BG was so much. Heck, they are really easy to swap later. I still kind of prefer the insulated chips. Again, either will work, and I agree that you should settle on one or the other.
Looks like you are down to a choice of just the circuit board or one complete kit!

You are making big progress!
Click to expand...

I am going to offer a choice of either the insulated or non-insulated chips for the lm3875.

I am going to make a website in a few days, to make all the details clear, once I get the kit information together.

3 kits seems to make sense now.. LM3875T kit and LM3875TF kit, along with a bare pcb.

--
Brian
 
#110
I am working up the contents of the kits, and will have a new Wiki page up in a couple of hours. The initial list is here:
http://www.diyaudio.com/wiki/index.php?page=Initial+List+for+NI+GC+PCB

and the new page for the next phase of this order will be put up in the same place as the first list:
http://www.diyaudio.com/wiki/index.php?page=NI+GC+PCB+Group+Order

I should have something up by this afternoon, with all the details for the kit and order, and an initial cost estimate for the kits and bare pcbs.

--
Brian
 
#111
Brian,

1) Is this a power amp or an integrated amp? Would a 2 channel VR be included in the kit if it's a 2 channel integrated amp?
2) What is the approx. watts per channel for this amp?
3) Does it need 2 transformers for 2 channels?

As you can tell, I have not been following the gainclone thread(s).

With some many different type of group-buys going on at the same time ... a kit ... to be able to built it in a couple hours ... is very tempting!
 
#117
fcel,

These amps have enough gain so people use them without a preamp with a pot at the input. It looks like Brian won't be including a pot, which makes sense because some use them with a pre amp and some have specific pot desires. You can browse the many gainclone circuits to see how to wire up the pot.

You can use one transformer for 2 channels 40-60 w/ch I think

It seems that with 8 diodes ordered Brian is planning separate
bridges for each channel?
****Brian is this true?****

If so, you could add a second transformer later if desired.
 
#118
fcel said:
Brian,

1) Is this a power amp or an integrated amp? Would a 2 channel VR be included in the kit if it's a 2 channel integrated amp?
2) What is the approx. watts per channel for this amp?
3) Does it need 2 transformers for 2 channels?

As you can tell, I have not been following the gainclone thread(s).

With some many different type of group-buys going on at the same time ... a kit ... to be able to built it in a couple hours ... is very tempting!
Click to expand...

Sorry, didn't see your post earlier. This is a normal 40-50w amplifier, depending on your power supply voltage. Visit www.national.com and read the datasheet for the LM3875 for details on power output. It is a very simple chip amp that allows for a very easy, and pleasant amplifier. The power supply uses one transformer, and will handle 2 channels.


Variac said:
These amps have enough gain so people use them without a preamp with a pot at the input. It looks like Brian won't be including a pot, which makes sense because some use them with a pre amp and some have specific pot desires. You can browse the many gainclone circuits to see how to wire up the pot.

You can use one transformer for 2 channels 40-60 w/ch I think

It seems that with 8 diodes ordered Brian is planning separate
bridges for each channel?
****Brian is this true?****

If so, you could add a second transformer later if desired.
Click to expand...

I have looked at getting a bulk order of those stepped attenuators in a 20k value, as they would be perfect for this amplifier.

Here is a diagram of how the amplifier is wired up (found this in another thread):

The schematic should clear up the questions about the transformer and wiring.

NOTE: The new List is up, so fill out how many kits/bare pcbs you want. This list is replacing the initial interest survey. Please fill it out by the end of the week, so I can get an accurate number of parts that I need to order.

--
Brian
 

Attachments

  • my gc.jpg
    my gc.jpg
    50.2 KB · Views: 1,094
Status
Not open for further replies.
Top Bottom