Da5id4Vz said:
How strange that you would ask. I measured it today in lab at school. I measured 30W into 8 ohms, and around 35W into 4 ohms (resistive load box). This was determined from the RMS AC voltage just below clipping.
(Vac(RMS))^2/(load impedence)
All that I know is that this is more than enough power to keep my 87dB efficient 4 ohm Thor TL speakers happy (well, I am happy with the loudness, keeping it around 1/2 volume most of the time). This is with my 2x24vac 320VA Victoria Magnetics transformer that you can see in the pictures on my website:
http://brian.darg.net/gallery/nigc-kit
Also, with my volume pot turned all the way up with my Seas Thor TL speakers (4 ohm load), I had no signs of clipping.
This was also with the LM3875TF package. My case got reasonably warm when I had it at almost full power (just below clipping on both channels)
--
Brian
BrianGT said:
Isn't that a bit low? With a 34V supply rail (24*1.414) you should be over 50W into 8 ohms.
Or am totally misreading the LM3875 datasheet?
tg3 said:
All I know is that is the RMS power output recorded driving it with a sinusoidal input (1khz).
Someone please correct me if I am incorrect in this.
If I was looking for peak power, wouldn't it be the RMS power observed * sqrt(2). If this is the case, then it would be at 50w peak power into 4 ohms, and about 42w into 8 ohms. The application note says that the maximum power into 4 ohms is 50w.
--
Brian
Da5id4Vz said:
Yeah, Dr. Leach as an Audio Precision System 2 in his lab, but I was busy most of the night putting together kits. I will run some more measurements later on, probably next week. I managed to get a large portion of the remaining kits done last night. I have off work tomorrow, so I should be able to finish the rest tonight and tommorrow morning.
--
Brian
Brian is still working on the manual, until then, check out his web site.
http://brian.darg.net/gallery/nigc-kit
http://brian.darg.net/gallery/nigc-kit
Da5id4Vz said:
I just had my bandwidth counter reset.
I just got back from the post office. 95% of all the orders have now been mailed out. Today was the largest batch mailed out so far, 48 packages mailed out today.
As for the last little bit of orders, I ran out of 220 ohm resistors for the last of the kits. More of these resistors should arrive tommorrow or Friday. I will get the orders mailed out on Monday, along with an extra pcb set to compensate for the extra delay.
I will send out e-mails later on today (probably this evening) to those whose order did and did not ship out today, detailing the status of their orders.
Today, orders shipped out to these countries: US, Canada, Germany, Ireland, Italy, UK, Norway, Netherlands, Australia, Spain, Israel, France and Sweden.
Thanks for your patience, and everyone should have their orders soon. Over 200 kits have been shipped out so far, and I hope to see at least 25% of these become finished amplifiers in the next couple of months.
I will be busy this weekend, getting married, so I might not respond to your e-mails right away.
--
Brian
Maybe I'll catch s@it for this, since I've already gotten my order, but I know that I will be ordering more in the future!!.
Anyway , after you have done this whole first group buy, I think you should add something like $10 per kit to your price. Otherwise I think you will burn out on doing this. It's not a lot of money for you , but would at least cover your time. The price to us might even not go up much because with enough lead time you can get the parts at a better price from one source. Also, you might not be contributing to DIY Audio the same amount- maybe a fixed percentage.
Also, with some profit, you could maybe sell some parts separatelty such as the diodes, insulators, 3875 chips(still) (things that I need!!)
I guess you would have to move to the Trading Post.......
Anyway , after you have done this whole first group buy, I think you should add something like $10 per kit to your price. Otherwise I think you will burn out on doing this. It's not a lot of money for you , but would at least cover your time. The price to us might even not go up much because with enough lead time you can get the parts at a better price from one source. Also, you might not be contributing to DIY Audio the same amount- maybe a fixed percentage.
Also, with some profit, you could maybe sell some parts separatelty such as the diodes, insulators, 3875 chips(still) (things that I need!!)
I guess you would have to move to the Trading Post.......
It only has one PSU board. I think you need a second to monoblock. That's cheap and easy- you just order a second circuit board (it breaks into 2 amp channels plus one power supply bridge. The problem is that Brian doesn't have an option to just get the power supply components. (8 diodes + the small blackgate) That is one of the additional options that I was requesting above.
Probably he will be able to accomodate us. Brian: After you are married, can you have a PSU parts kit?
I also want to do monoblocks
Probably he will be able to accomodate us. Brian: After you are married, can you have a PSU parts kit?
I also want to do monoblocks
Indeed, the profits were quite low on this order. The goal was to get as many kits out there as possible (over 200) at a reasonable price. I didn't take account for the paypal fees ($700+ taken), all the packing materials, and all of the shipping charges resulting from having to order from multiple vendors to get the exotic parts. I actually lost money on the BG 4.7uF N capacitor upgrades, as the paypal fees took $0.50 from the $5. Expect a modest increase in the prices for the next round, to account for these charges.
I will start organizing a second phase of the LM3875 NI GC order next week. I am currently considering charging around $65 for a premium kit, with the same components from this order, along with the BG 4.7uF N caps. This is a $5 increase (as the BG 4.7uF N caps add $5). I would also be offering a basic kit for around $35, which would include standard resistors instead of the Caddock resistors. The basic kit would clearly be the cheapest amplifier kit out there.
In addition to the 2 types of kits, I am thinking of offering combos, like a Premium Dual mono kit, with an extra PCB set, and power supply components.
I will look into getting the parts next week. The Caddock resistors will have a lead-time of about 2 weeks+, so if I order them next week, I will be able to start offering kits again by the end of April. This will also give me a break from the long nights of putting kits together.
I am also considering a bridgeclone kit sometime in the future, once I have time to make a working prototype in my hands.
I received a couple of the Elma attenuators today, and they look like nice units. I will post pictures of them soon. I am looking at doing a group order of these. I put up a Wiki here:
http://www.diyaudio.com/wiki/index....tor+Group+Order
I am currently looking at both the series and ladder audio attenuators that they offer, and will pick one of them for the order, after I evaluate both of the units. It seems like the series attenuator will work fine, and is quite a bit cheaper than the ladder one shown in the Wiki.
I will send out e-mails tonight to let people know if their order has shipped, or has been delayed until Monday. There are only a handful of orders that haven't shipped out.
I will be around the computer infrequently from now until Monday, as my relatives are starting to arrive for the wedding on Saturday.
Thanks to all who participated in this group order. I hope to see a lot of finished amplifiers in the future. I will put up a gallery soon, and start taking submissions consisting of a few pictures of the finished amplifier (not just assembled board, but an amplifier being used to play music), and a brief build description. For the first submissions built from a kit that I mailed out (no limit set yet), I will mail out a free PCB set. After there are a decent number of entries, I will award a prize for the best looking amplifier in the galleries, and awarding a prize.
--
Brian
I will start organizing a second phase of the LM3875 NI GC order next week. I am currently considering charging around $65 for a premium kit, with the same components from this order, along with the BG 4.7uF N caps. This is a $5 increase (as the BG 4.7uF N caps add $5). I would also be offering a basic kit for around $35, which would include standard resistors instead of the Caddock resistors. The basic kit would clearly be the cheapest amplifier kit out there.
In addition to the 2 types of kits, I am thinking of offering combos, like a Premium Dual mono kit, with an extra PCB set, and power supply components.
I will look into getting the parts next week. The Caddock resistors will have a lead-time of about 2 weeks+, so if I order them next week, I will be able to start offering kits again by the end of April. This will also give me a break from the long nights of putting kits together.
I am also considering a bridgeclone kit sometime in the future, once I have time to make a working prototype in my hands.
I received a couple of the Elma attenuators today, and they look like nice units. I will post pictures of them soon. I am looking at doing a group order of these. I put up a Wiki here:
http://www.diyaudio.com/wiki/index....tor+Group+Order
I am currently looking at both the series and ladder audio attenuators that they offer, and will pick one of them for the order, after I evaluate both of the units. It seems like the series attenuator will work fine, and is quite a bit cheaper than the ladder one shown in the Wiki.
I will send out e-mails tonight to let people know if their order has shipped, or has been delayed until Monday. There are only a handful of orders that haven't shipped out.
I will be around the computer infrequently from now until Monday, as my relatives are starting to arrive for the wedding on Saturday.
Thanks to all who participated in this group order. I hope to see a lot of finished amplifiers in the future. I will put up a gallery soon, and start taking submissions consisting of a few pictures of the finished amplifier (not just assembled board, but an amplifier being used to play music), and a brief build description. For the first submissions built from a kit that I mailed out (no limit set yet), I will mail out a free PCB set. After there are a decent number of entries, I will award a prize for the best looking amplifier in the galleries, and awarding a prize.
--
Brian
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