NOOB! Thinking of building a 4 ch 3875 amp - questions..

quickshift · 2nd August 2005, 06:36 PM

Hello,

Just a bit of background. My electronics knowledge is limited to having built passive crossovers and replacing frazzled components so forgive me if these are really silly questions please.

I want to build a 4 ch amp to drive a set of bi-wireable speakers I'm building (8 Ohm or thereabouts) so the 3875 kit from madaboutsound.com looks like a good bet because all I have to do is soldering and case it up which I won't have a problem with.

I want to use 2 dual mono kits with 2 seperate transformers in a 2U 19" rackmount case.

My questions are...

Can I use a single set of inputs and connect them to the imputs of both amp kits or do I have to have 2 sets of inputs?

If I do have to have 2 sets of inputs, is there anywhere that does a pre-amp kit with dual pre-outs? Just a basic one with 5 inputs and no phono stage will be fine.

Sorry again if thse are really silly questions.

quickshift · 3rd August 2005, 12:51 PM

Sorted now.

I have found a preamp with dual pre-outs.

Dazza · 5th August 2005, 08:56 AM

Hey Quickie,
I have done exactly what you are planning. You can check out mine in these forums. There is some good pics which should inspire you.
Or Click here

Cheers

Dazza

quickshift · 5th August 2005, 09:22 AM

Hiya D,

WOW!!!

Nice job

That looks fab.

That's a lot more complex than what I was planning, I like the idea of adding speaker protection - it there a kit speaker protection module kit available? If I tried to build one from a diagram it would probably end up receiving radio 1 or something instead

Nice, Q

Dazza · 6th August 2005, 07:06 AM

Hey Q,
Glad u liked my amp. If you visit here you will find a speaker protection kit, actually you should be able to find plenty to suit your needs. As the site is here in Australia, the postage might be a bit expensive with the exchange rate and such.
Might be worth looking into, see how ya go.

Cheers

Dazza

quickshift · 7th August 2005, 09:58 AM

Thanks D,

In have had a search around and come up with this.

http://www.electronic-kits-and-projects.com/1112.htm

If seems to offer protection against various things and also soft start so it seems ideal. Lets hope it sounds OK.

Managed to resist the urge to buy LED VU meters too

Cheers, Q

Nuuk · 7th August 2005, 02:08 PM

Quickshift, if you have any more questions, you may find them answered on the Gainclone pages at Decibel Dungeon!

quickshift · 7th August 2005, 02:57 PM

Cheers Nuuk,

I have looked at that site and a few others over the last few weeks, I didn't really understand much of them though

I promise I have tried to answer my questions myself, like I say, I'm new to all this I'm afraid.

Anyway, I think I have all the info I need to lob something together now albeit merely assembled from kits.

2nd August 2005, 06:36 PM	#1
quickshift diyAudio Member Join Date: Jun 2005 Location: West London	NOOB! Thinking of building a 4 ch 3875 amp - questions.. Hello, Just a bit of background. My electronics knowledge is limited to having built passive crossovers and replacing frazzled components so forgive me if these are really silly questions please. I want to build a 4 ch amp to drive a set of bi-wireable speakers I'm building (8 Ohm or thereabouts) so the 3875 kit from madaboutsound.com looks like a good bet because all I have to do is soldering and case it up which I won't have a problem with. I want to use 2 dual mono kits with 2 seperate transformers in a 2U 19" rackmount case. My questions are... Can I use a single set of inputs and connect them to the imputs of both amp kits or do I have to have 2 sets of inputs? If I do have to have 2 sets of inputs, is there anywhere that does a pre-amp kit with dual pre-outs? Just a basic one with 5 inputs and no phono stage will be fine. Sorry again if thse are really silly questions.

7th August 2005, 02:08 PM	#7
Nuuk diyAudio Member Join Date: Feb 2003 Location: Somerset, SW England	Quickshift, if you have any more questions, you may find them answered on the Gainclone pages at Decibel Dungeon! __________________ The truth need not be veiled, for it veils itself from the eyes of the ignorant.

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3rd August 2005, 12:51 PM	#2
quickshift diyAudio Member Join Date: Jun 2005 Location: West London	Sorted now. I have found a preamp with dual pre-outs.

5th August 2005, 08:56 AM	#3
Dazza diyAudio Member Join Date: Feb 2005 Location: Sydney	Hey Quickie, I have done exactly what you are planning. You can check out mine in these forums. There is some good pics which should inspire you. Or Click here Cheers Dazza

5th August 2005, 09:22 AM	#4
quickshift diyAudio Member Join Date: Jun 2005 Location: West London	Hiya D, WOW!!! Nice job That looks fab. That's a lot more complex than what I was planning, I like the idea of adding speaker protection - it there a kit speaker protection module kit available? If I tried to build one from a diagram it would probably end up receiving radio 1 or something instead Nice, Q

6th August 2005, 07:06 AM	#5
Dazza diyAudio Member Join Date: Feb 2005 Location: Sydney	Hey Q, Glad u liked my amp. If you visit here you will find a speaker protection kit, actually you should be able to find plenty to suit your needs. As the site is here in Australia, the postage might be a bit expensive with the exchange rate and such. Might be worth looking into, see how ya go. Cheers Dazza

7th August 2005, 09:58 AM	#6
quickshift diyAudio Member Join Date: Jun 2005 Location: West London	Thanks D, In have had a search around and come up with this. http://www.electronic-kits-and-projects.com/1112.htm If seems to offer protection against various things and also soft start so it seems ideal. Lets hope it sounds OK. Managed to resist the urge to buy LED VU meters too Cheers, Q

7th August 2005, 02:57 PM	#8
quickshift diyAudio Member Join Date: Jun 2005 Location: West London	Cheers Nuuk, I have looked at that site and a few others over the last few weeks, I didn't really understand much of them though I promise I have tried to answer my questions myself, like I say, I'm new to all this I'm afraid. Anyway, I think I have all the info I need to lob something together now albeit merely assembled from kits.

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