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Old 29th September 2011, 04:27 PM   #11
ChrisA is offline ChrisA  United States
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Quote:
Originally Posted by lduarte1973 View Post
where are Earle's kit ?

The tweeters are 4 Peerless 810921 , in paralel to make 4 ohm load , 91 db

810921 - Peerless 1″ tweeter - Europe Audio

In short you have "over specified" the problem. That means you have so many conditions that not all can be true at the same time.

The tubelab simple SE could work for you. But you asked for a complete kit. If that is what you need look here:
DIYTube Dynaco ST35 Tube DIY Amp Kit Great for iPod
This is about $500, has all the power you asked for but is not single ended. But on the other hand the Dynaco ST35 is a very good and well respected amp with a long history and this kit ships with very good transformers.

I'm building something very much like the ST35 right now. but using Hammond transformers salvaged from a broken church organ. These salvaged transformers were designed to drive "tweeters", above 600Hz at 15W power but will handle bass fine if I limit the power. This amp will drive some 96dB speakers in an upstairs bedroom where not much volume is required. I could built this with new parts for 1/2 your budget
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Old 29th September 2011, 04:31 PM   #12
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Quote:
Originally Posted by data View Post
Australia, his amps are thought of very highly down here.

I'm not sure what taps the kits transformers have, but considering that he winds them himself I guess that's not really an issue. You would just need to talk to him about your situation.

Edit:Only problem is you may have a wait as he always has back orders due to demand, last time mentioned I think the wait for one of his non-kit amps was 3 or 4 months.
i meant the link to earls kits
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Old 29th September 2011, 04:32 PM   #13
data is offline data  Australia
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Was in my first post. He only has the one partial kit, it includes all the parts other than "Does not include valves, timber chassis plinth, feet, volume knob, and mains lead." All his other amps are as completed builds.

Here again...
sb343971 - Kit Amplifier

Last edited by data; 29th September 2011 at 04:38 PM.
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Old 29th September 2011, 04:33 PM   #14
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Quote:
Originally Posted by boywonder View Post
Lduarte: A few things.....If you are planning on running two tweeters in parallel for each channel, your combined sensitivity will be +3db (so 94db) and the combined impedance will be 4 ohm nominal; you will need an output transformer with 4 ohm speaker taps. If your are looking at the Chinese stuff, make sure that they have 4 ohm taps, or you will be loading the amp incorrectly.

Also, you want a relatively flat impedance curve.....

94db sensitivity will blast you out of the room at 12-20W unless you are into head-banging metal; 5-8W SE power should be plenty of volume, which is good news if you want a budget SE amp.

Are you planning on active crossover? That will make the apparent power delivered to the tweeters appear greater, since the amp does not have to use power to amplify LF energy that the tweeters can't use. If you are not planning on using an active crossover, then choice of coupling cap values in the amp can accomplish a similar goal. (they will filter out LF easing the burden on the amp). If you later decide to use the amp for full range service, you can just replace the coupling caps for that use.
ill be running active crossover with minidsp , i thought i need more power if 5-8w is enough its easyer
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Old 29th September 2011, 04:48 PM   #15
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Quote:
Originally Posted by data View Post
Was in my first post. He only has the one partial kit, it includes all the parts other than "Does not include valves, timber chassis plinth, feet, volume knob, and mains lead." All his other amps are as completed builds.

Here again...
sb343971 - Kit Amplifier
Thanks , silly me
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Old 29th September 2011, 04:50 PM   #16
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Quote:
Originally Posted by ChrisA View Post
In short you have "over specified" the problem. That means you have so many conditions that not all can be true at the same time.

The tubelab simple SE could work for you. But you asked for a complete kit. If that is what you need look here:
DIYTube Dynaco ST35 Tube DIY Amp Kit Great for iPod
This is about $500, has all the power you asked for but is not single ended. But on the other hand the Dynaco ST35 is a very good and well respected amp with a long history and this kit ships with very good transformers.

I'm building something very much like the ST35 right now. but using Hammond transformers salvaged from a broken church organ. These salvaged transformers were designed to drive "tweeters", above 600Hz at 15W power but will handle bass fine if I limit the power. This amp will drive some 96dB speakers in an upstairs bedroom where not much volume is required. I could built this with new parts for 1/2 your budget

ill be crossing the tweeters > 5khz , so maybe i dont need much power indeed
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Old 29th September 2011, 05:44 PM   #17
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i can double my budget cause id realy like to get a single ended amp , thought i could get away cheapier...

Last edited by lduarte1973; 29th September 2011 at 05:46 PM.
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Old 29th September 2011, 06:14 PM   #18
data is offline data  Australia
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Be careful with some of the Chinese amps, as often they state things like being "Class A" when they are not really "Class A". Whatever you are looking at, research it well.

Last edited by data; 29th September 2011 at 06:32 PM.
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Old 29th September 2011, 06:28 PM   #19
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Originally Posted by data View Post
Be careful with some of the Chinese amps, as ofter they state things like being "Class A" when they are not really "Class A". Whatever you are looking at, research it well.
thanks. i will , before i make any purchase ill check here
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Old 29th September 2011, 06:39 PM   #20
tinitus is offline tinitus  Europe
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there seem to be plenty of el84 SE schematics around
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