Hello everybody!
After reading and learning for over a year here I thought it was about time to introduce myself. I'm Martijn, a twentysomething Industrial Design student from the Netherlands. I have a limitless fascination for how stuff works, and can get truly excited when something is beautifully designed and made.
After building my first c-moy portable heaphone amp 10 years ago, the diy-hifi virus got me. I currently listen on:
- A pair of KEF 104.2's that I absolutely love. They are 4 Ohm and 92dba@2meters and I suspect them for being specifically designed for listening to dire straits 😀.
- An Opus DAC from Twisted Pear with a Lampizator tube output stage that I bypassed some time after installing because it mudded the sound and caused hum.
- An 'Audioanalyse' PA-90 integrated amp. This one has had half of it's guts removed and partially replaced because it started breaking down on me. It is now more of a power amp with a pot 😛.
I'm currently planning on building an amplifier from scratch together with a friend (so, 2 amps effectively). Since I have a hard time choosing a design, I've come here for help. I unfortunately only have a basic understanding of electronics so I rely on the opinion of others. I do am quite good at fabricating stuff, and being an engineering student I have the luxury of free access to (cnc) lathe's, mills and all other sorts of proper fabrication toys.
So, in short: I've landed on Nelson Pass's F5(t?) or Peter Daniel's LM3875. But which one? Am I missing other obvious contenders? I would be very grateful for some pointers and obviously plan on documenting my progress here in return.
Thanks!
After reading and learning for over a year here I thought it was about time to introduce myself. I'm Martijn, a twentysomething Industrial Design student from the Netherlands. I have a limitless fascination for how stuff works, and can get truly excited when something is beautifully designed and made.
After building my first c-moy portable heaphone amp 10 years ago, the diy-hifi virus got me. I currently listen on:
- A pair of KEF 104.2's that I absolutely love. They are 4 Ohm and 92dba@2meters and I suspect them for being specifically designed for listening to dire straits 😀.
- An Opus DAC from Twisted Pear with a Lampizator tube output stage that I bypassed some time after installing because it mudded the sound and caused hum.
- An 'Audioanalyse' PA-90 integrated amp. This one has had half of it's guts removed and partially replaced because it started breaking down on me. It is now more of a power amp with a pot 😛.
I'm currently planning on building an amplifier from scratch together with a friend (so, 2 amps effectively). Since I have a hard time choosing a design, I've come here for help. I unfortunately only have a basic understanding of electronics so I rely on the opinion of others. I do am quite good at fabricating stuff, and being an engineering student I have the luxury of free access to (cnc) lathe's, mills and all other sorts of proper fabrication toys.
So, in short: I've landed on Nelson Pass's F5(t?) or Peter Daniel's LM3875. But which one? Am I missing other obvious contenders? I would be very grateful for some pointers and obviously plan on documenting my progress here in return.
Thanks!
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Hi Kyuusai,
Welcome to the forum. Appears that you have been DIY'ing audio equipment for quite a while.
You might look again at a tubed buffer after your DAC. Some designs supposedly work very well. My main complaint was that they did add some noise and very low level hum from the original 'no noise' situation. Well if it's not audible from the listening position it might not matter (?). But the hum even though very low in level , bugged me and I could not get rid of it. With a dc heater it might have been possible to get rid of.
So does your power amp still use the original power amp circuit or it's based on some other design ?
Cheers,
Ashok
Welcome to the forum. Appears that you have been DIY'ing audio equipment for quite a while.
You might look again at a tubed buffer after your DAC. Some designs supposedly work very well. My main complaint was that they did add some noise and very low level hum from the original 'no noise' situation. Well if it's not audible from the listening position it might not matter (?). But the hum even though very low in level , bugged me and I could not get rid of it. With a dc heater it might have been possible to get rid of.
So does your power amp still use the original power amp circuit or it's based on some other design ?
Cheers,
Ashok
DC might indeed solve the hum or it might not. The kit I used had a rectifier and cap for DC heating and still hummed. I can't blame the design, since I am not knowledgeable enough to do so but suspect component choice and tube-type are the baddies, along with chaotic manual/support. I used this kit Lampizator - High End Lampizator Kit ver 3.0 (is that permitted here?). What kit would you suggest?
The power amp still uses it's original power amp circuit boards (mosfet, 20.000uf per channel, lots of dust). I removed the opamps and the (chip-based :L) input selecting circuitry, shielded the toroid (input signal cable went over it) and star-grounded (used to be a big loop). Sounds good to me, it does bother me that the right channel gets much hotter than left, untouchably hot :S. Here is a pic of the original amp: http://i43.tinypic.com/30b0fh0.jpg
Cheers!
The power amp still uses it's original power amp circuit boards (mosfet, 20.000uf per channel, lots of dust). I removed the opamps and the (chip-based :L) input selecting circuitry, shielded the toroid (input signal cable went over it) and star-grounded (used to be a big loop). Sounds good to me, it does bother me that the right channel gets much hotter than left, untouchably hot :S. Here is a pic of the original amp: http://i43.tinypic.com/30b0fh0.jpg
Cheers!
Martijn,
If one channel gets much hotter than the other, maybe it is time to check the bias current setting and adjust when necessary?
Jan
If one channel gets much hotter than the other, maybe it is time to check the bias current setting and adjust when necessary?
Jan
Welcome from Australia and while I am communicating with a person from the Netherlands can you confirm something for me. Recently I watched a documentary on the problems Holland has with low lying areas and the threat from the sea and the sea walls and other defensive measures. But also the program said that The Netherlands is the world's third largest agricultural exporter! They then showed a LOT of flowers leaving the country....etc.
Now I was a bit surprised by this figure. So is it true? Presumably that will be third largest by value rather than quantity.
Any thoughts pls?
Cheers, Jonathan
Now I was a bit surprised by this figure. So is it true? Presumably that will be third largest by value rather than quantity.
Any thoughts pls?
Cheers, Jonathan
@ Jan, I definately should check the bias current setting. Unfortunately I don't know how... I haven't been able to find a schematic, and even if I had one I would probably need someone else to verify what I'm doing. Is it possible to try and draw up the schematic from the circuit board (a few mystical components on there though :S)
@ Jonathan, that is completely true and of course by value. What metric do you suggest when you say volume? Cubic metre? Weight? How would you measure that on a global scale and what would it mean?
@ Jonathan, that is completely true and of course by value. What metric do you suggest when you say volume? Cubic metre? Weight? How would you measure that on a global scale and what would it mean?
Well, better late than never: Welcome Kyuusai (you were however one of the top threads and a dutchman 😛
And yes, Jonathan, we are a big agricultural exporter (also leading in seeds (tomatoes, carrots etc.) as well) and I dare say (one of the) world leader(s) in water management (just on the news tonight was an article about several dutch companies starting projects to build the Jakarta sea wall super project... That's why people say "God created the world but the Dutch created Holland."
And yes, Jonathan, we are a big agricultural exporter (also leading in seeds (tomatoes, carrots etc.) as well) and I dare say (one of the) world leader(s) in water management (just on the news tonight was an article about several dutch companies starting projects to build the Jakarta sea wall super project... That's why people say "God created the world but the Dutch created Holland."
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