Just bought those jlithen's pcb's for a test to drive JBL 2225H's (crossed at 500hz). I used Aleph 5 - clones before this. And what a disappointment 🙂 bass was much better with Alephs. Now it's loose, it doesnt go so low and muddy all the way. And theres quite loud 100hz buzz, but jlithen of course told me that before, so I was aware. It might also be mostly ground loop for my quick and dirty - setup. Well, going to do some tweaking and adjust my crossovers/DSP, then well see what happens.
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Of course, please see the picture
I mentioned it not just to state the obvious, but mostly because it is not so great for the sound 🙂
Otoh, the nhb-458/468 do use parallel devices...
I mentioned it not just to state the obvious, but mostly because it is not so great for the sound 🙂
Otoh, the nhb-458/468 do use parallel devices...
Yes, I agree but at some amplifier higher rail voltage, higher bias, more power etc it does makes some difference.🙂
Just bought those jlithen's pcb's for a test to drive JBL 2225H's (crossed at 500hz). I used Aleph 5 - clones before this. And what a disappointment 🙂 bass was much better with Alephs. Now it's loose, it doesnt go so low and muddy all the way. And theres quite loud 100hz buzz, but jlithen of course told me that before, so I was aware. It might also be mostly ground loop for my quick and dirty - setup. Well, going to do some tweaking and adjust my crossovers/DSP, then well see what happens.
I am disappointed to read your comments, there is a group of people who praise these amp and them lowe the sound there is another group of people who just not satisfied at all. 😕
I am disappointed to read your comments, there is a group of people who praise these amp and them lowe the sound there is another group of people who just not satisfied at all. 😕
There was a blink of hope in my message too, this was quick'n'dirty experiment, I will give this amp a second chance anyways 😉
It is hardly an amplifier capable of driving any speaker. DF may be one consideration. Low load impedance -another.
It is hardly an amplifier capable of driving any speaker. DF may be one consideration. Low load impedance -another.
That's true. 2225H should be relatively easy load for any amplifier.
I already finished groundings etc, so this amp is going to stay awhile now. Made star ground for PSU and separate signal ground, connected them with thick wire. Chassis connection through thermistor and amp is silent now. 132 000uF x 2, 42,4v rails and 545VA toroids x 2.
Did you attempt to recreate a protection circuit similar to the one used in the original?
In truth, having disassembled the DC servo circuit, a continuous but non-invasive protection, I had to foresee, to protect the speaker.
An externally hosted image should be here but it was not working when we last tested it.
It is the only requirement of the original project, to which I had to give up.
This will change the sound character a lot. And will necessitate the inclusion of emitter resistors...
I completely agree.
Just bought those jlithen's pcb's for a test to drive JBL 2225H's (crossed at 500hz). I used Aleph 5 - clones before this. And what a disappointment 🙂 bass was much better with Alephs. Now it's loose, it doesnt go so low and muddy all the way. And theres quite loud 100hz buzz, but jlithen of course told me that before, so I was aware. It might also be mostly ground loop for my quick and dirty - setup. Well, going to do some tweaking and adjust my crossovers/DSP, then well see what happens.
Despite not having had any particular problem and even having modified several times the feeding stage, with this type of amplifier, but also my personal experience was disappointing to listen.
What is the rail Voltage using one pair power transistors?
Thanks 🙂
Voltage 2x35 Vac - Power 800 VA.
About 50 Vdc on the positive and negative branches.
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Complete Pre-Assembled Kit
Did anyone buy the complete pre-assembled kit from Douk Audio? How does it sound?
Did anyone buy the complete pre-assembled kit from Douk Audio? How does it sound?
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Complete Pre-Assembled Kit
Thanks for the replies guys. The site I was referring to is: Douk Audio Professional Hi-End Non-NFB Power Amplifier Stereo HiFi Amp 250W@4ohm | eBay
Thanks for the replies guys. The site I was referring to is: Douk Audio Professional Hi-End Non-NFB Power Amplifier Stereo HiFi Amp 250W@4ohm | eBay
Btw, dartzeel is not the only amp out there without global feedback. Check out vintage Tandberg power amps, higher models all sport no global feedback. Long before dartzeel.
Complete Pre-Assembled Kit
I am thinking of purchasing a complete pre-assembled amp but it is rather confusing which one is of good design with a modest price.
I am thinking of purchasing a complete pre-assembled amp but it is rather confusing which one is of good design with a modest price.
Just bought those jlithen's pcb's for a test to drive JBL 2225H's (crossed at 500hz). I used Aleph 5 - clones before this. And what a disappointment 🙂 bass was much better with Alephs. Now it's loose, it doesnt go so low and muddy all the way. And theres quite loud 100hz buzz, but jlithen of course told me that before, so I was aware. It might also be mostly ground loop for my quick and dirty - setup. Well, going to do some tweaking and adjust my crossovers/DSP, then well see what happens.
This amp sounds more like tube amps than other SS designs. Has similar acoustics. You would not use them as a dedicated woofer amplifier knowing that. I use my single OP pair version on a 2 way bookshelf. The sound is detailed and soft, palpable. The Bass is ok, nothing to write home about. The highs are non metallic. There's a realism to the mids and lower mids. Very engaging, non-fatiguing sound. I am very pleased with them. Mine is powered by dual Toroids 40-0-40vac 400VA, giving me 55vdc rails. The amp clips at about 140watts into 8 ohms. Runs quite warm. Paired with a high DF sub amp, and you have a good combo
This amp sounds more like tube amps than other SS designs. Has similar acoustics. You would not use them as a dedicated woofer amplifier knowing that. I use my single OP pair version on a 2 way bookshelf. The sound is detailed and soft, palpable. The Bass is ok, nothing to write home about. The highs are non metallic. There's a realism to the mids and lower mids. Very engaging, non-fatiguing sound. I am very pleased with them. Mine is powered by dual Toroids 40-0-40vac 400VA, giving me 55vdc rails. The amp clips at about 140watts into 8 ohms. Runs quite warm. Paired with a high DF sub amp, and you have a good combo
Yeah, you might be right. Altough I read all reviews I could find about the original, and this is from 6moons: "The bass is killer - powerful, fast and precise."
Please note that my pcb is not that "1:1" clone board either, don't know is there how much difference in sound? Theres integrated speaker prot for example. Another thing to consider is that im using this with 96db/w sensitive speakers, does it "open up" when cranking more power out? Plus my rails are little lowish, 42,4v. Anyways, its in my system now and going to listen it for a while.
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