Thanks scott. I'll take a closer look at the umbilical. I checked continuities across the umbilical but maybe i missed something.
I will ahve to take a few days off as im out of irf610s.... Going to order some more.. Would irf4610 work or irf830?
How do you handle power on/off with your two chassis layout? Do you cut the power at the dc between the psu and aleph, or at the ac?
Maybe i should have built the psu boards into he same chassis, nice and close to the aleph boards... Didnt think having 5 feet betwwen them would cause any real trouble.
When improbe the positive to the negative at the aleph i get continuity through the caps when the lultimeter leads are reversed, but not the other way around.
Is this because of the low esr of the caps?
Im actually disappointed in veterans boards entirely. Im sure he was capable of better, but didnt see the point in revision after he got his own up and running. Im not ungrateful asi dont have what it takes to make a board myself.
Theyre too small for the wima caps, and all the solder pads are super close to one another making bridging almost impossible to avoid. Also its one sided, amd i find two sided tinned through to be more robust.
The gerenal layout may be okay, but its too cramped to fit the dale resistors i used which are all barely fitting. I would have prefered thicker boards too.
Id encourage a re-thinking of the boards ... Same layout, but with more space and tinned through. Ive already wrecked a solder pad at the input cap and had to wire it point to point to fix the lost continuity.
FormosaWest:
There is a mains power switch on the back side of my Aleph P 1.7 power supply that is never turned off. The preamp is on all of the time; the power switch on the front of the preamp only controls the Dantimax-supplied boards (i.e., the front display and the attenuator and source selection boards). The Aleph P 1.7 draws very little power and I've been told it sounds better if simply left on.
Regards,
Scott
Attachments
Double checked the umbilical. No shorting in the cord itself.
Gotta order some more parts.. Sometimes i wish id just got the dantimax control boards as it sure looks nice and neat. With my point to point input and output controls on protoboard and all the messy wires, its not as elegant. But alas, thats all luxury i cant afford until i figure out what is blowing my 610s.. It makes sound when running the full 88v unregulated.. Which is at least a good sign... And all the switches work as planned.
Gotta order some more parts.. Sometimes i wish id just got the dantimax control boards as it sure looks nice and neat. With my point to point input and output controls on protoboard and all the messy wires, its not as elegant. But alas, thats all luxury i cant afford until i figure out what is blowing my 610s.. It makes sound when running the full 88v unregulated.. Which is at least a good sign... And all the switches work as planned.
The irf610s im blowing are ones on the power supply boards...
Could r17,18 be responsible for that? Maybe the resistors to the gate on the power supply?
Thanks for your continued help. Ill get you the data in a couple days. Im away from home for a few days taking care of my dad, but ill be brainstorming... Its my escape.
Im confused. What 33ohm resistor. Theres a 3.3 ohm resistor om the + output. Theres also a 2.2k and 4.7k on the psu and a 221ohm on the gate to the 610 on the psu.
The only 33ohm resistor im aware of is on th aleph boards at r17 and 18 i think.. And thats between the source for one of the 610s on the aleph board and the ztx 450. I used 0.5 watt dales there as spec'd. The boards have never run longer than maybe a couple mins befor blowing the power supply 610s. They produce sound as expected.
No 33 ohm on the power supply.
Do you want the voltage drop on the 3.3 on the psu or the 33 on the aleph board? Or is the parts list flawed? I referenced the original schematic in the service manual... So confused.
Could the 33 ohm on the aleph board be responsible?
Whatever the problem is it must be common to both boards or power supplies.
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I think this might solve the problem!
I noticed when i powered up the aleph p1.7 boards from a fully charged and powered up psu, the 610 would blow, but it wouldnt if i by-passed the front panel switch and powered up he whole unit at once from the rear power switch... It would seem that by powering up the psu first and then powering up the boards, there is an inrush of current filling the capacitors on the aleph p boards from the power in the psu caps, which must over stress the 610 current capacity and blow it.
The problem is because of the way i power up the unit and power it off, by cutting the power to the aleph but allowing the psu to continue to remain powered up in the power supply chassis. It appears that cutting the flow of dc is not an appropriate way to power up and power off the aleph.
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Long journey indeed!
I want to thank all the fine gentlemen who helped me through my frustration and inspired me to continue looking for the problems that kept me from enjoying my project! Sakellogg, audiosan, aspringv, didiet78, mjf, 6l6, SRMcgee, zkri. Thank you. I've learned a lot and grown the confidence to try more! ... Though I can scarcely imagine how many more components there are left for me to try my luck at building!
Last night I met with my uncle who I do a lot of listening with, since I was a boy, but all through my adult life. He has a complete Mitchell a cotter system, a true reference system and reference kefs driven by an Aragon amplifier we call "the nuclear power plant" his system is a fine reference and has been for me for al my projects. Last night I brought all my stuff over (pearl 2, bridged balanced gainclone amp, and the aleph p for some critical listening. Initially we were incredibly impressed and thrilled with the results. I realized I disliked the lights and wished I hadn't use so many (so I plan to by pass them with a switch)... With truly critical listening we beg a. To feel that the system as a whole was ever so slightly strident up top .. Or a little too etched.. Now I'm talkng ever so slightly.. And with all the wonderful sound it was hardly worth mentioning. We both agreed. ... The it occurred to me that my pearl phono stage was set to loading for the fidelity research fr1 mk3f I have at home on my technics 1200, and not for the koetsu he had on his b1 turntable.. So promptly I dropped the load impedance one notch and said nothing. My uncle piped up immediately! That's it! What did you do? What did you change? I told him how it had just occurred to me that we had been listening to the koetsu at too high a load impedemce (and the koetsu is very particular about this loading.)
Immediately the strident over glossy top end calmed down, the midrange filled out and the whole system delved into a sweet harmonious step. From that point on we became enthralled with the music, outing piece after piece on, utterly impressed by how extraordinary the music sounded. Natural. Full bodied. Dynamic, detailed and so unshrouded, as if the equipment had disappeared entirely and all there was was music. The sound stage was expansive, tall and deep, with the placement of instruments so incredible. We could hear the placement of kickdrums in relation to cymbals, and each pipe in a pipe organ as each note danced across the soundstage. It was a truly magical experience. By the end of it, my uncle and I was totally impressed and had what we felt was a state of the art sound system. I left him to listen alone a while and when I came back he couldn't tell me enough how really Really good it was sounding. Near the end of the night, for the last hour we switched back to his cotter preamp and phono stage/step up and amp. And for the first time in my life I could sense he was disappointed and wanted to go back to mine. I felt the same way.. Having been so impressed by the pass designs I'd whipped together this year. I reminded him and reassured him that it was likely because we had turned off his Aragon amp and it was cold...and indeed, as it warmed up it regained its detail and heft and all of its wonderful characteristics. As we packed up he said to me "kid, what you have there is no compromise state of the art incredibly fine sounding stuff. It's perfect. Don't change a thing." I replied by saying, well
I'm going to put a switch in the bypass the indicator lights on the preamp as the blue lights weren't my favour." He said "nothing else! Dont. Go go messing with the sound. It's perfect. Perfect."
I was thoroughly impressed with the sound and performance of the aleph p clone, the pearl 2 and my bridged gainclone. It was fast, dynamic, accurate, warm, crystal clear, quiet, smooth, detailed, and tonally right on.
Now... Maybe next year I can build some linkwitz audio speakers... Or a pair of aleph mono blocks... Or a b22 headphone amp.... Or a balanced aes/ebu Dac.
Oh, the choices.
FormosaWest
What a wonderful review,,where i feel that the music come in first line,,and the component is the goal to heaven ,,
must see how the Aleph 1.7 will come to sound in my stereo,,
If i shall chose between new amp or speaker,i will go for better speaker,i think it give more bang for the money
Thanks Bjarne
What a wonderful review,,where i feel that the music come in first line,,and the component is the goal to heaven ,,
must see how the Aleph 1.7 will come to sound in my stereo,,
If i shall chose between new amp or speaker,i will go for better speaker,i think it give more bang for the money
Thanks Bjarne