Hi everyone,
finally got my hands dirty on this one! Thanks Zen, for providing the kit!
I got the boards stuffed with the parts, which worked pretty much straightforward, according to the circuit diagram. Found some deviations though - the Zeners in the kit are 8V2 as opposed to the 5V6 in the circuit, but since the only one to be stuffed left were ZD103-ZD105 anyway, I put it there and it all worked fine!
Firing up the amp worked without explosion and everthing looked good, no smoke! Had the Iq adjusted with P2 to 200 mV across R140, pretty much like 1,8 A. DC offset was reduced with P1 to about less then 100 mV, all pretty stable! Hooked up a signal generator and oszi and it gave me nice sqare waves, so pretty promising! I had this built as an integrated amp, using Papas BA3 frontend as a preamp, which I had used in a previous built for Papas F5.
Sound? Absolutelly excellent! Zen, what you have designed is truly a work of art! I was really impressed, how lively, dynamic and detailed it sounded. Feet are tapping!
I am having some hum though, but that is probably due to my bad wiring. Well, it is only a breadboard prototype anyway.
Really comparable to some 300B, just cheaper and with a bit more power, I believe.
I read somewhere: "run your triodes hot" - and yeah, man, that thing is getting hot! after 30 mins listening - 65 degrees on the heatsinks, it's getting nice and warm in here 🙂 What a wonderful amp, Zen, you are a genious! Now I will look for some housing with nice big heatinks...
BTW: how are you guys mounting the THF51s? I was using Nylon screws and ceramics plates with thermal compound underneath. But how can one do it a bit more stable without conducting the case of the THF51 to the heatsink and metal case?
Adding some pictures as well...
finally got my hands dirty on this one! Thanks Zen, for providing the kit!
I got the boards stuffed with the parts, which worked pretty much straightforward, according to the circuit diagram. Found some deviations though - the Zeners in the kit are 8V2 as opposed to the 5V6 in the circuit, but since the only one to be stuffed left were ZD103-ZD105 anyway, I put it there and it all worked fine!
Firing up the amp worked without explosion and everthing looked good, no smoke! Had the Iq adjusted with P2 to 200 mV across R140, pretty much like 1,8 A. DC offset was reduced with P1 to about less then 100 mV, all pretty stable! Hooked up a signal generator and oszi and it gave me nice sqare waves, so pretty promising! I had this built as an integrated amp, using Papas BA3 frontend as a preamp, which I had used in a previous built for Papas F5.
Sound? Absolutelly excellent! Zen, what you have designed is truly a work of art! I was really impressed, how lively, dynamic and detailed it sounded. Feet are tapping!
I am having some hum though, but that is probably due to my bad wiring. Well, it is only a breadboard prototype anyway.
Really comparable to some 300B, just cheaper and with a bit more power, I believe.
I read somewhere: "run your triodes hot" - and yeah, man, that thing is getting hot! after 30 mins listening - 65 degrees on the heatsinks, it's getting nice and warm in here 🙂 What a wonderful amp, Zen, you are a genious! Now I will look for some housing with nice big heatinks...
BTW: how are you guys mounting the THF51s? I was using Nylon screws and ceramics plates with thermal compound underneath. But how can one do it a bit more stable without conducting the case of the THF51 to the heatsink and metal case?
Adding some pictures as well...
Attachments
I'm repeating that all the time!
that covered in Singing Bush threads
see here, post #29 https://www.diyaudio.com/community/threads/the-singing-bush-tips-n-tricks.357497/post-6290565
you'll need plastic bushings for M4, with length appropriately cut ..... but that's the case with any bushing - better to byuy longer ones than getting too short ones
just do not power it On until you get proper parts; SIT is tough, but don't push your luck with plastic screws changing to bubblegum
...still cooking my SIT Nylon screws, man this amp is really good! I enjoy what I am hearing! Time for a decent housing and proper mounting gear...
Hey Guys - Another Scryer is cooking 🙂 It fired up without drama but the bias tops out at 168/184 mV. Looking back over the thread, it looks like changing R134 from the current value of 120R to 100R may enable a little higher Bias, but I wanted to ask before jumping in there.
Gate Voltages are as follows: M101 4.5V (left) 4.5 V (right) M102 -4.0V (left) -4.0 (right). Offset is minimal. Rail voltage 23.5.
Cheers,
Soren
Gate Voltages are as follows: M101 4.5V (left) 4.5 V (right) M102 -4.0V (left) -4.0 (right). Offset is minimal. Rail voltage 23.5.
Cheers,
Soren
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That did the trick. It has been cooking with the Iq just shy of 1.8A for the past 90 min. Looking forward to listening to it tomorrow 🙂
Looking forward to a thorough report on how the amp combines with your OSMCs (which I too am building at the moment), and how it compares to any other amps you have used with those speakers 😀
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Scryer is making music. It's been playing with my OSMC speakers for the past couple of hours and the first impression is favorable. This was built using a repurposed chassis and power supply, and some pics are included below (to preempt ZM's request for these). I will need some time to form an opinion, but, in the first few hours, it seems a bit softer (H2?), maybe with more sense of space, and less authoritative when compared to the XA252 (SET).
Thanks to ZM for another audio treat.
Thanks to ZM for another audio treat.
Indeed. I have been listening while working and am reminded of a KT88 based power amp I used to own.
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I don't go to the gym, I rotate amps...
Here is Scryer telling XA252 to vacate the stage for the weekend. There is something special and addictive about Scryer 😊
Happy Friday -
Here is Scryer telling XA252 to vacate the stage for the weekend. There is something special and addictive about Scryer 😊
Happy Friday -