Discussion in 'DIY' started by Jh4db536, Jun 4, 2016.
Enjoy the T3. It's a great choice.
Beezar kit packed this thing really nicely. The kit even came with a bag of silly putty. The parts count is not that high, there's a lot of big stuff in small space.
Got a few hours to myself between kids bday party and friends babyshower early in the morning and at night...
Managed to break a 1k RN55 metal film resistor, one side just fell apart when i was bending it on the lead bender. I'm gonna have to make a mouser order for a 10 cent part FML.
I guess ill order a different color LCD for the Gamma3, some CK2III parts, and 6 thermal pads while i'm at it.
Debating on whether i should do the Amtrans Plate resistor upgrade while i'm at it.
i was kind of dreading this part based on what i read, but it wasn't that bad. Just mock up for now. If i didn't have to make the mouser order i think i could be done today if i pushed.
I will eventually do a mainline if I like the sound of this parafeed topology...Im beginning to understand the simplicity offered by these high voltage tube with OT designs. It's one thing to see schematics and block stylized diagram and another to hear it through HDxx0
Yeah you could be done. That sucks. What size resistor did you need? If I have one, I'll send it down to So Cal from up here in the Bay so you don't need to pay $5 shipping on a $0.20 resistor.
Perhaps this could be in a new thread, but i promised a bonus build with the T.
I wish i could setup a build-a-loaner ______ mini meetup hehe.
Populated half the trannies; the bottom part will remain unpopulated as I'm going to bypass with a sigma22.
Mainline is a really fun and satisfying build and a wonderful hd800 amp. I'm still looking for an excuse to build a T3 as well though, especially as I continue to follow the T3 thread here! Have you finished off the ck2iii? How does it sound relative to the T3?
FWIW - for anyone who may not know, the mainline picture posted earlier in the thread does a nice job of showing the point to point but isn't the complete amp. With the 2 C4S boards, regulator board, parafeed caps, etc - it actually looks like this:
Almost done with the ck2iii from board completion perspective. Waiting on mail man for parts...rectifier diodes and opamp socket.
Also need to design the front panels and floor plan.
I'm interested to know what this thing sounds like too. I read it has a very different flavor than the rest of the amb line up and engineered by a guy with a different design philosophy.
Maybe ill be able to bring it to the November meet.
I'd enjoy hearing it! As a long time bottlehead fan, the concept of non-feedback solid state appeals to me as well - particularly after reading Pass' article on the pros and cons of global negative feedback. https://www.passdiy.com/project/articles/audio-distortion-and-feedback
That said, I recently discovered that I do really like the sound of at least one high feedback ss headamp: the Wire se se I just finished. Contrary to my expectations, although often referenced as a "measurement first" amp, it sounds nothing like the O2 or even the agdr boosted O2. Frankly, it is the first ss amp I can recall thoroughly enjoying with hd650's and sounds bloody great hooked up to my Yggdrasil.
In any event, it would be fun to do a side by side with the non-feedback ck2iii vs. a good high feedback implementation like the Wire. I'll have to bring it along in November as well.
Soldering all done for now. Will design the floor plan and FPD by the end of the week.
Sigma22 tests at +/- 15vdc
FPD version 1.0 done - estimated cost $125 for 4mm thick front and rears. keeping it simple but classy, no loopouts, one enclosure, Choice of headphone jack and RCA is based on leftover parts from my inventory that i need to just utilize. Using my green convention power switch and relay that SWA used in his CK2III build. Tried to keep it symmetrical as possible; however, given the tightness of enclosure i need to consider the huge Sigma22 heatsinks right behind the 1/4" jack and want to keep the RCA inputs directly in line with the input headers on the PCB.
Just received the enclosure for the CK2III. This is the proposed layout (imitated SWA layout). think i need to reorient the pot 90 degrees on the FPD so i can clear the front frames to avoid any metal work. The heatsinks on the Sigma22 barely clear the top, literally 2mm of clearance with 5mm standoffs...whew i thought it wasn't going to fit. Need to push the Sigma22 towards the back so i can have room for a 1/4" headphone jack.
Per Black Widow thread, too much empty case space, not consolidated boards, heatsinks should be about quadruple the size, and not sure I like the color of your ruler either. Might want to throw it all away and start over. (That's a joke in case you aren't familiar with that situation.)
I think I should change the font
What tubes should i roll? As long as it fits in the socket right?
Layout actually drawed out, drilled, counter sunk and implemented.
FPD version 1.1 - rearranged and optimized a few things now that i have a real piece of metal in front of me. I think this is good enough for production...proceeding with execution.
Edit1 - On the sound impressions which will change as i spend more time with it and as the new toy syndrome wears off. Also started trying different headphones.
Sound is upfront, intimate (headstage a bit small), and it's a liquid sounding amp with a natural tonality that i have never experienced before in any other amp. It's very detailed, resolves the environmental cues of the recording, but might be lacking in dynamics compared to a higher end amp. It's not laidback like other AMB amps.
The strength of this amp is it's natural tonality. This amp might be my new definition of "wire with gain".
I upped the QCurrent biase a little to make sure it stays just above the 14mV default (i really believe that is the minimum to keep the amp happy and it's very temperature sensitive...BJTs). The CK2III pairs really well with the HD650 imo. No other amp has made the 650 sing like this.
If i had to live with 2 amps only, it would be the Beta22 and the CK2III. For $150 cost in parts this thing is impressive.
I need to add ground loop to the pot and starground still, wire up the Power relay, and LED status lights on the switch.
FPD in, small adjustments to the frame with a file and air nibbler. 316 Stainless socket cap screws and button head as necessary.
Soldered up the insides with Cat5 strands
Finished everything except the power relay, need to figure out some connector issues...they don't fit the way i want.
I am starting to get a feel for what this amp is and is not good at. It has THE "intimate in your face style/signature" presentation down. This presentation is something that the MCubed also does well (it's dark compared to the CK2III though) and something i am not getting from my Torpedo 3 at all given it's other merits.
Don't like this amp as much paired with the HD800 compared to the HD650. IMO the amp isn't powerful enough to make them sound as good as i expect. In general i haven't liked the way the HD800 sound out of any single ended amp that i have. Word of caution, IMO don't pair this with a hd800.
Given it didn't play well IMO with the hd800, this is still a really good sounding hd650 amp.
Ground Loop and vol pot ground strap
So this amp actually sounds really good tonality wise, but i wasn't satisfied with the way this amp sounded with my HD800. It has potential just feels like it's lacking punch and body that my better amps can deliver. It is one of the clearest sounding amps that i have and very very transparent. What to do though if it doesnt work the way i want with my equipment? If i was not able, i would have to sell it off or let it collect dust. That's not me.
Im going to make this sht work right so i talked to the professionals and discovered that the amp was originally designed around out of production parts - Specifically the BJT Output Transistors. The current version BOM suggests Fairchild and ON Semiconductor which are cheap and readily available at your local mouser/digikey; however, sound nothing as good as the original. None of this is in the documentation. I bought an entire assortment of output transistors to roll in case i dont like these.
Step one - obtain unobtainium (used/pulled)
Step 2 - make room for unobtainium
They're in. I need to increase the quiescent current a little. It's not sounding anemic now
In case anyone missed the torpedo III upgrades i did last weekend:
Been collecting parts for the DG300B (Neurochrome) for a few months. As I've owned SACThailand amps, I ordered custom Silk c-core OPTS, and power transformer. assembling boards now. Not gonna rush it - I have 4 other projects on the bench right now. I'm definitely looking forward to it though.
Would be nice to here some opinions from your MisterRogers about the SAC Thailand components MisterRogers been curious on how they perform relative to the other well known stuff.
Separate names with a comma.