While I had it apart to replace the BD139/BD140 I decided to change up the power supply section. Pic on the left is before and then the next is after with R21's added. Rails at the boards are 38.5v and bias is set to 175mv. I also added speaker protection, cause why not, LOL. Max temps on the heatsinks so far have been 51C. New KEF LS50 drivers patiently waiting for crossover parts to come from Solen. Should be interesting to swap this one with the BabelFish F8 currently in play.
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Lookin' gooood gsrchrisu! 
While the boards are accessible, did you add the opto//resistor mod?
While the boards are accessible, did you add the opto//resistor mod?
Here you go:
Post in thread 'Babelfish XA252 / Babelfish XA252 SIT / Babelfish XA252 SET'
https://www.diyaudio.com/community/...2-sit-babelfish-xa252-set.373443/post-7919078
Post in thread 'Babelfish XA252 / Babelfish XA252 SIT / Babelfish XA252 SET'
https://www.diyaudio.com/community/...2-sit-babelfish-xa252-set.373443/post-7919078
I need a little help.
I have @wdavis009 XA252 build here at my place in the cold and damp Pacific NW. I have been watching the the "fix" suggestion here and pulled the amp from my rotation to do the resistor fix as suggested in post #2573. However, now that I opened it up, I don't see where I can do the mod suggested in the post. I don't seem to have the same PCB. What should I do to protect the amp/speakers?
Edit: It seems I am just dumb....I just need to add a resistor in parallal with OK1 and OK2 per the suggestion in post 2573.
I have @wdavis009 XA252 build here at my place in the cold and damp Pacific NW. I have been watching the the "fix" suggestion here and pulled the amp from my rotation to do the resistor fix as suggested in post #2573. However, now that I opened it up, I don't see where I can do the mod suggested in the post. I don't seem to have the same PCB. What should I do to protect the amp/speakers?
Edit: It seems I am just dumb....I just need to add a resistor in parallal with OK1 and OK2 per the suggestion in post 2573.
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easiest to do without any dissssssssssssasembling - 1206 smd resistor ditto at OK pins 1 and 2
Ok, now that I straightened myself out and before I melt tin and lead, a 47 ohm 0.25W resistor is a very reasonable option for OK1 and OK2? So 4 quantity total 47R installed for my fantastic sounding stereo XA252?
Since I didn't build this amp, I just am looking for that thumbs up for feel good factor before I take action.
Since I didn't build this amp, I just am looking for that thumbs up for feel good factor before I take action.
How does it sound? Oh, just like all of your other amps.
Edit: To follow up for clarity...
It sounds Phenomenal!
The XA252 and the F4 are at the top of my list of favorites so far. F4 has a bit more punch on the lower end, but the XA252 just beats the F4 in midrange by a tiny bit in my humble opinion.
Edit: To follow up for clarity...
It sounds Phenomenal!
The XA252 and the F4 are at the top of my list of favorites so far. F4 has a bit more punch on the lower end, but the XA252 just beats the F4 in midrange by a tiny bit in my humble opinion.
F4 is sounding as FE feeding it; though, per se, it must be punchier in low end, having significantly greater Rout than puckiepuckie gadget without trace of degeneration and more than enough feedback
if you miss some punchiness with XA252, either change spks or insert fraction of Ohm resistor in between amp and spk
or use some fancyschmanzy anemic tube preamp, it'll be so mushy and sweet, you'll not think of bass at all
if you miss some punchiness with XA252, either change spks or insert fraction of Ohm resistor in between amp and spk
or use some fancyschmanzy anemic tube preamp, it'll be so mushy and sweet, you'll not think of bass at all
Nothing is missing with XA252. I love the sound. XA252 has wonderful bass. F4 (with 'Yes It Can Dive An F4' front end) just has a tiny bit more 'slam' on some of the more bass heavy music, but its still at the top of the pile with the F4. I now have the F4 fed by Korg B1 NuTube on Aerial Model 10T and the XA252 was with Iron Pumpkin into Aerial Model 9's until last night. Had to swap in Aleph Jzm while I do the optocoupler resistor mod on XA252. Both setups sound sooo great! Fun to listen to both (not at same time of course).
F4 and XA252 were fed by Iron Pumpkin into Aerial Model 9s when I did my comparison. They both sound just awesome. That's how my AB comparison was done. Both F4 and XA252 are such amazing amps. Top two in my current experience (I'm still a noob at all this stuff). With that said my Aleph Jzm and F5m are also insanely good. Some may say I have "too many amps" (this gal I live with says that in particular), but I say it's "just a start" as I have a big "to build" list
My kiddo doesn't seem to care which amp or preamp we use. She just likes dancing with me in the living room. I just wish we didn't have to listen to the Frozen song "Let it go" over and over and over all the time 😆
F4 and XA252 were fed by Iron Pumpkin into Aerial Model 9s when I did my comparison. They both sound just awesome. That's how my AB comparison was done. Both F4 and XA252 are such amazing amps. Top two in my current experience (I'm still a noob at all this stuff). With that said my Aleph Jzm and F5m are also insanely good. Some may say I have "too many amps" (this gal I live with says that in particular), but I say it's "just a start" as I have a big "to build" list
My kiddo doesn't seem to care which amp or preamp we use. She just likes dancing with me in the living room. I just wish we didn't have to listen to the Frozen song "Let it go" over and over and over all the time 😆
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The 47R resistor mod for OK1 and OK2 on both channels is complete. Not pretty, but it was a little challenging to get the soldering tip in there, hold the resistor, and feed in the solder. I wasn't born with three hands.
I'm a little scared to just power up. Is it a good idea to use a DBT, or is that me being a scaredy-cat? I could just kick the Aleph Jzm out, power up and play tunes. Is that better 😉
I'm a little scared to just power up. Is it a good idea to use a DBT, or is that me being a scaredy-cat? I could just kick the Aleph Jzm out, power up and play tunes. Is that better 😉
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it would be easier if you formed it as vertical
anyhow, you did it
judging by pics, you're good to flip switch On
anyhow, you did it
judging by pics, you're good to flip switch On
Dang, you, your right, and when you're right, you're right. I've got some courage now, so thank you! I'll report back soon.
Wait until she gets to the "David Hasselhoff" stage. At least you missed disco duck and My Sharona.Nothing is missing with XA252. I love the sound. XA252 has wonderful bass. F4 (with 'Yes It Can Dive An F4' front end) just has a tiny bit more 'slam' on some of the more bass heavy music, but its still at the top of the pile with the F4. I now have the F4 fed by Korg B1 NuTube on Aerial Model 10T and the XA252 was with Iron Pumpkin into Aerial Model 9's until last night. Had to swap in Aleph Jzm while I do the optocoupler resistor mod on XA252. Both setups sound sooo great! Fun to listen to both (not at same time of course).
F4 and XA252 were fed by Iron Pumpkin into Aerial Model 9s when I did my comparison. They both sound just awesome. That's how my AB comparison was done. Both F4 and XA252 are such amazing amps. Top two in my current experience (I'm still a noob at all this stuff). With that said my Aleph Jzm and F5m are also insanely good. Some may say I have "too many amps" (this gal I live with says that in particular), but I say it's "just a start" as I have a big "to build" list
My kiddo doesn't seem to care which amp or preamp we use. She just likes dancing with me in the living room. I just wish we didn't have to listen to the Frozen song "Let it go" over and over and over all the time 😆
Powered up just fine. I did notice there was a new "hum" around volume "12" (of 24) that went away after going up to volume 16. So not sure if there is some sort of inpedance mismatch around 10-14 volume. Really odd as the hum rises in volume to a max at 12 on airon Pumpkin and then tapers off by 14 and is inaudible at 16.
With that said, at volume 16, zero audible hum and the XA252 is singing glorious tunes.
With that said, at volume 16, zero audible hum and the XA252 is singing glorious tunes.
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