Perfect! I will leave it alone.
Stable after 2hrs cooking. Ready to try some music, but I noticed when I shut down the power, I get 3V41 DC at outputs...
Null perfect when powered up, but a lot of DC at output at power down. Slowly drains over time.
Is that acceptable / expected? Seems like it may result in a BIG turn off thump? Is that correct, or am I paranoid again?
As always, thanks!
Edited to add - also checked at power up - 1V8 that then starts to decrease. Note, both turn on and off were w/o inputs shorted.
Stable after 2hrs cooking. Ready to try some music, but I noticed when I shut down the power, I get 3V41 DC at outputs...
Null perfect when powered up, but a lot of DC at output at power down. Slowly drains over time.
Is that acceptable / expected? Seems like it may result in a BIG turn off thump? Is that correct, or am I paranoid again?
As always, thanks!
Edited to add - also checked at power up - 1V8 that then starts to decrease. Note, both turn on and off were w/o inputs shorted.
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I had a quick nap (I'm either becoming old fart , or I'm becoming as Tesla - being able to sleep in bursts) in chair , so you did entire stint panic-more panic-eureka! no reason!! , without me even noticing
though , I'm 90% sure that I wrote in numbers about powering up/down behavior
Beautiful music on test speakers!
Once again with the new baby, thanks go to Nelson for the inspiration and of course to the Mighty Zen Mod for graciously sharing his design and having the patience for helping us noobs become less and less noobs.
who is Nelson???
my Pa is smarter than he is
LOL! Happening very soon. I have to wire RCA inputs to this chassis. I will let it cook with some music, then I have to remove back panel and add RCA jacks. Right now, I only have XLR.
I have pot on the way from Digi-Key with other parts for GB, and I ordered the 2U chassis for Iron Pre (will also fit balanced later).
I have pot on the way from Digi-Key with other parts for GB, and I ordered the 2U chassis for Iron Pre (will also fit balanced later).
Thanks @jwjarch!
ZM - I left the amp on for the evening and all morning. All stable!
I got the new pot for the Iron Pre this morning. Very early FedEx So, I swapped out the pot, and I have added the RCA inputs to the Babel J2 chassis.
I admit I get confused with some of the options for simply adding the input. For this amp which has In-, In+, and GND - I think I would:
1) Wire RCA Signal (center) to XLR pin 2 (In+)
2) Wire RCA GND to XLR GND (Pin 1). Note - Edited
I have seen some people use resistors between the two GNDs for the inputs. Is this necessary if only ever having one set of inputs connected? Recommended? Is this to reduce hum? I see lots of values used. If recommended, is there a value that you like?
When using RCA input for this amp, I would need to use a jumper to short pins 3 (In-) and GND (pin 1) at the XLR, correct?
Thanks as always for helping confirm silly things for nooooooob dodos.
ZM - I left the amp on for the evening and all morning. All stable!
I got the new pot for the Iron Pre this morning. Very early FedEx
So, I swapped out the pot, and I have added the RCA inputs to the Babel J2 chassis. I admit I get confused with some of the options for simply adding the input. For this amp which has In-, In+, and GND - I think I would:
1) Wire RCA Signal (center) to XLR pin 2 (In+)
2) Wire RCA GND to XLR GND (Pin 1). Note - Edited
I have seen some people use resistors between the two GNDs for the inputs. Is this necessary if only ever having one set of inputs connected? Recommended? Is this to reduce hum? I see lots of values used. If recommended, is there a value that you like?
When using RCA input for this amp, I would need to use a jumper to short pins 3 (In-) and GND (pin 1) at the XLR, correct?
Thanks as always for helping confirm silly things for nooooooob dodos.
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Thanks for confirming, ZM! I looked at a lot of examples, but I wanted to ensure I had it correct.
I had to pause for a few hours for some work. Below is some early porn with things still open-air. Babel J2 with new RCA inputs added and Iron Pre making beautiful music together. Chassis for Iron Pre should be here soon. New pot is installed, but I need to still order the pot extension to the front of chassis etc. to get it final and tidy.
Hooked it up to "main system" to enjoy until I have to tear it down to install into the chassis and get a remote / motorized pot. Too lazy ...
I had to pause for a few hours for some work. Below is some early porn with things still open-air. Babel J2 with new RCA inputs added and Iron Pre making beautiful music together. Chassis for Iron Pre should be here soon. New pot is installed, but I need to still order the pot extension to the front of chassis etc. to get it final and tidy.
Hooked it up to "main system" to enjoy until I have to tear it down to install into the chassis and get a remote / motorized pot. Too lazy ...
This thread hasn't had any action in a while.
I've had the J2 in place pretty much constantly since those posts... Today, on a whim... I decided to try the ACP+ (which I've heard called a mini-J2) with the Babel J2. I was curious if there was such a thing as too much of a good thing... Not to me. To my ears they sound just wonderful as a pair. I can't quite put my finger on the differences when the Iron Pre was swapped for the ACP+, they're subtle. I doubt I could pick them out blindly. It just goes to show how wonderful they both are.
FWIW - the Babel J2 is just magic to my ears. Thanks again ZM!
I've had the J2 in place pretty much constantly since those posts... Today, on a whim... I decided to try the ACP+ (which I've heard called a mini-J2) with the Babel J2. I was curious if there was such a thing as too much of a good thing... Not to me. To my ears they sound just wonderful as a pair. I can't quite put my finger on the differences when the Iron Pre was swapped for the ACP+, they're subtle. I doubt I could pick them out blindly. It just goes to show how wonderful they both are.
FWIW - the Babel J2 is just magic to my ears. Thanks again ZM!
naah
Babel J2 is for Sissies .......
and , Iron Pre and ACP+ are definitely on same quality level , while also having same weakness - both still having resistive attenuator
Hmmmmm... funny you should mention that... I've been reading about reptiles and vegetable matter for several hours...
This thread hasn't had any action in a while...
FWIW - the Babel J2 is just magic to my ears. Thanks again ZM!
I've played with BJ2 and made/listened to all 3 iterations.
My personal favourite is Hibrid version with Semisouth and IRFP.
Unfortunately, probably due to too much harassment of the pcb, right channel has developed strange humming noise that I wasn't able to remove... At the end it, both bc639 with zd102 died and I have - 24dvc on output. Tried several times to replace them, together with all BCs but no success.
One thing is true - this is really special sounding amp.
I can't wait to bring it back to life again
This thread hasn't had any action in a while.
I've had the J2 in place pretty much constantly since those posts... Today, on a whim... I decided to try the ACP+ (which I've heard called a mini-J2) with the Babel J2. I was curious if there was such a thing as too much of a good thing... Not to me. To my ears they sound just wonderful as a pair. I can't quite put my finger on the differences when the Iron Pre was swapped for the ACP+, they're subtle. I doubt I could pick them out blindly. It just goes to show how wonderful they both are.
FWIW - the Babel J2 is just magic to my ears. Thanks again ZM!
I believe you also made the sissysit. How do they compare?
I did... Your timing is uncanny...
I haven't ever done a back to back comparison using the same kit with those two. Also, I just got the SissySIT back a little while ago. I loaned it to a friend. So, I built the Babel J2
Now, they're both back in identical chassis / PSU boxes (only layout is a bit different).... and ready to go. I just got Sissy off the bench for her checkup to make sure all is well.
I can say without even listening back to back that they are two of the finest amps I've ever paired with my speakers. That's why I want to listen to them more closely together in time. I'm trying to learn a bit more about what works well with certain speakers - these both work for me!
FWIW - I'll be using the ACP+ as a pre-amp (at least at first).
Here are the siblings .... Left is J2 playing now. Right is SissySIT warming up to temp and getting all hot and bothered.
I'll post some thoughts in a few days or so. Keep in mind that my speakers (Tekton DIs) seem to play nicely with some amps and not others (to an extent). So, my impressions and needs may differ.
Edited to Add - Well, I may not use the ACP+ first. I just noticed that I forgot to put the RCA inputs on the SissySIT. I'll either use another commercial pre-amp or add the RCA inputs to the SissySIT tomorrow.
I haven't ever done a back to back comparison using the same kit with those two. Also, I just got the SissySIT back a little while ago. I loaned it to a friend. So, I built the Babel J2
Now, they're both back in identical chassis / PSU boxes (only layout is a bit different).... and ready to go. I just got Sissy off the bench for her checkup to make sure all is well.
I can say without even listening back to back that they are two of the finest amps I've ever paired with my speakers. That's why I want to listen to them more closely together in time. I'm trying to learn a bit more about what works well with certain speakers - these both work for me!
FWIW - I'll be using the ACP+ as a pre-amp (at least at first).
Here are the siblings .... Left is J2 playing now. Right is SissySIT warming up to temp and getting all hot and bothered.
I'll post some thoughts in a few days or so. Keep in mind that my speakers (Tekton DIs) seem to play nicely with some amps and not others (to an extent). So, my impressions and needs may differ.
Edited to Add - Well, I may not use the ACP+ first. I just noticed that I forgot to put the RCA inputs on the SissySIT. I'll either use another commercial pre-amp or add the RCA inputs to the SissySIT tomorrow.
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That's very kind... you're a busy, busy guy. I have more than enough good music and fun things to keep me busy for a while. This is waaaaaaaaaaay too much fun.
Edited to Add - OK - Funny moment with a beer and music... Song that just came on...
"We're never gonna survive... unless we get a little" wackoo... ok "crazy"...
Edited to Add - OK - Funny moment with a beer and music... Song that just came on...
"We're never gonna survive... unless we get a little" wackoo... ok "crazy"...
Great work IAIMH! If you haven't got one already, I think you would get some great returns on piece of mind with a variac. Particularly in light of your rate and quantity of builds of late.
Plenty of low cost options on Amazon:
Amazon.com: variac variable transformer
Personally I bought 2 of these bare Staco variable transformers and put one into a metal case and added my own wall outlet and IEC switched/fused inlet. Works like a charm! Right now I put a night light into one socket to tell me when it's on because I never use more than 1 socket anyway and I'm too lazy to look behind it to see if it's on.
Staco style Variac Transformer, 0-132 V, 3.0 A max, 0.4 kVA, without Knobs & Brush
Plenty of low cost options on Amazon:
Amazon.com: variac variable transformer
Personally I bought 2 of these bare Staco variable transformers and put one into a metal case and added my own wall outlet and IEC switched/fused inlet. Works like a charm! Right now I put a night light into one socket to tell me when it's on because I never use more than 1 socket anyway and I'm too lazy to look behind it to see if it's on.
Staco style Variac Transformer, 0-132 V, 3.0 A max, 0.4 kVA, without Knobs & Brush