Russellc - Great news!
PF - Oooooh - Pick me too! Thank you for posting that. I have the same Antek Russellc is using with the 2018 boards (one C and one R). Any help with the values for the 2018 board with the Antek is very welcome.
I have 2020 boards for the balanced build I'm planning. I think I just got my wiring plan down for it and a basic understanding of the schematic. I hope by the time, I'm ready to assemble it, I'll have learned how to do Quasimodo on my own. <crossing fingers>
PF - Oooooh - Pick me too! Thank you for posting that. I have the same Antek Russellc is using with the 2018 boards (one C and one R). Any help with the values for the 2018 board with the Antek is very welcome.
I have 2020 boards for the balanced build I'm planning. I think I just got my wiring plan down for it and a basic understanding of the schematic. I hope by the time, I'm ready to assemble it, I'll have learned how to do Quasimodo on my own. <crossing fingers>
Last edited:
You may learn before me? Aother question, I guess I don't have to wonder (as I will look at pics again of your board), If no cap and resistor in those locations, does anything have to be jumpered?
Im sure I will fire it up on a board before getting to Quasimodo...I too have thought of a balanced version, but I drift over to Zenmod's Iron turtle. The Iron pre is supposed to be fine, but going full on autoformer "spooky" and me likey some spooky. Then, I look to Iron Turtle Balanced and the cost makes me think, "well if balanced should it be Iron pre for less cost? But that removes Spooky from equation and I drift back to Iron Turtle SE.....then to compound it all, there is some way to splice in AVC $200 autoformer in some of Zenmod's posts....so little time (and so much money) so many builds.
Russellc
Im sure I will fire it up on a board before getting to Quasimodo...I too have thought of a balanced version, but I drift over to Zenmod's Iron turtle. The Iron pre is supposed to be fine, but going full on autoformer "spooky" and me likey some spooky. Then, I look to Iron Turtle Balanced and the cost makes me think, "well if balanced should it be Iron pre for less cost? But that removes Spooky from equation and I drift back to Iron Turtle SE.....then to compound it all, there is some way to splice in AVC $200 autoformer in some of Zenmod's posts....so little time (and so much money) so many builds.
Russellc
Last edited:
From Mark's email (Quoted without permission so hopefully Mark's okay with this ;-):
"We found that the optimum two component snubber for
the Antek 50VA transformer in Jim's house, and your assumed
diodes, was series_C = 0.15uF series_R = 68 ohms."
My transformer was not that Antek—so I had the pleasure of doing my own testing—and came up with a value for my 30VA—1U friendly—transformer...
"We found that the optimum two component snubber for
the Antek 50VA transformer in Jim's house, and your assumed
diodes, was series_C = 0.15uF series_R = 68 ohms."
My transformer was not that Antek—so I had the pleasure of doing my own testing—and came up with a value for my 30VA—1U friendly—transformer...
Attachments
Last edited:
Thanks for comment! I haven't read into Quasimodo yet, only heard of it. Am I correct to assume that it's measurement is specific to the transformer, and circuit it is connected to is irrelevant? If so I can plug and play those parts for now...I do need to do the Quasimodo, but so many projects in line...
Russellc
Russellc
PF - Thanks! Good news is that until I learn Quasimodo, I can use those values for the balanced build also. Once I build it and learn how to use the Quasimodo, it will be fun to see and measure the difference (if any) between the two configurations.
Russellc - Antek must be on a roll. I just got notice that my "cans" for my transformers shipped.
Russellc - Antek must be on a roll. I just got notice that my "cans" for my transformers shipped.
Yes, you are coming up with a snubbing R value to deal with a transformers individual ring characteristic (the PDF I linked to is some awesome reading—most of it over my head at the moment to be sure—but Mark is a DIYaudio treasure.). My understanding being that any extra noise you can get rid of translates eventually into more music.
Certainly I have experienced this farther down the chain. My first F5 was very noisy. All the fine peeps up here gave a million suggestions to change the internal layout—including in a big way ZM—and when I did that—the difference was unbelievable. I could state that I hadn't "really" heard the amp to begin with. Also recently have been changing just power cable vs signal cable arrangements in my "metal cabinet of audio death" where all these projects are housed at the moment... and am realizing A. that my AJ is actually freaking quiet, and B. that it's sounding better than ever the more I get rid of environmental noise sources...
Pretty sure you can just leave the spots empty and move along—similar to the diode portion of the DIYaudio PSU.
I hope I can learn it at all
Nope. No jumpers required.
LOL! I am salivating over the pumpkin. I am trying to be smart and go in a logical progression. Your thoughts and mine align almost perfectly. Priorities...
I'm trying to figure out different options for attenuation for the Iron Pre, so I can learn more about that. Relay-stepped, Muses, Dual 2-gang, Single 4-Gang, motorized, non-motorized??? Then, I want to try the magic of AVC.
Definitely small world... I haven't built any versions of the BA (yet). I have dreamt about them, and I've finally built up the nerve to do it. I've used Anteks in all my builds so far, but I considered Toroidy for the BA until: 1) I checked the price. 2) I realized that my Antek-based PSUs would be sufficient to "get by" unless/until I go full blown nuts.
To keep it on topic - the planned first recipients of the signal from my Iron Pre Balanced will be a pair of BA3b / BA2 monoblocks. I am still reading and planning, but parts are in the Mouser cart.
Definitely small world... I haven't built any versions of the BA (yet). I have dreamt about them, and I've finally built up the nerve to do it. I've used Anteks in all my builds so far, but I considered Toroidy for the BA until: 1) I checked the price. 2) I realized that my Antek-based PSUs would be sufficient to "get by" unless/until I go full blown nuts.
To keep it on topic - the planned first recipients of the signal from my Iron Pre Balanced will be a pair of BA3b / BA2 monoblocks. I am still reading and planning, but parts are in the Mouser cart.
just going through my BBA3 mono block box o' parts this evening.....
but on topic I have my transformer and will fire up the board in the morning.
I figure offset is measured at the R out and R out G, as well as L out and L out G, right?
The 15 volts set with pots measured at the 4 large pads in the center of board G and U on each side?
Last edited:
Goooooooood morning - Fantastic!
I checked your board pics and the schematic you sent me.
Yep - per your schematic.
You got it. Rock on. Not to influence the outcome, but I can't wait to hear what you think.
same as with any bridged gadget , most important offset is between two hot outputs - that's what your speaker will see and respond to ; as usual , clock it to 0mV , keeping on mind that up to 100mV is tolerable , steady state
second offset you need to think of is DC level of both outputs (together) ref. to GND
up to 500mV is ok , more than that will cut of available voltage swing
say that's on +10V ; rails are +/-25V ; there is 15V space to upper rail , and 35V space to lower rail ; guess which side voltage swing would first hit the ceiling
resulting in usable range of just 30Vpp , instead of 50Vpp (not counting losses)
I'm notoriously forgetting established names for these two offsets, one is Relative, other is Absolute ...... and I believe I got them in this tutorial (but lazy to check, so it's easier again to reveal my dumbness in Public) : Pass Labs X150.5 , checking/adjusting offsets ,Iq and gain | Zen Mod Blog
regarding actual tricks on particular pcbs, can't help - I'm not familiar with them , so better to ask someone who got them in hands
btw. - offset - taking in account that BBA3 OS - each group- is having independent DC offset setting mechanism , you can do each group in simplest possible way - setting DC offset between Hot and Gnd, fine tuning it on end as offset between two hots
second offset you need to think of is DC level of both outputs (together) ref. to GND
up to 500mV is ok , more than that will cut of available voltage swing
say that's on +10V ; rails are +/-25V ; there is 15V space to upper rail , and 35V space to lower rail ; guess which side voltage swing would first hit the ceiling
resulting in usable range of just 30Vpp , instead of 50Vpp (not counting losses)
I'm notoriously forgetting established names for these two offsets, one is Relative, other is Absolute ...... and I believe I got them in this tutorial (but lazy to check, so it's easier again to reveal my dumbness in Public) : Pass Labs X150.5 , checking/adjusting offsets ,Iq and gain | Zen Mod Blog
regarding actual tricks on particular pcbs, can't help - I'm not familiar with them , so better to ask someone who got them in hands
btw. - offset - taking in account that BBA3 OS - each group- is having independent DC offset setting mechanism , you can do each group in simplest possible way - setting DC offset between Hot and Gnd, fine tuning it on end as offset between two hots
ZM - As always, thank you!! I have copied and pasted in to my build notes. Some tea and reading. I had read that blog post awhile ago, but as you've seen - I need to read, think, read, sleep, think, ask ZM, read, sleep, and have more tea before I actually understand something. Funny part is that I think I do understand absolute vs. relative offset. 
Dennis - I don't have any control over when the store will put them up, but I hope to post a detailed build with the "store" layout of the boards to get you even more excited. I had a few learning experiences laying out my build.
Some tea and reading. I had read that blog post awhile ago, but as you've seen - I need to read, think, read, sleep, think, ask ZM, read, sleep, and have more tea before I actually understand something. Funny part is that I think I do understand absolute vs. relative offset. Dennis - I don't have any control over when the store will put them up, but I hope to post a detailed build with the "store" layout of the boards to get you even more excited.
I had a few learning experiences laying out my build.
Last edited:
story of my life , except few differences - I'm asking Pa , and coffee instead of tea , and I'm happy to understand 15% of all things I started thinking about
and yeah, I'm again in Pa's disgrace, so percentage is even smaller
(music is great help to enjoy and avoid disappointments)
Well poop. Everything going fine. ramping up variac. Rails up to 10 v, going to turn back off set which was below 2 mv dropped the tiny screw driver and the very small c21 exploded!
Let's find a spare and give it another go. On my boards this is the tiny cap next to the transistor back by the regulators. It now looks like a very small cotton ball.
Would attach a pic, but recently up graded from Windows 7 to 10, and don't seem to be able to upload pics now. I'll try a sim reader and see if that is a work around.
Russellc
Let's find a spare and give it another go. On my boards this is the tiny cap next to the transistor back by the regulators. It now looks like a very small cotton ball.
Would attach a pic, but recently up graded from Windows 7 to 10, and don't seem to be able to upload pics now. I'll try a sim reader and see if that is a work around.
Russellc
