Thank you!
Always wanted to try an AVC preamp but I need balanced outputs.
Zen Mod's quote"
"or you can go wild and connect commercial AVC to appropriate tap , as output autoformer and have 6db gain ...... that would be buffer -commercial AVC connected on proper tap"
That sounds like what I need! Can it be made with BAL outs?
If so, where do I get the boards for that version?
Always wanted to try an AVC preamp but I need balanced outputs.
Zen Mod's quote"
"or you can go wild and connect commercial AVC to appropriate tap , as output autoformer and have 6db gain ...... that would be buffer -commercial AVC connected on proper tap"
That sounds like what I need! Can it be made with BAL outs?
If so, where do I get the boards for that version?
YES!!!!!
Only listening so far is on some crappy earbuds—for testing on the bench—and making sure it's quiet—but what I heard was awesome—had depth (tube-y?).
Tomorrow IRON gets plugged into AJ!
Super happy with how it came out—remote control and all—little voltage regulator there to drop to 9V—thanks of course to 6L6 for part suggestions. Datasheet for regulator had a simple circuit. Only DRAMA was jacking the voltage in half when plugged in to the power outs of IRON on the V+ side—that wasn't happening (and there was a noob frying of circuit scare—6L6 had to stop ALL of his cookie baking routines to sort me out Haha.).... and the remote board has a muting relay—not sure if I'm gonna see if I can use that or not—not sure it's possible since ZM has thought of everything.....
Pics of the front later if anyone's interested—gloss black and white knobs.
Thanks ZM!!!!
Only listening so far is on some crappy earbuds—for testing on the bench—and making sure it's quiet—but what I heard was awesome—had depth (tube-y?).
Tomorrow IRON gets plugged into AJ!
Super happy with how it came out—remote control and all—little voltage regulator there to drop to 9V—thanks of course to 6L6 for part suggestions. Datasheet for regulator had a simple circuit. Only DRAMA was jacking the voltage in half when plugged in to the power outs of IRON on the V+ side—that wasn't happening (and there was a noob frying of circuit scare—6L6 had to stop ALL of his cookie baking routines to sort me out Haha.).... and the remote board has a muting relay—not sure if I'm gonna see if I can use that or not—not sure it's possible since ZM has thought of everything.....Pics of the front later if anyone's interested—gloss black and white knobs.
Thanks ZM!!!!
Attachments
Last edited:
it'll work , but I don't like it, due to fact that there is no series resistor from JFet buffer, and why harassing them with dead short to GND?
instead of that hard mute, try sort of softer mute - include series resistors between signal routes and your mute circuit - put there 100R in each line (RCOM and LCOM)
instead of that hard mute, try sort of softer mute - include series resistors between signal routes and your mute circuit - put there 100R in each line (RCOM and LCOM)
WOW!!!! YES!!!!!!!!! I'm too jacked up.
ZM— Couldn't be more happy. Gave this a good listen today with family too who say "they don't have opinions"—right—they DO!) ... —A/B vinyl on two decks (HOLY SH&$ SP-10MKII). Some random family movies—Hi-res digital via Tidal and an R2R DAC—Opera (Mozart at the Met free on the interwebs due to Covid).
Learned a TON. It's warm and lovely—but not overly so—FULL—RICH—DETAILED—LAYERED—PUNCH—audio descriptions are so subjective. This is with AJ—already on the meaty side—I like meaty. Will try with F5 and report back. A/B with Wayne's—which I also love but has a different character. SO FUN. EVERYONE NEEDS TO BUILD BOTH.
This is a total WINNER—Hats off bowing.
Soft mute is pretty trick. I didn't know what to expect. Pretty cool really. Works great—love having a remote. Tried 12 DB jumpers... think I prefer the 6 setting. AMP is quiet.
You can see the vision with the Wayne's stack, visually—just playing around.
NOW BACK TO LISTENING!
(I will build the balanced version. Getting there.....)
ZM— Couldn't be more happy. Gave this a good listen today with family too who say "they don't have opinions"—right—they DO!) ... —A/B vinyl on two decks (HOLY SH&$ SP-10MKII). Some random family movies—Hi-res digital via Tidal and an R2R DAC—Opera (Mozart at the Met free on the interwebs due to Covid).
Learned a TON. It's warm and lovely—but not overly so—FULL—RICH—DETAILED—LAYERED—PUNCH—audio descriptions are so subjective. This is with AJ—already on the meaty side—I like meaty. Will try with F5 and report back. A/B with Wayne's—which I also love but has a different character. SO FUN. EVERYONE NEEDS TO BUILD BOTH.
This is a total WINNER—Hats off bowing.
Soft mute is pretty trick. I didn't know what to expect. Pretty cool really. Works great—love having a remote. Tried 12 DB jumpers... think I prefer the 6 setting. AMP is quiet.You can see the vision with the Wayne's stack, visually—just playing around.
NOW BACK TO LISTENING!
(I will build the balanced version. Getting there.....)
Attachments
SE or Bal, whatever, lets talk about Rout per phase
Iron Pre - that would be Rout of buffer, multiplied with square of voltage ratio of output autoformer
Rout of complementary Toshiba JFet buffer is in range of 30R; when you choose 6db autoformer arrangement that's multiplied with 4 , so effective Rout is 120R; when you choose 12db arrangement , that's multiplied with 16, so effective Rout is 480R .....
Iron Pumpkin, having Iron on output which is serving same as attenuator and gain device ( autoformer) if chosen ;
lets set it for 0db gain , then highest effective Rout is on top tap (0db) and it's equal to Rout of my funny JFet buffer , which is having Rout in range of 20-25R ; every lower tap is resulting in dividing that with square of voltage ratio , so when you set volume to -6db , effective Rout is 25/4=6R25 , for -12db it is 25/16=1R5something
when you set AVC jumpers to, say, 6db gain , then you have highest Rout in top tap (6db) where you have JFet Rout multiplied with 4 , so that is 25*4=100R, while each lower volume step is having appropriately decreased effective Rout by same calculus
of course , everything explained applicable ditto for SE (Rca) and just double it for balanced
hope I was clear enough .....
