Zen Mod,
The Khozmo is a Shunt type RCA 64 steps with Takman REY + AMRG resistors.
Swap out the R2 47K for 330K resistors?
Not clear regarding optimize value of series resistor to give you minimal possible attenuation in lowest position." Are you referring to the input resistor on the attenuator board? It came with 51K resistors and I swapped in 10K.
Thanks,
Chip
Chip,
There is something different between the left and right channels, somewhere along the signal path.
Can you try swapping left and right outputs from the dac going into the BA3 preamp to see if the the low volume switches from one channel to the other?
There is something different between the left and right channels, somewhere along the signal path.
Can you try swapping left and right outputs from the dac going into the BA3 preamp to see if the the low volume switches from one channel to the other?
Dennis, I reversed channels from the DAC 5.1 to the BA3[2] with Khozmo and the left channel is still twice the volume of the right.
I next connected straight from the Node to the BA2 and both channels are balanced.
Weird.
I then connected the Node to the DAC 5.1 to the BA3[1] and the balance is correct.
OK. So the dac output on the dac you built is probably fine.
Then check the resistors as ZM asked in your BA3, including any modifications on your volume control board.
Then check the resistors as ZM asked in your BA3, including any modifications on your volume control board.
Hello,
ready for a ton of questions to follow this simple one?
I got the coupled FETs and the BA-3 board(s) (got an extra one just in case), almost sold onto the Sigma 22 as a PSU (in standard configuration, without for me to make any calculation, it will give 30V as suggested by quite a few of you on my previous posts around page 12x of this thread), would use transformers from Toroidy and make it dual mono with the help (I hope, gonna meet him tomorrow) of a very skilled friend.
First simple question with regards to the above, since I am starting to populate the BOM for the BA-3, are the linked above pots the right ones (3x channel) for the project given I got the Toshiba FETs and will couple the BA-3 with a work in progress F4 and/or a tube amp?
Grazie and get ready for a ton of other questions
Giovanni
1: Pots are fine for the Vgs of the Toshibas. But only two per channel, not three. The P3 adjustment pot is specified @ 100R, not 500R.
2: Unsure if the last part was a question. But with 30v rails you are good to go driving the F4 to full output with low levels of distortion 🙂
Regards,
Andy
Buongiorno Andy and thanks for quick reply, as you might have guessed:
- my mother tongue is not English...
- my skills with electronics are in the rational numbers domain...
So, trimmers wise, I need two 25 turns 500 Ohm, top slot, 500mW, 10% (any need to go for the 5% ones?) PC Pin and one the same besides 100 Ohm per channel, correct?
I am trying to figure the BOM to populate the BA-3 board considering I will feed either the FW F4 or my KT-88 one, don't know if there would be any difference in the dimensioning of components (like R13 to say one), re-reading the whole thread again helped to figure the trimpots which, if I got it correct in the above dimensioning with your suggestion, could get a green check and allow me to move on.
Grazie ancora
Giovanni
Grazie mille!
don’t fret about the pots, the suggested one is perfect. Look up the 100R one and you are good. Should end with 101LF or something like that.
for F4, use the exact values that are in the BOM. Goes for R13 too.
regards,
Andy
If unsure of the BOM/components, you could make a Mouser basket and share it with us to make comments and suggestions.
Dale RN55s are perfect resistors for this circuit/board. I also recommend 8-11mA grade JFETs.
For R13 you need a 3 watt resistor, same type as on output boards.
regards,
Andy
Grazie di nuovo Andy, learnt something thanks to you today, I can tell the trimpots have either lined up pins or center one moved offline, watching the BA-3 board pic it seems both kind can fit, if I got it correct I can pick any kind depending on availability since it seems Italian Mouser doesn't have many of them but just a few and some are way more expensive than others even tho I filtered results with same values, by example this one is available, would it fit?
I will sure make a BOM to share with you, thanks so much for suggesting
I did arrange a BOM on Mouser, made a pdf of it which I am trying to attach here, I already have MOSFETs and JFETs, what is missing is heatsinks which I dunno how to retrieve informations about to fit the bill.
Let me know if I hit it
Grazie
Let me know if I hit it
Grazie
This should be the heatsink as seen in the first post:
https://www.mouser.ca/ProductDetail/Aavid/551002B00000G?qs=sGAEpiMZZMuIeULrOsCjAy4brj%2BGcoBGjGiEJIBGBF4=
For your BOM I noticed you included some low power 2% resistors. Is there any reason why you didn't choose 1% parts since those should be readily available?
Cheers,
Dennis
https://www.mouser.ca/ProductDetail/Aavid/551002B00000G?qs=sGAEpiMZZMuIeULrOsCjAy4brj%2BGcoBGjGiEJIBGBF4=
For your BOM I noticed you included some low power 2% resistors. Is there any reason why you didn't choose 1% parts since those should be readily available?
Cheers,
Dennis
^ +1 to Mr. Hui.
Also... It may just be a typo (I didn't look in the Mouser cart, but you want a 1k (not 500R) for P1 and P2 if using the Fairchild outputs.
Giovanni - Sent you an example BoM via e-mail.
Edited to add - It has the exact same heatsinks that Dennis linked to above. 😀
Also... It may just be a typo (I didn't look in the Mouser cart, but you want a 1k (not 500R) for P1 and P2 if using the Fairchild outputs.
Giovanni - Sent you an example BoM via e-mail.
Edited to add - It has the exact same heatsinks that Dennis linked to above. 😀
He has Toshibas 🙂^ +1 to Mr. Hui.
Also... It may just be a typo (I didn't look in the Mouser cart, but you want a 1k (not 500R) for P1 and P2 if using the Fairchild outputs.
Giovanni - Sent you an example BoM via e-mail.
Edited to add - It has the exact same heatsinks that Dennis linked to above. 😀
or does he?
giovanni: can you confirm you have 313 and 2013 MOSFETs? You wrote Toshiba fets. I read that as MOSFETs.
If Fairchild the value for P1-2 is 1K.
@Dennis Hui Ciao Dennis, I updated the BOM, will upload it again, the issue being I choose among 1/4 to 1/2 W and only 2% available, gone for 1/4 W and could pick the 1% ones.
@ItsAllInMyHead Patrick I followed the suggestions in the reply on top of the page, by the way I got these ones "K170/J74 and K2013/J313", which ones should I order?
@ItsAllInMyHead Patrick I followed the suggestions in the reply on top of the page, by the way I got these ones "K170/J74 and K2013/J313", which ones should I order?
^ Great call out, Andy. I had the benefit of some other PMs and notes.
Giovanni - I think you had the Toshiba JFETs from the DIYA store (Q1, Q2) vs. the Toshiba MOSFETs for Q3-Q4. Make sure you clarify.
Edited to Add - LOL - Typing at the same time. Giovanni - Thanks! I thought you only had the JFETs. Apologies. You are good to go. 😀
Giovanni - I think you had the Toshiba JFETs from the DIYA store (Q1, Q2) vs. the Toshiba MOSFETs for Q3-Q4. Make sure you clarify.
Edited to Add - LOL - Typing at the same time. Giovanni - Thanks! I thought you only had the JFETs. Apologies. You are good to go. 😀