The boards with matched JFETs and resistors should be available in the store soon. You will have to supply the remaining components yourself.
Pass DIY Addict
Joined 2000
Paid Member
Looking forward to a fun project to make! Many thanks to Nelson for his incredible gift and to Soundhappy and Bob for handling things along the way!
DQ828: another reference for your attenuator is here: Mini-V Resistor Lists
Eric
DQ828: another reference for your attenuator is here: Mini-V Resistor Lists
Eric
Pass DIY Addict
Joined 2000
Paid Member
I don't remember where I found this table, but this might also be helpful for you since it has lots of values for a variety of configurations:
Attachments
Question. I have had this idea and now I want to marry the Korg B1 together with it. I have a Bottelhead Quicksand and I want to use the Korg B1 with it to make a hybrid amp that runs on batteries. I am going to take a wild guess and assume the Korg B1 will not tolerate voltage drop, right? Would I have to regulate voltage? I have no knowledge, so don’t ask me why I choose to complicate things. Sorry.
Your obviously better at finding stuff them me, I went to that site & still missed that!
Many Thanks
Papa mentioned something about different voltage in post #1024:
https://www.diyaudio.com/forums/pass-labs/313612-b1-korg-triode-103.html#post5663570
Given that comment, I would definitely use 24V regulated.
Dennis
Dennis, you may have noticed that two of your boards were different
and intended for you - they are the DIY production and include provision
for both the Toshiba/LS Jfets but all the Fairchild/Onsemi. That should
cover the pinouts for all the To-92's I know of.
As you were provided with matched 2SK370's, you will want 0 ohms for the
R1 resistor values.
In case I failed to mention it....
and intended for you - they are the DIY production and include provision
for both the Toshiba/LS Jfets but all the Fairchild/Onsemi. That should
cover the pinouts for all the To-92's I know of.
As you were provided with matched 2SK370's, you will want 0 ohms for the
R1 resistor values.
In case I failed to mention it....
Thanks!
More questions if anyone is willing. So would I buy or build something like that to HiFi standard? If build, do you know of any plans online? Or buy, where and what?
Looking forward to the boards becoming available in the store. If matching JFETs are an option as well, that's great as it'll make the build that much easier.
Thanks all!
Thanks all!
Basic kit is pcb + matched Fairchild jfets. You can optionally buy LSK170
matched as an addition.
matched as an addition.
Hi Nelson,
I think you had previously mentioned the resistor was only needed
when using the fairchild jfets. Thank you for the reminder.
Cheers,
Dennis
I think you had previously mentioned the resistor was only needed
when using the fairchild jfets. Thank you for the reminder.
Cheers,
Dennis
Update on some tinkering I’ve been doing with my build:
I was messing around with some scope measurements on the DC input to the circuit and noticed more noise than I wanted. The CR filter was rejecting all of it by T2, but the frequency was higher than at the DC in. Looks like the buck converter I was using for the power led was responsible — I observed added noise with both the smps and a 24v LM317 PSU. I removed the buck converter and the noise significantly reduced with the SMPS and is completely gone with the LM317. I’m now running with the LM317 just because I had it available.
On second harmonic measurements, I’ve been having difficulty getting one of the channels to dial into a 1% 2H distortion within the recommended positive phase voltage range. It sticks around 1.3% or so with very low third harmonic. The other channel dials nicely into 1% within the .3v variance referenced by Papa. I can’t tell a difference in listening, i just found it an interesting observation.
Looking forward to seeing some more builds soon with the US nutube shipments out!
I was messing around with some scope measurements on the DC input to the circuit and noticed more noise than I wanted. The CR filter was rejecting all of it by T2, but the frequency was higher than at the DC in. Looks like the buck converter I was using for the power led was responsible — I observed added noise with both the smps and a 24v LM317 PSU. I removed the buck converter and the noise significantly reduced with the SMPS and is completely gone with the LM317. I’m now running with the LM317 just because I had it available.
On second harmonic measurements, I’ve been having difficulty getting one of the channels to dial into a 1% 2H distortion within the recommended positive phase voltage range. It sticks around 1.3% or so with very low third harmonic. The other channel dials nicely into 1% within the .3v variance referenced by Papa. I can’t tell a difference in listening, i just found it an interesting observation.
Looking forward to seeing some more builds soon with the US nutube shipments out!
Since the active regulation in the Nutube is simply the zener diode, I
assume you mean the H2 project?
You need a converter for the led? I just use a resistor to give it a couple mA.
assume you mean the H2 project?
You need a converter for the led? I just use a resistor to give it a couple mA.