I second that. His articles are great to read on tubecad.com.
I've been reading a lot about OTL's. Wonder if one day he'll come out with a pcb for that!
And more beautiful boards for power tubes or even hybrids he has talked about on tubecad.
raypalmer said:
😉 Yep, one stop shopping!
I built Mr. Bas' valve HT power supply because I wanted that "tube" PS sound, and I wanted the HT power to come up slowly. However, I did use a very compact and well designed board from JB for the heaters. 12V PS board with the tubes aligned in series via the jumpers on the Aikido board. (Why I like JB's Aikido Boards)(makes it easier to change different voltage octal tubes later)
Both Mr. Bas' and JB's boards are excellent quality, you should not have issues with either of them.
By the time I finish testing prior to building the case, I'll have 3 seperate transformers and 3 seperate PS circuits, ~300V HT/ 12V LT/ 5V digital attenuation & display......Sheesh!
Ron
I connected a log stereo pot not with good results. Everything is on the breadboard right now
Getting a lot of hiss coming through especially if I place my hand close to the signal wires. damn they are sensitive.
What is likely to be causing the hissing??😕
I understood that grounding problems tend to be of much lower frequencies causing a hum not a hiss.
Renron said:
I am also just putting finishing touches on a dual mono 9-pin JB Aikido using Bas' PS board and it sounds better than I expected. I have been so impressed with the Aikido that I re-tubed my Anthem Pre-1 just as a sanity check, and so far, I prefer the Aikido.
I'm presently running 6BQ7/6DJ8's for tubes per the values in JB's tables.
The last few evenings have been spent chasing hum issues, but that's just about solved after lifting signal ground off of chassis with a 20 ohm R, and using shielded heater wires. I am running AC heaters off of Bas' power board, a fairly common setup I imagine.
Future tweaks planned are a stepped attenuator in place of the Alps black beauty pot, a separate transformer for the 6X5 filaments, some tube rolling, and adding an input selector.
I built the pre in one chassis, although if I were to do it again, I would consider putting the PS in a separate enclosure. I'll post a few pics once everything is buttoned up.
Has anyone used JB's Janus PS board? This looks interesting, somewhat regulated B+ and heater supplies on one board.
I have been watching this thread from time to time with interest because I'm building the Aikido also. I was having hum and noise issues with mine that I thought was the fault of the switched volume that JB sells also. It would show up at specific settings of attenuation.
I finally added the capacitor coupling of the DC filaments. JB coments that this sometimes can make a dramatic improvement to hum and noise issues and it sure did!! All of my noise issues are completely gone now.
RG
I finally added the capacitor coupling of the DC filaments. JB coments that this sometimes can make a dramatic improvement to hum and noise issues and it sure did!! All of my noise issues are completely gone now.
RG
Can't wait to see pics of both of your setups. Do you spout the valves out the top for open-air cooling or are you leaving them under the case??
FreeCrowder,
Could you please explain this in more detail?
"I finally added the capacitor coupling of the DC filaments."
Thank you,
Ron
Could you please explain this in more detail?
"I finally added the capacitor coupling of the DC filaments."
Thank you,
Ron
Renron said:
Ron
Think he means refer P2 of JBs guide - which shows floating heaters to 1/4 of B+ with 0,1uf cap on the 100k 1/2W resistor. You can try just the cap alone to float the earth of the heaters as well.
I've done this likewise and have virtually zero 50Hz hum and only very low level hiss (have to put my ear to the tweeter to hear it).
I found using C7 and C9 made a nice reduction in noise so I thought using Russian PIOs 0,1uf with 6n23ps in the output tube position (same as 6DJ8). Try C7/C9 if you haven't already and let me know what you think. This grounds the shield between the triode halves in AC terms. FWIW I didn't like it as much when I shorted C7 and C9 to ground (can't do this on all 9 pin tubes however!!!).boywonder said:
By the way I am not grounding the PCBs at J2 (I think it is). Is this what others are doing? Rather I ground via the outputs via 10R/5W to mains earth and use a 0.1uf PIO over the 10R plus an Auricap over active/neutral (from J.Risch's site)
I also use a 4 pole Jensen in my HT filter - white paper read well, not sure how significant this was in the overall noise reduction strategy. I use DC heaters too.
You probably have an oscillation. If you don't have grid stopper resistors already, install them, keeping the resistors as close to the grid pins as possible.
Is this the 0.1uF cap that connects the ground to the chassis? He mentions on page 6 of his manual you can either use a jumper or small cap.
I'm using AC with 6N1P input tubes. I have a jumper in C9 position. Are you recommending putting a small cap here instead to connect to the internal shield of this tube?
i'll have to read up on grid stoppers. Not too familiar with them😕
I'm using Bas's psu as standard.
Sorry bit of a bum steer - there is no C9!!! 6n1p like 6dj8 (and 6CG7) has pin 9 as a screen. C7 as a 0.1uf cap will ground this in AC terms which I thought was better than having a short to ground at C7 in my Aikido.Brit01 said:
Looks like J4 connects PCB ground to chassis through the top centermost mounting hole - a 0.01 to 0.1uf high voltage cap can be used there - haven't tried that myself.
Mine's pretty quiet now anyway...
C11 I meant sorry. Yes this connects the ground to 6N1P's shield.
I put a jumper in here. Might try a small cap.
C7 (C8-C10) on my board is one of the small 10V elct. caps for DC heaters so I read. Mine are left out for AC.
Interesting article. Maybe highlighting the possible HF oscillation I'm getting.
I could try increasing the grid stopper (R3) to a higher value as suggested.
It also recommends trying 6N6P for a lower mu if used with a SS amp.
They read my mind. I have 10 in the post already🙂 🙂
http://www.diyhifisupply.com/files/david-basie-aikido.pdf
I could try increasing the grid stopper (R3) to a higher value as suggested.
It also recommends trying 6N6P for a lower mu if used with a SS amp.
They read my mind. I have 10 in the post already🙂 🙂
http://www.diyhifisupply.com/files/david-basie-aikido.pdf
Silver Stealth said:
Last night I rerouted the heater wiring and changed the heater bias bypass cap on Bas' PCB (C6 IIRC) from 47u to .1u (per JB's Aikido manual). I also left off the .1u cap or jumper that grounds the Aikido PCB's to chassis. I am using .1u caps to ground the (C6 and C7 on the 9-pin mono PCBs) tube shields. Pretty much hum free now.
excellent boywonder.
Now I realise what JB was talking about. C6 on Bas's board can be changed as per JB's comments. Great.
I don't have a 0.1 on hand. I have a 0.47uF 630 V. I could try this I think.
Now I realise what JB was talking about. C6 on Bas's board can be changed as per JB's comments. Great.
I don't have a 0.1 on hand. I have a 0.47uF 630 V. I could try this I think.
Silver Stealth said:
Cool !
Thanks SS, I found it on page 5 of my manual (octal)
It's attached to the 1/4 B+leg from the voltage divider to ground. Sweet and easy and cheap. (just like I like my women)
"Alternatively, you might experiment with floating the heater power supply, by "grounding" the heater power supply via only a 0.1uF film or ceramic capacitor. The capacitor will charge up through the leakage current between heater and cathodes. Not only is this method cheap, it is often quite effective in reducing hum."
Ron
😕 😕 😕
I need help with this hissing static noise.
I changed R3 grid stopper from 300 to 1K. No change.
C6 on the psu to 0.47uF. No change. Although it sounded like there was an improvement in the bass when I played music.
OK so I have the input RCA connected to the volume pot.
I attached a thick copper bar to the main grounding point on the Aikido board. The ground from the psu connnects to the grounding point on the Aikido.
The shields on the RCA input are connected directly to the copper bar for grounding.
The output grounds are connected to the output RCA's.
😕 😕 😕
I need help with this hissing static noise.
I changed R3 grid stopper from 300 to 1K. No change.
C6 on the psu to 0.47uF. No change. Although it sounded like there was an improvement in the bass when I played music.
OK so I have the input RCA connected to the volume pot.
I attached a thick copper bar to the main grounding point on the Aikido board. The ground from the psu connnects to the grounding point on the Aikido.
The shields on the RCA input are connected directly to the copper bar for grounding.
The output grounds are connected to the output RCA's.
😕 😕 😕