The large caps in the PS are generating huge inrush. Will be using an NTC inrush current limiter on the AC input before the transformer.
Attachment:
lomu_ps4.jpg [ 172.44 KiB | Viewed 6174 times ]
| DCAudioDIY.com http://dcaudiodiy.com/phpBB3/ |
|
| Simple Tube Preamp ideas? http://dcaudiodiy.com/phpBB3/viewtopic.php?f=4&t=2087 |
Page 6 of 7 |
| Author: | David McGown [ October 30th, 2021, 4:25 pm ] |
| Post subject: | Re: Simple Tube Preamp ideas? |
Shashi, We will have to arrange a time that you can either listen to it here, or borrow it for a while to see how it sounds in your system. Now that it is running right, I may take it up and try it in the main system. I have been hesitant due to having enough gain, running a passive (Dave Slagle autoformer) attenuators, but who knows what a bit more drive might do. Hmmm. David |
|
| Author: | Cogito [ October 30th, 2021, 5:30 pm ] |
| Post subject: | Re: Simple Tube Preamp ideas? |
David, Can I borrow it to listen in my system for a couple of days? I can pick it up either tomorrow or Monday and return next weekend when I come to attend CAF. |
|
| Author: | David McGown [ October 30th, 2021, 8:45 pm ] |
| Post subject: | Re: Simple Tube Preamp ideas? |
Shashi, Sure. I have it in my main system now and it sounds really good. David |
|
| Author: | Cogito [ October 30th, 2021, 9:01 pm ] |
| Post subject: | Re: Simple Tube Preamp ideas? |
Tomorrow I have to take my daughter to the Indian festival at Dulles Expo Center. Can we do Monday around 5pm? |
|
| Author: | David McGown [ October 30th, 2021, 9:34 pm ] |
| Post subject: | Re: Simple Tube Preamp ideas? |
Shashi, The Indian festival sounds like fun. Monday is OK, but I have a Zoom meeting of the Washington Recorder Society at 7pm that I am participating in, so will not have much time to talk or demo anything. David |
|
| Author: | Cogito [ October 31st, 2021, 12:07 pm ] |
| Post subject: | Re: Simple Tube Preamp ideas? |
The large caps in the PS are generating huge inrush. Will be using an NTC inrush current limiter on the AC input before the transformer. Attachment: lomu_ps4.jpg [ 172.44 KiB | Viewed 6174 times ] |
|
| Author: | Cogito [ October 31st, 2021, 12:36 pm ] |
| Post subject: | Re: Simple Tube Preamp ideas? |
I am big believer in the need for a robust low-noise Power Supply is crucial for good audio. During my research for effective EMI filtration came across a German guy explaining the principles of EMI filtration and design. Its a lengthy video, 1:20hrs. He goes thru the basis. Believe it or not, he even teaches capacitor bypassing. Very worthwhile video if you have time. https://www.youtube.com/watch?v=cSWUMly3nUE&t=176s Here is the circuit he discusses in the video. Attachment: emi_fil3.jpg [ 29.72 KiB | Viewed 6172 times ] Fortunately, he is selling it as an assembled module. I am ordering the 400V 0.5A version to install it on B+ supply after CLCLC filter. |
|
| Author: | David McGown [ October 31st, 2021, 12:48 pm ] |
| Post subject: | Re: Simple Tube Preamp ideas? |
Shashi, You need to pick your rectifier based in part on the inrush current. Is there a particular reason you are using 1N5406 diodes in a bridge? Personally I would use SiC Schottky diodes which are available in higher forward current. They also are free of switching noise, and are the best solid state diodes for audio. Don't let the default rectifiers in PSUD limit yourself. Look for the Cree and IXNS devices. Recommend 1000V capable and 6A forward current or more. David |
|
| Author: | David McGown [ October 31st, 2021, 12:56 pm ] |
| Post subject: | Re: Simple Tube Preamp ideas? |
Shashi, That is probably way overkill for a linestage. A low-level source like a phono preamp maybe, but you may be wasting your money. I would build it first with a well designed supply conventional supply, use rectifiers that won't generate switching hash, and see how it sounds. David |
|
| Author: | Cogito [ October 31st, 2021, 1:26 pm ] |
| Post subject: | Re: Simple Tube Preamp idea |
David McGown wrote: Shashi, You need to pick your rectifier based in part on the inrush current. Is there a particular reason you are using 1N5406 diodes in a bridge? Personally I would use SiC Schottky diodes which are available in higher forward current. They also are free of switching noise, and are the best solid state diodes for audio. Don't let the default rectifiers in PSUD limit yourself. Look for the Cree and IXNS devices. Recommend 1000V capable and 6A forward current or more. David IN5406s are the closest thing to Schottkys I could find in PSUD2, so used them for modeling. Shall use Cree Schottkys in the build. I might also try the damper diodes 6AU4/6AY3 at some point. |
|
| Page 6 of 7 | All times are UTC - 5 hours [ DST ] |
| Powered by phpBB® Forum Software © phpBB Group https://www.phpbb.com/ |
|