900v. 100ma. Power supply for 813 tube amplifier - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 3rd June 2004, 02:50 PM   #11
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Jax,

1N4007s are very noisy. UF4007s are inexpensive and MUCH easier to "snub" than 1N4007s are.

With a PIV of 1000, 2X '4007s in each leg of the bridge should be adequate. Voltage equalizing resistors are an "anal retentive" touch.

Have you considered a hybrid bridge with SS diodes forming the ground connection and vacuum damper diodes forming the B+ connection? The forward voltage drop in vacuum dampers is relatively low. No snubber is needed, as the vacuum diodes block the reverse recovery spike. The B+ rise is SLOW; so, no worries about cathode stripping. IMO, the hybrid bridge is very attractive.
__________________
Eli D.
  Reply With Quote
Old 3rd June 2004, 03:11 PM   #12
benny is offline benny  Australia
diyAudio Member
 
benny's Avatar
 
Join Date: May 2004
Location: Melbourne, Australia
Send a message via MSN to benny
hi,

i love that idea eli about the hybrid bridge rectifier.... i already plan to use it in my next project! thanks for that one!

by the way, i was curious... what's the advantage of using an ultra fast version over the standard version of a diode??? you mention more noise... how does this come about? thanks for your help.



when it cones to SS electronics, i have no idea, and i never really spend the time to get an idea, even though i should

so therefore, i have no idea what the ratings on those FET's and Transistors as i have none of the data sheets, and don't know where to source them.. that would mean i'd have to spend time searching... but anyway... you could try a voltage doubler idea in place of a bridge rectifier... if you do this, make sure you use a full wave version, as half wave will leave you with more ripple on the PS then what you get with full wave.

cheers
  Reply With Quote
Old 3rd June 2004, 03:14 PM   #13
G is offline G  United States
diyAudio Member
 
G's Avatar
 
Join Date: Apr 2002
Location: Belleville, IL.
Here is a transformer that would turn the trick for you:

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3025322003

900 VDC is a scary thing. Are you sure you want to build that monster? Also hammond makes a 700 series HV plate transformers that will supply that type of power. Not sure about chokes though. If the amp doesn't work out you will still have a damn nice welding rig.
__________________
Gavin
  Reply With Quote
Old 3rd June 2004, 03:37 PM   #14
benny is offline benny  Australia
diyAudio Member
 
benny's Avatar
 
Join Date: May 2004
Location: Melbourne, Australia
Send a message via MSN to benny
if you want a cheap as HV tranny, why not get an old microwave oven tranny, and rewind to suit??? these things can handle like at least 1000W normally, and have about a 2kV secondary... so they're monsters.

about working with very high voltages... while working with 900V there is of course a big potential danger (pun intended), but as long as propper care with both construction and layout is taken, you sould be safe... but for gods sake, be VERY CAREFUL. take all propper safety precautions when building, and remember that when working with something like this, it pays to be paranoid... especially when probing the live amp... i would suggest clipping BOTH of your meter probes on while the amp is OFF for every measurement you take, and keep hands well out of chassis while it's on... while there's not a potential for big arcs at this voltage, there is definately potential for arcing... so another thing to do would be make sure everything inside the amp is well away form any of the metal used that's either conected or is part of the external chassis... and use pots with plastic shafts on them... and another good thing i suggest once you know everything's working... paint all open leads/joins whatever with liquid electrical tape... this is another paranoid move that might just pay off oneday... and of course there are plenty other points to remember, but that's what i've got to say for now...

by the way G, just for future reference, you stated:

Quote:
Also hammond makes a 700 series HV plate transformers that will supply that type of power.
just remember when refering to power, we are refering to P = VI in this case (it's a slightly different equation for AC, but this is DC here)... this amp is only 900V and 100mA, so P = 900 x 0.1 = 90W... not a lot of power... just thought i'd point that out... probably just a mistake you made, but if it was what you thought, then hope i helped you out.

cheers
  Reply With Quote
Old 3rd June 2004, 03:47 PM   #15
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Quote:
by the way, i was curious... what's the advantage of using an ultra fast version over the standard version of a diode??? you mention more noise... how does this come about? thanks for your help.
ALL PN diodes exhibit switching noise called a reverse recovery spike. The spike of the UF varieties is of shorter duration; so, there is less noise. The late John ("Buddha") Camille devised a reverse recovery spike filter (RRSF) for use with the UF4007 that reduces its noise levels to those of vacuum diodes. Without "snubbing" of some kind, FREDs are the least noisy PN devices.

The "recent" introduction of high PIV Silicon Carbide (SiC) Schottky diodes by Cree is a milestone in SS rectified B+ supplies. Unlike PN devices, Schottky diodes do not exhibit a reverse recovery spike; therfore, they are dead quiet. Until the SiC parts were introduced, Schottkys were strictly a low voltage proposition suited to heater supplies only. The slow B+ rise of indirectly heated vacuum diodes is the last bastion of advantage for tubes. FWIW, I'd specify 1200 PIV Schottkys, not a 5U4, in a new design.
__________________
Eli D.
  Reply With Quote
Old 3rd June 2004, 04:54 PM   #16
benny is offline benny  Australia
diyAudio Member
 
benny's Avatar
 
Join Date: May 2004
Location: Melbourne, Australia
Send a message via MSN to benny
thanks for that eli.

i will still use a tube rectifier in my next design because it is for a guitar amp i am designing, and i still want rectifier sag. of course, the shottkeys would be the way to go in audio aplications because like you say, they've got no noise, and, they won't cause a circuit to 'sag' which is generally bad... just in guitar amps it's used to advantage to provide more compressed sound....

cheers,

benny
  Reply With Quote
Old 3rd June 2004, 05:30 PM   #17
benny is offline benny  Australia
diyAudio Member
 
benny's Avatar
 
Join Date: May 2004
Location: Melbourne, Australia
Send a message via MSN to benny
hi all,

noyan emailed me and asked me about wether it is alright to use a BUX98A in this PS. He sent me the data sheet which i did a screen shot of, and cropped down to attach here.

i told him to come here and see what other people have to say, but for now i am saying (guessing) that based on the ratings of this device, he should be fine to use it with a voltage doubler as oposed to a straight bridge safely because it looks like it is used as a sort of floating regulator, where it's referenced off higher voltage than ground, so pot. diff on all conections should be within ratings right???

cheers
Attached Images
File Type: jpg bux98a.jpg (45.0 KB, 450 views)
  Reply With Quote
Old 3rd June 2004, 06:02 PM   #18
Masami is offline Masami  Hong Kong
diyAudio Member
 
Join Date: Apr 2003
Location: HK
Default 866 tube power supply

Hi,

I also want to make the 813SE UL amp.
For the 900V B+, i will use 866 tube.
I want to use the CLC filter after the 866.
As I know, the first capacitor after 866 cannot use too large.
So what is the bigger value for the first capacitor?
If I use LC filter, what is the VAC is I want 900V B+?

Thanks.
__________________
Masami
  Reply With Quote
Old 3rd June 2004, 08:11 PM   #19
G is offline G  United States
diyAudio Member
 
G's Avatar
 
Join Date: Apr 2002
Location: Belleville, IL.
Quote:
Originally posted by benny



just remember when refering to power, we are refering to P = VI in this case (it's a slightly different equation for AC, but this is DC here)... this amp is only 900V and 100mA, so P = 900 x 0.1 = 90W... not a lot of power... just thought i'd point that out... probably just a mistake you made, but if it was what you thought, then hope i helped you out.

cheers

Thanks Benny. I assumed he meant 100mA per channel. If you add 200mA plus whatever the driver stages utilize it does start to add up a little. It's definately more power than I have ever designed for.
__________________
Gavin
  Reply With Quote
Old 3rd June 2004, 10:28 PM   #20
diyAudio Member
 
serengetiplains's Avatar
 
Join Date: Feb 2004
Location: Canada
Default Cree Schottkys

Quote:
Originally posted by Eli Duttman
The "recent" introduction of high PIV Silicon Carbide (SiC) Schottky diodes by Cree is a milestone in SS rectified B+ supplies. Unlike PN devices, Schottky diodes do not exhibit a reverse recovery spike; therfore, they are dead quiet. Until the SiC parts were introduced, Schottkys were strictly a low voltage proposition suited to heater supplies only.
Spec sheets look interesting, Eli. Do you know where these diodes can be purchased?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
I clonning Milbert BAM230/235 Car Tube Amplifier Supply ANALOG GUY Car Audio 8 22nd December 2013 02:40 PM
A good tube amplifier power supply Jean-Paul_2 Tubes / Valves 23 18th June 2009 11:19 PM
Tube power supply duderduderini Tubes / Valves 1 9th December 2008 04:33 AM
900v. 100ma. Power supply for 813 tube amplifier noyan Everything Else 0 5th June 2004 07:48 AM
Power Supply and VR tube help! AudioGeek Tubes / Valves 24 28th February 2004 12:16 AM


New To Site? Need Help?

All times are GMT. The time now is 08:53 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2