DIY Audio Projects Forum
 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

DIY Audio Projects Forum

Welcome to the DIY Audio Projects Message Forum. Use these forums to discuss Hi-Fi audio and to share your DIY Audio Projects. Registration is free and required to post messages and view the file attachments. Registration will only take a minute and registered users do not see any advertisements. After you have completed the online registration process, check your email (including spam/junk folder) for the verification email to activate your account. New members are under moderation - so your posts will not be visible until approved by a moderator. See the Read Me 1st, Forum RULES and Forum FAQ to get started on the forum.

It is currently 05 Apr 2020, 19:21

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 142 posts ]  Go to page Previous  1 ... 8, 9, 10, 11, 12, 13, 14, 15  Next
Author Message
PostPosted: 19 Jun 2010, 01:28 
Offline

Joined: 24 Feb 2009, 03:24
Posts: 562
Location: USA
Yesterday I bought 4 caps Mallory 0,1 uF instead 2 x 0,2 uF and I save 1 Eu, that's is more important. :D :idea:

_________________
Hi End is back proportional to the number of composite parts!
Projects: OTL 6AS7 Gen, Electric, SEs 2A3 RCA, 300B JJ, 6S4S, 4P1L, EL11 Telefunken, 6AS7 RCA, 6S33S, 6S41S, 6S19P, PP 6005 Gen. Ellectric , headphone ampl. OTL Loftin White 6AS7 RCA....SE E84L& E80CC Siemens&Tel-n.
http://azazello-sound.blogspot.com/


Top
 Profile  
 
PostPosted: 20 Jun 2010, 12:03 
Offline

Joined: 18 Jun 2010, 12:46
Posts: 284
Location: Northern VA
sampleaccurate wrote:
rock4016 wrote:
Have you looked at Gary Pimm's CCS loaded Pentodes? Lots of gain and voltage swing.
http://www.pimmlabs.com/web/drivers.htm

Thanks. I don't understand where the output comes from. It's shown coming out of the middle of the CCS. :confused:
Otherwise it's interesting. I understand the concept of using the CCS, but not the output shown on the schematics on the page. How can you take an output from the "center" of a CCS?

Check out his CCS links
http://www.pimmlabs.com/

If you are going to use a CCS I highly recommend Gary's design.


Top
 Profile  
 
PostPosted: 20 Jun 2010, 23:54 
Offline
User avatar

Joined: 05 Jan 2010, 21:16
Posts: 680
Location: Las Vegas Nevada USA
rock4016 wrote:
Check out his CCS links
http://www.pimmlabs.com/

If you are going to use a CCS I highly recommend Gary's design.

Hi. I looked at the links. It now makes sense. He's got some interesting current sources and even some methods of testing performance. This is exactly what I've been looking for, although the combination of an LM317 and a high voltage BUX85 transistor seems to be working as well as an LM317HV alone. I'll read all his articles this week.

Thanks! :up:

_________________
Stephen


Top
 Profile  
 
PostPosted: 29 Jun 2010, 19:10 
Offline
User avatar

Joined: 05 Jan 2010, 21:16
Posts: 680
Location: Las Vegas Nevada USA
TRANNYS!!!!!!!!!!!!!!!!!

Got my Edcor email - trannys arrive tomorrow. Yes!!!!!!!! 6 weeks, not 8. Can't complain.

Finally I'll have a chance to either get this working or make some smoke.

You can bet the video camera will be rolling when I flip the B+ switch on this baby. I'll be behind a sheet of Lexan at a distance! :smoking:

_________________
Stephen


Top
 Profile  
 
PostPosted: 01 Jul 2010, 01:00 
Offline
User avatar

Joined: 05 Jan 2010, 21:16
Posts: 680
Location: Las Vegas Nevada USA
rock4016 wrote:
sampleaccurate wrote:
rock4016 wrote:
Have you looked at Gary Pimm's CCS loaded Pentodes? Lots of gain and voltage swing.
http://www.pimmlabs.com/web/drivers.htm

Thanks. I don't understand where the output comes from. It's shown coming out of the middle of the CCS. :confused:
Otherwise it's interesting. I understand the concept of using the CCS, but not the output shown on the schematics on the page. How can you take an output from the "center" of a CCS?

Check out his CCS links
http://www.pimmlabs.com/

If you are going to use a CCS I highly recommend Gary's design.


This changes everything. I finally got around to reading this. I can see a string of souped up, high performance CCS assisted tube amps in my future. :smoking:

You gotta have some patience to read this and understand it, but WOW. Very cool stuff. All my GM70 driver problems are history - I can get two completely independent gain stages out of my 6SN7 driver using a CCS as a load with each of the triodes.

And I see a new JAN6418 headphone amp/preamp circuit on the horizon.

I wish he put a note on his schematics that the "MU" output is a tap on the souce of the bottom FET used for the CCS - it was a little irritating to expect people to just know this or read in depth to find out, but I can report it was worth digging for it.

_________________
Stephen


Top
 Profile  
 
PostPosted: 01 Jul 2010, 07:12 
Offline

Joined: 18 Jun 2010, 12:46
Posts: 284
Location: Northern VA
When you get a CCS on top, try using a LED or string of LEDs for the bais on the tube. Just calculate the cathode voltage you'd get with a resistor and use an appropriate LED to get the bias voltage you want.


Top
 Profile  
 
PostPosted: 02 Jul 2010, 02:19 
Offline
User avatar

Joined: 05 Jan 2010, 21:16
Posts: 680
Location: Las Vegas Nevada USA
rock4016 wrote:
When you get a CCS on top, try using a LED or string of LEDs for the bais on the tube. Just calculate the cathode voltage you'd get with a resistor and use an appropriate LED to get the bias voltage you want.

Without researching this may I ask why? I'll probably feel stupid for asking when you answer but it's late and my brain is shutting down right now.

Thanks.

_________________
Stephen


Top
 Profile  
 
PostPosted: 08 Jul 2010, 11:13 
Offline

Joined: 18 Jun 2010, 12:46
Posts: 284
Location: Northern VA
The reason is because a LED provides a DC bias with a fairly low AC impedance (say less than 10 ohms) So you don't need a cathode resistor and it's bypass capacitor in your signal path, but you still get the voltage gain from having one.

I try to have less capacitors in the signal path, my amps tend to sound better as a result. Your Mileage May Vary...


Top
 Profile  
 
PostPosted: 08 Jul 2010, 17:45 
Offline
Banned

Joined: 15 Mar 2010, 08:32
Posts: 487
Location: Canada
rock4016 wrote:
you don't need a cathode resistor and it's bypass capacitor in your signal path,

I try to have less capacitors in the signal path, my amps tend to sound better.

Hi.

I agree. Less resistors in the signal path better will be the sound. Bypass cap is gone with no cathode bias resistors. So less phase shift due to the bypass caps.

There are ways of providing the bias required by the tube without using the conventional cathode resistor (+bypass cap). Diode (or LED) is one way. But the much better sounding way, IME, is using batteries as long as the tube needs bias over 1.5V or so.

It is crucial to choose the right bias for phonostage tubes, being in the very front end of the audio chain. Thorsten is fond of using batteries or even gridleak bias/grounded cathode in his phonostage
design/builds. Obviously he does not like the sound of cathode resistors. Neither do I.

BUT but, different types of batteries give different sound. I spent enough time to try-&-error to get the best sounding battery for biasing my MM cartridge phonostage tube.

Guess what it is.

c-J

_________________
"If the facts don't fit the theory, change the facts" quoted Albert Einstein.


Top
 Profile  
 
PostPosted: 09 Jul 2010, 07:25 
Offline

Joined: 18 Jun 2010, 12:46
Posts: 284
Location: Northern VA
Energizer!
:king:


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 142 posts ]  Go to page Previous  1 ... 8, 9, 10, 11, 12, 13, 14, 15  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 12 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
DIY Tube Projects :: DIY Tube Amp Kits :: DIY Speaker Projects :: DIY Solid State Projects :: DIY IC / Op-amp Projects :: DIY Phono Projects :: DIY Cable Projects :: Hi-Fi Audio Schematics
© diyAudioProjects.com - Terms of Service - Privacy Policy