Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 18th April 2010, 12:15 AM   #11
diyAudio Member
 
apexaudio's Avatar
 
Join Date: Feb 2010
Location: Serbia
I'm not interested about best figure, can be better with BJT, but people just want tube/mosfet hibryd amplifier, and I don't want argue about that. Tube or SS also is not a question. Simple give people what they want.
Regards
  Reply With Quote
Old 18th April 2010, 12:25 AM   #12
diyAudio Member
 
apexaudio's Avatar
 
Join Date: Feb 2010
Location: Serbia
Quote:
Originally Posted by nigelwright7557 View Post
A simple way to do it is to take an SRPP valve front end and ac couple it to a classs AB MOSFET amplifier.
That is not hibryd. I have output stage in post #5, just not sure for VAS. SRPP is option.

Last edited by apexaudio; 18th April 2010 at 12:35 AM.
  Reply With Quote
Old 18th April 2010, 12:59 AM   #13
Gordy is offline Gordy  United Kingdom
diyAudio Member
 
Join Date: Nov 2006
This is just my theory...

Keep VAS simple, just a single tube...

Consider a triode connected 7788 (E810F)... load the anode with constant current source about 20 mA; will have a gain of approximately 50 with a reasonably low internal impedance (I do not have my note book here, but remember impedance as about 2 K Ohm, maybe lower).

Then AC (i.e. capacitor) couple it to your output stage.
  Reply With Quote
Old 18th April 2010, 01:13 AM   #14
diyAudio Member
 
apexaudio's Avatar
 
Join Date: Feb 2010
Location: Serbia
ECC88 is priority, I already have about 200 pieces.
  Reply With Quote
Old 18th April 2010, 01:54 AM   #15
Gordy is offline Gordy  United Kingdom
diyAudio Member
 
Join Date: Nov 2006
Quote:
Originally Posted by apexaudio View Post
ECC88 is priority, I already have about 200 pieces.
Yes, that does change things!

Well, ECC88 has nice characteristics, so a simple common-cathode amplifier should get you what you want. I would estimate using a CCS anode load of 15mA, a -2V bias point, and 110V on the anode. However the output impedance of the stage might be reasonably high at about 2700 - 3000 Ohms. Maybe that is OK for your circuit, or maybe you might need a source follower between tube and output stage.

For info, if you have not seen them, Mr Wim de Haan shows some hybrids here: Wim's DIY Audio Projects
  Reply With Quote
Old 18th April 2010, 06:10 AM   #16
diyAudio Member
 
apexaudio's Avatar
 
Join Date: Feb 2010
Location: Serbia
Quote:
Originally Posted by Gordy View Post
Yes, that does change things!

Well, ECC88 has nice characteristics, so a simple common-cathode amplifier should get you what you want. I would estimate using a CCS anode load of 15mA, a -2V bias point, and 110V on the anode. However the output impedance of the stage might be reasonably high at about 2700 - 3000 Ohms. Maybe that is OK for your circuit, or maybe you might need a source follower between tube and output stage.

For info, if you have not seen them, Mr Wim de Haan shows some hybrids here: Wim's DIY Audio Projects
Thank's for info,
Regards
  Reply With Quote
Old 18th April 2010, 10:04 AM   #17
diyAudio Member
 
apexaudio's Avatar
 
Join Date: Feb 2010
Location: Serbia
HT100 with VAS
Attached Images
File Type: jpg APEX HT100 schematics V1.jpg (423.5 KB, 1215 views)
  Reply With Quote
Old 18th April 2010, 04:06 PM   #18
diyAudio Member
 
Join Date: Aug 2008
Quote:
Originally Posted by qsa View Post
I mean IRFP240/9240 are not really complementary devices, it sound horribile in mosfet amp...... BJT Design Sound better compare to IRFP240/9240

we have test it in Mosfet amp and in my opinion IRFP240/9240 is no go in mosfet amp
In what way do they sound bad? How does it show on measurements?

Quote:
Originally Posted by apexaudio View Post
I'm not interested about best figure, can be better with BJT, but people just want tube/mosfet hibryd amplifier, and I don't want argue about that. Tube or SS also is not a question. Simple give people what they want.
Regards
I have always found tube/semiconductor amps kind of strange, or at least the reasons people wnat them. Hybrids are a sure way of getting the downside from both tubes and transistors at the same time......
  Reply With Quote
Old 18th April 2010, 04:42 PM   #19
diyAudio Member
 
apexaudio's Avatar
 
Join Date: Feb 2010
Location: Serbia
Quote:
Originally Posted by Rikard Nilsson View Post
In what way do they sound bad? How does it show on measurements?



I have always found tube/semiconductor amps kind of strange, or at least the reasons people wnat them. Hybrids are a sure way of getting the downside from both tubes and transistors at the same time......
People who want hybrid amplifier think that useing tubes and mosfets getting the best from both worlds at the same time.
  Reply With Quote
Old 18th April 2010, 04:54 PM   #20
diyAudio Member
 
Join Date: Aug 2008
Yes, I know. And I think just the opposite. Probably just me that´s odd actually.

  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
Maplin 100W mosfet amplifier - power supply problem HBrunt Solid State 32 3rd December 2013 07:11 AM
MOSKIDO - Hybrid Tube/MOSFET Amplifier Kashmire Pass Labs 7 22nd September 2011 08:30 PM
Hybrid Tube / Mosfet Amplifier poynton Tubes / Valves 8 10th August 2007 05:32 PM


New To Site? Need Help?

All times are GMT. The time now is 07:38 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