Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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

Sanity check on 807 pp amp, before pcb design
Sanity check on 807 pp amp, before pcb design
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 16th August 2019, 08:57 AM   #31
Miles Prower is offline Miles Prower  United States
diyAudio Member
 
Miles Prower's Avatar
 
Join Date: May 2005
Location: USA
Quote:
Originally Posted by heinrichs View Post
I really have to remember that different tubes are so incredibly different... Compared to transistors were I can make an ok amp with almost any power transistors in the output. I dont know if this is true.... but right know it feels true, tubes are confusing
That's the difference between high gain devices like transistors and low gain devices. Even in a low gain topology, the behaviour of a transistor circuit is largely independent of the active device (BJTs mainly). Unless you need some special characteristic, like an unusually low noise figure, it doesn't matter much what type of transistor you use so long as it can process the highest frequencies of interest. I've done lots of projects with those packets of "transistors anonymous" Rat Shack used to sell.

With tubes, it's different since these are low gain devices, and circuit performance is a good deal more dependent on the characteristics. That's why "tube rolling", especially where NFB isn't being included, can get you a different sound.

You can try and listen with the gNFB disconnected. It won't stay that way for very long.
__________________
Transistors have ratings; vacuum tubes have guide lines
  Reply With Quote
Old 16th August 2019, 09:28 AM   #32
baudouin0 is offline baudouin0
diyAudio Member
 
Join Date: Mar 2019
OK you may need to drop the values of C1 and C2. At the LF end if the pole of the transformer is similar to that of C1/R3 you will get poor phase margin here (motor boating). You should arrange C1/R3 to be the dominate pole. It also helps in preventing the transformer becoming saturated if there is a big LF signal. Maybe C1=C2=10 or 22nF

Last edited by baudouin0; 16th August 2019 at 09:30 AM.
  Reply With Quote

Reply


Sanity check on 807 pp amp, before pcb designHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Sanity Check (Peerless 830986 design) fiatlux Full Range 4 23rd January 2018 12:46 PM
GM70 SE direct coupled sanity check 1st design speedy6963 Tubes / Valves 12 9th January 2018 08:38 AM
Horn Design - Sanity Check deiksac Multi-Way 121 12th October 2008 08:09 AM
THAT transistor headphone amp (250ma discrete opamp) design sanity check. Russ White Headphone Systems 19 13th December 2007 12:52 PM


New To Site? Need Help?

All times are GMT. The time now is 09:04 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki