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

How does a VAC Renaissance 70/70 get 65W from 4 300Bs?
How does a VAC Renaissance 70/70 get 65W from 4 300Bs?
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 23rd September 2003, 09:32 PM   #11
Saurav is offline Saurav
diyAudio Member
 
Join Date: Sep 2002
Location: Oregon, USA
Thanks. Maybe I need to try building a PP amp after all...
  Reply With Quote
Old 23rd September 2003, 09:33 PM   #12
SY is offline SY  United States
On Hiatus
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
How does a VAC Renaissance 70/70 get 65W from 4 300Bs?
Well, I could always replace the regulator chip on the one you've already got
__________________
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 23rd September 2003, 09:38 PM   #13
Saurav is offline Saurav
diyAudio Member
 
Join Date: Sep 2002
Location: Oregon, USA
Quote:
Well, I could always replace the regulator chip on the one you've already got
My wife's response to the current version of my amp: (CCS'd ECC99 driver, current regulated 2A3 heater, UBT-3 OPTs, teflon caps) - "it sounds pretty good". Her response when I completed the first iteration of my 2A3 SET (125ESE OPTs, AC heaters, straight from the Angela website) - "it sounds... off".

I've been eyeing your amp lately... I'm pretty sure mine doesn't sound as good, but I want to know if I'm any closer than I was before

What would be great would be to bring my amp down to your place some day and get a lesson or two on chasing (RF, and other) gremlins, troubleshooting, improvements, just anything
  Reply With Quote
Old 23rd September 2003, 09:51 PM   #14
SY is offline SY  United States
On Hiatus
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
How does a VAC Renaissance 70/70 get 65W from 4 300Bs?
Well, I have another member coming down next weekend (weekend of the 4th) for some speaker work. If you're free, join us. We can probably fire up some dynamic speakers just so we don't torture your poor little amp too badly on the ESL panels.
__________________
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 23rd September 2003, 09:55 PM   #15
Saurav is offline Saurav
diyAudio Member
 
Join Date: Sep 2002
Location: Oregon, USA
Wow, that would be great! I'll try my best to be there. And I wasn't even thinking about real speakers so much as a test bench/power resistors.

I'll email you. Thanks for the offer.
  Reply With Quote
Old 23rd September 2003, 10:11 PM   #16
fdegrove is offline fdegrove  Europe
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

For our D'Haen:

Quote:
I've never see an engineering definition of pure Class A operation
In CLASS A OPERATION, current flows for 100% (360) of the input signal.

My guess is that the "pure" part refers to the 100% current flow although in most so-called amps it's more often than not not the case.

Cheers,
__________________
Frank
  Reply With Quote
Old 23rd September 2003, 10:13 PM   #17
SY is offline SY  United States
On Hiatus
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
How does a VAC Renaissance 70/70 get 65W from 4 300Bs?
Normally (but not "officially"), people use the term "pure" class A to distinguish a true silicon furnace from one of those Japanese sliding-bias units. People DO cheat the term a bit, as you imply; if you see an amp that's claimed to be 200 watts of "Class A," it had better be throwing off enough heat to roast a wildebeest.
__________________
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 23rd September 2003, 11:02 PM   #18
dhaen is offline dhaen  Europe
diyAudio Moderator Emeritus
 
dhaen's Avatar
 
Join Date: Jun 2002
Location: U.K.
Quote:
Originally posted by fdegrove
Hi,

For our D'Haen:



In CLASS A OPERATION, current flows for 100% (360) of the input signal.

My guess is that the "pure" part refers to the 100% current flow although in most so-called amps it's more often than not not the case.

Cheers,
That's what one would suppose, but what text book mentions the term?
And if I marketed a P-P amp that ran in limiting class A, and called it "Pure Class A", who could contradict me?

By "limiting class A" I mean including the last non-linear part of the transfer characteristic.

Cheers,
  Reply With Quote
Old 23rd September 2003, 11:20 PM   #19
fdegrove is offline fdegrove  Europe
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

Quote:
That's what one would suppose, but what text book mentions the term?
If you like I could doublecheck it and give you page #s frm the RDH and McGrawhill.

To my mind the description I posted is correct for all intends and purposes.

If you deviate from that you shouldn't call it a pure Class A amp.


Quote:
And if I marketed a P-P amp that ran in limiting class A, and called it "Pure Class A", who could contradict me?
I wouldn't. But then again I don't buy marketing hype either.

I know what you mean though...

My main quibble is mostly with the fact that the term is often used to market amps where, when you take a closer look it's not even close to Class A operation.
Big A small b if you're lucky.

Cheers,
__________________
Frank
  Reply With Quote
Old 23rd September 2003, 11:29 PM   #20
Saurav is offline Saurav
diyAudio Member
 
Join Date: Sep 2002
Location: Oregon, USA
I like the ones which call out "single ended" and "class A" as separate virtues, as in, "not only is it single-ended, it is *also* class A". And that too, in a linestage. How many push-pull class B linestages are there? PP maybe (or more likely, balanced or differential, neither of which would be single ended, right?), but I really wonder if there are many non-class A linestages.
  Reply With Quote

Reply


How does a VAC Renaissance 70/70 get 65W from 4 300Bs?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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Anyone familiar with Hyuger HK-300BS kit from Hino Audio? truenorth Tubes / Valves 0 21st November 2007 06:51 AM
FS: Morel/Renaissance tweeters MarkHathaway Swap Meet 0 22nd January 2006 06:38 AM
Morel Renaissance MLP-403.5 Stefano Multi-Way 2 6th October 2005 07:52 AM
who knows DIGITAL RENAISSANCE? fred38 Digital Source 0 16th August 2005 06:09 PM
FS: Shuguang 300BS-C garbage Swap Meet 0 20th January 2005 11:00 PM


New To Site? Need Help?

All times are GMT. The time now is 08:37 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki