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

The point of an 845, 211, 805 amp?
The point of an 845, 211, 805 amp?
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 25th June 2019, 09:38 PM   #11
Magz is offline Magz  United States
diyAudio Member
 
Join Date: Oct 2009
Location: New Jersey, USA
I listen to 200WPC 833C amps and drive a 717HP Challenger Hellcat with a manual transmission. I guess I like impracticality and excess. Sue me as I luxuriate in both, while I'm still allowed to.
Attached Images
File Type: jpg 833_amp_glowing_left1.jpg (17.2 KB, 583 views)
File Type: jpg 20190622_192015.jpg (868.2 KB, 569 views)
File Type: jpg 20190526_150538.jpg (795.5 KB, 559 views)
__________________
On the fast lane of the street I'm driving, sometimes, somewhere, I'm arriving. Every day and every night.
  Reply With Quote
Old 25th June 2019, 11:28 PM   #12
Tubelab_com is offline Tubelab_com  United States
diyAudio Member
 
Tubelab_com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
Quote:
the more transformers involved in a circuit, the more it will suffer
Good transformers can be made, they just cost a lot. That's why my 845 SE amp only has one transformer in the signal path....the OPT.

Quote:
I listen to 200WPC 833C amps and drive a 717HP Challenger Hellcat with a manual transmission. I guess I like impracticality and excess.
I remember the initial opening of your build thread......

"That's not an amp, that's a Midlife Crisis!" -My reply, "Hey, it's cheaper than a Corvette..."

I started down the same road, on a much lower budget. Budget for both evaporated when my 41 year engineering career ended. Let's just say that neither the 833A or the Challenger got completed, though both got to show off their abilities.

The 845 SE amp did too good a job heating my room. Not much fun when you are in a small room in South Florida, so it saw limited use.

It will be welcome here during the winter when the white stuff is taller than a 211 tube, therefore it will be rebuilt with some serious revisions.

No changes are needed in the sound department, but having exposed 1100 volt wiring is not good when there are young grandkids running about......for now it sits far from a power outlet.
Attached Images
File Type: jpg 200Wattsa-2.jpg (137.8 KB, 559 views)
File Type: jpg StratTest1.jpg (752.9 KB, 531 views)
File Type: jpg BothChassis_a.jpg (338.5 KB, 226 views)
File Type: jpg Amp_a.jpg (302.5 KB, 223 views)
File Type: jpg PowerSupply_a.jpg (279.5 KB, 210 views)
File Type: jpg Challenger_2.jpg (975.6 KB, 226 views)
File Type: jpg Challenger_3.jpg (817.0 KB, 178 views)
File Type: jpg DSCN0281_x.jpg (630.2 KB, 148 views)
File Type: jpg DSCN1258_x.jpg (521.6 KB, 178 views)
File Type: jpg DSCN0189a.jpg (67.6 KB, 179 views)
__________________
Tubelab, it's 5 year mission. To explore strange new tubes, to seek out new circuits and topologies, to boldly go where no tube has gone before......
  Reply With Quote
Old 25th June 2019, 11:49 PM   #13
grovergardner is offline grovergardner  United States
diyAudio Member
 
Join Date: Apr 2010
It's been years since I heard an 805 amp, and I'm not a big fan of the 211, but I can confidently say that the 845, if properly set up, has an authority and sense of realism that are difficult to duplicate with other output tubes. Rich, full-bodied voices, pianos and orchestras simply appear in the room. You don't need a ton of transformers, either. A triode-wired EL34 as driver, and a suitable small-signal input stage, all cap-coupled, will suffice. In SE, it has bass that you'll never get from a 300B. In PP, it can be simply glorious. I've heard a 100wpc PP 845 amp that had the ease and delicacy of an SE amp but none of the limitations, to say the least. And David Berning makes a PP 845 amp that stunned everyone who was at a demo he gave for a group of Maryland DIYers a couple of years ago.

It's not hype and it's not snake-oil. It's a glorious tube. But it's a pain to work with, the iron is perforce heavy, the voltages are truly deadly and they can heat a small barn. But there's nothing like it in my experience. I've built three SE 845 amps for friends, and 15 years later they are all still working and still being enjoyed. Unfortunately I forgot to keep one for myself. I don't have the energy to do it again, but I still have the iron (including the Magnequest FS-100's) and figure that *someday* I'll manage to build it again.

Last edited by grovergardner; 25th June 2019 at 11:53 PM.
  Reply With Quote
Old 26th June 2019, 12:18 AM   #14
Magz is offline Magz  United States
diyAudio Member
 
Join Date: Oct 2009
Location: New Jersey, USA
Quote:
Originally Posted by Tubelab_com View Post
Good transformers can be made, they just cost a lot. That's why my 845 SE amp only has one transformer in the signal path....the OPT.

I remember the initial opening of your build thread......

"That's not an amp, that's a Midlife Crisis!" -My reply, "Hey, it's cheaper than a Corvette..."
Yeah, I guess I ended up with the amps AND the car eventually. The Hellcat is a boat load of fun, for sure! That old school Challenger looks sweet; always loved them.
__________________
On the fast lane of the street I'm driving, sometimes, somewhere, I'm arriving. Every day and every night.

Last edited by Magz; 26th June 2019 at 12:20 AM.
  Reply With Quote
Old 26th June 2019, 11:12 AM   #15
Kay Pirinha is offline Kay Pirinha  Germany
diyAudio Member
 
Kay Pirinha's Avatar
 
Join Date: Oct 2011
Location: Somewhere in Germany
Quote:
Originally Posted by samsdad View Post
...the more gain stages an amplifier has, the less likely it is to be linear...
Who told you that? Have a look at McIntosh's MC-3550/MI-350 amplifiers: Seven cascaded active stages, including the finals, and super low THD and IMD of 0.15% each @ full nominal output power of 350 watts! All this throughout the frequency range of 20 to 20.000 Hz! And no transformers besides the PT's (there are two of them) and the OT.

I doubt that this amplifier's performance will be met by any of those old-fashioned, transformer coupled DHT designs.

Best regards!
__________________
"Bless you, Sister. May all your sons be bishops." (Brendan Behan)
  Reply With Quote
Old 26th June 2019, 11:41 AM   #16
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
People buy/build what they want to buy/build. They then seek to justify their choice by making technical claims which may or may not be true. In some cases they also seek affirmation of their choice from others who have made similar choices.

There are reasons why large old valves may be more linear than smaller modern valves. However, such large old valves often have low gain so for that and other reasons they may need some help from transformers. Transformers and other wound components are best avoided, except where they are necessary. They are big, heavy, expensive and usually fairly non-ideal in behaviour (much worse than most capacitors).

Modern electronics uses feedback to get a good result; this works because resistors (unlike valves and transformers) are fairly close to being ideal in their behaviour. Designs based on 100-year-old technology do things differently, or people convince themselves that linearity is not a requirement anyway.
  Reply With Quote
Old 26th June 2019, 11:46 AM   #17
Kay Pirinha is offline Kay Pirinha  Germany
diyAudio Member
 
Kay Pirinha's Avatar
 
Join Date: Oct 2011
Location: Somewhere in Germany
I've just noticed a typo error: The amplifier is the MC-3500, of course.


Best regards!
__________________
"Bless you, Sister. May all your sons be bishops." (Brendan Behan)
  Reply With Quote
Old 26th June 2019, 01:07 PM   #18
Tubelab_com is offline Tubelab_com  United States
diyAudio Member
 
Tubelab_com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
Some people have bigger budgets.....This system was set up, broken down, and moved a lot for concerts. There are multiple conflicting stories about which, and how many amplifiers were used in it, but the McIntosh MC3500 was always in the lineup, and usually some Crown DC300's were there too. Total power output was 20 to 30 Kilowatts....in 1973!

YouTube

A similar system was used at the original Woodstock Music Festival (1969) where the amps were reported to all be MC3500s. There are several conflicting schematics for the MC3500 and MI-350 on the web, but all used TV sweep tubes.

My "bucket list" still includes building a 1 KW vacuum tube HiFi amp (500 WPC). Do I need such an amp? Do I have speakers capable of eating that much power? Is there a sane reason for building it? We, all know the answers, but I may do it just because I can......and more importantly already have the expensive parts. I just need to build it while I am still physically capable of moving such a monster.
__________________
Tubelab, it's 5 year mission. To explore strange new tubes, to seek out new circuits and topologies, to boldly go where no tube has gone before......
  Reply With Quote
Old 26th June 2019, 01:19 PM   #19
Lingwendil is offline Lingwendil  United States
diyAudio Member
 
Lingwendil's Avatar
 
Join Date: Apr 2008
Location: Oakley California
You guys and your thirsty V8s, my car is a 73 Super Beetle with a dual carb 1776cc engine, and a bit of suspension work. Affordable to drive, and faster than it looks, good fit for my audio philosophy of low to moderate output push pull amplifiers I suppose

I'll buy a big heavy V8 once I build an amplifier using some big transmitting tubes one day
__________________
Check out My 6SN7 Push-pull Flea Amplifier project! PCB COMING SOON!
  Reply With Quote
Old 26th June 2019, 01:35 PM   #20
Bas Horneman is offline Bas Horneman  Netherlands
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Quote:
I’m trying to understand the point of an 845, 211, 805
Thoriated Tungsten Filaments.
__________________
If you can see the speaker cone move...it's not hifi.
http://basaudio.wordpress.com
  Reply With Quote

Reply


The point of an 845, 211, 805 amp?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
HQ Ceramic insulated turret terminals, chassis mount, for point to point amp/pre-amp cathodes Swap Meet 2 20th February 2017 10:12 AM
HQ Insulated turret terminals, chassis mount, for point to point amp/pre-amp etc cathodes Swap Meet 8 11th April 2016 03:44 PM
Lots of craziness (weird noises and osc) happening in point to point 5W EL84 Amp 777funk Instruments and Amps 17 2nd March 2014 06:20 PM
Anyone use magnet wire for point to point wiring projects? Hybrid fourdoor Parts 10 2nd February 2004 08:11 AM


New To Site? Need Help?

All times are GMT. The time now is 12:01 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki