new thread, 6BM8 PP build begins... - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

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

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 10th July 2007, 05:24 AM   #1
Nanook is offline Nanook  Canada
diyAudio Member
 
Nanook's Avatar
 
Join Date: Feb 2004
Location: Chinook Country.Alberta
Default new thread, 6BM8 PP build begins...

so I've finally found the circuit (ASL AV-8 amp), and power supply (5AR4 tube rectified PS).

I just ordered the parts, less tubes, and iron--$110 USD or so. To my suprize, the capacitors and connectors were where the lion's share of the money went. I figure that with tubes, and a chassis and iron, perhaps $250 USD.

And I'm hoping to have it done for the Vancouver Island DIYfest (July 28). I'll post the build results, schematic and my parts selection for those that may be interested.

morayj will be providing the iron (thanks mr. james ), my friend John will be providing some expertise and some small parts, and pcx for the ordered parts.

Once I get the power amp section working, I want to create a preamp w/phono stage, and internal 3 inputs, so I can have me an intergrated. When functionally complete, I'll start looking at cosmetics.

If any want to chime in please do so. And please, I'm no tube geek, so if you are, please don't ask me a bunch of technical questions. I am sure the tube geeks know way more than I do.
__________________
stew -"A sane man in an insane world appears insane."
  Reply With Quote
Old 11th July 2007, 03:11 AM   #2
Nanook is offline Nanook  Canada
diyAudio Member
 
Nanook's Avatar
 
Join Date: Feb 2004
Location: Chinook Country.Alberta
Default Mod ...please kill this thread

as no one has shown any interest.
__________________
stew -"A sane man in an insane world appears insane."
  Reply With Quote
Old 11th July 2007, 03:51 AM   #3
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Default Re: new thread, 6BM8 PP build begins...

Quote:
Originally posted by Nanook
so I've finally found the circuit (ASL AV-8 amp),
Can you post the schematic.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 11th July 2007, 07:11 AM   #4
diyAudio Member
 
Join Date: Feb 2006
Location: Malaysia
Nook,

If you go for high quality transformers, your total outlay will easily triple in a hurry... So do watch out for what you wish for.

Cheers
__________________
Audio_Idiot
  Reply With Quote
Old 11th July 2007, 07:33 PM   #5
svokke is offline svokke  Belgium
diyAudio Member
 
Join Date: Apr 2003
Location: Leuven
I'm also building something like this. I just made a prototype using some scrap transformers and four 6bm8 from the junk box. Output transformer is a hammond 125E.

My layout is voltage gain stage direct coupled to the cathodyne phase splitter. The output stage is class AB penthode with fixed bias.
The power supply is regulated with a string of zeners and a mosfet in "cathode follower" configuration. Unregulated voltage is 300V DC, regulated it is 250V.
I'm looking forward to see your schematic.
__________________
In illusion comfort lies
  Reply With Quote
Old 11th July 2007, 07:50 PM   #6
Nanook is offline Nanook  Canada
diyAudio Member
 
Nanook's Avatar
 
Join Date: Feb 2004
Location: Chinook Country.Alberta
Default Maybe I'm "too" sensitive...

I just figured that with no replies in a day or two, no one was interested.

Dave: I'll attach the schematic... the power supply portion isn't complete (it's a 5AR4 tube rectified one)

I have suitable iron,. original power transformer , original out put transformers, and Moray's old Wav-8 trannys (thanks to morayj--when the mail gets here ).

THe caps and connectors and sovkets cost a little bit of money, and I have looked at the costs of transformers. The goal is to create a tube intergrated with phono stage and one other input, a decent attenuator (Precision Electronics from Toronto), decent power switches. The changes that I have made are the 5AR4 tube rectifier and the inclusion of a couple of Black Gate capacitors (.47 uF) in the inputs to the pentodes.

Some like capacitors prior to the AC chokes, some after. The 5AR4's can tolerate 60uF in the filter. Please have a look. Any comments are welcome. As I have stated several times before, I am no amp guru, so if "too technical" questions, I will divert them to someone else.

Anyone else watch "Little Mosque on the Prairie" last night.?I forgot how lucky we are here in good old canuckland to have some seriously funny tv from the CBC, CTV, Global, and CITY.
Attached Images
File Type: jpg nanookwav8-small.jpg (97.4 KB, 459 views)
__________________
stew -"A sane man in an insane world appears insane."
  Reply With Quote
Old 11th July 2007, 09:01 PM   #7
diyAudio Member
 
Tom Bavis's Avatar
 
Join Date: Jun 2002
Location: Macedon NY
If you're using the Wave 8 power transformer, you'll need a full-wave bridge rectifier. The two diodes in the 5AR4 can form half of that bridge, and two solid-state diodes form the other half. You'll also need a 5V transformer to light the 5AR4 - it needs be isolated from other heaters. The filter must be capacitor input with this transformer, to get enough voltage. The choke should be low-resistance as well, as there isn't a lot of voltage to work with.
  Reply With Quote
Old 11th July 2007, 10:51 PM   #8
Nanook is offline Nanook  Canada
diyAudio Member
 
Nanook's Avatar
 
Join Date: Feb 2004
Location: Chinook Country.Alberta
Default stock schematic...

here's a copy of the stock schematic. (not my page)... HERE
__________________
stew -"A sane man in an insane world appears insane."
  Reply With Quote
Old 13th December 2007, 06:08 AM   #9
diyAudio Member
 
vinylkid58's Avatar
 
Join Date: May 2005
Location: Victoria, B.C.
Default Re: 6BM8 PP progress?

Quote:
Originally posted by Nanook
here's a copy of the stock schematic. (not my page)... HERE
Hi Stew,

I just stumbled on this thread in my search for the ultimate 6BM8 PP amp project/design. Any progress on your build?

Jeff
  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
Super Triode Connection Amplifier Build with 6BM8 and 6AK5 DerFly Tubes / Valves 35 3rd November 2009 07:45 AM
My SE KT-88 Build thread athos56 Tubes / Valves 13 21st December 2008 06:16 AM
The ESL Build Thread BillH Planars & Exotics 172 8th November 2006 09:01 PM


New To Site? Need Help?

All times are GMT. The time now is 08:33 PM.


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