Building a Aikido preamplifier - Page 3 - 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 24th September 2008, 04:49 PM   #21
diyAudio Member
 
ollebolle's Avatar
 
Join Date: Feb 2008
Location: Linkoping
This is good news

The total current will be: (5+5mA for 6N1P and 20+20mA for 5687) Total around 50mA!
50mA is within the limits for my choke
The 5687 will draw about 20mA with my B+ at 220V

Now I know how to read the table

Thank you all for the good help!
  Reply With Quote
Old 24th September 2008, 05:57 PM   #22
diyAudio Member
 
Join Date: Jan 2006
Location: Ireland
What happened me was during my build of SYs red district EL84 amp. I was using one of those transformers for the B+ - the heaters and a second B+ were coming off a different Tx.

What was happening was that the voltages were all over the place. I'd hook up one of the transfomers and get the right voltage, attach it to the circuit and it would be way off. Really difficult thing for someone inexperienced to figure. Anyway, thanks to shoog - he copped it right away. Once I replaced it the thing worked pretty ok. I think it was saturation or overloading or something (even though the current draw was very small - 10mA or something).

The ones I bought were supposedly pulls from working equipment - and in fairness the seller sent me 2 more to replace the first 2 ones which were bad - but they were bad too.....

I only mentioned it when I saw your pic of the Tx and thought oh oh! Look yours may be AOK.

To be honest I would like to hear a high voltage aikido as both of mine are the 24V type with 6GM8. These sound really good and yes, they have been put up against some really good gear and with a variety of experienced ears too.

If the worst comes to the worst, you might be able to get a 9V Tx and rectify and drop the voltage and run the heaters off that and a simple isolation transformer for the B+ - the one from a junked PC power supply might just do the trick. Ususally bathroom strip lights (ones with a shaver socket) have 20VA isolation transformers that could be pressed into service too. Not the highest quality, but they would allow you to get the thing working until you found something better.

Good luck with the build!

Fran.


ps somehow snag yourself a nice cap for the output position - a nice PIO or blackgate etc would be nice there.
  Reply With Quote
Old 24th September 2008, 06:10 PM   #23
Stixx is offline Stixx  Germany
I am
diyAudio Member
 
Stixx's Avatar
 
Join Date: Sep 2003
Location: Southern Germany
Quote:
ps somehow snag yourself a nice cap for the output position - a nice PIO or blackgate etc would be nice there.
Or try some NOS ERO KP caps...
they are getting expensive (at least in Germany), but are worth every penny (well, cent nowadays... )
  Reply With Quote
Old 24th September 2008, 07:15 PM   #24
diyAudio Member
 
ollebolle's Avatar
 
Join Date: Feb 2008
Location: Linkoping
Thanks for the advice!
  Reply With Quote
Old 24th September 2008, 07:22 PM   #25
diyAudio Member
 
ollebolle's Avatar
 
Join Date: Feb 2008
Location: Linkoping
Quote:
Originally posted by Brit01
Hi guys,

I'm just about to order the Aikido Stereo 9-pin kit from JB.
I'm a total newbie.

I was donated 4 6N1P valves from a very kind member from Netherlands.

I will probably have to have a transformer built by a local tech here. I live in Uruguay so very little available. My girlfriend will be in USA in Oct so I am getting her to bring the kit and parts back from JB.

Exactly what kind of transformer do I need to have built. I understand I need the 6.3 V DC supply for the 6N1P. We have 230 V here.

Also do I need to order the following from the kit?

'Supporting and power supply caps'.

I'm also getting hold of the power supply board from another member.

Many thanks

Chris
Hi Chris!

John Broskie offers boards for both octal tubes, and 9-pin!
6N1P is a 9-pin tube. Choose boards for 9-pin tubes if you use 6N1P

About the power transformer: Some transformers can be wired for both 110V and 220V
This might be good choice if you want to use it in both 110 and 220V countries!

On the secondary you will need a 6,3V winding for the heater. One 6N1P draws 0.6A. Four of them = 2,4A
Choose a transformer that can deliver some more current! 4A or more should be good i think...
Then you need a winding for the anode voltage!

Some transformers are center-tapped, some are not!

The power supply circuit (and board) decides which power transformer you need!
How is it designed?
  Reply With Quote
Old 24th September 2008, 07:50 PM   #26
Brit01 is offline Brit01  United Kingdom
diyAudio Member
 
Join Date: Jul 2008
Quote:
The power supply circuit (and board) decides which power transformer you need!
Great info. Thanks Olle.

I will hopefully be getting hold of the psu by Bas Horneman designed for the Aikido Line stage.

I believe it is like the one here:
Poll..anyone interested in an Aikido linestage PCB group buy?

I will have to confirm once I receive it.
  Reply With Quote
Old 24th September 2008, 08:09 PM   #27
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
What I would suggest is something like 250V secondary with say 150mA current.

And as ollebolle says "Choose a transformer that can deliver some more current! 4A or more should be good i think... " for the 6,3V

Since the voltage in Uruguay is the same as in Europe...specify a 230VAC primary. So that you can use it in the UK as well if you ever move back there.
  Reply With Quote
Old 24th September 2008, 08:17 PM   #28
diyAudio Member
 
ollebolle's Avatar
 
Join Date: Feb 2008
Location: Linkoping
Yes, I agree

And do not exceed the max rating in the datasheet
Maximum 250V for 6N1P

Higher voltage will shorten the life of your tube.
  Reply With Quote
Old 24th September 2008, 08:26 PM   #29
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Well in this case (Aikido) each 6N1P will see roughly half the b+ so a b+ of 300V is fine.
  Reply With Quote
Old 24th September 2008, 08:33 PM   #30
Brit01 is offline Brit01  United Kingdom
diyAudio Member
 
Join Date: Jul 2008
Hi Bas,

Thks for jumping in.
I didn't want to bombard you with questions to your personal email.

So I need a transformer: 230 VAC input(primary) with 2 outputs, one of 6.3V DC with 4 amps and the second output with 250V DC with 150 mA?

The anode voltage is the B+ voltage?

Sorry as you can see I have a lot to study but very little time at the moment.
  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
Use 9 pin Aikido PCB kit or buy 8 pin ? Renron Tubes / Valves 6 25th November 2007 04:52 PM


New To Site? Need Help?

All times are GMT. The time now is 06:56 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