DIY Audio Projects Forum
 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

DIY Audio Projects Forum

Welcome to the DIY Audio Projects Message Forum. Use these forums to discuss Hi-Fi audio and to share your DIY Audio Projects. Registration is free and required to post messages and view the file attachments. Registration will only take a minute and registered users do not see any advertisements. After you have completed the online registration process, check your email (including spam/junk folder) for the verification email to activate your account. New members are under moderation - so your posts will not be visible until approved by a moderator. See the Read Me 1st, Forum RULES and Forum FAQ to get started on the forum.

It is currently 21 Aug 2018, 16:40

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 51 posts ]  Go to page 1, 2, 3, 4, 5, 6  Next
Author Message
PostPosted: 24 Aug 2017, 07:45 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4918
Location: Australia
Once more I put it on Suncalc to design me a 6C33C cathode follower amp. The whole crux of this project is to have these large tubes jutting out of a 1U 19" rack mount enclosure. And only the tubes exposed. No OPTs or trannies of any kind. I had seen a commercial version of this idea which used SMPSs and wanted to copy the idea.

What I will have to do is power the amp with an external tranni box. Because I require 6A at 12V to power the 6C33C heaters and 300VHT at just less than 400mA the trannies must be robust. Two 160VAC trannies, back to back should do the job. The 12V tranni is rated at 12A.

The design uses a 4S driver stage and will allow driver stage tube rolling. I have a quite few different 12A*7s. The big bonus with the external tranni box, with XLR sockets, is I can us it to power lots of other amps. This is a similar idea to the 6L6 tranni box I recently made. This time though the box will rectify and two stage filter the HT. That means in the ampamps I only need limiting resistors and a final filter stage. Save lots of money and allows easy amp rolling.

I have started on the tranni box, images to follow. Take a llok at Suncalcs design;-
Attachment:
6C33CSchematic.jpg


This post has a file attachment. Please login or register to access it. Only Registered Members may view attached files.


_________________
Projects: "Lagoon" - tube preamp with cathode follower | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


Top
 Profile  
 
PostPosted: 26 Aug 2017, 07:38 
Offline
User avatar

Joined: 01 Jun 2013, 09:05
Posts: 655
Its interesting to see the ideas,

Also not many comments :)

These tubes 6c33c are like cooker elements (very hot).
The biggest problem is usually the driver stage and blocking distortion usually overcome with higher voltages on the driver stage.
When I used the 6c33c in an OTL I burned the tubes in for 12 hours (heaters only) before applying HT.
This is based on many peoples comments about tube failure if they aren't burnt in. (something to do with the elements expanding into position) but each to their own ideas.
I used them in mixed bias.
On an OTL it is possible to use heater selection I used Left/ right /both so I could reduce the power consumption with single heater.
The left / right meant I could get equal wear over a period. Interestingly the tubes change sound after a while running, this was obvious when changing from one side heater to the other on first run. (burn in).

For interest I used my heaters in series to cut the current which seemed to fry the sockets when in parallel.
I floated the heaters with a capacitor.
That's just my thoughts. I'm sure there are many builders that have more extensive experience with 6c33c than I do.
Romy the cat has/had a site linked to these type of tubes.
http://www.goodsoundclub.com/Forums/Sho ... ostID=6140
Best of luck..

Regards
M. Gregg


This post has a file attachment. Please login or register to access it. Only Registered Members may view attached files.


_________________
What is the sound of one hand clapping?


Top
 Profile  
 
PostPosted: 26 Aug 2017, 08:05 
Offline
User avatar

Joined: 01 Jun 2013, 09:05
Posts: 655
Thought it worth a mention,

I run 4 6c33c and the listening room heats up very quickly.
It sounds good but again is coupling cap dependant<< I melted Jupiter wax caps and oil caps in the chassis nowhere near the power tubes behind a heat shield.
I eventually sorted the heat flow.

Regards
M. Gregg

_________________
What is the sound of one hand clapping?


Top
 Profile  
 
PostPosted: 26 Aug 2017, 10:03 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4918
Location: Australia
I though each tube required 6V for the hearts in total. I have 12V @12A tranni. To me I can run the two tube heaters in series. Right.

_________________
Projects: "Lagoon" - tube preamp with cathode follower | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


Top
 Profile  
 
PostPosted: 26 Aug 2017, 10:07 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4918
Location: Australia
It's alright I have it sorted.

_________________
Projects: "Lagoon" - tube preamp with cathode follower | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


Top
 Profile  
 
PostPosted: 26 Aug 2017, 11:58 
Offline
User avatar

Joined: 01 Jun 2013, 09:05
Posts: 655
mwhouston wrote:
I though each tube required 6V for the hearts in total. I have 12V @12A tranni. To me I can run the two tube heaters in series. Right.


The more voltage you can use the lower the current (as you know :) )
So its better to run in series I used 24V but that was for 4 tubes.
I also switched the heaters, however I guess you are just using both sides of the tube.

I run the driver with DC heater and 6c33c AC.
I found a few problems trying to balance the hum but that's a different story.
You need high melt point solder on the bases. I used different solder on the heater connections.

Cathode bias creates heat, lots of it.
The tubes seem to sound different depending on bias type.
However I just thought it might be some use.
Things like flying leads and remote power supplies suffer with volt drop over distance linked to current draw by the equipment.

In these kind of builds think CURRENT<<its a main priority also PSU is or can be dangerous.
I switched off while testing during the build and dropped a B+ wire on the chassis it hadn't discharged completely, it blew a 1mm hole straight through a 3mm piece of aluminium. Be careful.. :up: That was on an OTL your amp may be different.
The capacitors can supply high current with 300v the mA rating of the tube draw is misleading.
I'll shut up now. :D

Regards
M. Gregg


This post has a file attachment. Please login or register to access it. Only Registered Members may view attached files.


_________________
What is the sound of one hand clapping?


Top
 Profile  
 
PostPosted: 26 Aug 2017, 12:37 
Offline
User avatar

Joined: 01 Jun 2013, 09:05
Posts: 655
One other thing I found with OTL,

The more current you can deliver the more bass drive you get. And transient response!
Ie chokes reduce bass, however I wound a couple and used them in the PSU.

Even cable type and cross section made a difference, so its something to consider with types of leads/ plugs and sockets.
Sorry I'm getting side tracked. :sleep:

Regards
M. Gregg

_________________
What is the sound of one hand clapping?


Top
 Profile  
 
PostPosted: 26 Aug 2017, 18:00 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4918
Location: Australia
All good info. Thanks.

_________________
Projects: "Lagoon" - tube preamp with cathode follower | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


Top
 Profile  
 
PostPosted: 05 Jan 2018, 22:06 
Offline

Joined: 28 Dec 2013, 13:11
Posts: 6
Location: Canada
Hi mwhouston, did you have proceded with this amplifier, i am rather curious. It seem rather simple operation, it would be a good match with high effeciency speaker.


Top
 Profile  
 
PostPosted: 06 Jan 2018, 02:32 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4918
Location: Australia
mtlsir wrote:
Hi mwhouston, did you have proceded with this amplifier, i am rather curious. It seem rather simple operation, it would be a good match with high effeciency speaker.

The PS design I was going to use didn't work and left me wondering how I was to get the voltage and the huge filament current required. I have come up with another way to do it, a voltage doubler. In the meantime I got a couple of commission jobs and was distracted by other projects.

Not off the todo list just must finish a couple of jobs I started including a Jean Hiraga le monster.

_________________
Projects: "Lagoon" - tube preamp with cathode follower | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 51 posts ]  Go to page 1, 2, 3, 4, 5, 6  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: Google [Bot], Google Adsense [Bot] and 12 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
DIY Tube Projects :: DIY Tube Amp Kits :: DIY Speaker Projects :: DIY Solid State Projects :: DIY IC / Op-amp Projects :: DIY Phono Projects :: DIY Cable Projects :: Hi-Fi Audio Schematics
© diyAudioProjects.com - Terms of Service - Privacy Policy