Mono push-pull driver PCB - Page 11 - 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 23rd November 2012, 01:10 PM   #101
pso is offline pso  Spain
diyAudio Member
 
Join Date: May 2010
Location: Valencia
Hi, the voltage in my house ranges between 220-228V, that primary would be more appopriate for the transformer? 230 or 240V.
  Reply With Quote
Old 24th November 2012, 01:22 AM   #102
pso is offline pso  Spain
diyAudio Member
 
Join Date: May 2010
Location: Valencia
Hi George, I'm beginning to think that this project will be a lot for me, it seems no one else is interested in the triode-KT88, only think of great powers.

I do lot of questions and you just answer me, so I will store my tubes and to retake my first choice, your SSE ( Just ordered your board ), is very easy to start, instructions and detailed parts list, to many people who built and much more willing to help.

One more question:

I will order the custom transformer, if one day I come back to this board, will have twice the capacity than necessary for the SSE, there may be
a drawback in that ( Vibrations, hum, etc...)?

Thanks.
  Reply With Quote
Old 24th November 2012, 01:42 AM   #103
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
Quote:
Originally Posted by pso View Post
Hi, the voltage in my house ranges between 220-228V, that primary would be more appopriate for the transformer? 230 or 240V.
230....but since i build my own traffos, i design for 225, our power situation is about the same....
  Reply With Quote
Old 24th November 2012, 01:44 AM   #104
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
Quote:
Originally Posted by Cassiel View Post
Wow George, you're playing in major league INDEED. I'm just a small-time player.
OT, i just do not know if George is on first or third or plays shortstop.......
  Reply With Quote
Old 24th November 2012, 04:05 AM   #105
Cassiel is offline Cassiel  Libya
diyAudio Member
 
Cassiel's Avatar
 
Join Date: Sep 2004
Location: Madrid
I don't know, all I know is that I want a 813 amp now. It's not about power, it's just that gorgeous looking tube. Tired of playing with 6V6's and EL84's... not exciting anymore. Time's up.
__________________
Effeminate Audio
  Reply With Quote
Old 24th November 2012, 09:52 AM   #106
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
amigo, time to step up your game......
  Reply With Quote
Old 24th November 2012, 09:58 AM   #107
pso is offline pso  Spain
diyAudio Member
 
Join Date: May 2010
Location: Valencia
Thanks Tony.
  Reply With Quote
Old 24th November 2012, 01:20 PM   #108
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
Quote:
Hi George, I'm beginning to think that this project will be a lot for me, it seems no one else is interested in the triode-KT88, only think of great powers.
I don't know what your experience and skill level is, but Pete cautioned that this was not intended to be a plug and play board. Some degree of experimentation and tweaking will be needed for any implementation until someone builds something and documents it. I have the equipment to turn knobs and take readings that can be used to provide a starting point for someone to build from. This is what I just attempted to do with the 13GB5's. Maybe Tomlang will document his build such that others can duplicate it, I don't know.

This situation just happened with Pete's big red board, I stuck the 6HJ5's in it and cranked them up, forum member Rknize made an amp using that concept, then several similar amps were built.

I fully intend to test KT88's with this driver board, but my work situation is rather busy right now, so I really can't say when. Odds are that this board will not be powered up again this year after this weekend.

Almost 5 years ago a thread was started discussing 6L6GC's in AB2. Over a 2 year period I assisted a person on the other side of the world to design his amp. He did all the building and testing, I directed and performed a few experiments. There were set backs and successes, and finally he built a pair of very nice mono block amps. I built a breadboard that used trioded KT88's. I have never had the time to build a completed amp. The entire design and build is chronicled here (schematic in post #460):

6L6GC AB2 Amp

Quote:
I will store my tubes and to retake my first choice, your SSE ( Just ordered your board ),
The SSE is a good choice for a first build since it is pretty much plug and play. You can use KT88's in it. One of my SSE's uses KT88's. I will take the board to the post office this morning. They are open on Saturday morning.

Quote:
I don't know, all I know is that I want a 813 amp now. It's not about power, it's just that gorgeous looking tube.
I know that there is another box with more big transmitter tubes in this house somewhere, but I can't find it. I did find a box full of 828's but they aren't as pretty.

Quote:
OT, i just do not know if George is on first or third or plays shortstop.......
Lately, all I have time for is being a designated hitter.....I just smack it out of the ballpark, then stand back and watch while someone else does the running!
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 24th November 2012, 02:18 PM   #109
tomlang is offline tomlang  United States
diyAudio Member
 
tomlang's Avatar
 
Join Date: Oct 2009
Location: Augusta, GA
Here are my plans at present (with big asterisk) that I will get to in a minute.

First off, here are the output transformers I plan to use in a 13GB5 triode strapped amp: 70.7 VOLT-4,8 ohm LINE TRANSFORMER 4 lbs. Buy It Now $16.00 172812 HT-327 | eBay

The seller will negotiate for large purchases. I (stupidly?) bought several of these to play with. Specs are attached. Why this transformer? With 8 ohms on the 4 ohm tap will be 1250 ohm primary. Also dirt cheap in keeping with the 13GB5 price.

I looked for a power transformer with the "proper" low voltage for the B+ and found one that should also do duty for the 13GB5 filaments, etc, pic attached. Hard to find a transformer that yields less than 300 VDC. 240VAC secondaries are easy to find but yield way over 300 VDC.

I should be able to "overload" the 14.8 vac at 2 amp winding with 4 parallel 13GB5's drawing a total of 2.4 amps.

The 390 VCT should yield about 260 VDC or so. If you put a FWB on it, you'd get over 500 VDC so this trans should be useful for other builds.

I'll run a voltage doubler on the 195 VAC winding for the phase inverter and of course the 64 VAC for bias.

New Tortran 750VA Toroidal Power Supply Transformer TN741-M390-CPE new * | eBay

Now for the big asterisk. I own Pete's other red board, not the two separate ones so this build will be different. I'm posting in this thread because of the 13GB5 testing done by George. I hope that is okay.
Attached Images
File Type: jpg ht-327.JPG (144.6 KB, 317 views)
File Type: jpg toroid transformer.JPG (40.3 KB, 314 views)
  Reply With Quote
Old 24th November 2012, 04:13 PM   #110
diyAudio Member
 
pmillett's Avatar
 
Join Date: May 2005
Location: Dallas (but I am not a Texan!)
Quote:
Originally Posted by pso View Post
Hi George, I'm beginning to think that this project will be a lot for me, it seems no one else is interested in the triode-KT88, only think of great powers.
Don't give up yet... indecision is starting to get to me!

I just set up the breadboard for split supplies (lower voltage for driver + screen if needed, higher for plates). Played with the 829B some... it worked well, though it was difficult to make the feedback stable, especially with a big Tamura F-2012 OPT.

Having realized that the KT88 is actually rated for 600V in triode mode (!) I went back to the KT88 trioded, running 250V on the driver and 450V (as high as my bench supply goes) on the plates. Biased class-AB with 50mA total idle current. Getting 0.06% THD @ 1 watt and clipping around 28 watts (5k load).

I'm thinking 250V for the driver and 500V for the KT88 would be a nice operating point.

Hmmm....

Last edited by pmillett; 24th November 2012 at 04:16 PM.
  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
idiot proof mono push pull 6l6gc schematic wanted jasondace2b Tubes / Valves 29 13th October 2011 01:22 AM
Mono 5W-17W Power Amp using EL84 push-pull nbraz Tubes / Valves 30 27th July 2011 11:12 PM
Please Explain difference Mono vs Push Pull vs Single End etc hdlcx2 Tubes / Valves 11 3rd August 2008 02:27 AM
Push-Pull driver stage? alexmoose Tubes / Valves 12 18th September 2006 11:38 PM


New To Site? Need Help?

All times are GMT. The time now is 04:38 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