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

6SN7 push pull flea amplifier project
6SN7 push pull flea amplifier project
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 14th June 2018, 01:02 PM   #191
Carlp is online now Carlp  United States
diyAudio Member
 
Join Date: May 2006
Location: A New England
6SN7 push pull flea amplifier project
Sheesh, you're doing all this with a 2 year old in the house? Good on ya! Mine are 13 & 15, more independent but then they have lots of activities...

I would have suggested Elna for the caps, though there are some great Panasonic low ESR caps out there. If I can dig up some specific suggestions I'll do so. Anyway, good work!
  Reply With Quote
Old 14th June 2018, 02:13 PM   #192
Lingwendil is online now Lingwendil  United States
Now with high-fructose ASSAULT-gluten!
diyAudio Member
 
Lingwendil's Avatar
 
Join Date: Apr 2008
Location: Oakley California
6SN7 push pull flea amplifier project
Yep. He is way too smart for his own good. He is usually in my lap helping whenever I'm measuring resistors, mocking up parts, or doing design work on the laptop. At two years old he can already correctly use a screwdriver, put resistors into a breadboard, and loves to help out with everything he can, he is way too smart for his own good

Part of our nightly routine includes him turning off the main amplifier (while saying "night!" to it!) and then watching the tubes cool down. He's a treasure.




For capacitors, any part suggestions (preferably with links to digikey, mouser, newark, etc) would be appreciated! The film caps have a dual pattern for either 20mm axial or 15mm radial lead spacing, and the electrolytics have a 6.35mm lead spacing, with the main reservoir cap at power entry to the board having a dual pattern to also fit 7.5mm spacing... of course it's trivial to simply fit whatever you like in place by simply bending the leads a smidge. Hopefully I'll do a parts order this afternoon so I can stuff a couple mosfet and amplifier boards, as I'm planning on using one of the mosfet boards to build a big bench supply, and would prefer to grab some isolated mosfets, since I need to order PSU caps anyway. Isolated fets would mean that for most builds one could simply bolt the PSU straight to the chassis, since it's not likely to be dropping more than a watt or so in most applications.
__________________
Check out My 6SN7 Push-pull Flea Amplifier project! PCB COMING SOON!
  Reply With Quote
Old 14th June 2018, 05:12 PM   #193
pcan is offline pcan  Italy
diyAudio Member
 
Join Date: Dec 2015
6SN7 push pull flea amplifier project
On my build, the cathode capacitors are RS components part number 224-4404 (Rubycon YXF 10000h 105C), the 33uF filter capacitors are RS components part number 715-2325 (Nichicon CS 10000h 105c), and 10 uF filter capacitors are part number 726-0732 (Rubycon BXC 10000h 105c). My chassis is made of wood without ventilation and I selected high temperature long life parts. This was actually unnecessary because this amplifier is cold.
  Reply With Quote
Old 14th June 2018, 06:19 PM   #194
Lingwendil is online now Lingwendil  United States
Now with high-fructose ASSAULT-gluten!
diyAudio Member
 
Lingwendil's Avatar
 
Join Date: Apr 2008
Location: Oakley California
6SN7 push pull flea amplifier project
Good prices on those rubycon parts, and I've used them in the past so know they are good parts. I think that's a reasonable call out for the BOM for sure. 5mm lead spacing, but they will slide right into the PCB without fuss (and I'm running 5mm caps personally, I am also enlarging the through holes to accommodate multiple types, and will probably add additional holes on the next run of boards anyway)



35YXF470MEFC10X20 Rubycon | Capacitors | DigiKey

50YXF470MEFCG412.5X20 Rubycon | Capacitors | DigiKey


0.57USD each, or 4.01USD for ten is a good deal for sure too, for a 35 volt part, 0.90USD each, or ten for 6.60USD for the 50 volt version, not bad at all for a 10,000 hour part!
__________________
Check out My 6SN7 Push-pull Flea Amplifier project! PCB COMING SOON!
  Reply With Quote
Old 14th June 2018, 06:35 PM   #195
Lingwendil is online now Lingwendil  United States
Now with high-fructose ASSAULT-gluten!
diyAudio Member
 
Lingwendil's Avatar
 
Join Date: Apr 2008
Location: Oakley California
6SN7 push pull flea amplifier project
For power caps, there are a bunch of good looking rubycons with a 10,000hr+ rating, but 10, 22, and 47 are the values most likely to be used here, I suspect.

https://www.digikey.com/short/j9zz5f
1.34USD each,

https://www.digikey.com/short/j9zz20
1.37USD each,

https://www.digikey.com/short/j9zznf
2.04USD each.

47uF for the main reservoir, and either 10uF or 22uF at the splitter would work well. I think for now these will be the callouts on the BOM too. If anyone has any similar parts to suggest let me know.
__________________
Check out My 6SN7 Push-pull Flea Amplifier project! PCB COMING SOON!
  Reply With Quote
Old 14th June 2018, 06:43 PM   #196
pcan is offline pcan  Italy
diyAudio Member
 
Join Date: Dec 2015
6SN7 push pull flea amplifier project
They have a very good price/performance ratio. I used 50V parts because they have slightly lower ESR (and to avoid stocking both 35V and 50V parts for my projects). According to Rubycon current literature, the recommended general purpose long life and low impedance series for new designs is YXJ, it has same or better specification than YXF but is smaller. The YXF parts will probably be phased out in the future, but today they are a little bit cheaper and easier to source.
  Reply With Quote
Old 14th June 2018, 07:23 PM   #197
Lingwendil is online now Lingwendil  United States
Now with high-fructose ASSAULT-gluten!
diyAudio Member
 
Lingwendil's Avatar
 
Join Date: Apr 2008
Location: Oakley California
6SN7 push pull flea amplifier project
I really like the rubycon caps, and they are definitely a good value and great performance.


For the coupling caps, I like axial lead poly types, but since I'm running out of my favorites (Siemens 250 volt 100nF polyester film, the yellow dudes) I've selected these 400 volt guys from Vishay-

BFC237351104 Vishay BC Components | Capacitors | DigiKey

If anybody can recommend something similar, I'm all ears, but these are very nice quality, and 0.92USD each, or ten for 7.02USD. Any 15mm box type cap will likely fit well. Alternatively, if you want what I like to use, these are my usual coupling cap for ~300 volt supply applications, and only 40 each-

West Florida Components - 0.1uF .1 uF 250V Axial Polyester Film Capacitor Vintage Siemens

West Florida components has some cool stuff, btw. Nice place to grab axial type caps, and a handful of other neat and useful older parts.
__________________
Check out My 6SN7 Push-pull Flea Amplifier project! PCB COMING SOON!
  Reply With Quote
Old 18th June 2018, 04:51 PM   #198
kodabmx is offline kodabmx  Canada
diyAudio Member
 
Join Date: Oct 2011
Location: Toronto
What do you think of using fixed bias on this design instead? I've used it on higher power amps with toroidal PT OPTs with good success, but the power is so low I'm thinking you could just use 9V batteries for grid bias. I'm gonna kang one together and see how it is.
  Reply With Quote
Old 18th June 2018, 05:06 PM   #199
Lingwendil is online now Lingwendil  United States
Now with high-fructose ASSAULT-gluten!
diyAudio Member
 
Lingwendil's Avatar
 
Join Date: Apr 2008
Location: Oakley California
6SN7 push pull flea amplifier project
I've had a design drawn up for a while that is parallel outputs (4x per channel) that is fixed bias, with direct coupled ZVN0545 source followers to drive the grids. The secondaries of the output transformer are connected in series, with the center tap grounded, and either end is stacked under the cathode of each side for differential local feedback in the output stage. I figure it should be good for 7-8W or so without abusing things. If anything it should be more efficient but at these power levels, what's a little waste among friends?

Fixed bias would be a tad simpler, but loses the whole "it just automagically works" thing it's got going on. Still, it's worth a build, in my opinion. Could be a neat variant. If going fixed bias, source followers seem to be a given, too easy not too, then we can have some real fun
__________________
Check out My 6SN7 Push-pull Flea Amplifier project! PCB COMING SOON!

Last edited by Lingwendil; 18th June 2018 at 05:09 PM.
  Reply With Quote
Old 18th June 2018, 05:16 PM   #200
Carlp is online now Carlp  United States
diyAudio Member
 
Join Date: May 2006
Location: A New England
6SN7 push pull flea amplifier project
Quote:
Originally Posted by kodabmx View Post
What do you think of using fixed bias on this design instead? I've used it on higher power amps with toroidal PT OPTs with good success, but the power is so low I'm thinking you could just use 9V batteries for grid bias. I'm gonna kang one together and see how it is.
If you're talking about fixed bias on the output tubes, then it becomes a very different animal. It may be a terrific animal, but very different. The garter arrangement provides a measure of balance using a feedback mechanism that is worlds apart from fixed bias. Since balance in the output PP architecture is vital to the sound of a PP amp, some mechanism to accomplish that is pretty important. Particularly in my case where I want to work with 6AS7 tubes, whose dual triodes are notoriously imbalanced within any one tube (and where we're talking about a pretty big negative supply for fixed bias, not a 9v). Note though that the feedback of the garter arrangement seems, in my mind, to push the cathode bias of the output to act somewhat like a fixed bias arrangement, so I've wondered if garter bias would adopt a sound somewhere between fixed and cathode bias.

I also plan to try the 6SN7 version, though, so I'm interested in your test, particularly if you can compare it to to the garter bias of this design.
  Reply With Quote

Reply


6SN7 push pull flea amplifier projectHide 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
Chinese amp: 2A3 6SN7 6SJ7 5Z5P push pull Alexontherocks Tubes / Valves 16 7th May 2013 04:37 AM
6SN7 & 6V6 Push Pull - increase gain laosei Tubes / Valves 18 26th February 2013 08:01 AM
6sn7 driving Push Pull Parallel kt88's? ruben alstad Tubes / Valves 58 21st November 2012 11:08 PM
VTV Push-Pull 6SN7/KT88 Amp: DIY or China? 88man Tubes / Valves 5 18th October 2009 02:27 PM
YAPPAP (Yet Another Push-Pull Amplifier Project) arnoldc Tubes / Valves 16 6th July 2006 02:51 AM


New To Site? Need Help?

All times are GMT. The time now is 06:01 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki