Go Back   Home > Forums > Live Sound > Instruments and Amps

Instruments and Amps Everything that makes music, Especially including instrument amps.

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 16th January 2013, 03:20 PM   #101
m145mcc is offline m145mcc  United States
diyAudio Member
 
Join Date: Sep 2011
Location: My parents basement
The misses didn't want me spending 60 bucks on a transformer, so I down graded to a head phone amp. I'll replace the 12.6 with this guy 166L16 Hammond Manufacturing | HM533-ND | DigiKey I'm still going to build the 40w amp just not in the immediate future.

Last edited by m145mcc; 16th January 2013 at 03:23 PM.
  Reply With Quote
Old 16th January 2013, 04:03 PM   #102
diyAudio Member
 
Robert Kesh's Avatar
 
Join Date: Oct 2012
Quote:
Originally Posted by m145mcc View Post
The misses didn't want me spending 60 bucks on a transformer, so I down graded to a head phone amp. I'll replace the 12.6 with this guy 166L16 Hammond Manufacturing | HM533-ND | DigiKey I'm still going to build the 40w amp just not in the immediate future.
My Hybrid's power transformer cost 10, which I think is $16. 80VA 22V toroidal. And this **** is more expensive in the UK. Shop around.
  Reply With Quote
Old 17th January 2013, 10:19 AM   #103
m145mcc is offline m145mcc  United States
diyAudio Member
 
Join Date: Sep 2011
Location: My parents basement
I fount this transformer, VPS28-6250 Triad Magnetics | 237-1282-ND | DigiKey and run my total again. I think I will use the 40W chip-amp. Anything wrong with electrolytic cap in the signal path, I have heard mixed things about it.
  Reply With Quote
Old 17th January 2013, 12:24 PM   #104
diyAudio Member
 
Robert Kesh's Avatar
 
Join Date: Oct 2012
Quote:
Originally Posted by m145mcc View Post
I fount this transformer, VPS28-6250 Triad Magnetics | 237-1282-ND | DigiKey and run my total again. I think I will use the 40W chip-amp. Anything wrong with electrolytic cap in the signal path, I have heard mixed things about it.
Do you mean at output? It's unnecessary unless you are doing single sided supply. I can't see a electrolytic on your 40W schematic.

If you mean input, remember this isn't hi-fi, it's guitar, so you only have to pass things from 80Hz. If you set the input cap for 40Hz you can do this with a cheap film cap easily. The 0.1u on your schematic is fine, the 10u unnecessary, as I've already said.

For single sided guitar amp speaker cap, where a bit of distortion is ok, it's not a problem to use electros really, provided you get the value and voltage right. You don't want it rolling off the bass, or being burned out by the signal peaks.

If you want to do it completely right, you make sure that the input cap has a higher roll-off than the speaker cap and nfb cap. That way the good quakity cap (at input) does the work, and the electrolytics don't
  Reply With Quote
Old 17th January 2013, 12:58 PM   #105
JMFahey is offline JMFahey  Argentina
diyAudio Member
 
JMFahey's Avatar
 
Join Date: Mar 2009
Location: Buenos Aires - Argentina
Quote:
I fount this transformer, VPS28-6250 Triad Magnetics | 237-1282-ND | DigiKey and run my total again. I think I will use the 40W chip-amp.
What power amp will you use?
The LM2876 or the 2822?
This power transformer suits none of them.
Sorry.

Quote:
Anything wrong with electrolytic cap in the signal path, I have heard mixed things about it.
You'll already have a few electrolytics in the signal path, if you build tube, and even more if you go SS, so .....
Besides, it's a *guitar* amp.
People who build one or two amps or factories who build 10 amps a year worry about them; those who make millions, do not.
Think Marshall/Fender/Peavey/Laney/ ...... (insert 2000 more) ..... /Vox/etc.

As a guide, I suggest everybody who wants to design (fine with me), to take a hard good look at *many* successful commercial designs.
Darwinist competition sure cleans the ranks very fast and leaves only the fittest.
Not to copy anybody, but to get a general feel of what "works".
At the beginning of this thread (which already surpasses 100 posts) I suggested , given the stated goal, to build a straight Orange Tiny Tube cropped and adapted to drive a chip amp.

By the way, ***Orange*** themselves are doing this too !!!!!
They call it "Micro Terror". Probably use an LM1875 .
http://www.youtube.com/watch?v=XzDohmkXeJs

Last edited by JMFahey; 17th January 2013 at 01:17 PM.
  Reply With Quote
Old 19th January 2013, 06:47 AM   #106
m145mcc is offline m145mcc  United States
diyAudio Member
 
Join Date: Sep 2011
Location: My parents basement
I know the transformer is not up to par (didn't think about it till after I posted it), I'm taking a step and evaluating what I got so far.
  Reply With Quote
Old 19th January 2013, 12:49 PM   #107
JMFahey is offline JMFahey  Argentina
diyAudio Member
 
JMFahey's Avatar
 
Join Date: Mar 2009
Location: Buenos Aires - Argentina
It isn't that
Quote:
the transformer is not up to par
, in fact I think it *is* good quality .... but the voltage and current suit neither chip !!!
  Reply With Quote
Old 19th January 2013, 08:35 PM   #108
diyAudio Member
 
Robert Kesh's Avatar
 
Join Date: Oct 2012
That 2x14VAC transformer is probably all right if you used a 4 ohm speaker on the 2876. Too many VA, but not enough to cause a problem.
  Reply With Quote
Old 24th January 2013, 11:00 PM   #109
m145mcc is offline m145mcc  United States
diyAudio Member
 
Join Date: Sep 2011
Location: My parents basement
After some thought I have come up with this design, I'm actually pretty sure it will work this time. I have double checked the cap values with a simulation. I'm 76.2% sure I have the tubes biased right. The second stage uses local negative feedback. The tube supply transformer will be VPS230-570 Triad Magnetics | 237-1272-ND | DigiKey I still need to draw up a supply. For the power amp section I decided to cheat and go with this Kemo M033N 18 Watt Universal Mono Amplifier Module 320-553 I'm not sure if the specs provided on the parts express website are correct they seem kind funny to me, but i'm going to take a gamble. To power the amp module and tube heaters I'm going to use this ALS75-24 Triad Magnetics | 237-1296-ND | DigiKey I have double checked the specs on all supply's and transformers and they should supply sufficient power. I value your guy's input so please let me know if I'm in error. Oh and the tubes are clipping fairly symmetrically I used B2 spice to model everything, thanks in advance.
Attached Images
File Type: jpg amprev.JPG (285.5 KB, 26 views)
  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
Hybrid tube headphone amp design ashok Headphone Systems 21 30th December 2012 05:17 PM
any suggestions for a mid-amp transformer for a hybrid design... like this circuit... bassetrox Tubes / Valves 9 5th October 2011 08:47 AM
Hybrid Amplifier Design Luck Chip Amps 32 3rd March 2009 02:43 AM
Question about a hybrid PSU design reaction Tubes / Valves 2 10th October 2004 11:45 PM


New To Site? Need Help?

All times are GMT. The time now is 11:10 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