Cheap and nice looking SE OPT - 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 1st July 2007, 10:28 AM   #1
mus is offline mus  Canada
diyAudio Member
 
Join Date: Mar 2006
Location: bc
Default Cheap and nice looking SE OPT

Hi,

Has anyone had experience with this SE OPT?

http://cgi.ebay.ca/Output-Transforme...QQcmdZViewItem

I'm wondering is it good for HiFi use? Thanks.
  Reply With Quote
Old 1st July 2007, 01:33 PM   #2
diyAudio Member
 
Sal Brisindi's Avatar
 
Join Date: Nov 2006
I spoke with the seller about a month ago, he said these audio transformers were designed mainly for guitar amplifiers and not audio. He is thinking of designing audio transformersand having them made in Asia in the future.. I am not sure these are them. You can ask.

Regards,
Sal Brisindi
  Reply With Quote
Old 1st July 2007, 04:10 PM   #3
pftrvlr is offline pftrvlr  United States
diyAudio Member
 
Join Date: Feb 2007
Location: SoCal
What are the difference between audio opt and guitar opt?
  Reply With Quote
Old 1st July 2007, 06:09 PM   #4
Jeb-D. is offline Jeb-D.  United States
diyAudio Member
 
Jeb-D.'s Avatar
 
Join Date: Nov 2005
Location: SoCal
Quote:
What are the difference between audio opt and guitar opt?
Bandwidth.

Usually guitar OPT's only go down to 100Hz. And some times the upper frequency is limited as well.
  Reply With Quote
Old 1st July 2007, 06:59 PM   #5
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
The range of fundamental frequencies of a guitar run from 82Hz to around 1000Hz depending on the number of frets. Harmonics range up to 10KHz. Many guitar amp OPT's are designed with this in mind.

A guitar OPT is often wound with cost as the primary factor. There is usually NO interleaving, and there is less iron which is usually power transformer quality. This usually will reduce the bandwidth at both ends of the audio spectrum. Most P-P guitar amp transformers are usually wound with one primary half on first, then the entire secondary, then the other primary half. This causes one primary half to have a higher DC resistance than the other half, although I have seen transformers wound with a larger wire on the outer winding to compensate. Phase balance between the two halves is less than perfect. The efficiency will be poorer than an equal size HiFi OPT due to the poorer iron.

Now that I have trashed the thought of using a guitar amp transformer for HiFi, I must state that there are some guitar transformers out there that do quite well for HiFi in spite of their limitations. My 300Beast (300B P-P) uses guitar amp OPT's. I have tried several other transformers, and I still come back to the $16 Ebay guitar amp transformers. I am running an "80 watt" transformer at 30 watts which makes up for the smaller iron. The HF response rolls off (-3db) at 20 KHz which is still better than my aging ears.

Each transformer will be different, so the only way to tell would be to try one.
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 1st July 2007, 07:45 PM   #6
pftrvlr is offline pftrvlr  United States
diyAudio Member
 
Join Date: Feb 2007
Location: SoCal
I sent a email regarding the frequency range to the seller. Will post the response.
  Reply With Quote
Old 1st July 2007, 11:59 PM   #7
pftrvlr is offline pftrvlr  United States
diyAudio Member
 
Join Date: Feb 2007
Location: SoCal
Here is the response from the seller:


It's designed to cover the range of a guitar speaker, 82Hz to 6KHz. It would not generally be usable outside of Guitar or radio applications.
  Reply With Quote
Old 2nd July 2007, 04:57 AM   #8
mus is offline mus  Canada
diyAudio Member
 
Join Date: Mar 2006
Location: bc
Thanks, everyone!
  Reply With Quote
Old 2nd July 2007, 10:43 AM   #9
diyAudio Member
 
Join Date: Dec 2003
Location: earth
and don't forget, guitar tx's are possibly designed to saturate a bit for part of the distorted sound, too.

its not just the preamp sound which causes guitar amp distortion.

preamp distortion is asymetrical clipping, single ended.

you have phase splitter distortion,

power amp distortion, push pull symetrical clipping.

your tx may saturate

your speaker may distort, too

and your power supply may sag.

all are integral for an 'interesting' guitar amplifier,

its the whole darn thing distorting, which is why just rack guitar preamps don't give the full works, as that's just preamp distortion.


what's the difference? smaller cores to start with.

that one is only 2 lbs, so won't do a 300b which needs absolute minimum of 4 lbs, 2 kg or so, typical chinese entry level
7lbs better, 3-4 kg average tx for a 300b
12lbs about the best, 5-6kg, top end

does say its interleaved tho'
  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
Goldwood OB speakers cheap...nice audiophile36 Full Range 51 16th April 2008 05:56 AM
WTB: Some nice cheap KT88s please... horace Swap Meet 2 19th October 2007 11:45 AM
Mosquito, a new cheap and nice project filippo22 Multi-Way 0 10th March 2005 11:23 AM
Nice Big Heatsinks Cheap! MattM Pass Labs 5 14th February 2005 11:21 PM


New To Site? Need Help?

All times are GMT. The time now is 09:44 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