Output transformers bandwidth/frequency range - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs 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

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
Thread Tools Search this Thread
Old 15th March 2009, 05:52 PM   #1
diyAudio Member
Join Date: Mar 2009
Default Output transformers bandwidth/frequency range


I am looking around for affordable output transformers for my EL84 SE diy project. They have to have a good frequency range. I want them to at least match my old Kenwood KA-4002A solid state amplifier (frequency range 18-30.000Hz).

As far as i have found are the following:

1. NTR AU4a ( old louwe trafos ) frequency range unknown ( could somebody provide these details?
2. Edcore XSE15-8-5K, "only" 70-18.000Hz

Does someone know better output transformers? or do i have to buy in the 150,- euros and higher segment? ( Or maybe push-pull is a better idea, these are around ~70,- euros.

Does anybody have comments on this?

Thanks in advance,

  Reply With Quote
Old 15th March 2009, 06:04 PM   #2
vuki is offline vuki  Croatia
diyAudio Member
vuki's Avatar
Join Date: Jun 2002
Location: zagreb, croatia
elettronica novarria
  Reply With Quote
Old 15th March 2009, 06:11 PM   #3
diyAudio Member
Ty_Bower's Avatar
Join Date: Mar 2007
Location: Newark, DE
These 8k Transcendar output transformers might be something to consider. The shipping costs will be higher to Europe. I've used his 5k transformers with a single ended EL34 amp, and was very pleased with the results.
  Reply With Quote
Old 15th March 2009, 06:23 PM   #4
diyAudio Member
SpreadSpectrum's Avatar
Join Date: Nov 2007
18Hz-30kHz. Is that 3dB down? If you want at least 18Hz-30kHz you may want to consider building a push pull amp. If frequency response is your driving requirement, an SE amp with air-gapped cores will not be the best choice.
  Reply With Quote
Old 15th March 2009, 08:00 PM   #5
Jeb-D. is offline Jeb-D.  United States
diyAudio Member
Jeb-D.'s Avatar
Join Date: Nov 2005
Location: SoCal
Keep in mind, the edcor's bandwidth spec is at rated power. If you run it at a lower power, the bandwidth will be wider. Also, if your not paranoid about adding a little NFB, you can further increase bandwidth.
  Reply With Quote
Old 15th March 2009, 08:16 PM   #6
diyAudio Member
Tubelab_com's Avatar
Join Date: Jul 2005
Location: West Virginia panhandle
As stated the Edcors are rated for reasonable performance at 15 watts. The stated frequency response is probably realistic for operation at that power level. I have made some measurements on the XSE15-8-5K at low powers using a 300B tube. The type of tube has a very small effect on the frequency response. The current has a greater effect on the low frequency response and the distortion. These transformers would be a good choice for an EL84 SE amp.

Measurements at 1 watt: frequency response is 8.3Hz to 45.9KHz with 50mA, and 16.6Hz to 45.6KHz with 80 mA.
Tubelab, it's 5 year mission. To explore strange new tubes, to seek out new circuits and topologies, to boldly go where no tube has gone before......
  Reply With Quote
Old 15th March 2009, 08:17 PM   #7
diyAudio Member
Join Date: Mar 2009
I think the output will not exceed 5Watts, its for an EL84 amplifier, just one EL84 tube in the channel ( with ECC8(3/2/1) preamplifier tubes.

It is good to know this, is there a website which has a list of transformer producers in Europe? I have found one but a lot of pages are already gone.

Thanks so far!
  Reply With Quote
Old 15th March 2009, 08:40 PM   #8
diyAudio Member
Join Date: Mar 2009
Hi tubelab.com,

We posted on the same time.

I have a pair of B&W loudspeakers ( V201, 8ohm impedance, 50watts and a frequency response of 59Hz-22KHz ). Is that also on maximum level? or is that below that level?

I think iŽll go for the Edcor trafos, they are brand new and I think that is better compared to buying components that have been on the shelve for a long time. It also saves me some money which I could spend on better capacitors and loudspeaker connectors etc..
  Reply With Quote


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
Frequency range of the human voice & full range center channel speakers jwmbro Multi-Way 31 20th January 2008 03:07 PM
Output transformers and frequency response dsavitsk Tubes / Valves 21 3rd December 2006 06:48 PM
aleph 1.2 high frequency rool off and restricted bandwidth ackcheng Pass Labs 8 14th August 2006 05:15 PM

New To Site? Need Help?

All times are GMT. The time now is 06:03 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2