Wurlitzer side man Speaker Impedence? - diyAudio
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 15th March 2006, 11:04 PM   #1
diyAudio Member
 
Join Date: Nov 2002
Location: New York
Default Wurlitzer side man Speaker Impedence?

Howdy Everyone,

I have a Wurlitzer side man that is being used as a guitar amp...and I'm looking into replacing the speaker in it with new one.

I've looked everywhere for the speaker Ohm, (yes, I did look on the back of the speaker...it's blank) and I can't find out any information.

I've hooked up my meter to test it, but I'm not fully sure how to test it,....so that was pointless for the moment.

Eventually I would like to hook up two speakers to it, but I don't want to fry the output Trans. in the process....But, I would like to get the most out of the amp.

Any ideas??? Also, I'm looking for any other specs on it...like wattage....and if anyone else has tinkered around with this tube amp.

Any help would be great!!!

Newpaltzwonder
  Reply With Quote
Old 16th March 2006, 06:45 AM   #2
lndm is offline lndm  Australia
diyAudio Member
 
Join Date: Mar 2006
Location: nsw
Typically, if you measure the DC resistance of the voice coil, the nominal impedance will be 1.25 higher. If your findings are ambiguous, the nominal value is probably an exponent of 2, like 4,8,16.

Paralleling devices into a valve amp doesn't carry the same dangers as overloading a solid state amp. Still it is best to do things right. Running an incorrect impedance will likely increase distortion or limit output.

Try to find different impedance taps on the OPT if you can.

You might guess the power by looking at the output devices. Maybe you would get the spec sheets and compare the recommended application notes.
  Reply With Quote
Old 19th March 2006, 10:27 PM   #3
diyAudio Member
 
Join Date: Nov 2002
Location: New York
Thanks.....

When I tested it before....I was getting a reading of 2 ohms. That was with the speaker still connected though, I don't know if that will make a difference? I didn't want to turn it on with no load....just in case I was going to kill it.

As for the size of the Transformer, I took the amp over to a shop a few weeks ago, and the guy said that it is at least 50 watts. He showed me a transformer from an amp he is repairing and it was a 50 watt bass amp, and the trans from mine was almost twice the size. But that was a solid state amp, compared to the tube amp I have.

I did get two new Crate speakers...12" SLM 50w 8 ohm speakers, I was thinking that I should wire them for 16 ohm just to be safe, unless I hear otherwise....

If anyone has any suggestions...that would be great!!!

Thanks,

Newpaltzwonder
  Reply With Quote
Old 20th March 2006, 12:13 AM   #4
lndm is offline lndm  Australia
diyAudio Member
 
Join Date: Mar 2006
Location: nsw
The guy at the shop was probably looking at the power transformer as most solid state amps do not have an output transformer. Typically, valve amp power transformers have heavy gauge heater windings included within so will be larger for the same power.

You need to disconnect your speaker from the amp to measure the speakers resistance. Typically, 8 ohm speakers will measure 6 ohms give or take. When you know, label the opt winding you used.

On averages, I would guess it is likely that your amp will have a 4 ohm tap.
  Reply With Quote
Old 31st March 2006, 12:53 AM   #5
diyAudio Member
 
Join Date: Nov 2002
Location: New York
Well,

The cabinet is together and the speakers are in, wired at 4 Ohms. I did a test today and all went well, there was a slight hum but I think that can be remedied when I put the amplifier in it's new case. Which is going to be reworked after I felt how much heat is coming off the 6BQ5 tubes...Wow.

Besides, I'm looking into a pre amp that I can use with the Wurlitzer amp. I've been looking at the Tube Pedal on Hoffmanamps.com...seems pretty good. But I'm going to keep looking. I want to go with tubes with the preamp...I'm goofy like that.

I think I'll add a post later on when I have more time to see if anyone has built a tube pedal that is similar or even better.

Thanks for your help.....


Newpaltzwonder
  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
Testing a speaker's impedence Austin Duggan Multi-Way 14 19th April 2008 02:09 PM
Speaker impedence Sammich Solid State 17 2nd July 2007 01:21 PM
speaker impedence inrank Multi-Way 5 12th May 2006 05:28 PM
Inline resistor raise speaker impedence? Westrock2000 Multi-Way 20 28th November 2002 05:09 PM
Speaker impedence and amp THD--the connection is...? Bill F. Solid State 9 31st May 2002 08:27 PM


New To Site? Need Help?

All times are GMT. The time now is 11:50 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