I was browsing around the "AA5 Hot-rodding site" and came across a nice tip:
You can use a 6.3v CT Filament transformer in place of your audio output transformer if it's bad.

You can use the 6.3v winding with an 8 ohm speaker and the 3.2v tap for a 4 ohm speaker. .. Or whichever seems to give the best results as you test it... also depends if you are using a 50C5 or a 41 or 6v6 etc.
I tried this tonight with very good results on the output of a 50L6.
It even worked quite well with an old 120/10 vac door-bell chime transformer.

Here's the site:
http://www.geocities.com/wa2ise/radios/repair.htm#if

Here's the excerpt:
"Audio output transformer bad? In a pinch, one can use a power transformer with a secondary of 6.3V center-tap. The turns ratio of the 120V primary to 6.3V secondary is 20 to one. With an 8 ohm speaker as load, that works out to be 8*(202)=3200 ohms on the primary side, close enough to the 2500 ohms a 50C5 wants to drive. Output power will be a dB or so lower, but that will be not noticeable. If driving a 3.2 ohm speaker, use half of the secondary, ie, 3.15V. That's from one end to the center tap. That will look like 3.2*(402)=5120 ohms. Kinda high, but the output power will be half the original value. But you'll be back "on the air". Changing the speaker to an 8 ohm one would probably be worth the effort here. The frequency response of a power transformer will be adequate for an AA5 radio, but won't be hi-fi."

I even saw/read somewhere a while ago where a person used an automotive ignition coil as an audio output transformer. I tried it and I was surprised at how it sounded, however I don't think I would use an ignition coil for permanent fix though.

Radiodoc
***********

:Undr the heading of Tips & Tricks:
:
:I was browsing around the "AA5 Hot-rodding site" and came across a nice tip:
:You can use a 6.3v CT Filament transformer in place of your audio output transformer if it's bad.
:
:You can use the 6.3v winding with an 8 ohm speaker and the 3.2v tap for a 4 ohm speaker. .. Or whichever seems to give the best results as you test it... also depends if you are using a 50C5 or a 41 or 6v6 etc.
:I tried this tonight with very good results on the output of a 50L6.
:It even worked quite well with an old 120/10 vac door-bell chime transformer.
:
:Here's the site:
:http://www.geocities.com/wa2ise/radios/repair.htm#if
:
:Here's the excerpt:
:"Audio output transformer bad? In a pinch, one can use a power transformer with a secondary of 6.3V center-tap. The turns ratio of the 120V primary to 6.3V secondary is 20 to one. With an 8 ohm speaker as load, that works out to be 8*(202)=3200 ohms on the primary side, close enough to the 2500 ohms a 50C5 wants to drive. Output power will be a dB or so lower, but that will be not noticeable. If driving a 3.2 ohm speaker, use half of the secondary, ie, 3.15V. That's from one end to the center tap. That will look like 3.2*(402)=5120 ohms. Kinda high, but the output power will be half the original value. But you'll be back "on the air". Changing the speaker to an 8 ohm one would probably be worth the effort here. The frequency response of a power transformer will be adequate for an AA5 radio, but won't be hi-fi."

:Peter,
:
:I even saw/read somewhere a while ago where a person used an automotive ignition coil as an audio output transformer. I tried it and I was surprised at how it sounded, however I don't think I would use an ignition coil for permanent fix though.
:
:Radiodoc
:***********
:
::Undr the heading of Tips & Tricks:
::
::I was browsing around the "AA5 Hot-rodding site" and came across a nice tip:
::You can use a 6.3v CT Filament transformer in place of your audio output transformer if it's bad.
::
::You can use the 6.3v winding with an 8 ohm speaker and the 3.2v tap for a 4 ohm speaker. .. Or whichever seems to give the best results as you test it... also depends if you are using a 50C5 or a 41 or 6v6 etc.
::I tried this tonight with very good results on the output of a 50L6.
::It even worked quite well with an old 120/10 vac door-bell chime transformer.
::
::Here's the site:
::http://www.geocities.com/wa2ise/radios/repair.htm#if
::
::Here's the excerpt:
::"Audio output transformer bad? In a pinch, one can use a power transformer with a secondary of 6.3V center-tap. The turns ratio of the 120V primary to 6.3V secondary is 20 to one. With an 8 ohm speaker as load, that works out to be 8*(202)=3200 ohms on the primary side, close enough to the 2500 ohms a 50C5 wants to drive. Output power will be a dB or so lower, but that will be not noticeable. If driving a 3.2 ohm speaker, use half of the secondary, ie, 3.15V. That's from one end to the center tap. That will look like 3.2*(402)=5120 ohms. Kinda high, but the output power will be half the original value. But you'll be back "on the air". Changing the speaker to an 8 ohm one would probably be worth the effort here. The frequency response of a power transformer will be adequate for an AA5 radio, but won't be hi-fi."

I used to use filament transformers for output transformers all the time. They are sometimes quite plentiful at American Science and Surplus. I made my brother a small portable AA5 guitar amplifier, complete with vibrato, using an AC transformer as an output transformer (35Z5-rect, 50L6-output, 12SQ7-1st audio, 12SK7-pre-amp, 12SA7-vibrato). It's a shame that I used to build on wooden chassis, because I had to filter quite a bit to prevent spurious high frequency oscillation. I usually got pretty good results, though. Ah....back in the days of no responsibilities. I'd spend hours and days making various things. Any tube or transformer would do the trick. I built an amplifier once with a damper tube, a HOT, and some vertical triode....all old 1950s octal TV tubes. I didn't realize back then that those tubes don't necessarily operate linearily. The amplifier worked well enough, though. I've heard worse. Those tubes drew a lot of filament current.

T.

"An old TV transformer, high voltage winding to push-pull 807 or 6L6-GC tubes makes a POWERFUL guitar amp with enhanced bass response. "


OF COURSE.....he's referring to the use of a sets power transformer" not the hoz sweep components flyback transformer, with its optimal 15,750~'s design center
....as any very lower audio spectra would be down -60-80 db in any attempted trial to be used in that manner.


73's de Edd

:Interesting about the flyback transformer. It uses a ferrite core, too, so it's really quite efficient.
:
:I used to use filament transformers for output transformers all the time. They are sometimes quite plentiful at American Science and Surplus. I made my brother a small portable AA5 guitar amplifier, complete with vibrato, using an AC transformer as an output transformer (35Z5-rect, 50L6-output, 12SQ7-1st audio, 12SK7-pre-amp, 12SA7-vibrato). It's a shame that I used to build on wooden chassis, because I had to filter quite a bit to prevent spurious high frequency oscillation. I usually got pretty good results, though. Ah....back in the days of no responsibilities. I'd spend hours and days making various things. Any tube or transformer would do the trick. I built an amplifier once with a damper tube, a HOT, and some vertical triode....all old 1950s octal TV tubes. I didn't realize back then that those tubes don't necessarily operate linearily. The amplifier worked well enough, though. I've heard worse. Those tubes drew a lot of filament current.
:
:T.

T.

How can I get a schematic for one of these guitar amps? I would love to build one for my son.
Jon.
:
::Peter,
::
::I even saw/read somewhere a while ago where a person used an automotive ignition coil as an audio output transformer. I tried it and I was surprised at how it sounded, however I don't think I would use an ignition coil for permanent fix though.
::
::Radiodoc
::***********
::
:::Undr the heading of Tips & Tricks:
:::
:::I was browsing around the "AA5 Hot-rodding site" and came across a nice tip:
:::You can use a 6.3v CT Filament transformer in place of your audio output transformer if it's bad.
:::
:::You can use the 6.3v winding with an 8 ohm speaker and the 3.2v tap for a 4 ohm speaker. .. Or whichever seems to give the best results as you test it... also depends if you are using a 50C5 or a 41 or 6v6 etc.
:::I tried this tonight with very good results on the output of a 50L6.
:::It even worked quite well with an old 120/10 vac door-bell chime transformer.
:::
:::Here's the site:
:::http://www.geocities.com/wa2ise/radios/repair.htm#if
:::
:::Here's the excerpt:
:::"Audio output transformer bad? In a pinch, one can use a power transformer with a secondary of 6.3V center-tap. The turns ratio of the 120V primary to 6.3V secondary is 20 to one. With an 8 ohm speaker as load, that works out to be 8*(202)=3200 ohms on the primary side, close enough to the 2500 ohms a 50C5 wants to drive. Output power will be a dB or so lower, but that will be not noticeable. If driving a 3.2 ohm speaker, use half of the secondary, ie, 3.15V. That's from one end to the center tap. That will look like 3.2*(402)=5120 ohms. Kinda high, but the output power will be half the original value. But you'll be back "on the air". Changing the speaker to an 8 ohm one would probably be worth the effort here. The frequency response of a power transformer will be adequate for an AA5 radio, but won't be hi-fi."

::Not knowing any better, I have been doing this since I was in my teens. At age 62, I still build a lot of my own stuff using salvaged parts. If you are willing to sacrifice high-frequency response, almost any 120 in to 5-20 volts out will 'work' as an output transformer. Any old power transformer from an old vibrator type car radio works GREAT with enhanced bass, using a pair or quad of 6V6-GT in push-pull. An old TV transformer, high voltage winding to push-pull 807 or 6L6-GC tubes makes a POWERFUL guitar amp with enhanced bass response. (But don't plug the guitar in with the amp turned up, or you will blow the speaker cone right through the grill cloth.)
:
:How can I get a schematic for one of these guitar amps? I would love to build one for my son.
:Jon.
::
:::Peter,
:::
:::I even saw/read somewhere a while ago where a person used an automotive ignition coil as an audio output transformer. I tried it and I was surprised at how it sounded, however I don't think I would use an ignition coil for permanent fix though.
:::
:::Radiodoc
:::***********
:::
::::Undr the heading of Tips & Tricks:
::::
::::I was browsing around the "AA5 Hot-rodding site" and came across a nice tip:
::::You can use a 6.3v CT Filament transformer in place of your audio output transformer if it's bad.
::::
::::You can use the 6.3v winding with an 8 ohm speaker and the 3.2v tap for a 4 ohm speaker. .. Or whichever seems to give the best results as you test it... also depends if you are using a 50C5 or a 41 or 6v6 etc.
::::I tried this tonight with very good results on the output of a 50L6.
::::It even worked quite well with an old 120/10 vac door-bell chime transformer.
::::
::::Here's the site:
::::http://www.geocities.com/wa2ise/radios/repair.htm#if
::::
::::Here's the excerpt:
::::"Audio output transformer bad? In a pinch, one can use a power transformer with a secondary of 6.3V center-tap. The turns ratio of the 120V primary to 6.3V secondary is 20 to one. With an 8 ohm speaker as load, that works out to be 8*(202)=3200 ohms on the primary side, close enough to the 2500 ohms a 50C5 wants to drive. Output power will be a dB or so lower, but that will be not noticeable. If driving a 3.2 ohm speaker, use half of the secondary, ie, 3.15V. That's from one end to the center tap. That will look like 3.2*(402)=5120 ohms. Kinda high, but the output power will be half the original value. But you'll be back "on the air". Changing the speaker to an 8 ohm one would probably be worth the effort here. The frequency response of a power transformer will be adequate for an AA5 radio, but won't be hi-fi."