Guys,
I am about to replace the output transformer on my champ clone. Since i d like to have a bit more headroom and bass response, i was looking for a bigger one. Don t worry, I m not going crazy trying to squeeze in a 50 watt OT, just to be clear.
I have found this one:
Guitar Single Ended Transformer
Selectable impedance: 5-8 kOhm/4-8-16 Ohm
PRI inductance: 10-17Henry
PRI resistance: 220/290 Ohm
Max DC current: 70 mA
SEC resistance: 0.48/0.69/0.9 Ohm
BW +/-1dB 46-53kHz
BW +/-3dB 23-60kHz
induttanza dispersa media: 39mH
It should be a better transformer. My only doubt, the product is advertised 10w el84 (3 section). Looking at the chart it seems within specs. Please help me understand.
There is also the direct replacement 8 watt Bronco/champ
Which is already an improvement since the stock Ot i have now comes from a very cheap cinese champ clone.
Output transformer question
Moderators: pompeiisneaks, Colossal
Output transformer question
You do not have the required permissions to view the files attached to this post.
Re: Output transformer question
this is trafo from Piemme,
https://shop.piemme-elektra.it/products/8120
I have ordered it also but it fits better for EL34 purpose (70mA) ..
For the SE trafo if is made for nominal current it should be run on this current..This current is making magnetic bias in the core, with low current you can make transformer to work in out of optimum area and have not so ok bass. If you can find it for single 6V6 it is better to select 40mA transformer, cca 5k
https://shop.piemme-elektra.it/products/8120
I have ordered it also but it fits better for EL34 purpose (70mA) ..
For the SE trafo if is made for nominal current it should be run on this current..This current is making magnetic bias in the core, with low current you can make transformer to work in out of optimum area and have not so ok bass. If you can find it for single 6V6 it is better to select 40mA transformer, cca 5k
Re: Output transformer question
Thank you,
What do you mean with 5k at the end of your post?
What do you mean with 5k at the end of your post?
-
Stevem
- Posts: 4576
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Output transformer question
That trans is good choice for more lows and tighter lows provided by its greater mass, but if you really want the head room your likely looking forI have found thru trial & error that the added performance of running the 5.5 watts of clean power that you do have into a 12” driver is the only way to go.
I started off with my Vibrochamp by installing a 10” driver into the stock cabinet.
It’s a tight fit, and you have to liking do what I did and cut a rib out of the speaker frame to clear the can cap, but it does fit.
Unfortunately the cab is too small, and not only depth wise to allow the 10” driver to work as well as it could.
Sound absorbing material lining of the cabinet walls did help I bit.
Next I made a cabinet just for the champ chassis and picked up a used Epiphone 12” cabinet and then had that smile on my face from ear to ear.
It’s a dream set up for recording and for Micing up when playing live.
Everyone who plays thru this set up wants one for themselves.
Since a Champ/ Bronco combo is so small you can install a special 1/4” jack off of the speaker that will cut out the internal speaker and then power a external cab.
I started off with my Vibrochamp by installing a 10” driver into the stock cabinet.
It’s a tight fit, and you have to liking do what I did and cut a rib out of the speaker frame to clear the can cap, but it does fit.
Unfortunately the cab is too small, and not only depth wise to allow the 10” driver to work as well as it could.
Sound absorbing material lining of the cabinet walls did help I bit.
Next I made a cabinet just for the champ chassis and picked up a used Epiphone 12” cabinet and then had that smile on my face from ear to ear.
It’s a dream set up for recording and for Micing up when playing live.
Everyone who plays thru this set up wants one for themselves.
Since a Champ/ Bronco combo is so small you can install a special 1/4” jack off of the speaker that will cut out the internal speaker and then power a external cab.
You do not have the required permissions to view the files attached to this post.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Output transformer question
I agree with you, that is why i run my champ through a princetone reverb sized cabinet loaded with a 10 inch speaker.
I am pleased overall but i got to say, it gets too compressed when you raise the volume up and even squishy when you crank it, way too much and i can tell it is because the undersized OT. I have a solid state rectifier on my champ, not talking about the Sag, which is already negligible on a single ended tube amp.
When i say i need more headroom i don t mean volume.
There is another candidate, too expensive though, this one
I am pleased overall but i got to say, it gets too compressed when you raise the volume up and even squishy when you crank it, way too much and i can tell it is because the undersized OT. I have a solid state rectifier on my champ, not talking about the Sag, which is already negligible on a single ended tube amp.
When i say i need more headroom i don t mean volume.
There is another candidate, too expensive though, this one
You do not have the required permissions to view the files attached to this post.
-
Stevem
- Posts: 4576
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Output transformer question
Another thing to look at then is drive signal level to the output tube grid by viewing it on a scope.
Most 12ax7s in good shape start to clip long after there already driving the output tube into clipping, and this greatly effects the dynamic range you have to use.
A 12AY7 makes for a nice improvement in that regard.
Most 12ax7s in good shape start to clip long after there already driving the output tube into clipping, and this greatly effects the dynamic range you have to use.
A 12AY7 makes for a nice improvement in that regard.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Output transformer question
Right now there is an high gain 12ax7, Tungsol, not my choice, long story. Maybe i can lower the cathode resistors a little bit on this kind of tube? It has a very early preamp distortion.
Re: Output transformer question
I have had good success with Edcor GXSE series. 10W rated 40hz-18khz. Also has 40% UL tap, which may help clean things up. (I often will add the UL option on a switch to go from Pentode/UL)
https://edcorusa.com/collections/tube-a ... ransformer
My amp has a 6L6GC running on near stock voltages with a SS rectifier, and stiff filtering. I also have a choke filtering the entire B+ line, so it has a very low noise floor for a SE amp. The amp was built to lean more towards distortion tones, but it does a pretty nice clean, and the low end response is very good, especially through an external cab with either a closed back or bass porting. The combo is going to lack lows, by design. I have a 10'' Lil' Buddy in mine, and while it has way more balls than a stock champ, the cab is really the limiting factor.
https://edcorusa.com/collections/tube-a ... ransformer
My amp has a 6L6GC running on near stock voltages with a SS rectifier, and stiff filtering. I also have a choke filtering the entire B+ line, so it has a very low noise floor for a SE amp. The amp was built to lean more towards distortion tones, but it does a pretty nice clean, and the low end response is very good, especially through an external cab with either a closed back or bass porting. The combo is going to lack lows, by design. I have a 10'' Lil' Buddy in mine, and while it has way more balls than a stock champ, the cab is really the limiting factor.
It's true i've lost my marbles and i cant remember where i put them
Re: Output transformer question
Thanks for the infos.
My amp does not fart or have a poor bass response. There is plenty of volume too.
The speaker in the cabinet is 25 watt rated and it is not moving at all.
For my experience, small Ot transformers will lead to early distortion and compression and i can definitely hear that.
I am just looking for a little upgrade in terms of craft quality but also, for a transformer capable to handle 5 watt at least
Now come on, it is almost smaller then the smallest choke i have ever seen
My amp does not fart or have a poor bass response. There is plenty of volume too.
The speaker in the cabinet is 25 watt rated and it is not moving at all.
For my experience, small Ot transformers will lead to early distortion and compression and i can definitely hear that.
I am just looking for a little upgrade in terms of craft quality but also, for a transformer capable to handle 5 watt at least
Now come on, it is almost smaller then the smallest choke i have ever seen
You do not have the required permissions to view the files attached to this post.