Hi everyone, I am pleased to present my fourth tube electronics project. It is a single-ended amplifier using the 45. This one was inspired by a schematic from the Japanese Isamu Asano. The heart of the design consists of a 6SL7 SRPP upstream of the 45 power tubes.
The interest in this project began about 4 years ago. At that time, I had been able to listen to a friend's 2A3 monoblocks (3.5W) in my high-efficiency system (101-105 dB). I had loved these amplifiers. Then, discussions on a French-speaking forum about the 45 had piqued my curiosity given the subjective qualities announced when using this tube that many enthusiasts around the world have appreciated for several decades already.
Having no experience in wiring for heating filaments in AC, my friend who already built this amplifier suggested that I start with DC heating of the 45. That's what I did while adding a current regulation with Coleman regulators. I also took a voltage regulation module for the 6SL7 that I had recovered from a previous project.
Once the schematic was specified, I supplied the various components. The output transformers with a choice of 4kO at the primary were wound by Charly Doria from Dissident Audio. It is the DA1018 model. The power supply transformer and the inductors were made by Étienne Tessier (former Hexacom). This is the first project where I left the all-wood chassis to let myself be tempted by a 4 mm thick steel plate for the top of the box. I drew the cuts for this plate on the computer and entrusted the laser cutting to a specialized Montreal company.
At the head of the high voltage filtering, I have a Russian PIO capacitor. The high voltage capacitors of the 6SL7 and 45 are also decoupled by Russian Teflon capacitors for their contribution in the high frequencies. The high voltage rectification is done by a 5Z3 rectifier. I also inserted Sophia Electric's high voltage delay module. The high voltage arrives after about 60 seconds of preheating the filaments.
Here's the schematics:
Amplifier stage:
Power supply:
I took a lot of time to complete this project, wanting to advance it only when the real desire to work on it was there.
Here is a photo showing the inside of the amp and a photo showing the outside:
I finished the construction last spring. Given the French friends who helped me in the realization of this amplifier. I named it the 45 French Connection.
Sébastien
The interest in this project began about 4 years ago. At that time, I had been able to listen to a friend's 2A3 monoblocks (3.5W) in my high-efficiency system (101-105 dB). I had loved these amplifiers. Then, discussions on a French-speaking forum about the 45 had piqued my curiosity given the subjective qualities announced when using this tube that many enthusiasts around the world have appreciated for several decades already.
Having no experience in wiring for heating filaments in AC, my friend who already built this amplifier suggested that I start with DC heating of the 45. That's what I did while adding a current regulation with Coleman regulators. I also took a voltage regulation module for the 6SL7 that I had recovered from a previous project.
Once the schematic was specified, I supplied the various components. The output transformers with a choice of 4kO at the primary were wound by Charly Doria from Dissident Audio. It is the DA1018 model. The power supply transformer and the inductors were made by Étienne Tessier (former Hexacom). This is the first project where I left the all-wood chassis to let myself be tempted by a 4 mm thick steel plate for the top of the box. I drew the cuts for this plate on the computer and entrusted the laser cutting to a specialized Montreal company.
At the head of the high voltage filtering, I have a Russian PIO capacitor. The high voltage capacitors of the 6SL7 and 45 are also decoupled by Russian Teflon capacitors for their contribution in the high frequencies. The high voltage rectification is done by a 5Z3 rectifier. I also inserted Sophia Electric's high voltage delay module. The high voltage arrives after about 60 seconds of preheating the filaments.
Here's the schematics:
Amplifier stage:
Power supply:
I took a lot of time to complete this project, wanting to advance it only when the real desire to work on it was there.
Here is a photo showing the inside of the amp and a photo showing the outside:
I finished the construction last spring. Given the French friends who helped me in the realization of this amplifier. I named it the 45 French Connection.
Sébastien
Nice project Sebastien. I believe you have Kanedas too, did you like the 45 better? Would be nice to hear how they compare in your system. What was the price of the output transformers?
Hi swak,
Thanks for the reply. The price for the pair of output transformers was $200 USD, plus shipping, about 4 years ago.
Here's a review I did back a few months ago on a French forum. It will give you an idea of my appreciation:
"I started my listening without any pretension, without really setting up for a critical listening, letting a few records go on the turntable. Right from the start, it was the sound level that surprised me. It must be said that I was going from my reference power amp, a Kaneda 225 that makes 300 W under 4 Ohms with my Onken W to this new amp of…. 1.6 W. I don’t know if it’s the legendary linearity of this power tube, my high-efficiency speakers, a good power supply, etc…? but I didn’t feel any lack of power.
For the moment, the amplifier is not break in and I myself don’t really know what to think about the break in in the sense that I have never been impressed much by the break in of components. In short, my first subjective impressions are given after only about twenty hours of listening, but I like to do them while they are still fresh.
So, I dug out my reference vinyl recordings to get a good idea of what this new amp is capable of. Here are my listening notes:
Miles David, So what:
A superb trumpet by Miles. We can “see” the artist’s playing better. The sound is less aggressive. This is also confirmed with the entry of the first saxophone. The soundstage is a little wider than with the Kanéda. The dynamics are incredible and the tonal balance is excellent. The piano playing is very readable. Although this is also a particularity of this Analogue Productions’ UHQR edition. There is no feeling of a lack of power vs. the Kanéda.
Lhasa, Love came here:
The impact of the bass drum is less, but the whole remains extremely coherent. Lhasa’s voice is simply mind-blowingly natural. I notice a reduction in some sibilance in the voice that I had before. The truthfulness and micro-details of the electric guitar playing are incredible. We are in the territory of a rediscovered recording.
Jack Johnson, Posters:
The bass is less deep and ample, but it remains quite satisfactory. We do not feel a flagrant lack. The extension and duration of the cymbal sounds are striking. The voice gains in naturalness. Once again, the electric guitar is fabulous! The lot of details and nuances added are notable. Ditto for the resonance of the metal cables under the snare drum.
Daniel Lanois, Frozen:
The high frequencies at the beginning of the piece are less aggressive. Even if it is less deep, the electric bass remains very engaging. His playing even gains in nuance. New details are revealed and the extension of the cymbals continues to be striking.
Pixies, Hey!
In this piece which contains large differences in intensity and a raw sound, Black Francis' voice is better than ever! And the SE 45 continues to have fun amplifying this electric guitar brilliantly. The timbres and accuracy of the electric bass are excellent. The breadth is there and once again new details of instrumental playing, voices and back vocals appear in this piece that I know like the palm of my hand. Awesome!
Sigur Rós, Ágætis Byrjun:
A big wow! is combined with a huge smile on my face. How well this amp plays! Pure happiness for this last piece. The details of the guitar and xylophone at the beginning of the piece are striking! The soundstage is wider than with the Kaneda.
At lower volumes, the amp is just as excellent and balanced. This SE 45 has a sound that is always homogeneous and very musically engaging. I don't find it romantic at all as other tube amps might be described. It is in no way a "round" sound, quite the contrary! It is very precise, while being natural in tone. Very balanced and endearing. In addition, I had read it many times, but I remain extremely surprised by this feeling of power that this amp delivers which with my operating points offers only 1.6 W."
Sébastien
Thanks for the reply. The price for the pair of output transformers was $200 USD, plus shipping, about 4 years ago.
Here's a review I did back a few months ago on a French forum. It will give you an idea of my appreciation:
"I started my listening without any pretension, without really setting up for a critical listening, letting a few records go on the turntable. Right from the start, it was the sound level that surprised me. It must be said that I was going from my reference power amp, a Kaneda 225 that makes 300 W under 4 Ohms with my Onken W to this new amp of…. 1.6 W. I don’t know if it’s the legendary linearity of this power tube, my high-efficiency speakers, a good power supply, etc…? but I didn’t feel any lack of power.
For the moment, the amplifier is not break in and I myself don’t really know what to think about the break in in the sense that I have never been impressed much by the break in of components. In short, my first subjective impressions are given after only about twenty hours of listening, but I like to do them while they are still fresh.
So, I dug out my reference vinyl recordings to get a good idea of what this new amp is capable of. Here are my listening notes:
Miles David, So what:
A superb trumpet by Miles. We can “see” the artist’s playing better. The sound is less aggressive. This is also confirmed with the entry of the first saxophone. The soundstage is a little wider than with the Kanéda. The dynamics are incredible and the tonal balance is excellent. The piano playing is very readable. Although this is also a particularity of this Analogue Productions’ UHQR edition. There is no feeling of a lack of power vs. the Kanéda.
Lhasa, Love came here:
The impact of the bass drum is less, but the whole remains extremely coherent. Lhasa’s voice is simply mind-blowingly natural. I notice a reduction in some sibilance in the voice that I had before. The truthfulness and micro-details of the electric guitar playing are incredible. We are in the territory of a rediscovered recording.
Jack Johnson, Posters:
The bass is less deep and ample, but it remains quite satisfactory. We do not feel a flagrant lack. The extension and duration of the cymbal sounds are striking. The voice gains in naturalness. Once again, the electric guitar is fabulous! The lot of details and nuances added are notable. Ditto for the resonance of the metal cables under the snare drum.
Daniel Lanois, Frozen:
The high frequencies at the beginning of the piece are less aggressive. Even if it is less deep, the electric bass remains very engaging. His playing even gains in nuance. New details are revealed and the extension of the cymbals continues to be striking.
Pixies, Hey!
In this piece which contains large differences in intensity and a raw sound, Black Francis' voice is better than ever! And the SE 45 continues to have fun amplifying this electric guitar brilliantly. The timbres and accuracy of the electric bass are excellent. The breadth is there and once again new details of instrumental playing, voices and back vocals appear in this piece that I know like the palm of my hand. Awesome!
Sigur Rós, Ágætis Byrjun:
A big wow! is combined with a huge smile on my face. How well this amp plays! Pure happiness for this last piece. The details of the guitar and xylophone at the beginning of the piece are striking! The soundstage is wider than with the Kaneda.
At lower volumes, the amp is just as excellent and balanced. This SE 45 has a sound that is always homogeneous and very musically engaging. I don't find it romantic at all as other tube amps might be described. It is in no way a "round" sound, quite the contrary! It is very precise, while being natural in tone. Very balanced and endearing. In addition, I had read it many times, but I remain extremely surprised by this feeling of power that this amp delivers which with my operating points offers only 1.6 W."
Sébastien
Your comparison is very interesting for me. I am collecting parts for the 293/4.
When I read about your 45 I thought you were powering only the horns with them! It is pretty surprising to hear the Onken W works so well with them.
I am in the making of a 45, but I am slow. I have tango transformers for them and also Coleman regs, but, as I don't have the sensitivity of your OnkenW, it will power only mid-highs.
When I read about your 45 I thought you were powering only the horns with them! It is pretty surprising to hear the Onken W works so well with them.
I am in the making of a 45, but I am slow. I have tango transformers for them and also Coleman regs, but, as I don't have the sensitivity of your OnkenW, it will power only mid-highs.
Actually, I like the 45 very much to amplify bass, mid and tweeter, but I consider to give bi-amplification a try in the future with the Kaneda 225 to amplify the Onken W bass cabinet.
Quickly said, the 45 offers very nice bass nuances but the Kaneda 225 will go much deeper with an excellent control. Unfortunately, in 3 ways, the frequency cutoff is around 500 Hz and it is less then ideal to cross-over at this place, but I'd like to give it a try.
Sébastien
Quickly said, the 45 offers very nice bass nuances but the Kaneda 225 will go much deeper with an excellent control. Unfortunately, in 3 ways, the frequency cutoff is around 500 Hz and it is less then ideal to cross-over at this place, but I'd like to give it a try.
Sébastien