The very first tube amplifier I owned, which incidentally was the first proper Hi-Fi integrated amplifier my father bought for himself in 1966, was an André Dumortier Sforzando. At that time Mr Dumortier's designs were really bespoke, high quality, somewhat innovative and very well regarded "niche" products, designed and hand built in Belgium (I"m Belgian). My father bought it for 6000 Belgian Francs, with a cumulative inflation index between 1966 and 2025 of 679.93% that gives us about 1020 Euro ..., whereas an equivalent small manufacturing scale tube integrated amplifier in today's money would most likely cost around 6K Euro?! This tube integrated amplifier was designed around a PP output of quad 7189A tubes and a pair of custom wound Belgian OPTs). When my father gifted this amplifier to me (some 20 years ago) it had been slightly modified (just by making slightly different pin connections on the output tubes) to use a quad of 16P14P EV (be cause NOS 7189A are kind of unobtainium...). The amp still had the original preamp tubes (which I still have and sometimes still use), 1965 Telefunken ECC82 and ECC83 diamond bottoms. Needless to say that this amp worked his magic on me (could have been much worse as a first encounter with a vintage tube amp, hey) and had me signing up with the fervent tube afficionados. Compared to all the other amps I owned afterwards, tube and SS, the Sforzando was way more noisy and coloured, but also way more charming and pleasant to listen to. It had a wonderful natural, gentle and unforced presence and physicality to its presentation that gave real substance to more recent and processed recordings but also and foremost revealed the true essence of recordings of that era (i.e. recordings made with tube gear in the 50's and 60's), regardless of genre. This amp was equally capable of bringing me to tears of joy or to have me dancing around my listening room entranced, while it also served as reference amplification when recording my own productions of electronic music (not dance music...), disarmingly honest... I sadly parted with it, miss you buddy ! This video might be redirecting me to the EL84 option (currently running a PP of EL34), thank you Janos, Frank & Co 🙂
Hi Janos, thank you for your kind words. I also feel that you channel is more like a group of remote friends engaging in audio topics than a normal YT channel with a comment section. My previous comment was probably deleted by YT because I shared a buying experience as well regarding the OPT's discussed. I will not make that mistake again.
Oh no! YT from time to time goes berserk, and starts deleting the most random posts (even mines). I have noticed most of the time when I accidentally do not leave space after the dot, then YT assumes it's a link of some sort and there's a good chance it deletes it. The longer the post, the greater the chance. I made it a habit that I hit copy on any post that is longer than three lines before I hit enter, and in case YT eats it, I paste it again. Often that's enough to get it past the algorithm. If not, I start looking for missed spaces and take out a link. Indeed, I try to run this channel more like a friend-group or user-group or club of friends who are motivated to explore audio and music... thank you Hugo for taking part in this experience!
Hello Janos! I also used to have a Philips Radio from 1959 with an EL84. It sounded wonderfully. That radio also used tube rectification. I only sold it because I cannot stand woke radio.
Indeed, that's the only bad thing with radio - the programs are what they are. In Hungary I grew up listening a lot to the Bartok Radio, which was a treasure. An absolute wonderful radio channel on classical music, and they always had the full pieces without any interruption, with lots of live concerts broadcast directly. I used to record some to tape, and they were absolutely amazing, such integrity and deep absorbtion. Then CD came out, and I expected so much, and was so appalled how bad CD sounded compared to the tapes made from Bartok radio... sure, no surface noise, but other than that CDs let me access nothing of the music. Like a window bolted shut, with triple blinders on.
While I'll stay away from PP, I can ditto much of remarks by you and Frank on the Japanese OPTs.. I bought a potted Hashimoto 20W OPT and coming from a similar AM core your speak of and Lundahl OPTs, I was impressed by their natural timbre and low-high harmonic coherence/integration which I found on a different level... like you said, it feels like it has a soul and they're very nicely made - no cut corners. Yes, it's expensive relatively but at some point it makes sense. I do still like my 93H 10K:10K AM paper/copper wound interstages... they're not like the 'HIFI' sounding AM OPTs; my speculation on that is that the relatively low current variation minimises the 'AM' artifacts.
also with a 1:1 less things can go wrong. Maybe they got lucky with that design. The bigger one with the two seperate coils rings like crazy because its badly designed.
@@Nils31199 Hi Nils!! Great points and unfortunately its very hard to see bad design from the outside.... I also feel it's not just about the IT itself, but the mix, so with an iron OPT, an AM yields a different overall sound than lets say an iron Lundahl LL1660.
I'm glad you tried out the Hashimoto and it was what I expected it to be! Also glad that the 93H 10K IT has that signature, as I have a pair of them :) I already told you about that, but I have not had time since to play around with them yet.
Decades ago when I still messed with vintage amps, I had a Dynaco integrated amp that showed me what this tube was capable of. Lately I am building with unusual tubes because NOS tubes are still available. If I were to build an amp with new production tubes it would be with EL84 outputs.
Hi Janos! I am also considering building an EL84-based PP amp, and have of course heard a lot of praise for the ST-35 amp. It uses solid state rectification, and I think I heard you say in the past that "-There are many tube amps with solid state rectifiers that sound wonderful, but generally, they always sound even better with tube rectification" . Would you recommend modifying the ST-35 circuit for tube rectification ?
The st35's speciality is that it is a ridiculously tiny amplifier. To add a tube rectifier, it would be best to rebuild it on a bigger chassis, and that would also allow use of better capacitors in the power supply. (DC link film caps). Yes would be a significant change towards the better.
I think the price of quality tubes might discourage many people. It seems to me that amplifier theory should be paramount. Quality tubes can be rolled in later as required. Low quality tubes would be better for testing new builds. In case something goes wrong. Some might be happy with the cheap tube sound. For a while. 😊
Yes, I agree with that - test with cheaper tubes, and get the expensive ones after the childhood diseases are all weeded out. (Pretty bad day when an expensive tube gets cooked because of a stupid error, like a miswired tube socket.) :). Also, there's 6CW5, and a lot more variants which are dirt cheap but very good tubes, lot better than modern EL84.
The very first tube amplifier I owned, which incidentally was the first proper Hi-Fi integrated amplifier my father bought for himself in 1966, was an André Dumortier Sforzando. At that time Mr Dumortier's designs were really bespoke, high quality, somewhat innovative and very well regarded "niche" products, designed and hand built in Belgium (I"m Belgian). My father bought it for 6000 Belgian Francs, with a cumulative inflation index between 1966 and 2025 of 679.93% that gives us about 1020 Euro ..., whereas an equivalent small manufacturing scale tube integrated amplifier in today's money would most likely cost around 6K Euro?! This tube integrated amplifier was designed around a PP output of quad 7189A tubes and a pair of custom wound Belgian OPTs). When my father gifted this amplifier to me (some 20 years ago) it had been slightly modified (just by making slightly different pin connections on the output tubes) to use a quad of 16P14P EV (be cause NOS 7189A are kind of unobtainium...). The amp still had the original preamp tubes (which I still have and sometimes still use), 1965 Telefunken ECC82 and ECC83 diamond bottoms. Needless to say that this amp worked his magic on me (could have been much worse as a first encounter with a vintage tube amp, hey) and had me signing up with the fervent tube afficionados. Compared to all the other amps I owned afterwards, tube and SS, the Sforzando was way more noisy and coloured, but also way more charming and pleasant to listen to. It had a wonderful natural, gentle and unforced presence and physicality to its presentation that gave real substance to more recent and processed recordings but also and foremost revealed the true essence of recordings of that era (i.e. recordings made with tube gear in the 50's and 60's), regardless of genre. This amp was equally capable of bringing me to tears of joy or to have me dancing around my listening room entranced, while it also served as reference amplification when recording my own productions of electronic music (not dance music...), disarmingly honest... I sadly parted with it, miss you buddy ! This video might be redirecting me to the EL84 option (currently running a PP of EL34), thank you Janos, Frank & Co 🙂
That you for sharing! What a special amplifier.
Hi Janos, thank you for your kind words. I also feel that you channel is more like a group of remote friends engaging in audio topics than a normal YT channel with a comment section. My previous comment was probably deleted by YT because I shared a buying experience as well regarding the OPT's discussed. I will not make that mistake again.
Oh no! YT from time to time goes berserk, and starts deleting the most random posts (even mines). I have noticed most of the time when I accidentally do not leave space after the dot, then YT assumes it's a link of some sort and there's a good chance it deletes it. The longer the post, the greater the chance. I made it a habit that I hit copy on any post that is longer than three lines before I hit enter, and in case YT eats it, I paste it again. Often that's enough to get it past the algorithm. If not, I start looking for missed spaces and take out a link.
Indeed, I try to run this channel more like a friend-group or user-group or club of friends who are motivated to explore audio and music... thank you Hugo for taking part in this experience!
Hello Janos! I also used to have a Philips Radio from 1959 with an EL84. It sounded wonderfully. That radio also used tube rectification. I only sold it because I cannot stand woke radio.
Indeed, that's the only bad thing with radio - the programs are what they are. In Hungary I grew up listening a lot to the Bartok Radio, which was a treasure. An absolute wonderful radio channel on classical music, and they always had the full pieces without any interruption, with lots of live concerts broadcast directly. I used to record some to tape, and they were absolutely amazing, such integrity and deep absorbtion. Then CD came out, and I expected so much, and was so appalled how bad CD sounded compared to the tapes made from Bartok radio... sure, no surface noise, but other than that CDs let me access nothing of the music. Like a window bolted shut, with triple blinders on.
While I'll stay away from PP, I can ditto much of remarks by you and Frank on the Japanese OPTs.. I bought a potted Hashimoto 20W OPT and coming from a similar AM core your speak of and Lundahl OPTs, I was impressed by their natural timbre and low-high harmonic coherence/integration which I found on a different level... like you said, it feels like it has a soul and they're very nicely made - no cut corners. Yes, it's expensive relatively but at some point it makes sense. I do still like my 93H 10K:10K AM paper/copper wound interstages... they're not like the 'HIFI' sounding AM OPTs; my speculation on that is that the relatively low current variation minimises the 'AM' artifacts.
also with a 1:1 less things can go wrong. Maybe they got lucky with that design. The bigger one with the two seperate coils rings like crazy because its badly designed.
@@Nils31199 Hi Nils!! Great points and unfortunately its very hard to see bad design from the outside....
I also feel it's not just about the IT itself, but the mix, so with an iron OPT, an AM yields a different overall sound than lets say an iron Lundahl LL1660.
I'm glad you tried out the Hashimoto and it was what I expected it to be! Also glad that the 93H 10K IT has that signature, as I have a pair of them :) I already told you about that, but I have not had time since to play around with them yet.
Decades ago when I still messed with vintage amps, I had a Dynaco integrated amp that showed me what this tube was capable of. Lately I am building with unusual tubes because NOS tubes are still available. If I were to build an amp with new production tubes it would be with EL84 outputs.
Hi Janos! I am also considering building an EL84-based PP amp, and have of course heard a lot of praise for the ST-35 amp. It uses solid state rectification, and I think I heard you say in the past that "-There are many tube amps with solid state rectifiers that sound wonderful, but generally, they always sound even better with tube rectification" . Would you recommend modifying the ST-35 circuit for tube rectification ?
The st35's speciality is that it is a ridiculously tiny amplifier. To add a tube rectifier, it would be best to rebuild it on a bigger chassis, and that would also allow use of better capacitors in the power supply. (DC link film caps). Yes would be a significant change towards the better.
I think the price of quality tubes might discourage many people.
It seems to me that amplifier theory
should be paramount. Quality tubes can be rolled in later as required.
Low quality tubes would be better for testing new builds. In case something goes wrong. Some might be happy with the cheap tube sound. For a while. 😊
And rebels dream of transistors 😋
Yes, I agree with that - test with cheaper tubes, and get the expensive ones after the childhood diseases are all weeded out. (Pretty bad day when an expensive tube gets cooked because of a stupid error, like a miswired tube socket.) :). Also, there's 6CW5, and a lot more variants which are dirt cheap but very good tubes, lot better than modern EL84.