SET amp owners thread

[NellTheAkita]

Usually the path of SE lovers is quite the same, they start with something popular like 300B, then they think they need more power and explore GM70 or 211 etc, but if space is not a limiting factor they end up with small triode for the mids/highs and tailor SS amplification for the woofers.

 

[Musica Bella]

NellTheAkita, my path was the opposite. I started with 805, 845 and 211 tubes years ago and recently started focusing back on the Classics. 45, 2A3, etc.
They all certainly have their place.

 

[NellTheAkita]

NellTheAkita, my path was the opposite. I started with 805, 845 and 211 tubes years ago and recently started focusing back on the Classics. 45, 2A3, etc.
They all certainly have their place.

Hmm so you are heading to the small power tubes camp, just like I mentioned above For a few months I was also running 30W 211 monoblocks, but 45 or 300b is just more me.

 

[Musica Bella]

Hmm so you are heading to the small power tubes camp, just like I mentioned above For a few months I was also running 30W 211 monoblocks, but 45 or 300b is just more me.

View attachment 148717

Yes, I have moved into the smaller DHTs as I prefer them for linestages as well as input stage for GaN FET hybrid amps. And obviously set amplifiers. I did do some work with the GM70 lately but decided not to market it.
We build lots of SET amps and my preference changes depending on mood. (I obviously have a lot of product here) Right now I’m running the 2A3 Linestage into a Hybrid amp currently running 2A3’s into 300 watt GaN FET.
I appreciate and enjoy many technologies.
Your system! I would never leave the room!

 

[bonzo75]

Hmm so you are heading to the small power tubes camp, just like I mentioned above For a few months I was also running 30W 211 monoblocks, but 45 or 300b is just more me.

View attachment 148717

Are these the TAD clones from Vietnam? You have subs with them?

 

[NellTheAkita]

Are these the TAD clones from Vietnam? You have subs with them?

No and no. I made them myself here in Denmark and by that I mean the cabinets because everything else is actually original TAD drivers including horns and crossovers.
And they didn't need any subs in my room.

Recently I went active, and my new loudspeakers Sveda Audio due to the size are supported with two tailored subwoofers from the same company.

 

[Musica Bella]

No and no. I made them myself here in Denmark and by that I mean the cabinets because everything else is actually original TAD drivers including horns and crossovers.
And they didn't need any subs in my room.

Recently I went active, and my new loudspeakers Sveda Audio due to the size are supported with two tailored subwoofers from the same company.
View attachment 148726

Love the TAD drivers. Years ago when I was an Usher dealer, I had a pair of the D2’s while they were still using the original TAD 2001 horn driver.

 

[cal3713]

No and no. I made them myself here in Denmark and by that I mean the cabinets because everything else is actually original TAD drivers including horns and crossovers.
And they didn't need any subs in my room.

Recently I went active, and my new loudspeakers Sveda Audio due to the size are supported with two tailored subwoofers from the same company.
View attachment 148726

That's quite the change!

 

[Amir]

I think you'll find that if you can keep the bass out of the SET it will sound better (smoother, more detailed) right away.

SETs have real troubles with bass because the output transformer would be enormous (small refrigerator size) if it were to actually have enough inductance to support the bass frequencies and doing so would mean it has no high frequency bandwidth. It doesn't due to a 'cut core' which is used to prevent saturation distortion in the core (magnetic laminations) of the output transformer. So lower distortion is traded off for limited low frequency capability due to low inductance at low frequencies.

Since inductance is what makes transformers work, the load impedance to which the output tube is subjected gets very low (approaches the DC resistance of the wire in the primary winding, which is only a few hundred Ohms) and isn't the sort of thing the tube should endure. So limiting the bass response is helpful. It will also help you have more power available to the overall result is lower distortion at nearly any volume at which you can play the system right now.

There are very simple ways to do this- by using a small coupling caps that limits the bass at the input of the amp, or by replacing an existing cap inside the amp to achieve the same result.

Thank you very much for information.

I did not have Lamm ML2 but Romy think the bass of Lamm ML2 is very good

Lamm measurements in stereophile :

Lamm ML2.1 monoblock power amplifier Measurements

Sidebar 3: Measurements Following Vladimir Lamm's instructions, I let the ML2.1 run for an hour or so before I checked the output tube's plate voltage and current. While the voltage was correct at 175V DC, the current was a little high at 0.35A. I adjusted it to read exactly 310mA, as...

www.stereophile.com

As you see the bass response of Lamm ML2 is very extended .


I have checked many stereophile measurements of different tube amplifiers but non of them was as good as Lamm in bass extension.

I hope you have a good description for this.

 

[PeterA]

Thank you very much for information.

I did not have Lamm ML2 but Romy think the bass of Lamm ML2 is very good

Good post Amir. I watched this latest video from Romy. He is not the only listener who thinks the bass of the Lamm ML2 is very good. You should talk to David Karmeli about this subject. In his experience, no amplifier presents a more natural bass. The issue is finding the appropriate speakers.

 

[Amir]

Good post Amir. I watched this latest video from Romy. He is not the only listener who thinks the bass of the Lamm ML2 is very good. You should talk to David Karmeli about this subject. In his experience, no amplifier presents a more natural bass. The issue is finding the appropriate speakers.

Yes Peter, when I checked the stereophile measurements I found no tube amplifier and even no hybrid amplifier come close to bass extension of Lamm ML2.

both Romy and David believe the proper bass reproduction is very very important.
I also read some articles that shows the proper extended bass has huge impact on midrange quality/musicality.

 

[Atmasphere]

Thank you very much for information.

I did not have Lamm ML2 but Romy think the bass of Lamm ML2 is very good

Lamm measurements in stereophile :

Lamm ML2.1 monoblock power amplifier Measurements

Sidebar 3: Measurements Following Vladimir Lamm's instructions, I let the ML2.1 run for an hour or so before I checked the output tube's plate voltage and current. While the voltage was correct at 175V DC, the current was a little high at 0.35A. I adjusted it to read exactly 310mA, as...

www.stereophile.com

View attachment 149361

As you see the bass response of Lamm ML2 is very extended .


I have checked many stereophile measurements of different tube amplifiers but non of them was as good as Lamm in bass extension.

I hope you have a good description for this.

I do. This amp uses several techniques used to extend bass response.

The first, which is more common in modern SETs, is to make the output transformer quite a bit larger than needed, in this case much larger than needed for a mere 10-15 Watts.

The second is to sacrifice high frequency bandwidth a bit, IOW the transformer is optimized to favor low frequencies over the highs. Most SETs are the other way 'round, since the speakers they are often used with don't have much bottom octave response.

Finally negative feedback is used, which makes the Lamm unusual in the pantheon of SETs. Feedback helps linearize bandwidth at both extremes.

But the measurements are incomplete.

A more telling squarewave analysis would have been to use a 20Hz signal rather than 1KHz (FWIW our OTLs are full power to 2 Hz which allows for no squarewave tilt on a 20Hz squarewave).

One of the more telling measurements is full power bandwidth (not seen in the Stereophile measurements), which in most tube amps looks quite a bit different from their 1 Watt bandwidth!! If there is a deficiency of inductance in the output transformer to make bass, it's less likely to show at lower power levels. If the Stereophile measurements had shown distortion vs frequency, an obvious rise in distortion would be noted at lower frequencies approaching the cutoff frequency. This is a good way to tell if the output transformer has sufficient inductance.

If you'll note, the bandwidth measurements are made at 2.83Volts (1 Watt into 8 Ohms). Bass is the region where most of the musical energy resides and so is where most of the amplifier power is used, so if you clip an amplifier, its likely that you will be doing it with some sort of bass notes. Thus, finding out what the -6dB from full power bandwidth and the full power bandwidth is will tell a lot more about what is going on. I seriously doubt this amp can make full power at 20Hz! But having had this amp in our shop, I can also say it does play bass better than most SETs (which wimp out), when bass heavy tracks are thrown at it.

But if you compare this amp to one that can make full power at 20Hz, then you'll see (hear) what is going on.

 

[Amir]

I do. This amp uses several techniques used to extend bass response.

The first, which is more common in modern SETs, is to make the output transformer quite a bit larger than needed, in this case much larger than needed for a mere 10-15 Watts.

The second is to sacrifice high frequency bandwidth a bit, IOW the transformer is optimized to favor low frequencies over the highs. Most SETs are the other way 'round, since the speakers they are often used with don't have much bottom octave response.

Finally negative feedback is used, which makes the Lamm unusual in the pantheon of SETs. Feedback helps linearize bandwidth at both extremes.

But the measurements are incomplete.

A more telling squarewave analysis would have been to use a 20Hz signal rather than 1KHz (FWIW our OTLs are full power to 2 Hz which allows for no squarewave tilt on a 20Hz squarewave).

One of the more telling measurements is full power bandwidth (not seen in the Stereophile measurements), which in most tube amps looks quite a bit different from their 1 Watt bandwidth!! If there is a deficiency of inductance in the output transformer to make bass, it's less likely to show at lower power levels. If the Stereophile measurements had shown distortion vs frequency, an obvious rise in distortion would be noted at lower frequencies approaching the cutoff frequency. This is a good way to tell if the output transformer has sufficient inductance.

If you'll note, the bandwidth measurements are made at 2.83Volts (1 Watt into 8 Ohms). Bass is the region where most of the musical energy resides and so is where most of the amplifier power is used, so if you clip an amplifier, its likely that you will be doing it with some sort of bass notes. Thus, finding out what the -6dB from full power bandwidth and the full power bandwidth is will tell a lot more about what is going on. I seriously doubt this amp can make full power at 20Hz! But having had this amp in our shop, I can also say it does play bass better than most SETs (which wimp out), when bass heavy tracks are thrown at it.

But if you compare this amp to one that can make full power at 20Hz, then you'll see (hear) what is going on.

Thank you very much for information

 

[PeterA]

Yes Peter, when I checked the stereophile measurements I found no tube amplifier and even no hybrid amplifier come close to bass extension of Lamm ML2.

both Romy and David believe the proper bass reproduction is very very important.
I also read some articles that shows the proper extended bass has huge impact on midrange quality/musicality.

I agree, Amir. I judge the quality of the ML2 when listening to music with an appropriate speaker at realistic volumes in my room. The measurements are also interesting to look at.

 

[Atmasphere]

Yes Peter, when I checked the stereophile measurements I found no tube amplifier and even no hybrid amplifier come close to bass extension of Lamm ML2.

both Romy and David believe the proper bass reproduction is very very important.
I also read some articles that shows the proper extended bass has huge impact on midrange quality/musicality.

Of course Stereophile hasn't measured every amplifier out there.

If the bass isn't right the ear might tilt your perception to the highs. If there's too much bass, the ear might perceive the presentation as muddy or rolled off on top, even though its not. So yes, very important to get the bass right.

 

[Amir]

I agree, Amir. I judge the quality of the ML2 when listening to music with an appropriate speaker at realistic volumes in my room. The measurements are also interesting to look at.

Dear Peter, I talked to David recently and asked some questions about turntables, RF problem, cables and David kindly answered all of my questions.

Lamm was a great designer

 

[Amir]

Of course Stereophile hasn't measured every amplifier out there.

If the bass isn't right the ear might tilt your perception to the highs. If there's too much bass, the ear might perceive the presentation as muddy or rolled off on top, even though its not. So yes, very important to get the bass right.

Thank you, I agree you.

 

[PeterA]

Of course Stereophile hasn't measured every amplifier out there.

If the bass isn't right the ear might tilt your perception to the highs. If there's too much bass, the ear might perceive the presentation as muddy or rolled off on top, even though its not. So yes, very important to get the bass right.

I think when the bass is right, all else falls into place.

 

[Ron Resnick]

I think when the bass is right, all else falls into place.

I know that David Karmeli teaches this audio maxim.

Say there is an imbalance, an emphasis, in the treble region. How can the bass being "right" make "all else" right, if something is not right?

 

[microstrip]

I think when the bass is right, all else falls into place.

My interpretation of this often referred sentence is simply that the bass is the harder part of the whole to get right.