Frankly, I do not know if any scheme similar to the DLH has been created previously (neither when nor by whom). I only know of my personal effort to arrive at the design that I have presented to the DIY community. That effort was without looking for something pre-existing to work on, since it is not my way of working. I always try to be myself in my designs, since I am too obsessive with methods and calculations (many things have to necessarily pass through my hands and I do not usually take anything for granted). That is my technical spirit.
In the development path of the DLH, there was an origin and successive functional attempts of circuits. Some of them might look like the same Death of Zen. Others are rarely seen. Parts of the "primates" circuits could be successfully implemented in other more contemporary circuits of that evolution. As a result of all that evolution, would appear the "homo sapiens" of those circuits: the DLH or our Frankenstein.
The concept was always the same: keep a low number of stages, simplicity and quality. Lastly, with the DLH I tried to improve the performance of the "primates" circuits. As a side effect, the possibility arose of adjusting the mode of operation of the output between SE and PP. That's why I saw the possibility that the DLH formed a nice trilogy with the JLH and the PLH. That is the history of the DLH.
There have been many more links in this evolution, only that I mention the most representative and those that integrate interesting parts to implement.
I really like that you have been encouraged to simulate and test variants of the DLH, kokoriantz!!!
.
The greatest of my respects
In the development path of the DLH, there was an origin and successive functional attempts of circuits. Some of them might look like the same Death of Zen. Others are rarely seen. Parts of the "primates" circuits could be successfully implemented in other more contemporary circuits of that evolution. As a result of all that evolution, would appear the "homo sapiens" of those circuits: the DLH or our Frankenstein.
The concept was always the same: keep a low number of stages, simplicity and quality. Lastly, with the DLH I tried to improve the performance of the "primates" circuits. As a side effect, the possibility arose of adjusting the mode of operation of the output between SE and PP. That's why I saw the possibility that the DLH formed a nice trilogy with the JLH and the PLH. That is the history of the DLH.
There have been many more links in this evolution, only that I mention the most representative and those that integrate interesting parts to implement.
I really like that you have been encouraged to simulate and test variants of the DLH, kokoriantz!!!
.The greatest of my respects
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It would be necessary to carry out the long-term tests, according to the heat sinks that you have. Try to see what happens first with a relatively low bias, permanently watching how it evolves over time. Then, progressively adjust the bias and retest until that bias is stabilized in an immovable value.
My brief tests on the videos were like this (without source resistors) at important currents (between 1 A and 1.3 A, approximately).
Has anything improved with the modifications I suggested?
Tell me if the DLH or DLHSB performance suits you.
Regards
My brief tests on the videos were like this (without source resistors) at important currents (between 1 A and 1.3 A, approximately).
Has anything improved with the modifications I suggested?
Tell me if the DLH or DLHSB performance suits you.
Regards
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I have developed ,diegomj1973, a technique of using in amplifiers, negative impedance load that I baptized it the Phoenician .The last example you can see posted in the Phoenician follower the Phoenician follower
As logic ,I installed a phoenician upon a common source irfp150, driven by an input differential pair of P mosfet zvp3310 .The circuit looked like Nelson's Aleph ,but providing 25W . Three months ago , as I saw your technique of using complimentary differential , that I applied it to the Phoenician Aleph ,passing its open loop frequency response from 10khz to 100khz . The problem was the input impedance , becoming much lower, I could not use an input volume controle of 10k ,so I went hybrid and added an ecc88 as cathode follower . Although the amp has a gain of 20 and the tube running with 22v p/k it has less than 0.1% distortion at 25W.
As you can see ,by working on this amp, same type of DLH, I am getting new ideas about your amp ,and it is not yet finished , now I will transform your circuit into a hybrid 75w class B DLH amplifier.
In the precedent versions that you posted yesterday , I saw the third upper right circuit nearly the same as mine ,so with your permission I will deposit the copyright as HDC hybrid amplifier. I'll record the sound comparative to 300B and post it within two months on youtube . By the way , why you did skip this version ?
Kokoriantz
As logic ,I installed a phoenician upon a common source irfp150, driven by an input differential pair of P mosfet zvp3310 .The circuit looked like Nelson's Aleph ,but providing 25W . Three months ago , as I saw your technique of using complimentary differential , that I applied it to the Phoenician Aleph ,passing its open loop frequency response from 10khz to 100khz . The problem was the input impedance , becoming much lower, I could not use an input volume controle of 10k ,so I went hybrid and added an ecc88 as cathode follower . Although the amp has a gain of 20 and the tube running with 22v p/k it has less than 0.1% distortion at 25W.
As you can see ,by working on this amp, same type of DLH, I am getting new ideas about your amp ,and it is not yet finished , now I will transform your circuit into a hybrid 75w class B DLH amplifier.
In the precedent versions that you posted yesterday , I saw the third upper right circuit nearly the same as mine ,so with your permission I will deposit the copyright as HDC hybrid amplifier. I'll record the sound comparative to 300B and post it within two months on youtube . By the way , why you did skip this version ?
Kokoriantz
7 Watt Class-A Audio Amplifier - RED - Page177
3 - 5 Watt Class-A Audio Amplifier - RED - Page80
For simplicity, a pedestrian darlington like a BDX53 etc could do in a pinch instead of the boring bjt they use (with certain adjustments). Modding the above circuit with a rush cascode could be a good fun as well.
There are multiple variations on the theme possible. I'm about to recap an abomination of mine from very early 90s, already did another. Some work better than others, but it's all a good fun. Diodes imo work better than RC combos at setting the quiescent current, but they are so class-b. NE553x seem to use a similar biasing scheme.
Also note, that even if that totem output configuration at first glance looks like a JLH output stage, it works in a totally different way. So can't be called a JLH-alike.
3 - 5 Watt Class-A Audio Amplifier - RED - Page80
For simplicity, a pedestrian darlington like a BDX53 etc could do in a pinch instead of the boring bjt they use (with certain adjustments). Modding the above circuit with a rush cascode could be a good fun as well.
There are multiple variations on the theme possible. I'm about to recap an abomination of mine from very early 90s, already did another. Some work better than others, but it's all a good fun. Diodes imo work better than RC combos at setting the quiescent current, but they are so class-b. NE553x seem to use a similar biasing scheme.
Also note, that even if that totem output configuration at first glance looks like a JLH output stage, it works in a totally different way. So can't be called a JLH-alike.
I am very happy to see that part of the idea of the DLH has served to implement differentiated schemes of the most commonly known.
As indicated correctly anti, the primate of the DLH had gestation from a proposal to improve a scheme suggested by a dear friend at Forosdeelectronica.com called Juan Carlos Hernández Púa, since a moderator of that same forum considered that the topic was beginning to have own life and decided to separate it from another thread. Great luck for me was that situation as it allowed me to develop several improvements and then present different variants of it.
You can see the whole story there:
Otro amplificador de 3 Transistores ! BBB ! | Foros de Electronica
Evolucion del mitico amplificador JLH 1969 | Foros de Electronica
Amplificador Clase A 4 W con SRPP + Bastode | Foros de Electronica
Here is the exact place where the DLH was born:
Amplificador HDC 20 W, clase A, 2 en 1 !!! | Foros de Electronica
Regards
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I built these amp, I did not test because I do not have the inductors which withstand 3A or more per channel.
Maybe I will test it without the inductors.
What do you think (I know these only an SE amp to me still a simple not over complicated version.
Maybe I will test it without the inductors.
What do you think (I know these only an SE amp to me still a simple not over complicated version.
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Although I have not simulated it, I already saw it a while ago. It resembles in part the power follower of Andrea Ciuffoli or the power follower of Pavel Macura.
What I do not like at all is the rectification system. This system could cause a ripple superimposed on the traditional one, by differences in the Vd of the diodes or between the voltages of the secondary windings. Even that effect could be aggravated with high consumption if armored type transformers are used (traditional core E-I).
The PSRR of such a circuit usually does not exceed 45 to 50 dB at 100 or 120 Hz.
On October 3, 2010, I had built a power follower using an extremely "quiet" power supply in terms of noise, given its layout and the use of four transformers for a stereo system.
My greatest regards
p.s. As a possibility of improvement to that power follower, it could have been to use only positive voltage regulators.
What I do not like at all is the rectification system. This system could cause a ripple superimposed on the traditional one, by differences in the Vd of the diodes or between the voltages of the secondary windings. Even that effect could be aggravated with high consumption if armored type transformers are used (traditional core E-I).
The PSRR of such a circuit usually does not exceed 45 to 50 dB at 100 or 120 Hz.
On October 3, 2010, I had built a power follower using an extremely "quiet" power supply in terms of noise, given its layout and the use of four transformers for a stereo system.
My greatest regards
p.s. As a possibility of improvement to that power follower, it could have been to use only positive voltage regulators
.Attachments
Hello all,
I populated the DLH pcb's from Prasi (a joy to solder on these pcb's by the way ).
The 56ohm resistor is 0.6W and not 1W (a mistake in the BOM I guess). Is this a problem?
The speaker GND wire, I take it from pcb's GND or from a star ground that should exist near the power supply?
Thanks!
I populated the DLH pcb's from Prasi (a joy to solder on these pcb's by the way
). The 56ohm resistor is 0.6W and not 1W (a mistake in the BOM I guess). Is this a problem?
The speaker GND wire, I take it from pcb's GND or from a star ground that should exist near the power supply?
Thanks!
The 56 ohm resistor could be 0.6 W, but I would suggest that the voltage of the input signal in this case does not exceed 1.9 V RMS.
In relation to the terminal (-) of the speaker: it will depend on the layout and the type of power supply used.
A scheme of power supply that has given me excellent results is in which the secondary has two independent windings (4 terminals instead of the more traditional 3 terminals). It uses two rectifier bridges for each channel and no charge current from the main capacitors for filtering flows through the 0V reference terminal. In this way, the reference terminal is free from the noise peaks associated with the instance where the main filtering capacitors are charged. This gives a lower spectral content in high frequency at the reference point, due to the charging action in the main capacitors. The crosstalk is greatly increased and there is less pollution of the spectrum due to asymmetries in the consumption between rails or asymmetries between the rail voltages.
Regards
In relation to the terminal (-) of the speaker: it will depend on the layout and the type of power supply used.
A scheme of power supply that has given me excellent results is in which the secondary has two independent windings (4 terminals instead of the more traditional 3 terminals). It uses two rectifier bridges for each channel and no charge current from the main capacitors for filtering flows through the 0V reference terminal. In this way, the reference terminal is free from the noise peaks associated with the instance where the main filtering capacitors are charged. This gives a lower spectral content in high frequency at the reference point, due to the charging action in the main capacitors. The crosstalk is greatly increased and there is less pollution of the spectrum due to asymmetries in the consumption between rails or asymmetries between the rail voltages.
Regards
No. That was a clarification only for the special condition that arcgotic intends to use: a resistor of 56 ohms x 0.6 W instead of the 56 ohms x 1 W suggested in my schemes.
With 0.6 W, the input voltage is between 0 and 1.9 V RMS maximum. With 1 W, the input voltage is between 0 and 2 V RMS maximum.
Regards
With 0.6 W, the input voltage is between 0 and 1.9 V RMS maximum. With 1 W, the input voltage is between 0 and 2 V RMS maximum.
Regards
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Still had no time to add the 100pF cap in the feedback network as soon I do I will report here.
About your PSU configuration, the - of each bridge is connected to the relative rail capacitor string, and the end of the strings are connected together to form the middle point of the star?
Is-it possible to do it with only one bridge?
The power follower power supply scheme that I built in 2010 serves as a schematic only. If you want to properly design the physical distribution layout of the components for that power supply, you should not design the PCB based on the arrangement of components and connections in the schema. To arrive at an adequate layout design, you can follow the example I explain below:
In this example, you will notice that for the terminal TP1 (the reference, 0 V or ground) there is no charge pulse of the previous capacitors (those on the left). TP1 is a very clean point of reference.
My old power follower:
For thimios: the reason is that I had several transformers (of which were used for the obsolete halogen lamps of 12 V) and I found them useful to achieve a truly quiet power supply and, its construction is particularly suitable to operate at constant demand and at full power (the fixed losses are equal to the variable losses at the point of its maximum power of 50 VA and not at a lower power point). Therefore, they show their highest performance at a point close to their maximum power of 50 VA (suitable to operate in a power follower or in a little A class amplifier, too).
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To complete with some data that may be of great interest for those who want to build, these are the simulations of the open-loop gain and the closed-loop gain of the DLH.
It is interesting to note the large open-loop bandwidth that the DLH has. It is very difficult to find something like this in other types of circuit configurations. This would allow to obtain incredible high frequency quality parameters.
regards
It is interesting to note the large open-loop bandwidth that the DLH has. It is very difficult to find something like this in other types of circuit configurations. This would allow to obtain incredible high frequency quality parameters
.regards
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