Apparently so, but I replaced two diodes connected in series with one and replaced the 330k resistor with a diode. The question is whether, thanks to the lower voltage drop on one diode, the magic loop will react more quickly? Kind regards.
Hello everyone very warmly. The motive for writing this post is the completion of the construction of my amplifier based on the DJCheester project presented here, for which I would like to thank you very much, because the knowledge I gained here, as well as specific solutions turned out to be crucial. And I started in 2017 with the purchase of a power transformer and two loudspeakers (which I then had to change) ... then PCB design, enclosures, looking for components ... and so a few years passed. My amp looks like this: When making the housing, I was inspired by a photo seen on the web some time ago. I designed the PCB myself and commissioned them: The power supply has three circuits: Anode: for PCL86 and EM84 lamps. Glows: 6.3V and 14.5V (doubler). Control: layout delayed switching on of the anode voltage and illumination of PCL86 lamps (they are illuminated from the bottom with an amber LED).
I finally knitted the magic eyes according to the instructions from previous posts: I changed the input resistor from 56k to 15k, the capacitor from 150n to 100n and connected the input to the speaker terminals. Thanks to this I got the expected effect.
I attach some photos:
The amplifier sounds surprisingly good - sure, it's not DREAM AMP from Noise Reducer, but for its simplicity, you can enjoy the sound of a tube amplifier. I encourage you to do it, because it's really worth it. Regards.
The game is better in my opinion than ECL/PCL86, besides about 5W per channel, not 2W. I recommend trying to build it in the future.
In general, you would need to choose speakers with good efficiency and soft bass suspension for a tube amplifier, then the amplifier will transfer the bass beautifully.
And when it comes to DREAM Reducer, I had the opportunity to listen to it, and I will say that it did not captivate me with its sound, although it plays correctly and is PP, but for me it has a lot of minuses.
Firstly, it's not cheap. Hits for PP are expensive but if someone can afford ... PP network transformers are also expensive. Double the number of lamps so the price does its job.
Secondly, the bass-trebble equalizer - for me, an unnecessary gadget
I compared my EL84 SE with this PP and with my speakers, and to be honest, apart from the power, I didn't notice any differences.
Well, this is my subjective assessment, if someone is "burning" to build PP, I'm not discouraged, once I wanted to do a project on the EL34 for training, but so far the prices are scaring me away and the trouble with getting them.
Well, in the DIY EL84 project, you can use the same transformers as are used in Bambino, so recovery.
TG2.5 will approach EL84 because it has taps that allow you to use these transformers, it's about TG2.5-1-666 and network TS40/29/676
My amplifier cost about PLN 200, I mean EL84, i.e. two speaker transformers + mains + EL84x2 and ECC83 tubes.
It's not bad for the cost. Do you have any way to check the lamps? He has several - once there was an idea to build a simple tube amplifier, but there was no motivation. I have to put together what I have - I probably miss tube transformers. Lamps should also be checked.
Hello, to check the type of lamps, it does not work or "by ear" to assess whether the lamp is playing and whether the sound is clear wacniacz is enough, however, in lamps it is useful to know the parameters and wear of the lamp, measuring the parameters and comparing them with the catalog data of the checked lamp.
A great solution once appeared in the journal Elektronika Praktyczna - a microprocessor meter for electron tubes.
Although the topic and idea of building a vacuum tube meter was born on the trioda.pl forum, below is the link to the topic.
It has a catalog with the parameters of over 100 tubes, most of them for audio applications because it was created with this in mind, the processor controls a very extensive power supply where, depending on the choice of a particular tube, anode and grid voltages are given. Three anode catalog voltages and lower and higher are set to outline the slope of the characteristic, calculates the gain and internal resistance as I remember correctly, so this meter replaces the test stand, of course it also has the option of working in manual mode and working as a power supply you set the voltages yourself and you can test a lamp not from the catalog.
As for me, this is a great device, of course, when using it, you should think about testing tubes, especially in manual mode.
I suggest reading about 100 pages on the triode and the documentation from the AVT website, you will know exactly what the meter measures, and after the measurement, we can compare the measured parameters with the catalog data, so we can immediately see if the lamp parameters differ significantly from the catalog ones.
