The Amp Garage

I once had the experience of creating a high-gain preamp in a similar enclosure. On the third attempt, I was able to defeat the problem of the oscillations. I had to optimize the topology of printed circuit boards. By the way, there were no air vents in that case, but I can't say that it was excessi...

if you take into account the working location of this device (on the floor under your feet), then the concept you showed with the upper location of the ventilation holes and the use of fabric may not be optimal. For such devices, a side ventilation arrangement will be much more practical. imgrc00773...

I once faced a similar problem. There was a strange low-frequency level in the sound of the amplifier. There was no oscillation.
But that amplifier had a GNFB switch, and I noticed that turning on the feedback increased the volume level of the amplifier. So I realized that the feedback is positive.

lovetone wrote: ↑Wed Oct 28, 2020 10:36 pm Thats a great build and sounding amplifier, Can I ask which schematic you worked from and if any what changes you made?

The layout of AN Wonderland was taken as a basis. But I used JJ6V6S as power tubes.

http://www.savinoluce.it/

If I understand the question correctly, you have some kind of transformer with an unknown location of windings and an incomprehensible color marking. I hope this technique will help you find the answer to this question: First - use the multimetr and check the resistance and connection between the wi...

Thank you )
The main part of the components I buy in tube-town.net. But some parts I buy from local sellers.

I don't think the hum problem right now is related to the type of solder. Although of course this can create problems in the future. How is grounding heating winding in this amplifier? I don't see any balancing resistors, but maybe it's the central tap of winding? Another source of noise can be the ...

Very often, the source of the hum is the heating wiring. To check this problem, it is enough to power the heater through the switch, and open the heater circuit while the amplifier is running. By the way, I used to think that the heater wiring can only cause interference with a frequency of 50(60)Hz...

I did some work with the photofilters. I hope this can be useful

No, I was referring Martin's PDF file. PDF files can be printed on a papaer and used as a template for drilling. Sometimes I use Corel Draw to import pdf, transform, resize, and then print on paper. This is usually enough for making boards. As for the *.lay6 files, this is for processing in the Spri...

The location of the bands on the body of this resistor is more like 5 bands. This Board also has MF resistors with 4 bands and these bands are arranged differently. A brown color on a blue background looks like gray. In this case, it can be brown/brown/black/orange/red, which corresponds to 110 kOhm...

What can you say about the value of the first plate resistor? If you decipher the value of the color bands it looks like 80 kOhm. But I have never seen such a value. Could it be that this resistor has another band, that is hard to notice in this photo with low resolution?

I think there's an answer here https://ampgarage.com/forum/viewtopic.php?f=5&t=29630