plainbriny
New Head-Fier
- Joined
- Apr 7, 2016
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My previous amp is a DAC/AMP combo xDuoo TA-01, which is a great little hybrid amp using 12AU7 tube. I like it very much and it is powerful enough to drive my cans.
However, I always want to try a PURE tube amp. There are various options, but it would be better if I can build one from the kit! So after some search, I found one which uses 6n5p (6AS7/6080) + 6n11 (6DJ8/6922). The total cost with PCB, parts, transformer, potentiator, case etc (tubes excluded) is only a tiny fraction of other amps. This amp doesn't have brand, but they call it Qing Feng (Breeze Audio) E-100. You may also see assembled amp named Nobsound, I think they are the same thing, rebranded maybe.
The assembling is straight forward and can be done in several hours. But I spent some time figuring out how to assemble the case..
Edit June 6th: well, this kit is cheap but some of the components are wrong. For example, one of the 5W resistor is wrong (1.5K instead of 5.6K), cause extremely high temperature (from higher than expected current) and the PCB is smoked. I have desoldered them and will replace once the new resistors I ordered arrived.
I got the tubes locally, because they only provide Chinese 6n5p and 6n11. 6n5p is compatible with 6AS7(G) and 6080 (perhaps others), and 6n11 is compatible with 6DJ8 and 6922. My first combination is Thomson-CSF 6080WA and Mullard PCC189.
The box of CSF 6080WA is ridiculously huge....
This combination is very nice and c/p value is good. I have also tried some 12AU7 (with adapter) but the sound is muddy. Looking at the spec I found the resistance is much higher in 12AU7 and mu is lower, maybe that's why 12AU7 is not performing well in this amp. The first image is Sveltana 6H13C with Mullard PCC189, this combination is also good.
So far I am very pleased with this amp, and more mods to come. The only issue right now: it's too darn hot! (Edit: which might be due to the 5W resistor with wrong ohm value and thus causing higher than expected current and temperature. Will fix in the next couple days.)
June 6th: desoldered the wrong 5W resistor
The PCB is smoked since the current and power (heat) is several times of those of the adjacent one.
I also removed some other capacitors, to improve mid-high frequency response with a 2.2uF in stead of 0.1uF one. Ordered but not yet arrived.
June 8th update: the replacement parts arrived
The resistors were moved to the back side of the PCB, will be on the top after assembled.
Some capacitors replaced.
At first, I found that the the volume of left channel seems to be louder than the right, perhaps the wrong resistor (and current) did some damage to the other parts? I need to listen more to make sure. Update: After some cross testing, it seems to be the fault of 3.5 to 6.3 mm adapter. All is well now.
June 11 update: tried some means to lower the temperature. This has some effects, at least I can comfortably use the turning knob now.
Haven't applied thermal paste yet, should be able to decrease the temperature further.
However this limited the space for 6AS7/6H13C tubes...
June 26 update: rolled e88cc to dual 5654W (6ak5) with adapter, they are far exceeding my expectations, considering the price of 5654, this configuration is very cost-effective.
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