So I tried different valves in my Micro Dark

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So I tried different valves in my Micro Dark

Post by megalithic » Fri Aug 12, 2016 5:06 pm

I tried a lot of them, interesting results. I tried most of them at least 2 times.

Standard Gain Valves

Sovtek 12AX7WA, WB, WC - tried 2 or 3 WAs, 1 WB, 2 WCs. Fizzy top end when cranked, not that great set clean and with a pedal for distortion either.

On the other hand, two of them (one 12AX7WA and one 12AX7WC) are super low gain: I can set the volume at half and gain at full (or the other way around) and it will be really quiet, so quiet that I could probably jam in a room next to a room where someone is sleeping and they won't wake up. I tried them in my Orange Valve Tester and they check out fine. Would it do any damage to keep using them? I'm thinking of doing this and using the Micro Dark as a practice amp.

JJ Tubes ECC83S - I tried four of them. I wouldn't be able to say which one actually came with the amp, but two were kind of fizzy and not that great, and the other two were a bit lower gain but had the best sound: sounded best with pedals with the gain set low, and also sounded good (not fizzy) with the gain maxxed, although not enough gain without pedals for metal unfortunately. I like to set the tone at around 11 o'clock to get a good scoop and not too much high end. I guess they must have designed the amp with these valves in mind.

Long Plate Valves

Sovtek 12AX7LPS and JJ ECC803S - besides slightly higher gain, nothing to write home about. Fizzy.

High Gain Valves

Electro Harmonix and Tung Sol (both 12AX7) - They both provide enough gain for metal with the gain cranked. As with the OR15, if you put the gain above the first notch, the sound will not be clean anymore. However, they certainly do not sound as good distorted as the OR15. The EH is really fizzy, super compressed with the gain on max. Sounds almost like a fuzz. The Tung Sol is smoother. however for some reason I prefer the Electro Harmonix if I had to chose between these two.

Low Gain Valves

JJ EEC81 and ECC82. For some strange reason, the ECC82 (12AU7) was much louder than the ECC81 (12AT7). I don't think I'm crazy about them, might try them more.

note: in the Micro Terror (not Micro Dark) I prefer the JJ ECC803S.

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Re: So I tried different valves in my Micro Dark

Post by Pi3rral » Tue Dec 11, 2018 2:41 am

Thanks for your post!

I'd like to have less distortion on the gain of my micro dark (having more headroom before saturation arrives).
Will a 12AT7 is safe to do that ?
I read about voltage and I'm afraid to do that..

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Re: So I tried different valves in my Micro Dark

Post by Les Paul Lover » Tue Dec 11, 2018 1:47 pm

You won't really increase the headroom, but I think it'll do what you want.

Essentially, you will have the same headroom and clean volume, but you will achieve that later on the gain control, with less gain available overall. Well, that is assuming that's what the ECC83 controls in that amp.... in a full valve amp, that's how it would work. Here, with the micro dark, the ECC83 isn t enough to provide all the gain stages the amp does, so it must have transistors/some chip in the mix too.

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Re: So I tried different valves in my Micro Dark

Post by Pi3rral » Fri Dec 14, 2018 2:09 pm

Ok cool, thanks (sorry for late response).

I also looked at 5751 and 12AY7 which seems to have same characteristics.

I'll try one of theses!

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