Mystery Magicians' M808A 2 Channel Tube Pre
Feb 13, 2024 4:34:54 GMT -6
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chessparov and ontravelling like this
Post by poppaflavor on Feb 13, 2024 4:34:54 GMT -6
Mystery Magicians M808A
Haven't seen this one discussed much here (or anywhere).
www.mysterymagicians.com/m808a-preamplifier
www.mysterymagicians.com/products/p/m808a-dual-channel-mircrophone-instrument-preamplifier
A really flexible and extensive feature set.
I got one a couple weeks ago and still exploring it. Early days yet. Had a great conversation with Arash from MM. Good fellow with lots of knowledge and plans, and very informative and open about their design decisions.
It has a auto detecting 120/240 internal power supply.
So far I can say it can be really clean but also get juicy warm when the second stage is pushed into the attenuator. The pentode vs triode option is really nice and makes a big difference in tone, although the gain difference makes it so comparisons aren't really just a flip of a switch.
Has 150 ohm and 600 ohm outputs from a center tapped transformer that impact the saturation, tone and depth as well. The 150 vs 600 also impacts the level out.
With the pad, pentode/triode, 150/600, gain knob and attenuator it's a bit complex to get the output and tone dialed in. But very flexible.
It has HPF and LPF and also send/receive inserts for the mic and DI inputs. Nice VU metering as well, with +4/+8 level switching. Although I'd prefer backlit rather than bottomlit since the bottom lit can get a bit glaring when the unit is mounted lower in a rack and I'm looking down at it (the Pynamic 500 comp had this same glaring bottomlit VU issue imo).
It also has dedicated line inputs but frustratingly those line inputs are AFTER the filters and inserts (and also after the pentode/triode). This runs contrary to what I anticipated and to my original intended purpose of line level stereo mix bus with insert processor. The impact of this design decision is that if I want to use the filters or inserts or switch the pentode/triode tone on line level inputs I have to pad the line with something like an Avedis' LPZ-2 and go into the mic input. Not a deal breaker for me but not optimal. For me it basically defeats the entire purpose of dedicated line in jacks. I REALLY wish the line in could natively use the filters, inserts and tube switch without having to pad the line level and go into the mic input!
Once I get more familiarity I'll try to upload some samples. It sounds great even just running stereo bus through without tweaking the bells and whistles. Softens transients but isn't dull or lifeless. The THD is about 0.5% at +6db into the line in driving into the attenuator. It's nearly all 2nd order, so looks like it's mostly tube saturation and perhaps less so transformer saturation.
One strange thing is that the THD on one channel is about twice that is the other channel. Anywhere between 0db, +6db, +14db into the line in I get twice as much THD on one of the channels as the other using a sweep in REW. At the max driven input I get like 1.3% THD at +14db in one channel and 0.6% THD on the other. So when driven I'm concerned it may get noticeable for stereo bus processing. I'm hoping it's a tube match issue, so I can replace tubes, and not that this difference is baked into the circuit. I've got some more documentation to do (and want to make sure it's actually an issue when listening) and then will ask MM for info/help.
Seems to have good fidelity for mids and highs and the bottom doesn't really fart out (at 600 ohm output) even with a fairly hot input and bass heavy material. Not sure about the bass response though, still exploring that. Seems to perhaps not give me quite enough low end sub thickness by ear, but that may be because it's tightening the subs up and making them less flabby. I looked at the frequency response with REW and there is no roll off down below 10 hz so maybe it's my imagination (or the Coil CA70S has me too spoiled for wicked awesome low end lol).
Stay tuned :-)
Haven't seen this one discussed much here (or anywhere).
www.mysterymagicians.com/m808a-preamplifier
www.mysterymagicians.com/products/p/m808a-dual-channel-mircrophone-instrument-preamplifier
A really flexible and extensive feature set.
I got one a couple weeks ago and still exploring it. Early days yet. Had a great conversation with Arash from MM. Good fellow with lots of knowledge and plans, and very informative and open about their design decisions.
It has a auto detecting 120/240 internal power supply.
So far I can say it can be really clean but also get juicy warm when the second stage is pushed into the attenuator. The pentode vs triode option is really nice and makes a big difference in tone, although the gain difference makes it so comparisons aren't really just a flip of a switch.
Has 150 ohm and 600 ohm outputs from a center tapped transformer that impact the saturation, tone and depth as well. The 150 vs 600 also impacts the level out.
With the pad, pentode/triode, 150/600, gain knob and attenuator it's a bit complex to get the output and tone dialed in. But very flexible.
It has HPF and LPF and also send/receive inserts for the mic and DI inputs. Nice VU metering as well, with +4/+8 level switching. Although I'd prefer backlit rather than bottomlit since the bottom lit can get a bit glaring when the unit is mounted lower in a rack and I'm looking down at it (the Pynamic 500 comp had this same glaring bottomlit VU issue imo).
It also has dedicated line inputs but frustratingly those line inputs are AFTER the filters and inserts (and also after the pentode/triode). This runs contrary to what I anticipated and to my original intended purpose of line level stereo mix bus with insert processor. The impact of this design decision is that if I want to use the filters or inserts or switch the pentode/triode tone on line level inputs I have to pad the line with something like an Avedis' LPZ-2 and go into the mic input. Not a deal breaker for me but not optimal. For me it basically defeats the entire purpose of dedicated line in jacks. I REALLY wish the line in could natively use the filters, inserts and tube switch without having to pad the line level and go into the mic input!
Once I get more familiarity I'll try to upload some samples. It sounds great even just running stereo bus through without tweaking the bells and whistles. Softens transients but isn't dull or lifeless. The THD is about 0.5% at +6db into the line in driving into the attenuator. It's nearly all 2nd order, so looks like it's mostly tube saturation and perhaps less so transformer saturation.
One strange thing is that the THD on one channel is about twice that is the other channel. Anywhere between 0db, +6db, +14db into the line in I get twice as much THD on one of the channels as the other using a sweep in REW. At the max driven input I get like 1.3% THD at +14db in one channel and 0.6% THD on the other. So when driven I'm concerned it may get noticeable for stereo bus processing. I'm hoping it's a tube match issue, so I can replace tubes, and not that this difference is baked into the circuit. I've got some more documentation to do (and want to make sure it's actually an issue when listening) and then will ask MM for info/help.
Seems to have good fidelity for mids and highs and the bottom doesn't really fart out (at 600 ohm output) even with a fairly hot input and bass heavy material. Not sure about the bass response though, still exploring that. Seems to perhaps not give me quite enough low end sub thickness by ear, but that may be because it's tightening the subs up and making them less flabby. I looked at the frequency response with REW and there is no roll off down below 10 hz so maybe it's my imagination (or the Coil CA70S has me too spoiled for wicked awesome low end lol).
Stay tuned :-)
