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Old 29th September 2010, 09:18 AM   #21
imagios is offline imagios  Czech Republic
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One more thing on the tube... I assume that if I change the delivered one with the mentioned Telefunken 12AU7 that the socket will fit and I dont need to revire any cables, or are there diferences within the tubes?
well guys as Im not realy skilled with tubes can please some one tell if its so?
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Old 29th September 2010, 07:47 PM   #22
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Here is a guy that makes high quality condenser capsules. These are great for swapping out with the ones the Chinese mics come with:

Peluso Microphone Lab

Dave
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Old 29th September 2010, 09:02 PM   #23
imagios is offline imagios  Czech Republic
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Thanks, I might be a option but these capsules are even more expensive than the whoule kit. I might build it and exchange the capsule later.

For now my biggest concern is the tube. The supplier confirmet its a chines tube, im not sure that I can easy just put a other inside, I saw some nice russian golden tube for 70 bugs i would consider... but as I made only one tube project ant that was micro tubes I have no experience on that, nor knowledge.
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Old 2nd October 2010, 04:47 PM   #24
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Thanks, I might be a option but these capsules are even more expensive than the whoule kit. I might build it and exchange the capsule later.

For now my biggest concern is the tube. The supplier confirmet its a chines tube, im not sure that I can easy just put a other inside, I saw some nice russian golden tube for 70 bugs i would consider... but as I made only one tube project ant that was micro tubes I have no experience on that, nor knowledge.
I just recieved my Aurycle mic kit 3 days from final click to my driveway!

I purchased it to act as a testbed for circuits, tubes, and capsules, and I am not disappointed with the construction quality. It looks alot like a raw Apex460. I think I'll build it stock first before I start putting my own circuits in, just as a baseline. I have Peluso capsules, AKG teflon CK12, and a couple of Neumann capsules I want to try eventually. Tubes on my list are 12AY7, EF86 triode mode, 5840, and 5703WB.

The way I see it is for about $130 you get a $250 mic, but upgrading the capsule, tube, and maybe OPT for an additional $200 or so you can end up with something equivalent to (or even better than) a Peluso or cheap RFT M16 mic you would pay over $1000 for.

Anyway, I'll post the progress and let you know if I succeed.

As far as tube substitution goes, the Aurycle circuit is pretty standard for tube mics with typical voltages and impedance values. It uses cathode auto-bias, so the Rk may need to be changed for different tubes. I would probably try a 12AY7 first. It looks like it will drop in with the same Rk abd bias up to a reasonable point. You should have somewhere between 40-80V on the plate if the bias is correct, which is about .5 mA plate current assuming 120V B+.

The circuit may also be picky about the individual tube. It's a good idea to get a couple or 3 tubes to try. Some may work/sound better than others. The tube needs to be really clean and gas-free, and some occasional tubes will work in other circuits but not in a tube mic due to grid leakage.

I haven't heard of a 12AU7 in a tube mic but I'm sure it's worth a try. You may need to change the Rk value to get the proper bias.

Cheers,

Michael

Last edited by Michael Koster; 2nd October 2010 at 04:56 PM.
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Old 2nd October 2010, 06:39 PM   #25
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Originally Posted by Michael Koster View Post
I just recieved my Aurycle mic kit 3 days from final click to my driveway!

I purchased it to act as a testbed for circuits, tubes, and capsules, and I am not disappointed with the construction quality. It looks alot like a raw Apex460. I think I'll build it stock first before I start putting my own circuits in, just as a baseline. I have Peluso capsules, AKG teflon CK12, and a couple of Neumann capsules I want to try eventually. Tubes on my list are 12AY7, EF86 triode mode, 5840, and 5703WB.

The way I see it is for about $130 you get a $250 mic, but upgrading the capsule, tube, and maybe OPT for an additional $200 or so you can end up with something equivalent to (or even better than) a Peluso or cheap RFT M16 mic you would pay over $1000 for.

Anyway, I'll post the progress and let you know if I succeed.

As far as tube substitution goes, the Aurycle circuit is pretty standard for tube mics with typical voltages and impedance values. It uses cathode auto-bias, so the Rk may need to be changed for different tubes. I would probably try a 12AY7 first. It looks like it will drop in with the same Rk abd bias up to a reasonable point. You should have somewhere between 40-80V on the plate if the bias is correct, which is about .5 mA plate current assuming 120V B+.

The circuit may also be picky about the individual tube. It's a good idea to get a couple or 3 tubes to try. Some may work/sound better than others. The tube needs to be really clean and gas-free, and some occasional tubes will work in other circuits but not in a tube mic due to grid leakage.

I haven't heard of a 12AU7 in a tube mic but I'm sure it's worth a try. You may need to change the Rk value to get the proper bias.

Cheers,

Michael
I have a few of the Apex 460 mic's that are in various stages of upgrades. So far I've had the best sound with the 12AY7 tubes. I am also going to make some socket adapters and try some "pencil" tubes such as 6111 and 6021 and see how those sound.
Those kits sound like a good deal for someone that is going to do the mods as it is cheaper than buying the APEX 460's and modding them.

Dave
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Old 2nd October 2010, 08:16 PM   #26
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I have a few of the Apex 460 mic's that are in various stages of upgrades. So far I've had the best sound with the 12AY7 tubes. I am also going to make some socket adapters and try some "pencil" tubes such as 6111 and 6021 and see how those sound.
Those kits sound like a good deal for someone that is going to do the mods as it is cheaper than buying the APEX 460's and modding them.

Dave
Let me clarify a little. These are not identical to an Apex 460. First, they're not multipattern and have only a single side capsule.

What I mean is that they're built like a 460 in construction style. OPT shielded at the bottom, nearly identical headbasket construction, but the parts e.g. capsule mount are really low end where the 460 is a notch up or so. These also have a different circuit board. E.g. the wiring for variable polarization voltage is there onthe PCB and in the cable but not connected...

I agree that these are a better deal if you're planning to replace the capsule and do more extensive original mods. On the other hand, if you want to do the mods on the Apex 460 mod web pages step by step this mic won't work. It's not compatible to that level.

For me it's a way to experiment with circuits and components.

I think I'll end up with the Peluso CEK-12, Cinemag CM-2480 OPT, and a 12AY7 using the AKG C12 circuit with variable pattern and maybe a little different bias scheme. The pattern control can go inline.

Michael
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Old 7th October 2010, 11:49 PM   #27
imagios is offline imagios  Czech Republic
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One more thing on the tube... I assume that if I change the delivered one with the mentioned Telefunken 12AU7 that the socket will fit and I dont need to revire any cables, or are there diferences within the tubes?
Well guys im realy a nood, can anyone please tell me if i can do so?
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Old 8th October 2010, 12:06 AM   #28
TheGimp is offline TheGimp  United States
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The kit states it comes with a 12AX7. The 12AU7 will need to be biased differently to work.

Physically it will fit, but you will need to change some components to different value ones on the circuit board, and the 12AU7 will provide less gain.
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Old 8th October 2010, 12:36 AM   #29
ChrisA is offline ChrisA  United States
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Well guys im realy a nood, can anyone please tell me if i can do so?
You can swap a 12au7 for a 12ax7 and likely it will still work to a degree but if the goal is to improve the sound you'd need to swap out a few resisters. The AX and AU are different tubes wit the same pin outs The AX is a high gain tube the AU is a high current tube.

There are others in the series too, like the 12AT7 that fall between the AX and AU
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Old 8th October 2010, 08:13 AM   #30
imagios is offline imagios  Czech Republic
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Ok since I able to solder it but nor realy able to decide what resistors to change to what value, what if I would just swap the manufacturer stay with the 12AX7 but instead of a chinies tube I would buy a russian, would that work or still I would need to change some resistors?
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