Modded TCM1150 APEX460 disaster

  • Thread starter Thread starter amzavareei
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Turns out there was a lead missing that should have been going across one of the boards. All the grounds weren't linked. So I fixed that. Now the tube warms, and signal is getting to my preamp. Haven't listened yet. My roomie is using my monitors. But the needle is moving to the sounds fairly acurately. But there seem to be some random spiking. Maybe a loose connection. I'll check tomorrow. Just got to let that ansar and black gate break in some.

Thanks all for your help. Next, off with the CF! Then C9 and 10. Those are low pass filters, I believe. Anyone know the frequency those cut at? I assume at 6db per octave. And also I've heard of C7 being removed. What is that cap for? Thanks again! I look forward to the next phase.
 
amzavareei said:
Turns out there was a lead missing that should have been going across one of the boards. All the grounds weren't linked. So I fixed that. Now the tube warms, and signal is getting to my preamp. Haven't listened yet. My roomie is using my monitors. But the needle is moving to the sounds fairly acurately. But there seem to be some random spiking. Maybe a loose connection. I'll check tomorrow. Just got to let that ansar and black gate break in some.

Thanks all for your help. Next, off with the CF! Then C9 and 10. Those are low pass filters, I believe. Anyone know the frequency those cut at? I assume at 6db per octave. And also I've heard of C7 being removed. What is that cap for? Thanks again! I look forward to the next phase.
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Sounds like you've got it!!

Good job! :)
 
So does anyone that remove the CF notice a definite improvement, or is it just a change of character? And does anyone know what removing C7 would do?

And some more mods. A thin layer of foam under the capsule should cut down on some internal reflections. A pad and a hpf would be cool, but it would be better to have those on the mic itself, and not on the power supply, no? To actually stop those freqs and levels from hitting the tube. That would be tricky.

Thanks again for everyone's help!
 
So the mic shootout wasn't what me, or my friend thought. I didn't end up going. It turns out some lawyer rented a studio and all these mics to buy a setup for his own rich ass hobby. He wanted to sound like Journey. Apparently his highs really need some work. Some of the mics he tried were:
C800,U47, 67, 87, C24, SM58, a couple sound deluxes, and that new neuman digital mic. A few others I don't remember. I didn't hear them yet, but I have the files. The winner was th U67. And super losers were the soundeluxes. Apparently that digital mic is pretty weird. Not necessarily bad, just different. They didn't mess with it much.

So I didn't meet Roy yet, probably do that within the next couple weeks. We're gonna compare our modded 460s to some other mics. Probably a 67 and a c24, and hopefully an unmodded 460 too. This guy is supposed to be some kind of genius. There's some mystery box in the pulltec that he figured out. So he makes his own. He actually showed someone from that company, and he was impressed! And he makes his own distressors too. He calls it The Johnson. It's supposed to be more versatile too. I think he's going to 'mass' produce those too. I'll probably get one.

Anyway, now I'm rambling! Later!
 
amzavareei said:
So the mic shootout wasn't what me, or my friend thought. I didn't end up going. It turns out some lawyer rented a studio and all these mics to buy a setup for his own rich ass hobby. He wanted to sound like Journey. Apparently his highs really need some work. Some of the mics he tried were:
C800,U47, 67, 87, C24, SM58, a couple sound deluxes, and that new neuman digital mic. A few others I don't remember. I didn't hear them yet, but I have the files. The winner was th U67. And super losers were the soundeluxes. Apparently that digital mic is pretty weird. Not necessarily bad, just different. They didn't mess with it much.

So I didn't meet Roy yet, probably do that within the next couple weeks. We're gonna compare our modded 460s to some other mics. Probably a 67 and a c24, and hopefully an unmodded 460 too. This guy is supposed to be some kind of genius. There's some mystery box in the pulltec that he figured out. So he makes his own. He actually showed someone from that company, and he was impressed! And he makes his own distressors too. He calls it The Johnson. It's supposed to be more versatile too. I think he's going to 'mass' produce those too. I'll probably get one.

Anyway, now I'm rambling! Later!
Click to expand...

Ramble on man-- please let us know about those distressor clones, particularly if they're any more affordable than the el's! :D
 
I'm not sure how many of those johnsons he's building, but I think I might be able to get one for a couple c notes. I'll keep the group updated.

Does anyone know how much of a difference a premium power cable would make on this mics power supply?
 
amzavareei said:
I'm not sure how many of those johnsons he's building, but I think I might be able to get one for a couple c notes. I'll keep the group updated.
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:eek:
Please do-- I'd be interested! Thanks!
 
amzavareei said:
So does anyone that remove the CF notice a definite improvement, or is it just a change of character? And does anyone know what removing C7 would do?
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I like the sound better without the CF. With it, it seemed like the bottom end was too overhyped to the point where it sounded a bit lumpy for my taste. Without it, it seemed just right. That was using the CEK12 and CEK67 Peluso capsules, which are larger than the capsule you have. You could have slightly different results with the smaller capsule.
 
Well, it turns out there was never anything wrong with it in the first place. The PCB needed to be screwed back onto the chassis to complete the ground. I thought it was going to chassis somewhere else, or just to the pins groud. So it worked fine, just tested it for a minute before I took the cathode follower off. Now I just get a hum. Tube's warm though! I removed r8, shorted 6, 7, and 8 together, cut any leads going to them, connected C8 to the junction of pin1 and R2. Also removed c7, c9 and c10. Is there anything wrong in the theory of any of that? Or did I probably just mess something else up?
 
Why did you remove C7? It bypasses C6. You can remove the C6 (along with C7) to see if you like it better that way, but not the C7 alone.

But this is a side way issue. For now you need to make it work, so...
Double check one end of C8 goes to junction pin 1/R2 and another one to transformer. Double check if you did not lift or cut any traces while removing C9/10.
Check and post DC voltages on pins 1 and 3 and then we can go from there.
 
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mbrebes said:
So what did you think?
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It really opens up the dynamics. It almost sounds squashed without the mod. It becomes much more open and wide and reacts quicker.

They both get it!
 
OK. Now I need help. I did the first one with the CF mod, and it came out perfectly! I did the second one and now the damn thing is stuck in omni mode. I traced the leads and double/triple checked everything and can't seem to find my mistake.

Help? :(
 
PhilGood said:
OK. Now I need help. I did the first one with the CF mod, and it came out perfectly! I did the second one and now the damn thing is stuck in omni mode. I traced the leads and double/triple checked everything and can't seem to find my mistake.

Help? :(
Click to expand...

It means you are not getting voltage on capsule (the lead connected to pin 3 through 51 Mohm resistor).

First, make sure you have 120V (or whatever B+ is there) on pin 3 in fig8, half of that in cardioid, and 0V in omni. If everything is OK, then the problem is in continuity of traces on the path from pin 3 to the capsule, or short to ground from the capsule, or faulty 59Mohm.

If you don't get any reading on pin 3, then check cable and PSU one at the time, swaping them from a good one.
And away ya go...
 
Well, I think one of the boards was pinching and shorting out something. I tested the lead from pin 3 and it worked just the way it's supposed to. Now I put the mic back together and it's working fine.

Hope that doesn't happen again. Very frustrating. :mad:

Thanks for the help! :)
 
PhilGood said:
Well, I think one of the boards was pinching and shorting out something. I tested the lead from pin 3 and it worked just the way it's supposed to. Now I put the mic back together and it's working fine.
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Hahaha! The best way to fix your old tube TV is to give a good kick with your fist. :)
 
I replaced C7. Pin 1 is 66 volts and pin 3 is 1.08 volts. What's that mean? Tubes warm, only a slight hum outputing. Thanks for the help!
 
Oh yeah, and pins 4 and 5 are still ~6 volts. What the heck?
 
Anyone also know if there are any roadcases around that this would fit just right in? I've got the foam bottom section everything fits in. The SP T3 case looks about right It's sold in the marketplace at pmiaudio.com
It looks like it's got a really open grill on it. All those people were tearing the mesh off their 460s, remember? I wonder how close this is to the 460? The body is obviously a touch different. And it uses a 12ay7. Isn't that even more gain than an x?
 
I think the C1 body is a bit wider. Don't know about the length.

The gain factor on a 12AY7 is 45, whereas on a 12AX7 its 100.

I took the inner 2 layers of mesh out of my 460s and thought it sounded better.

Wish I could help more with your electrical problem. I wouldn't worry about pin 3 as that's the cathode. 66 volts on pin 1 has me worried, as that's the B+ voltage. Check it just before R1. It should be around 160v. Is the dial on the PS set to cardioid?
 
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