Fosgate T1500 Hissing/squealing noise from amp itself

[zoltman1991]

So I have a brand new T1500-bdCP.
Two 12" CompQs wired to 1ohm.
LC2i in place.

I have set my LC2i per Audio Control's manual.
-Test tone with volume at 75%.
-Clockwise until maximized light turns on, back off a bit.

I set my T1500 using a DD-1.
When I dial my gain close to the DD-1's light trigger, there is a small hissing noise coming from the amp itself - seems to be right where the gain dial is.

When I play music, amp cuts off, presumably in protection, at high volumes.

Everything should be set correctly.
Could a voltage drop cause this? This is something I have yet to check. Also, when I am I able to play it for a brief period, it is no where near as loud as I thought it would be. Granted they are in a sealed. I went from a single 12" ported to two in a sealed box. I was hoping the added cone area would compensate for the loss of output. But I suppose that's another question. Is the amp's hissing noise telling me the gain is too high - despite my DD-1 not lighting up?

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[Doxquzme Premium Member]

So I have a brand new T1500-bdCP.
Two 12" CompQs wired to 1ohm.
LC2i in place.

I have set my LC2i per Audio Control's manual.
-Test tone with volume at 75%.
-Clockwise until maximized light turns on, back off a bit.

I set my T1500 using a DD-1.
When I dial my gain close to the DD-1's light trigger, there is a small hissing noise coming from the amp itself - seems to be right where the gain dial is.

When I play music, amp cuts off, presumably in protection, at high volumes.

Everything should be set correctly.
Could a voltage drop cause this? This is something I have yet to check. Also, when I am I able to play it for a brief period, it is no where near as loud as I thought it would be. Granted they are in a sealed. I went from a single 12" ported to two in a sealed box. I was hoping the added cone area would compensate for the loss of output. But I suppose that's another question. Is the amp's hissing noise telling me the gain is too high - despite my DD-1 not lighting up?

So, need to know. What is the electrical setup? Any other amps, speakers, crossovers, DSP etc. How is everything wired? It should be as equally loud as it was before.

 

[1aespinoza Premium Member]

I set my T1500 using a DD-1.
When I dial my gain close to the DD-1's light trigger, there is a small hissing noise coming from the amp itself - seems to be right where the gain dial is.

No matter how one sets their amp it should not be making any type of noise. Looking at gut pics of that amp you find the capacitors behind the Gain. Caps hiss when they have issues and I do not recall any other components that hiss. Fosgate amps are known for noisy toroid inductors but those vibrate or hum.
Contact RF or the seller.

 

[zoltman1991]

So, need to know. What is the electrical setup? Any other amps, speakers, crossovers, DSP etc. How is everything wired? It should be as equally loud as it was before.

Stock 130 alt. AGM in hood.
No other amps/devices.

I had a JD1000/1 with no issues. I'm thinking maybe this T1500 is dropping voltage too much so it goes into protect because it drops too low.

Even with the JD1000/1, it would sometimes drop from 13.5 to the 12s. Maybe this extra draw is too much so it's going into protection. Amp was brand new, so certainly nothing wrong with it (at least I hope).

 

[zoltman1991]

No matter how one sets their amp it should not be making any type of noise. Looking at gut pics of that amp you find the capacitors behind the Gain. Caps hiss when they have issues and I do not recall any other components that hiss. Fosgate amps are known for noisy toroid inductors but those vibrate or hum.
Contact RF or the seller.

What issue would cause a capacitor to hiss? voltage issues? My fear is that my stock 130a alt can't keep up with this new amp.

 

[Doxquzme Premium Member]

It's nothing to do with the alt. If its the only amp then how are you feeding it?

I would be runnin no less than 4 gauge ofc wire and preferably 1/0 gauge depending on the length, but that's me. Could be that your starving it,

As for any noises or hissing, if it's coming from the amp, you may have an amp problem, right out of the box.

 

[zoltman1991]

It's nothing to do with the alt. If its the only amp then how are you feeding it?

I would be runnin no less than 4 gauge ofc wire and preferably 1/0 gauge depending on the length, but that's me. Could be that your starving it,

As for any noises or hissing, if it's coming from the amp, you may have an amp problem, right out of the box.

4awg ofc. Same wire that was running my JD1000/1, but I switched it out to the T1500.

I think the amp itself accepts 4awg, even supported by the manual for the product.

I guess part of me doesn't want to accept it's a faulty amp out of the box? Bought it from a local shop.
So there is a way I can 'trim the fat' of my power cable and ground. There's about 2ft unnecessary 4awg cable in the trunk and I can probably trim the ground about 8in.

 

[Doxquzme Premium Member]

4awg ofc. Same wire that was running my JD1000/1, but I switched it out to the T1500.

I think the amp itself accepts 4awg, even supported by the manual for the product.

I guess part of me doesn't want to accept it's a faulty amp out of the box? Bought it from a local shop.
So there is a way I can 'trim the fat' of my power cable and ground. There's about 2ft unnecessary 4awg cable in the trunk and I can probably trim the ground about 8in.

I don't think that is enough to make any difference. if you have 15 ft runs, 1/0 preferably with potential (not real world but) draw of up to 130A so at least 2 gauge. That said, it needs to be independently checked. If you purchased it at a local shop, take it in and have them check it out. Even if they didn't install it, they should still be able to test it out or listen and see if the sound it's making is indicative of a problem amp, out of the box - It happens. Amps should not be making noise. If they give you $hit, call JL.

 

[shredder1 10+ year member]

I'd start this drama with the manufacturer, is 4ga enough for the amp according to Fosgate?
Idk but zero gauge ofc would be
my minimum with a legit 1.5k like a T1500. If I ran something like that, knowing my usage I'd probably min run at least 200A of alt with 1/0 wire runs.
I'm an extreme user and abuser of amplifiers so I always make sure the current offering is sufficiently fed.

Hissing sounds like a slow burn somewhere, capacitors or something else not good.

As to your output woes, going sealed was and is what I predicted. You're car, your money

 

[zoltman1991]

I'd start this drama with the manufacturer, is 4ga enough for the amp according to Fosgate?
Idk but zero gauge ofc would be
my minimum with a legit 1.5k like a T1500. If I ran something like that, knowing my usage I'd probably min run at least 200A of alt with 1/0 wire runs.
I'm an extreme user and abuser of amplifiers so I always make sure the current offering is sufficiently fed.

Hissing sounds like a slow burn somewhere, capacitors or something else not good.

As to your output woes, going sealed was and is what I predicted. You're car, your money

Would you recommend then a 0awg to 4awg reducer? The amp itself will only accept 0awg at the terminals.

Also.. Could a voltage drop cause an amp to cut off? I run at 14v. When playing a song this morning, it dropped to 11v. HOWEVER, the amp did not cut off. This was a high freq and 55hz.

Other songs cut off at high volumes - probably mid 12v - but freq is about 45hz. I'm thinking maybe it's starving for power and that's what's causing the amp to cut out.

 

[shredder1 10+ year member]

Would you recommend then a 0awg to 4awg reducer? The amp itself will only accept 0awg at the terminals.

Also.. Could a voltage drop cause an amp to cut off? I run at 14v. When playing a song this morning, it dropped to 11v. HOWEVER, the amp did not cut off. This was a high freq and 55hz.

Other songs cut off at high volumes - probably mid 12v - but freq is about 45hz. I'm thinking maybe it's starving for power and that's what's causing the amp to cut out.

I never recommend anything, the interwebs are snowflake. But reducers are common and used quite often so your choice.
As far as output goes in your situation I'd go ported but smallish airspace. Ported for your power with delay in mind. Anyone who went sealed after having ported probably had a less than ideal enclosure imo.
Ported done right or higher order enclosures done right negate the sealed vs ported argument. I've almost 40yr as an enthusiast, competitor and sometime paid help. Top of the garbage heap in my class/org for almost 2yr once upon a time.

I'm not someone who just throws comments at the wall most the time. I'm an amateur designer, tons of testing and probably a little too humble. I'd never claim palmares like "professional" or some chit. You never know it all.

 

[1aespinoza Premium Member]

Other songs cut off at high volumes - probably mid 12v - but freq is about 45hz. I'm thinking maybe it's starving for power and that's what's causing the amp to cut out.

I think I missed this part but, how is your amp grounded? A Fosgate Power series should be turning those Kickers to Swiss cheese and not cutting out. Leads me to believe something is wrong in the power supply chain.

 

[zoltman1991]

I think I missed this part but, how is your amp grounded? A Fosgate Power series should be turning those Kickers to Swiss cheese and not cutting out. Leads me to believe something is wrong in the power supply chain.

So it's grounded pretty well. I had the same power/ground in my JD1000/1 set up with no issue- all I did was swap out amps and ensured proper connections.
I think my issue is it's too hungry and I don't have the power to feed it. When playing "Soul Call - Canabliss", at a 55hz bass drop, I dropped voltage to 11v. amp did NOT cut off. However when playing other songs at high volumes, it drops down to 12s and it does the cut off.

I think I've deduced it to my power. Would this be an agreeable cause? running off a stock 130a.

 

[1aespinoza Premium Member]

I think I've deduced it to my power. Would this be an agreeable cause? running off a stock 130a.

I agree. The alternator is what keeps the voltage up while playing. If you are pumping out 1000 watts that is ~100 amps. Have you gotten your battery load tested at Autozone?

 

[zoltman1991]

I agree. The alternator is what keeps the voltage up while playing. If you are pumping out 1000 watts that is ~100 amps. Have you gotten your battery load tested at Autozone?

Not yet. What exactly is "battery load"?

I have a 70ah 760CCA AGM. I've tried looking into new AGMs, but all seem to be similar in specs.

I think I have to bite the bullet and get an alternator