OK, I have my DPL12 right here with me... pretty thing, really. 🙂 And, I have my power amp, granted not the best for sub duty, but all I have, nonetheless. It is a Peavey Classic 60/60, stereo power amp, two 6L6's per channel, push-pull. Rated at 31VRMS output (60W). So, I hook this thing up, one channel per VC and fire her up, after proper warmup time. 😉
Ok, I get no sound. Strange... but wait, the cone is BARELY moving, you can only tell by touching it. So, I investigate, crank the volume on the amp to max, moves a tad more, still not visible. Crank my receiver volume (it is connected to my sub-preout) and it moves quite a bit more, visible now. Only problem, I cannot hear ANYTHING from it. When I get close enough (less than 6 inches) to the speaker to hear sound, I can hear his PT (sound it out 😉 ) sound when the bass hits, like from a kick-bass drum. Same problem I had with my old ('70's) solid-state 125WRMS amp. That PT sound. But, the speaker is barely audible, so I preamp it. The PT sound overpowers everything and it sounds absolutely horrible. I hit standby REALLY fast.
So, what is going on here? Why is this speaker so darn hard to drive? What can I do? I cannot spend anymore money, hardly... And I don't know what to do about this. 🙁 What is wrong? Can I fix something?
What about just building a gainclone with paralleled chips? Would it be better? So sad... I wanted the tube amp to work so I could justify having it...
Ok, I get no sound. Strange... but wait, the cone is BARELY moving, you can only tell by touching it. So, I investigate, crank the volume on the amp to max, moves a tad more, still not visible. Crank my receiver volume (it is connected to my sub-preout) and it moves quite a bit more, visible now. Only problem, I cannot hear ANYTHING from it. When I get close enough (less than 6 inches) to the speaker to hear sound, I can hear his PT (sound it out 😉 ) sound when the bass hits, like from a kick-bass drum. Same problem I had with my old ('70's) solid-state 125WRMS amp. That PT sound. But, the speaker is barely audible, so I preamp it. The PT sound overpowers everything and it sounds absolutely horrible. I hit standby REALLY fast.
So, what is going on here? Why is this speaker so darn hard to drive? What can I do? I cannot spend anymore money, hardly... And I don't know what to do about this. 🙁 What is wrong? Can I fix something?
What about just building a gainclone with paralleled chips? Would it be better? So sad... I wanted the tube amp to work so I could justify having it...
Obvious question, but is it wired correctly? Next question, does it move and you get no sound, or not? And what happens when you drive just one channel?
I'd also mention that the DPL12 is not very efficient at the best of times.
Steve
I'd also mention that the DPL12 is not very efficient at the best of times.
Steve
trespasser_guy said:
It sure sounds to me like you've got the voice coils wired in opposite direction, therefore they are pushing against each other and cancelling out. Have you tried driving just one voice coil? Have you tried playing music through it full range? Do you have access to a DMM? Can you measure the resistance through one coil?
Scott
Ok... was it wired correctly, yes. Wired with one amp channel per coil, positive to positive, negative to negative.
No... it isn't very efficient, but with 60W, it should be louder than this. We are talking quiet music listening loud.
I did try full range music through it, played off of my receiver (65WPC solid-state) with VC's in parallel for 4-ohm load, and it was still NOT loud at all.
Drove one VC, not loud...
Can measure DCR, but... not at this moment. 😉 I am enjoying the tube amp through my main speakers, and liking it... but I don't understand why that thing is so darn quiet.
No... it isn't very efficient, but with 60W, it should be louder than this. We are talking quiet music listening loud.
I did try full range music through it, played off of my receiver (65WPC solid-state) with VC's in parallel for 4-ohm load, and it was still NOT loud at all.
Drove one VC, not loud...
Can measure DCR, but... not at this moment. 😉 I am enjoying the tube amp through my main speakers, and liking it... but I don't understand why that thing is so darn quiet.
What are you playing through it, and how much is the cone moving?
I'd suggest hooking it up full range like you have done to your solid state receiver (One VC per channel would be best - +ve to +ve as you have done.)
Do you own Dark Side of the Moon on CD/LP/anything?
If so, play Speak to Me at a fairly high volume. You should get suitable huge amounts of excursion as this contains 25Hz or so bass. You may not hear that much though - what you are looking for is the excursion. Assuming the cone is moving as it should (Check my website - I have a video of a DPL12 in a sealed box in action during this track), it should be fine. You are looking for at least 15mm of p-p excursion, hopefully a little more. Make sure you don't over do it, though!
If the above test produces good cone movement, play the second track full range. You'll get heaps of distortion, but should get good bass out of it - this time you should be able to hear it.
What sort of box do you have the DPL12 in? Is it sealed or vented, and if vented, what are the internal volumes port info etc?
The webpage with the movie on it is at:
http://www.massey.ac.nz/~jcmarsha/hometheatre
The movie is on the DIY sub page at the bottom.
I'd suggest hooking it up full range like you have done to your solid state receiver (One VC per channel would be best - +ve to +ve as you have done.)
Do you own Dark Side of the Moon on CD/LP/anything?
If so, play Speak to Me at a fairly high volume. You should get suitable huge amounts of excursion as this contains 25Hz or so bass. You may not hear that much though - what you are looking for is the excursion. Assuming the cone is moving as it should (Check my website - I have a video of a DPL12 in a sealed box in action during this track), it should be fine. You are looking for at least 15mm of p-p excursion, hopefully a little more. Make sure you don't over do it, though!
If the above test produces good cone movement, play the second track full range. You'll get heaps of distortion, but should get good bass out of it - this time you should be able to hear it.
What sort of box do you have the DPL12 in? Is it sealed or vented, and if vented, what are the internal volumes port info etc?
The webpage with the movie on it is at:
http://www.massey.ac.nz/~jcmarsha/hometheatre
The movie is on the DIY sub page at the bottom.
5.35cu.ft. ported, tuned to 16Hz for home theatre slam mostly. Can be sealed for music.
And, I don't have that disc... 🙁 I think I might try preamping this tube amp before I get too uptight about it not working. Now... which opamp to use to throw out 2V P-P...
And, I don't have that disc... 🙁 I think I might try preamping this tube amp before I get too uptight about it not working. Now... which opamp to use to throw out 2V P-P...
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