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Ampeg V4 Club
- Thread starter birdman14
- Start date
Count me in!
I've got a 71 or 72 (going by the pots) V4 which chrome knobs, no distortion, and no AMPEG logo on the front, but it is a Magnavox.
Picked it up in a little NC pawn shop for $100 a year or two ago.
Link Removed
(Yes all that stupid black tape on there is gone)
It's much cleaner now.
Still has half of its original tubes, is missing the wooden "H" backplate, and the reverb doesn't work.Also, it's been properly grounded... none of this two prong BS on a 100w tuber.
Great score!!!
Thanks Matt
You'll find more info/pics of my cab here: http://www.talkbass.com/forum/f15/seeking-info-about-hiwatt-bass-cabs-375079/
After I posted that thread, I received some PM's stating Dave Hewitt/Georgia Satellites Bassist gigged (and recorded 'keep your hands to yourself') with a pair of HIWATT cabs that had 6 yellow-stripes stencilled on the back, just like mine:
Got a hook on some great condition Mesa 1x15 diesel cabs with original drivers. He isn't sure he wants to sell both just yet, but I'm going to take one regardless.
I miss my V4 (I think it was the guitar version, had a reverb tank) and it was a MONSTER. I used it to power a large 18" folded horn cabinet and a 2 - 15" cabinet. Was always yelled at to turn it down! Cant imagine what an SVT would be like if this 100 watter was this much of a killer.
- Apr 3, 2003
- 35,515
- 19,942
- Disclosures
- Editor-in-Chief, Bass Gear Magazine
I have a question. About impedence. I wish to connect my VT-22 combo to my BA-115HPT combo, so as to use the 15" speaker and 1" horn, in addition to the two 12" speakers in the VT-22. I will, of course, disconnect the speaker(s) in my BA-115HPT from the amp in that combo, so that it works a simply a cabinet.
My question relates to where I might set the impedence switch in my VT-22, when the 15" speaker and 1" horn is added. Here is what I know.....or think I know: The impedence switch is normally set at 8 Ohms. The speakers are the stock, regular speakers (Eminence?) which are connected in series. According to my understanding, the VT22 sometimes came with upgraded Altec speakers in which case the impedence switch is normally set at 4 Ohms. In this scenario, if the additional (Altec) cabinet is added, the switch goes to 2 Ohms.
In the case of the stock, regular speakers, the impedence switch is normally at 8 and, if another cab is added, it is set at another position. 4 Ohms, for example. In my case, according to the specs, the 15" speaker in my BA-115HPT is rated at 4 Ohms. So.....I am wondering what is the impedence of my existing, stock, regular (Eminence?) speakers. Again, they are wired in series. Presumably, their existing (series-wired) impedence is 8 Ohms. In what position do I set the impedence switch when I have added the 4-Ohm speaker(s) within the BA-115HPT?
On a more general note, I gather that the transformers in these V-series amps are robust. Of course, even so, I want to ensure that I do not create damage. What is the greatest danger? Setting the impedence switch too high or too low?
My question relates to where I might set the impedence switch in my VT-22, when the 15" speaker and 1" horn is added. Here is what I know.....or think I know: The impedence switch is normally set at 8 Ohms. The speakers are the stock, regular speakers (Eminence?) which are connected in series. According to my understanding, the VT22 sometimes came with upgraded Altec speakers in which case the impedence switch is normally set at 4 Ohms. In this scenario, if the additional (Altec) cabinet is added, the switch goes to 2 Ohms.
In the case of the stock, regular speakers, the impedence switch is normally at 8 and, if another cab is added, it is set at another position. 4 Ohms, for example. In my case, according to the specs, the 15" speaker in my BA-115HPT is rated at 4 Ohms. So.....I am wondering what is the impedence of my existing, stock, regular (Eminence?) speakers. Again, they are wired in series. Presumably, their existing (series-wired) impedence is 8 Ohms. In what position do I set the impedence switch when I have added the 4-Ohm speaker(s) within the BA-115HPT?
On a more general note, I gather that the transformers in these V-series amps are robust. Of course, even so, I want to ensure that I do not create damage. What is the greatest danger? Setting the impedence switch too high or too low?
Demonstrating that I am not averse to doing my own homework, I found these remarks on the Ampeg website. They do not pertain specifically to the V-series amps but rather, were made in reference to more modern amps. Still......:
Q5) Can I combine cabinets of different impedances?
It can be done, but it will cause a mismatch of levels. This is not recommended.
Q6) What is the impedance of an eight ohm cabinet combined with a four ohm cabinet?
2.7 ohms. This is not recommended
It is my understanding that calculating impedence when using mismatched cabs is difficult. It is also my understanding that the lower impedence speaker will "sink" more power than the wimpier (higher impedence) speaker. I wonder if either speaker will be louder than the other.
Q5) Can I combine cabinets of different impedances?
It can be done, but it will cause a mismatch of levels. This is not recommended.
Q6) What is the impedance of an eight ohm cabinet combined with a four ohm cabinet?
2.7 ohms. This is not recommended
It is my understanding that calculating impedence when using mismatched cabs is difficult. It is also my understanding that the lower impedence speaker will "sink" more power than the wimpier (higher impedence) speaker. I wonder if either speaker will be louder than the other.
Hot news flash! I was wrong, the speakers are wired in parallel. The speakers are connected in parallel. Weird. The hot lead is connected to one speaker and the ground lead is connected to the other. But there are two short wires connecting the two speakers together, + to + and - to -. Parallel.
The resistance reading I get with my meter is 13.5 Ohms on one speaker and 13.5 Ohms on the other. So.....they are two 16 Ohm speakers wired in parallel for 8 Ohms. Right?
So...what about this business of connecting to speakers of different impedence?
The resistance reading I get with my meter is 13.5 Ohms on one speaker and 13.5 Ohms on the other. So.....they are two 16 Ohm speakers wired in parallel for 8 Ohms. Right?
So...what about this business of connecting to speakers of different impedence?
I would go along with your assessment of the speakers themselves. And you're right...the lower impedance cab will "sink" more power.
If it were me, I'd set it for 2ohms. But I'm hardly qualified to suggest what you should do. It just makes sense to me to set the tap to a lower value than the expected impedance, such as you'd do when you run a "4ohm" Fender head into an 8ohm cab; something I've done a lot over the years without problems. As Jimmy notes, the 15 will get more juice in that set-up. Whether that's good or bad, I dunno. I think if I were going to crank this rig on a regular basis, I'd go find an 8ohm replacement 15.
Old Fart - what's the impedance of the BA-115 speaker you are wanting to hook up? If it's 8 ohms, then you would have 8 ohms in parallel with the existing VT-22 8 ohm load, and you would set the switch for 4 ohms.
And pentode tube amps actually like a lower impedance instead of a higher impedance. That's why the speaker jack is a shorting type. If you run a pentode tube amp into an open circuit, it can fry the output transformer due to insane voltage spikes. Solid state amps would rather run into an open circuit instead of a dead short, as the dead short would fry the output transistors due to excessive current, but pentode tube amps are the opposite.
Chris
edit - just saw that the BA-115 has a 4 ohm speaker. So your load will be 2.67 ohms, and the 15 will be getting 2/3 of the power. Theoretically you would want to set the switch for 4 ohms. Personally, I would disconnect the 2 - 12's and just run the 15 by itself at 4 ohms. Playing bass through those open-back 12's is eventually gonna kill them.
And pentode tube amps actually like a lower impedance instead of a higher impedance. That's why the speaker jack is a shorting type. If you run a pentode tube amp into an open circuit, it can fry the output transformer due to insane voltage spikes. Solid state amps would rather run into an open circuit instead of a dead short, as the dead short would fry the output transistors due to excessive current, but pentode tube amps are the opposite.
Chris
edit - just saw that the BA-115 has a 4 ohm speaker. So your load will be 2.67 ohms, and the 15 will be getting 2/3 of the power. Theoretically you would want to set the switch for 4 ohms. Personally, I would disconnect the 2 - 12's and just run the 15 by itself at 4 ohms. Playing bass through those open-back 12's is eventually gonna kill them.
Wow. Not having a lot of experience trying out a lot of different cabs, I didn't think it would make too much of a difference. I just took a gamble on the Diesel 1x15, didnt have my head or bass with me at the time to try it out. Just played for a bit once i got it home. The bottom is way more tight/focussed then on my avatar 212, in a good way. The note definition is there. The mids are punching and the highs are sparkling, as if I put on a fresh pair of strings. Might have to turn the ultra high off my v4b but we'll see (will definitely have to turn off the "attack" on my b3k). Notice a rattle coming from somewhere, though it may just be all the **** in my bedroom. I am thoroughly impressed by the sound quality.
Sparkle in the highs will definitely happen with the ultra-hi switch on
No doubt but I've never wanted sparkle in my tone.
- Apr 3, 2003
- 35,515
- 19,942
- Disclosures
- Editor-in-Chief, Bass Gear Magazine
Sparkle in the highs will definitely happen with the ultra-hi switch on
Not so much with my avatar 212 neo. I always had it on with the avatar, now its almost too much with the diesel cab.
