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2013 Ampeg V-4B 100W Reissue Pt2

#2,381
As far as the impedance, 2.67 ohm load could use the 2 ohm or 4 ohm tap. The difference 2 ohm slightly "harder on output tubes, 4 ohm slightly "harder on the output transformer. Slightly being in bold as the chance of you experiencing any change in life or performance is greater with the varying impedance of any speaker than the choice of OT tap.

As far as heat goes, "they" (class A, B, A/B, C) are great heaters as 40% or more of the expended energy is as waste heat, not the desired "work" (watts out). There have been amps so poorly "designed" that amp cases have caught fire (JMI VOX). So If they didn't do something is not a real valid argument. If you can easily hold your hand on the amp case for 5 seconds, it is fine and of no real concern. Hey, tube "bottles" operate between 90 to 300 degrees celsius normally.
 
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#2,382
rodl2005 said:
I've used tube amps since I was 12 y.o. Some with fans that got HOT....SVT2. some without fans that get hot. .. Never a problem. But they all get hot. @rickbass1 I think most tube amps are made to handle an impedance mismatch of some degree.... using the V4B at 2.67 ohms. ..If probly use the 2 ohm plug/socket. .... But I'm sure the 4 ohm one would be fine also.
Perhaps @B-string or others who actually know what they're talking about might chime in here.
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Thanks rodi2005.
 
#2,383
What's the story on the -15db input. I significantly prefer it to the 0db. It seems to smooth out the highs and give a generally sweeter tone. Unfortunately I'm finding the -15db input and a single 210av have limits.

I remember reading back about the -15db input does anyone have that info? Also considering adding a 2nd 210av. Any reason I should consider the 212av or something else?
 
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#2,385
peterpalmieri said:
What's the story on the -15db input. I significantly prefer it to the 0db. It seems to smooth out the highs and give a generally sweeter tone. Unfortunately I'm finding the -15db input and a single 210av have limits.

I remember reading back about the -15db input does anyone have that info? Also considering adding a 2nd 210av. Any reason I should consider the 212av or something else?
Click to expand...

I recall writing something but I can't find it.

I did find something that I posted that applies to the V4BR because it is related to the SVT-CL:

I was looking at the SVT CL input a while ago. It uses a 12AX7 tube in the first stage. There are 0 dB and a -15dB inputs accomplished with a pad. On the 0 dB input, the grid resistance is about 18K; on the -15db input, the grid resistance is around 100K. Now, based on my rough calculations, these resistances combine with the tube capacitance at higher frequencies (called the Miller capacitance) to form a LPF of around 58.6 kHz on the 0 dB input, and 10.5 kHz on the -15 bB input. The Miller capacitance is based on the tube characteristics and the gain of that stage. So it will vary depending on the tube and the amp's design.

Designers of high gain amps use this to their advantage. By using a higher grid resistance, they lower the low pass filter break point. This reduces higher frequency harmonics making the distortion sound better, less high frequency spikey.

Just to be clear, the numbers above were based on some assumptions so the actual numbers will differ slightly. The important point to take away is that at higher frequencies, the -15db input is bandwith limited. If your playing style and or strings has high frequencies, perhaps this rolloff is helping to give you a sound that you like.
 
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#2,387
beans-on-toast said:
I recall writing something but I can't find it.

I did find something that I posted that applies to the V4BR because it is related to the SVT-CL:

I was looking at the SVT CL input a while ago. It uses a 12AX7 tube in the first stage. There are 0 dB and a -15dB inputs accomplished with a pad. On the 0 dB input, the grid resistance is about 18K; on the -15db input, the grid resistance is around 100K. Now, based on my rough calculations, these resistances combine with the tube capacitance at higher frequencies (called the Miller capacitance) to form a LPF of around 58.6 kHz on the 0 dB input, and 10.5 kHz on the -15 bB input. The Miller capacitance is based on the tube characteristics and the gain of that stage. So it will vary depending on the tube and the amp's design.

Designers of high gain amps use this to their advantage. By using a higher grid resistance, they lower the low pass filter break point. This reduces higher frequency harmonics making the distortion sound better, less high frequency spikey.

So at higher frequencies the -15db input is band limited. If your playing style and or strings has high frequencies, perhaps this rolloff is helping to give you a sound that you like.
Click to expand...

That is it thanks. To replicate that sound from my acoustic image head I engage the HPF, boost lows to 2 o'clock, mids to 10 o'clock and treble to 8 o'clock. Still not as sweet sounding.

Using the V4b 0db input I reduce the the gain from 1 o'clock to 11 and cut treble. Not quite as sweet to my ear. With the -15db I run everything at noon with ultra low and high off.

Still debating if I should get a 2nd 210av or something else. I really prefer to not have a tweeter
 
#2,388
peterpalmieri said:
That is it thanks. To replicate that sound from my acoustic image head I engage the HPF, boost lows to 2 o'clock, mids to 10 o'clock and treble to 8 o'clock. Still not as sweet sounding.

Using the V4b 0db input I reduce the the gain from 1 o'clock to 11 and cut treble. Not quite as sweet to my ear. With the -15db I run everything at noon with ultra low and high off.

Still debating if I should get a 2nd 210av or something else. I really prefer to not have a tweeter
Click to expand...

The -15db input will have an effect on higher harmonics. It's an interesting option to take advantage of.

Tweeters can be turned off or disabled. I know what you mean about tweeters though.
 
#2,389
beans-on-toast said:
The -15db input will have an effect on higher harmonics. It's an interesting option to take advantage of.

Tweeters can be turned off or disabled. I know what you mean about tweeters though.
Click to expand...
I have both an EA NL210 & NM410 so I've got the modern tweeter style cabs covered. I just want something that's matchy matchy.
 
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#2,391
peterpalmieri said:
What's the story on the -15db input. I significantly prefer it to the 0db. It seems to smooth out the highs and give a generally sweeter tone. Unfortunately I'm finding the -15db input and a single 210av have limits.

I remember reading back about the -15db input does anyone have that info? Also considering adding a 2nd 210av. Any reason I should consider the 212av or something else?
Click to expand...

We tested the -15dB input as being right about -13dB, relative to the 0dB input, so no surprises, there. The input impedance is different for each input, though. Invalid Link Removed

This could help explain what you are hearing.
 
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#2,392
tombowlus said:
We tested the -15dB input as being right about -13dB, relative to the 0dB input, so no surprises, there. The input impedance is different for each input, though. Invalid Link Removed

This could help explain what you are hearing.
Click to expand...

Does this suggest the padded input might work better for piezo-equipped gear, like a URB pickup for instance?
 
#2,393
TomB said:
Does this suggest the padded input might work better for piezo-equipped gear, like a URB pickup for instance?
Click to expand...

The other way around. Piezos are better matched with an amp that has a higher input impedance.

A 1M ohm input impedance is pretty standard in the industry. With a piezo pickup, you want a higher impedance, up to 10M is often used, to ensure optimal bandwidth. Otherwise, you will loose high end fidelity because the impedance between the pickup and the input of the amp is not optimally matched.

So using a piezo with the V4B's -15db input will decrease your performance.
 
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#2,396
I got the opportunity to gig my V4B and 212AVs for the first time over the weekend (everything to that point had been home practice or rehearsals). With my PBass, I have to say it was by far the happiest I've ever been with my tone EVER. My band mates and a few fellow musicians in the audience were really complimentary about the vibe and tone of my setup as well. I brought my Fender Super Bassman as a backup, in case this rig didn't give me the the volume/clean headroom I needed. It stayed in the car, because the V4B exceeded my expectations in this regard - I ran with the master wide open and gain around 10'oclock and it was plenty. Nice, warm and fat - easy to dial in and sat perfectly in the mix. LOVE it!

Roy%20Gig%20Photo_zpsstzl7ziu.jpg
 
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#2,397
Alexander said:
I got the opportunity to gig my V4B and 212AVs for the first time over the weekend (everything to that point had been home practice or rehearsals). With my PBass, I have to say it was by far the happiest I've ever been with my tone EVER. My band mates and a few fellow musicians in the audience were really complimentary about the vibe and tone of my setup as well. I brought my Fender Super Bassman as a backup, in case this rig didn't give me the the volume/clean headroom I needed. It stayed in the car, because the V4B exceeded my expectations in this regard - I ran with the master wide open and gain around 10'oclock and it was plenty. Nice, warm and fat - easy to dial in and sat perfectly in the mix. LOVE it!

Roy%20Gig%20Photo_zpsstzl7ziu.jpg
Click to expand...

Just my opinion but that my friend is "THE RIG" to end all rigs. I have 2\3rds of it and will someday have that full rig.
 
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