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Ampeg SVT-IIP Users

#21
Thanks for the pic. Based on what you mentioned and what I've read, the tubes I initially removed (Mesas) were not the original ones. So far the groove tubes have done a nice job, although the difference hasn't been that great. At least I know they won't die out anytime soon :).

Is that a Gator rack case? I have one as well and I'm happy with it.
 
#22
Hello,

Yeah it is, works a treat and has saved my gear from some serious damage many a time. Have fun with your new preamp, and look after it as there's not many around now and I doubt Ampeg will make anything close to the tone it produces in preamp form ever again(Apart from the SVP-PRO/CL but that's debatable) :)

Michael.
 
#23
Yay, my SVT-IIP came in the mail yesterday! I tried it out in the garage last night, and first impression is very good. It's going to be feeding the power side of my SM-900, into Eden cabs. Great big rock tone for the guitar-driven rock that my band plays. Can't wait to hear it at rehearsal this weekend!

I haven't opened it up yet, and don't know anything about the age or maker of the tubes, but it seems to be completely functional. It is missing the two case screws in the middle top of the unit (the ones that go into the standoffs - anybody know the size/pitch of these?).

Anybody have a schematic for this unit?
 
#24
Update: The debut of the SVT-IIP at band rehearsal today was not quite what I had hoped. I had a very hard time compensating for what appears to be a pretty large difference in output level between the IIP and the SM-900's own preamp.

I was feeding the IIP to the 900's mono effects return jack (27 k-ohm input impedance), but it just wasn't punching through the mix, even with the 900's master knob maxed out (whoa!).

I struggled with this most of the rehearsal, then switched back to the 900's preamp near the end (just to make sure I wasn't crazy, or being fooled by the earplugs). BOOM. All the rig's power and volume returned.

Is this pre *supposed* to be this quiet, or is it possible that something is wrong that can be repaired? I'd hate to think that I just bought a pre that I can't use with the rest of my rig.

There was a secondary phenomenon happening that I probably can't explain well. While playing thru the IIP, I saw some cone movement on the cab that looked odd to me. It's like there was a big push outward at the beginning of the note, but then instead of a gradual decay in the oscillations, the excursions got very small very quickly (as if being damped by something?). I've not owned an all-tube pre before, so I don't know if this sort of driver behavior is typical.

My gut tells me that something is wrong here. Seems like this pre should sound much better with my rig than it does. What can I check? Is there a schematic/test procedure out there anywhere? Any guidance would be greatly appreciated.
 
#26
IndyBass said:
I was feeding the IIP to the 900's mono effects return jack (27 k-ohm input impedance), but it just wasn't punching through the mix, even with the 900's master knob maxed out (whoa!).

I struggled with this most of the rehearsal, then switched back to the 900's preamp near the end (just to make sure I wasn't crazy, or being fooled by the earplugs). BOOM. All the rig's power and volume returned.

Is this pre *supposed* to be this quiet, or is it possible that something is wrong that can be repaired? I'd hate to think that I just bought a pre that I can't use with the rest of my rig.
Click to expand...

The SVT IIP is the preamp section of the SVT II ( non pro ). The poweramp section of this amp only needed an input of 0.25 volts to achieve max watts. It is possible that it doesn't have a strong enough output for your SWR. A similar problem was reported by users of the SVPCL.
 
#27
IndyBass said:
Is this pre *supposed* to be this quiet, or is it possible that something is wrong that can be repaired? I'd hate to think that I just bought a pre that I can't use with the rest of my rig.

There was a secondary phenomenon happening that I probably can't explain well. While playing thru the IIP, I saw some cone movement on the cab that looked odd to me. It's like there was a big push outward at the beginning of the note, but then instead of a gradual decay in the oscillations, the excursions got very small very quickly (as if being damped by something?). I've not owned an all-tube pre before, so I don't know if this sort of driver behavior is typical.

My gut tells me that something is wrong here. Seems like this pre should sound much better with my rig than it does. What can I check? Is there a schematic/test procedure out there anywhere? Any guidance would be greatly appreciated.
Click to expand...

It's already been mentioned, but my first suggestion would be to turn the FX loop to full "WET". Next would be to turn the gain volume up on the IIP. It's not quiet, but it doesn't have a HUGE amount of output. I had one for a few years and it sounded amazing. The only thing I missed was a seperate master volume level on it. After that would be to change the tubes in it. My guess is that it still has the original tubes in it (most do...mine did after 17 years!!!). They might finally be coming to their end and a new set of tubes would give ya more juice.

Your speakers are fine. If the note sounds clean with no farting or bottoming out then their working as they should. Now...if you had everything cranked and they didn't move at all (aka no sound coming out either), then you'd be in trouble.
 
#32
anderbass said:
Your SM-900 seems to have both mono and stereo FX return jacks. The SVT-IIp output connected
to the SWRs mono return will feed both power amps. If you connected to the stereo return you'd
only be feeding one power amp channel...

Which one did you use?
Click to expand...

I did indeed use the mono return, thanks.

I think this afternoon I'll see what it sounds like if I take the IIP into the "active" instrument input of the 900. It somewhat defeats the purpose of getting another pre if I end up using the 900's pre anyway, but maybe some of the Ampeg character will still get through. :(
 
#33
johndanielmoore said:
The SVP-PRO has 2.0 volts output. A completely different animal.
Click to expand...

The owner's reference guide for the IIP lists the output as "1 Volts RMS maximum, 3.5 Volts RMS w EQ". Since I was running with EQ knobs flat and graphic EQ disengaged, I suspect my output was running well below 1 Volt, as johndanielmoore suggests.

What power amps have proven themselves good partners to low-output pre's in pre/power setups?

The input sensitivity for Ampeg's SVP1600 is listed at 0.5 V, for example, while the Carvin DCM1000 has an input sensitivity of 1.0 V. Does this mean that the Carvin needs more input voltage to reach max power than the Ampeg does?

By contrast, the SM-900's sensitivity at the effects return is listed as 1.6 V. And there we are.
 
#34
Have you tried engaging the EQ but keeping all the sliders ate equal levels? The overall level control on the EQ will give you pretty significant boost. If this doesn't work, I'd suspect a real hardware problem.
 
#35
lug said:
Have you tried engaging the EQ but keeping all the sliders ate equal levels? The overall level control on the EQ will give you pretty significant boost. If this doesn't work, I'd suspect a real hardware problem.
Click to expand...

You can definitely boost the overall level this way, but it will affect your tone. Instead of just running your signal through the basic EQ section, it will go through the basic EQ section and then through your flattened graphic EQ section. So you're EQ-ing it twice whether you want it to or not. And from the way the final sound came out, it seemed like the EQ's were summed together.

Anyways...if you find the IIP isn't for you, I think I might know someone who will take it off your hands for ya ;)
 
#36
NKUSigEp said:
You can definitely boost the overall level this way, but it will affect your tone.
Click to expand...

Yeah, that's kinda why I was steering away from using the graphic eq for this, although it may be a wash if I end up running the IIP through an instrument input on the 900. I'm sure that will change the tone, too.

NKUSigEp said:
Anyways...if you find the IIP isn't for you, I think I might know someone who will take it off your hands for ya ;)
Click to expand...

LOL, thanks! I'm not sure I'm ready to cut bait on the IIP just yet. The sound would really compliment the stuff my band is writing right now. Even though I really wanted to keep the cash outlay to a minimum, perhaps a different, used power amp is the way to go here. I see that both Crest and Crown amps have selectable input sensitivities that go down to 0.775 volts. Think that would be low enough?
 
#37
I don't have any experience with Crest or Crown amps, but I ran mine through a Mackie 1400i (which I still have) and it was absolutely a beast of a rig! I got the poweramp for $300 and would recommend to anyone for any style of music. It really excels at providing LOTS of power, headroom, and low-end.
 
#38
NKUSigEp said:
I don't have any experience with Crest or Crown amps, but I ran mine through a Mackie 1400i (which I still have) and it was absolutely a beast of a rig! I got the poweramp for $300 and would recommend to anyone for any style of music. It really excels at providing LOTS of power, headroom, and low-end.
Click to expand...


I've run a SVP-IIP through a mackie 1400i (input sensitivity 1.15 V) for many years, loud as hell. Also though a peavey DPC1000 (input sensitivity of 1.4 v) w/o problems. I always use the Graphics EQ though. I'm thinking you need to find a different power amp to borrow to see if the pre has a problem or not.
 
#40
Update: The technician called back this morning, and reported that my IIP had one 12AU7 tube installed along with two 12AX7 tubes, rather than the three 12AX7's it's supposed to have. I should have checked that.

He replaced the tube. Also, he noted that there has been some after-market soldering work done, so he removed the circuit card and touched up the solder work on the back side of the card.

He says the pre now sounds great and has "tons of output", so I'll pick it up Monday or Tuesday and see if I can hear a difference.
 

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