Ampeg SVT-IV Pro

Tube pre amp with mosfet power amps. This head has 2 seperate power amps which allows you to run mono,stereo or biamped. You can also bridge the power amps to get 1600 watts of power. Effects loop, tuner in with mute switch, direct out, 9 band graphic equalizer.

Sound was O.K. Didn't seem to have the power I expected from 1600 watts. I ran it bridged through Ampeg SVT 810E cabinets and was disappointed with the tone and volume. I play in a blues band and I had the gain set to just before the clip light came on (as directed in the owner's manual) and had the master up to 3/4 and still had trouble hearing myself. We are not a very loud band. My Gallien Krueger 800RB was much louder and clearer than this head.

I didn't keep it long so I can't comment on the reliabilty.

I contacted customer support and they were very helpful. They suggested that the head might be defective and that I should return it and exchange it.

I didn't like this head at all. I took it back thinking that maybe it was defective but had the same trouble. I ended up trading for an SVT Classic all tube head which I love. For comparison, I took the SVT4Pro and the SVT Classic side by side. I set the tone controls flat on both and set the gains and masters the same. The all tube SVT Classic had much better tone and was at least 1/3 louder. I gradually increased the master volume on each head and found the SVT Classic to be louder and clearer throughout the range of the master.

I bought this amp 5 years ago. I believe it was about 3 years old when I got it off a internet auction. It has all you could ask for in the feature department. Like so many amps these days it's almost too much. I play alternative / metal and tone wise it worked out (at low volume) but volume was another story. The louder you try to go the worse this thing sounds.

Now to the volume issue. This thing is so under powered. I'm using a Rick bass (non active) with a old ampeg 4x12 (8 ohms) and a Sunn 2x15 (8 ohms). I got this thing so cheap I couldn't say no to it but it never did get used in a live situation. In fact, I couldn't use it for anything othe rthan a practice amp. I couldn't get over the drums. To be completely honest I hated this amp. I mean Ampeg really gave people the shaft on this particular model. Over priced and under powered. As you crank the volume up you would start to get alot of noise and loose your tone.

Oh yes there is more bad news about this amp. It gets hot and it shuts down. Luckily I sell electronics and one of my customers is the authorised Ampeg repair station. I turned it over to him. They went through that thing frontwards, backwards and sideways and found it to be perfect. The man told me my best option was to sell it to someone I didn't know. How comforting...

Ampeg is the big name in bass equipment and they will handle any problems or questions you have about their products. Have to give em credit in this department.

I have been playing 14 years. I currently use a Sunn 300t stack. For smaller venues i use a Carvin r600 solid state. I wouldn't recomend the Ampeg SVT Pro-4 solid state to anyone. i just couldnt use it for anything more than jamming at home alone or playing to a record. It's live aplication just never happened. if you are looking for power look somewhere else. I sold the thing for basically what i had in it($400.00). The guy who uses it now had the same problems so he bought a 1000 watt power amp to push his 8X10 Ampeg. He doesn't have any complaints once he did that. But at what this head would normally cost. It's just not worth it.

This a message to the last entry - Acme's only come in 4 or 8 ohm impedances.

What this means is that if you are currently running an 8 ohm cab, adding an 8 ohm cab in parallel (unless you are re-wiring, thats what you are doing) makes the amp see a 4 Ohm load.

If you are adding a 4 ohm cab in parallel, the amp sees a 2.667 Ohm load. Well below recommended rating, thus causing the thermal shutdown and damaging your amp.

I purchased this amp new about 4 plus years ago. I have played in at least one but useually two busy cover bands playing Beatles to Godsmack and just about every style in between. This amp has just about all the features you'd ever want. Built in compression is nice (and rare) but I would like a bit more control as there's just one knob. The effect of the compressor is VERY subtle.

The only other feature I would LOVE is if they built in a tuner on the face of the amp. But it seams no manufacturer ever gets it completely right.

I have been powering a very inificient but incredible sounding 8 ohm Acme B-4. Recently I added an Acme Low B-2 which has dropped the impedence to 5.6 ohms. I'll address this issue in the reliabilty section.

I mainly play two Dingwall 5-strings as well as a G&L L2000 4-string and a Charvel neckthrough 4-string for slap. The Ampeg has the most robust tone of any amp I've used and has that coveted "Ampeg" sound. It has a very round and warm bottom end and the mid's are voiced just right. Tons of flexibilty on the controls, plus three tubes in the input section will get you any sound you desire.

I play the amp pretty loud. The input gain is set to 12 o'clock and the master volume is about 3 o'clock. No real heavy boosting or cutting in the eq or tone controls.

Here's where the problem lies. It has worked well for 4 years but I have always been suspect of it because it has always run VERY HOT. This has been powering an 8 ohm cabinet until about 2 months ago when the impedence the amp saw dropped to 5.6 ohms when I added more speakers.

After using the new speaker set up for about two months, the amp fried during the first set of a gig. Luckily the preamp out still worked and I had a spare amp in our slave rack and was able to get through the night.

I keep the amp racked in an SKB 4 space case along with a Furman power conditioner with built in tuner.

Upon opening the amp to have a look at the fry job I did, I noticed what I believe to be an absolutey horrible design. The air vents are located on the left and right sides of the amp case so once it's racked there is practically no air flow acrross the power transistors or the power transformer. Plus, the fan is located in between these two heat makers. To me this is down right stupid. Suck it in the front and exhaust it out the back.

Another idiotic design which I see many manufactures employing is a thermal switch on the cooling fan. One more thing to fail. Now your high priced amp is depening on an 89 cent part to stay alive. You can't make power transistors too cold, so just wire the fan to the power switch so it's on all the time. Is that so hard to figure out?

Ampeg's literature says it can drive a 4 ohm load but I'm here to tell you there is no way unless it's for a very short while and not turned up very loud.

I believe the amp may work well if the air flow is modified but that's not something I'm going to tackle. Once it's fixed, it's going on e-bay.

Luckily the amp was still within it's 5 year warranty and is being fixed locally for free. Since I couldn't find the receipt from 4 plus years ago I called Ampeg who looked up the serial number and said "abslutley it's under warranty and if your shop has any problem with that you have them call me direct!" I thought that was nice.

I have been playing bass for 27 years. I have a GK 800RB I use as a backup amp and two Euphonic Audio single 10 cabs. The Ampeg sounds sweet through the EA's as well.

After the "fry" incident and discovering Ampeg's poor cooling design I would not buy another one. A killer preamp (TBD) and a very lightweight QSC PLX 1602 will make up my next rig.

With active EQ and the extra punch selections, this amp is un-touchable. I love the input/output ports and tone selections. To me this is the only amp on the market to buy.

I use two ampeg 4x10 cabnets with an Ibanez Ergodine 4 and 5 string. I can get any sound i desire with this setup. The amp is powerfull. useing both channels and speakon cables you can't stop this beast. My shit says BOOOOOM.

I bought this head two years ago. The first head i took back to the seller do to a popping after the tubes warmed up. The new head I have had no trouble with. I play 4 days a week and I am extremely hard on my gear and I have no complaint about this gear.

The first head I returned do to a pop. I had no problems with this task. Ampeg is the shit. If you are dis satisfied with the gear get off your ass, stop crying and use the warrenty. Duhh

I have been playing for over 20 years. I have owned all types of gear. I am so happy I have my SVT-4. If you are looking for clean solid power this head is the one. I suggest no other...

I think Ampeg has went downhill as of late. I've owned an Ampeg PR810H Pro series cabinet and two PR410H Pro cabinets and I've blown speakers in all of them. The warranty helps but it is very annoying to have to be replacing speakers. The Ampeg SVT 4 Pro has great tone and is very powerful.My problem with this amp is that I purchased the amp "NEW" in January and after having the amp for only 2 months the amp developed a loud, annoying, clicking sound that you could hear when you'd stop playing. To tell you the truth, I never even sent it in for warranty work. I sold the head and got out from under it. I've owned Trace Elliot, GK, SWR and Eden heads and never had one problem out of any of them. It really aggrivated me that after having the amp for only 2 months it had a problem.
My advise is if you like the sound of Ampeg gear and have to have it, buy it knowing that there is a good chance that your going to have to have it serviced within a year. This has been the case with all of the ampeg gear that I have bought, speaker cabs included and I baby my equipment. I can see any company having a problem every now and then but not with every piece of equipment that you buy.

Features already mentioned below.

Veriety of Basses from Gibson 4 Artist to custom 10 string Accacia. This amp allows the character of the instrument to come through with a openess of rich highs and thunderous lows. I amazed at how clear and articulate the tones are with each setting.

This is my first Ampeg piece of equipment, but they have been around since I heard the SVT's back in the late 70's so that should give a little hint.

Excellent warrenty 5 Years and Customer Support seems to be pretty good. I called three times just for general information and someone got back to me fairly quickly eiather by calling or e-mail.

I've been playing for 30 something years and have played on everything from SWR, Fender, Eden, Hartcke, GK, Peavey,..etc and this buy far is the best for my purposes. Note: Everyone has different ears, but the tones and power that this amp generates is truly an experience you have to hear and feel. I know if I had to do this all over again no question... I would purchase!

Can't get it to work....I think I got a bum deal...

I can't get it to sound good at all.. I am running into one SWR 4x10.
Honestly my old Peave 4x10 cab with the 400w Yourkville had more balls.

I get a strange cackle for the first 20 min everytime....someone help me

Haven't even tried yet

Not impressed. Like I said earlier I think I got a bum deal. I know other bassists who use it and love it. Just after I bought it I found out it was just returned from another unhappy user. Maybe there is something wrong with it and I am stuck. I brought it back to the dealer and he can send it away .... well we all know what thats like, maybe in a month or so I'll get it back...what am I supposed to use in the meantime.... I am going to try my luck with Ampeg direct. If anyone can help please do so.

its got it all!! all you need is an effects board .

this is the coolest amp iv'e ever bought . it has a wide variey of ounds. can keep you very busy .

i have owned this amp for only 4 months but , know peope that aplause ampeg fo reliability . THE " TOYOTA'S" of amps. a fie year warranty is a good sign.

ive never dealt with them . have a feeling i wont need to either .

overall i give this amp a 9 . if i have problems i will cahnage it. the best thing ive ever bought.i use a 4 - 10 classic ampeg cab. souds amazing. cant wait to get 2 - 15's and 2 - 12's !!!!

This beast is packed with professionally features. It won't be necessary for me to get into detail, the reviewer belowed just about covered it. This animal has more power than I can ever handle..1600 watts whew!! but i run it to an ampeg hlf cab that handles 500watts at 4 ohms and from the specs it puts out 490 RMS at 4 ohms..so that's how much i'm using, which is plenty . I know I won't have any more problems geting lost in the mix going up against those damns Marshalls now....bring it on!

I use 2 Ibanez SR400 with EMGs...boy can they punch through anything! I also have a fender jazz with EMGs and a Stuart Spector Czech. All my basses sounded great through this amp! It does have a bit of hiss with the treble boosted, but all ampegs are like that as well as most if not all bass amps that has their treble at higher settings, other than that it's just wonderful. This amp is extremely flexible, it definitely retains the traditional ampeg flavor of the past with it's all tube preamp , but also giving you todays cutting edge sounds with excellent flexiblity with it's mosfet power section. You can get just about any sound imagine, from slap and pop to finger style to picking.. all it takes is some tweaking and you've got tone for days. One thing I have to mention is that it does have some noise coming from the fan.

I have great confidence that this baby will last me for many years to come! I still have my svt III since 91 and it's never let me down...not once! Gigs, rehearsals... it's always been there when i needed it. It's a workhorse and i have no doubt this will be also. I heard many people saying how reliable their ampegs are... and i will say the same thing...no question about it.

never had to deal with them. The 5 year warranty is great! 2 thumbs up for backing their products up!

I've been playing for 12 years. I've tried out many bass amps and their are alot of good ones out there! Eden, GK, SWR, Ashdown, Trace Elliot and many others. You really couldn't go wrong with any of them, you just have to pick out the one that suits your taste. The only one that has relability issues is GK...unfortunately it's true, but they do provide great customer service. Ampeg has been known for it's reputation for quality, reliablity, and most importantly TONE! This is definitely a winner!

It has so many features i dont even know em all yet! its got all the tone shaping tools i would ever need...9 band e.q plus another three band e.q. witha mid selector...compresor/limiter,gain controls to get that growl..mute and -15db switches...speakon connectors..its got all kinds of plug ins on the back for other inputs..other amps and mics...features 1600 watts mono-bridged..kinda useless unless you have an ampeg 8x10...which i do...those two together sounds so awesome and to top it of i have a spector ns5crfm...this rig sounds great...i wish it had more gain...so i could get some distortion..but its all good...i probably rather use a pedal..like a big muff...it features three tubes for the pre and a solid state mosfet power section...this amps got everything!

This and my spector go hand in hand..this amp really makes some great noise...cause it makes all the noises you would want..i can get basically any tone i want from this amp and it has an awesome grwol and bite to it...ive never played on a better amp..and thats the truth...ive played on alot of differnt ones at stores like swr...hartke etc. etc...and even other ampegs, but none of them sound as good as the svt4-pro..its the best in my opinion

It seems pretty durable but i still need to buy a rack for it...its seems somewhat fragile without the rack..but i know it wont break...the fan inside, which is also a great feauture, is starting to make some noise but i dont think it will be a problem...just replace it easily..pretty tough

havent had to but we will see...tube replacements..fan replacement...

like i said this is the best amp in my opinion and it sounds soo great with my other equipment...i love all the features but they can almost, but not quite, get to be too much...atleast in the beginning beacuse i couldnt find the right tone...but that came with experiance and gettin used to the amp...if it were stolen i would buy the excact same amp...no doubt about it!

Too many to list. Check out Ampeg website.

The sound is somewhere between classic SVT and SWR. Not as sterile or modern as the SWR but not the real warm tube sound of the original.Plent of power but only if you use 4 or 2ohm speaker cabs. Especially effective in bridged mode but make sure your speaker(s) can handle the output.Not as sweet a sound as some seperate tube pre-amp/ power amp rigs but more convienient and powerful enough.

I had some trouble when I first bought it. The first one had a loose piece of wire or solder and it shorted out the voltage regulator and fried all of the ICs. The replacemet was fairly reliable but very sensitive to low voltage and would go into protect intermittantly at the worst times on stage. Usually when at an outdoor festival in front of thousands of people. Luckily I'm an amp tech and can fix my own stuff.

i think the warranty is 5 years but I allways do my own work to save time and frustration.

I've been playing for 20 years now and have owned and tried many amps. I am currently enjoying tube amps for there tone and warmth. This amp doesn't really capture the "ampeg" sound and it doesn't do the modern SWR/Eden thing either but it does have a lot of features and power in a relatively small package. The mute switch is nice for tuning. The compressor is practically useless because it is in the wrong place in the signal chain. It should be somewhere after the EQ section working at line level, not instrument level. The limiter on the other hand is quite effective and can prevent a very expensive repair bill if the the amp was clipped to hard.and last but not least, it should have a ground lift switch for the direct output. About a third of the time the soundman would have to use a direct box because of AC hum.

Gain, variable Compression, Ulta Hi-Ultra Lo, Bass, Midrange, Mid Frequency, Treble, Brite, Graphic EQ, Line Out Level, Effects Bypass, Limit Defeat, Master, Frequency-Balance. The graphic EQ adds a sub roll-off and has freq. of 33,80,150,300,600,900,2K,5K,8Khz. The rear panel has line outs, effect loops, multiple spkr.outs, and connectors to loop signals for Bi-Amping. This amp is a dual amp that can run bridged mono, dual mono, or Bi-Amp modes. Power is rated at 625 watts X 2 @ 4 ohms, or 1200 watts bridged.

I play Fender P basses thru this head. This amp produces a full sound that is clean and tight. With the Ultra Lo switch on the lowest notes are very rich and deep, the midrange scooped, and the highs are clear and controlable. This amp lets you select your tone shaping and has plenty of power to deliver what you select without any limitations! The internal fan can be heard in a studio or quiet environment when you're not playing. The 3 12AX7s produce a clean sound that has more "life" and dynamics than pure solid state amp circuits. I'm using this head with a pair of EVM 15s (1 15L & 1 15B), so other speaker combinations would change the quality of this head. When I fire this up I am always amazed how good it sounds!

I've only had this amp for 6 months, but it seems to be rock solid and overbuilt to hold up to heavy road use.

Haven't needed it.

This is definatly the most versital bass amp I've ever owned. With the effects and line outs I could use this in almost any situation, in any size venue. One could argue that it doesn't have that "SVT tube sound", but it provides a full, clean, powerful sound that is maybe a little more sophistcated than the pushed, round tubey bass sound.