Marcus Cornall

just pm d you about this...very interested! 

7 hours ago, Reggaebass said:

Nice one Marcus, sounds great and glad you got sorted 

Thanks mate! Yeah it is BIG enough. 

The strange bit was, on the gig ,realising the essential difference from all my previous experience: the notes were all clean and the same no matter how much I turned it up, but I mean referring to the cab..I realised all other cabs had coloured the sound far more than  I thought..certain notes begin to boom out more than others or sound tonally different, because of cab resonances and such.

And its so weird being able to play at volume (or at all ,if I think about it) without that .,well.,limitation of other cabs.

At first I was disappointed to have lost it! But I thought it good to be ..erm..properly HiFi I suppose, and to enjoy getting used to what the bass should sound like uncoloured by cab limitations.

I can always get a pf 115 or 410 for those trad sounds.

But this is lighter,more responsive and I am enjoying the contrasting cleanliness and responsiveness instead.

The other paychoacoustic effect of that on me is that because that cab character is missing...my mind says it doesn't SOUND as loud! And I ended up turning it up quite a lot before realising how much I was putting out,as it was so unobtrusive (but inducing of kneecap vibration at close range!)

I am glad I got the kW amp though. It just kept de.ivering MORE low end no matter how much I turned it up.

Plenty of clean headroom even at gig volume is also a thing previously unknown for me. 

We don't have a gig u till August now and I'm itching to take it out again .

Hello all,

I know it's been a while, but I have closure on this issue at last, and i thought I'd share it..

The used SVT 7 pro had an issue.It hissed badly .

Having never had an amp that powerful,nor a FRFR cab, I didn't know if it was just something to expect,but I thought surely not?

But LO! Something rattled inside! 

It turned outntonbe a capacitor that had not just broken loose in transit,but had been MELTED somehow.

The guy I got it from was fully decent and honest and I'm sure he didn't know.

He used it with a tweeterless 1x15.

I got my money back.

I was put off another one.Purely because I didn't know for sure if they all hissed or if it was because of the melted cap,and I didn't have time to mess about sending another one back.

So.,a new SVT 7 Pro? £nearly 900.nearly double used prices. 

Alternatives?

I thought on the PF800 or even 500 .but due to the way the wattage works,I'd only be getting 400wnout of the 800, and 375 from the 500.

Was that 'enough' ? In the end ,how could I know?

I had a gig coming,and I decided I couldn't take the risk of being underpowered.

And besides anything else ,actually GETTING any new Ampeg above the pf500? 

10-12 weeks awaiting stock ,said all the major (and minor) suppliers!

Oh.well that also swayed me..towards...

The Peavey Minimega.

Only just over HALF the price of a new SVT 7,the same price as a used one...1000w giving 700 at 8 ohms..

Seemed perfect.

And my old head is a Peavey.

But could it do that fat Ampeg-like sound ?

Aside from the hiss,the 7 pro sounded FAT at home.i didn't get chance to try it at rehearsal volume. 

But I needed something,so took the risk With the Minimega.

At home where  I plugged it into the BF,I hadnt yet plugged a bass in ,because I wanted to hear if it hissed.

Even with the gain and vol up full,and the tweeter fully on,and the treble up..the thing was so silent I thought it was broken!

When I plugged a bass in (having turned the gain and vol back to home levels!) 

The weight,clarity and power were wonderful.

The immediacy of attack was incredible,and it allows so much more accuracy with the right hand touch because the amp and cab are so much more responsive than anything I've known.

And on the gig?

Amazing .!!!!!

The dispersion of the BB astonished me,and the band.You can hear it clearly off axis or yards away.

It was a hit with the band because they could feel me and hear me better onstage than the bass in the monitor,or front of house leakage of subs.

I loved the tone and yes  I got the one I heard in my head.

Not Ampeg of course,  but Ampeg-like fatness.

And the power was amazing too. 

Huge clean lows aplenty

(And everything else of course, but it being a Reggae gig and me liking a trad sound,I had some mids but not too many upper ones,and no tweeter)

And the MM is even smaller and lighter,so total rig weight around 18kg.

So ,thankyou to all of you for helping,and because of that help I now have an amp and cab I love ,that make the sound I wanted,and are so responsive as to give me the chance to really play it as i feel it,and that have all the power I will ever need

I'm sorry to hear you are not wel,and may you get better soon.

I was packing it up but just for you I got it out and opened it again.

But i just can't get it to focus enough on the little component numbers so they are legible.

My hands shake quite a lot I'm afraid ,so that adds difficulty.

I just couldn't get good enough shots.

Sorry to disappoint you, and get well soon

And thanks once again for your highly valued input.

12 hours ago, Downunderwonder said:

Post the pics anyway, some of us are locked up at home with a nasty virus, too weak to leave the couch, and too cheap to pay for Netfix so scouring photos of amp gizzards counts as entertainment.

Hello and dont worry I didn't touch anything or do any more than remove the lid.

I looked with a magnifier and a torch.

I couldn't see anything untoward.No obvious sticking out legs or connections,no outlined numbered area without a component there.

In the bits that I could see.

There were caps behind things I could just make out,so it could have come from there somewhere.

I couldn't find c25 despite scouring the visible areas for half an hour.

I also realised that tonget a zoomable resolution I would have to take a good few pictures.

At that point I am afraid I gave up, put the lid back on and packaged it.

I figured that if I couldn't see it ,you probably couldn't, given the  ore limited viewpoints of pictures.

And anyway past a certain point I am sure you have better things to do than scouring pictures of circuit boards looking for problems.

actually Gents, I am going to take the lid off before I package it up today,and attempt to find C25 and photograph it. I bet I find a gap there! 

It's for 'closure for you,. I know sometimes you work a thing out for someone, and you remain interested to see if you were right! 

So I'll be back with a pic in a few hours.

It's the least I can do.

And I want to know myself now

Wow! So it actually even accounts for the precise fault I had! 

I'm amazed at how much time and effort you have put it here .

I feel bad ! I had hoped for help, but I never expected free technical analysis and diagnostics to this level!

You guys are fantastic  thanks again so much .

It's even helping the seller get it repaired, so you're saving an amp too.

I sort of feel bad I haven't photographed the circuit boards so you can confirm it for your own satisfaction!

 But I already feel like I have impinges a lot on your time.

DGBsss you've done an amazing job with forum diagnosis.

4 hours ago, DGBass said:

Just for info, I had a look at the SVT7 Pro SMPS power board schematic and there are a few possibilities on it for similar spec caps as well. It's the age old issue of trying to figure out whats wrong from a forum post and the SVT7 Pro is also fairly complex bit of kit anyway. A Tech and some bench time are probably the best option when it comes down to it if you have an amp problem. I wouldn't write off class D, I've used Markbass kit as an example regularly and it was very impressive and reliable in my experience. 

Thanks again .I' d say you'd managed the diagnosis pretty well! The seller intends to have it repaired ,and was grateful that I had told him what you had said about it.

The help inhave had here has been just outstanding! Thankyou so much. And your time was not wasted.i have learned a great deal from the experience.

Especially not to be such an idiot, and to magnify any loose bits immediately:) 

25 minutes ago, DGBass said:

It's definitely the remnant of an electrolytic capacitor. Difficult to tell the rating but I can make out a 47uf or maybe 0.47uf rating and maybe 25V or 250V voltage rating. There isn't anything anywhere near those ratings on the pre-amp schematic. On the power amp schematic there are a few possibilities

 

C141   0.47 250V

C173  0.47 250V

C25     47uf 25V

 

I'm not familiar enough with these amps ( class D design possibly as it uses a pair of IRS209555 driver chips ). Whatever happened to the suspect cap, it must have let go in a spectactular fashion as the pressure cap is completely gone as are the leads that connected it to the board. Odds on if it came from your amp, there will be a couple of stubby wires protruding from the board somewhere. C25 looks the most likely candidate as the other caps C141 and C173 are integral to the driver chip circuits and i'm guessing the amp might not work at all if those failed. Class D amps by design require noise filtering because of the high frequencys involved in their workings. I know its probably not helpful but if I was to venture into non full blown tube SVT territory, I'd plump for the tube pre-amp class A/B power amp SVT3 Pro and give the class D SVT7 Pro a wide berth. I'm sure the SVT7 Pro is a capable enough amp, and a good replacement might be just what you are after. If its going back to where it came from at least you'll have an option to think about a replacement amp whether thats Ampeg or something else.

 

That's so UNBELIEVABLY kind ,helpful and insightful and I  ant thank you enough.

Your knowledge of these things is obviously consumate.

I am going to relook at the 3 pro.

I was trying to keep weight down, and then there's the cab- I have a Barefaced Big Baby Ii ,And it's able take 800w. The designer recommends 600w to get the maximum out of it. I am unsure if a lower wattage amp will give me enough ,given jt's only putting out some but not all it's potential.

I dont play stupidly loud onstage,but it's Reggae and I have learned that the bigger wattage is to deliver the bigger lows (I hope I have that right.it's all been a steep learning curve as I am replacing a 30yr old rig of low quality and dont have experience of other amps and cabs.

I will say that the BB II is AMAZING. Such deep clear lows and seeminlgy instant transient response.a total revelation.

I chose the 7 Pro as it gave 600w at 8 ohms,and I wanted the kind of colour you get from ampegs.(I rehearse with someone else's pf350) 

It's a whole other can of worms I know.

I am beginning to feel like I ought to avoid class D .

Thanks again SO MUCH for your input here.

38 minutes ago, Chienmortbb said:

Where did it come from? What I mean is the component reference i.e. C1-C302 etc.

It was rattling about inside the amp.

6 minutes ago, paul_5 said:

That was an electrolytic capacitor, it certainly shouldn’t look like that!

Thanks.i read 'uF' on there and thought I remembered that as a capacitor.

Have messaged the guy and told him it's going back. He has already said he would give me a refund.

DOWNUNDERWONDER you certainly deserve your name! 

You've solved it.I am eternally grateful .

There's NOTHING wrong with your eyes.

I hadnt even made out writing ,and I wear reading glasses.

I worked out how to zoom on my tablet camera, and here are the results,and oh dear.lots of writing and yes it is a component.

So back it goes.

Here are the pics.i could only make it out when I zoomed.

23 hours ago, Reggaebass said:

Thanks again guys.

15 hours ago, Reggaebass said:

It’s a tricky one isn’t it, not knowing whether it’s how they are or if it’s something else, i think @beastie had one a few years back, perhaps he could advise 

yes,that's the position.and thankfully ,he did...

12 hours ago, Beedster said:

Bottom line is that there is no objective measure of noise here, I’ve owned units by PJB, Markbass, Fender, and many others whose hiss and/or fan noise was too much, while I’m sure to others the levels were tolerable. None were faulty per se but each was moved on.

Thanks that's a really good way to look at things. 

11 hours ago, BassmanPaul said:

As your years of playing live music passes, less and less will hiss be a factor or even heard!

Ahaha! Sorry,what was that? I have still got treble up to about 18k.i've been  careful, and lucky.but yeah eventually it will al go ,and then at least this won't be an issue.

9 hours ago, Downunderwonder said:

I just noticed the date on this exchange. Seriously?!?

 

What is up with everyone ignoring the rattle of presumably conductive parts inside this amp?

 

Or am I the April Fool?

No, you are not the April fool,and no I didn't forget that.I'm sorry I thought I had posted about it.

It turned out to be a little metal sleeve encased in some mangled plastic.i'm attaching a couple of pictures. It doesn't look like a component. I can't find anywhere where there's a part like it or a gap where it should be.

When you say conductive,then yes since it's metal.

It was in the bottom of the tray below the boards when I turned it on,so it wouldn't have shorted anything. Or do you mean it's conductivity implies it'll be missed if it did break off? And please forgive my lack of knowledge of circuitry.

I suppose I sort of discounted it as being responsible,and now feel a bit dumb.

4 hours ago, Reggaebass said:

Hi Marcus, I never use the tweeter on my bb2 it’s permanently off as I find it quite a clean sound anyway, have you tried it with it off and the treble up on your amp for the highs you want , do you still get the hiss 

Hello ! Good to hear from you. Youve been really supportive man NUFF RESPECT!

Well, if I turn the tweeter down much of it goes away.there's a little bit left coming from the woofer although it's 'grey noise/ upper mid hiss .'

It goes away slightly more if I leave the tweeter up but put the treble down.

I hadnt actually tried your suggestion of turning the tweeter off but the treble up! 

I tried it just now.i get more of the grey hiss in the woofer.

For what we're doing I wouldn't turn the tweeter on,and would have the treble off as well.

I do take the points that I haven't used it at a gig and yes you hear far more at home. 

And that if you're going to amplify a signal to 600w the innate gain of that is a lot bigger than  your hifi,so you'll hear more noise floor.

And that all amps hiss,especially through a good tweeter.

On the other hand, I might be getting more noise than I should be. 

I don't know how I can know without a lot of hassle.

So at the moment I am inclined towards keeping it,using it for my current gig, as that was the purpose of buying it. And if I ever did a Prog gig with it, I'd just make sure they DI'd it,as it would sound nasty mic'ed with the treble and tweeter up!

And maybe i'll get something else quiet for at home and recording. 

Thanks guys.

On 07/04/2023 at 18:35, BassmanPaul said:

The Pandemic has caused a huge rift in the electronic parts supply chain.  This is affecting products being made and released across the world from cars and trucks to yes, bass amplifiers

Of course I am mindful of how things have been affected.I just found it strange considering giant brands presumably hold huge stocks and manufacture large amounts of units,that it affected several amps at once.Perhaps they share chips?

On 08/04/2023 at 08:09, Elfrasho said:

I'm sure this has already been covered but if the tweeter is adjustable I'd do that. Or even try it with a different cab just to see if it's the cab that's emphasising the hiss.

 

Also... have you tried it out in the wild yet? A hiss at house volumes will seem far worse than once you actually crank the amp at a rehearsal or gig?

Yes,it has ,but thanks.If I turn the tweeter down it goes away.Fine for my current gig,but I do some gigs where I need a lot of treble (Geddy type tone) and think it  might be an issue then.

And no I haven't tried it in the wild yet,and that's a very good point.

21 hours ago, MrDinsdale said:

Might help if you could record a clip of the hiss along with some playing to compare. Maybe people will be in a better position to help assess if it's to be expected. 

It's difficult for me to record here at suitable quality.but the other thing is,the hiss goes with the master, so I could put that up half and the gain at,say half,and get one relative level of hiss, and then turn the volmdown and the gain up and get the same volume but with less hiss, so I don't know if it would help.

But thanks for being willing to listen to it in order to help.

I changed the tube,but the hiss was still the same.There was a small metal Bush loose inside.couldnt find anywhere it had detached from.

I found there are no SVT 7 pros available new for 2 month

I thought of a Minimega instead.Also seemingly not available for same period.

Do all amp manufacturers go on a works holiday or  something? 

So now choices a keep a hiss amp,

What 2 months and spend double just to possibly end up with the same hiss, 

Wait 2 months for a minimega

Or abscond to Markbass or someone else, just because their amps are actually available.!

Thanks everyone for your input anyway.

7 hours ago, Bill Fitzmaurice said:

Usually hiss is created early in the signal chain, so gain amplifies it, making it worse as the gain is increased. If it's there no matter where the gain is set then it's taking place further along the signal chain. That could indicate a fault in the amp, perhaps something as simple as a broken PC board trace or a cold solder joint on a component. That's something that could have occurred when it was shipped. I'd call around to see if a nearby store has one that you could compare yours to. That way you'd know if yours is within spec.

Thankyou so much Bill. That's superbly helpful,and I'm most deeply grateful to  you.

It was very well packaged but things can still be jarred by impact inside packaging. I hadnt realised things like solder joints might be an issue but it makes sense.

The guy I got it from is being very  good about it.he is sending me a new tube (because some said it could be that. I didn't see how,since it was the vol and not gain, but I have no experience..he said he had used it with a tweeterless 1x15 and so wouldn't have heard the hiss.

And he has said he will have it back and refund me if I am still not happy.

There are no stores near me with one unfortunately, so I can't do a comparison.

I guess i will try the tube,since he's been good enough to send it, and if it still hisses I will send it back to him and then if he wants to claim for it being damaged in transit ,he can do that.

And I'll have to try another one.

Now wondering whether to get another 7 Pro used (probably a bit put off that !) ,spend double the money on a new one,or try a different amp altogether. I like the sound of it though.

Thankyou Bill.i acknowledge your expertise and welcome your input.

The hiss is there when I turn the volume up,and it doesn't  matter where I set the gain,from off to virtually full (at which point some extra hiss but ok )

And no ultra high.

So if Ampegs aren't hissy, do I have a faulty one do you think?

Another thing has started happening today..when I switch the amp on,after 10 secs or so I get a 'pop' ,and sometimes  a further one.thats with nothing plugged in.

Sorry ....continued... you have helped a lot with that knowledge even if that's after the fact,and I am grateful.

On 30/03/2023 at 12:27, Chienmortbb said:

To be a bit more serious, this was/is a problem with the big guitar rigs of the past when an affulent father would buy a 100W Marshall Head with 2 4x12s for his son. Then would come the complaint that the amp was noisy compared to his Leak HiFi amp.

 

So, not to put too fine a point on it, the SVT range were desiggned to drive cabs that have a limited HF response (like your 15s and the Ampeg Fridges).

The SVT 7 Pro has an awful lot of 4580 op amps and the cumulatuve noise of those in addition to the design itself, could be the problem. Agedhorse would probably call me out on that and I woud bow to his superior knowledge.

 

I must say that I have used Ashdown, Bugera, GK amps with tweetered cabs over the years and never had a probelm with noise/hiss.

Thankyou and wish I had known about the amp structure causing noise.

I did t realise that essentially then the ampeg is limited to old sounds only in that way.Rock players still use them,including Billy Sheehan,so I would've expected to hear talk of hiss issues in online discussions,but have not.

This factor is never mentioned when discussing amps' performance.

Anyway,if it's just how they are and there's nothing wrong with it,the  I am stuck with it for now anyway.

I will have to buy another one in the future and get rid of this.you 

Yeah? You think the tube? 

My first tube so I don't know them.

The seller said he would check the tube.

Thing is i may not have long enough to get one before my window for arguing a return runs out.

I'm just really trying to find out if it's in working order but it hisses and that's the way it is,or if there's something actually wrong with it,because if so...not sold as described,and return.

Thanks for chiming in Fretmeister,

I didn't realise Ampegs were known to be noisy. Are they all like that? 

Since my old head is 30yrs old SS , thought the hiss sitatuionmwould have improved. Is it because it's a real tube? The master is what makes it hiss though and it's the same at low gain or high.well..last bit of the gain adds a bit more,but I would expect that 

 I put the treble down for Reggae anyway of course,and yes I would be turning the tweeter off too..that makes the hiss go away.

But I also play rock ,and use a clattery Geddy type sound from a rojndwoind jazz,

Ie a 'normal' bass sound full open with treble.And with this amp the hiss would become nasty.

Not an issue when playing, but let's put it this way- I wouldn't want to mic the cab.

I got  proper speakon lead too but it didn't help.

But since you've been good enough to help,maybe you can reassure me further  about the ampeg -? 

I tested my Peavey FB head ,and firstly,there is less hiss with the peavey,although I am gauging volumes by ear here,so it isn't technically accurate.

 Secondly,it seems as loud as the ampeg , yet is only 475w at 8 ohms. Again use me that's by ear.

Thirdly , when i  first plugged the ampeg in ,the pre gain was clipping at about ten o clock. But second plugging in and subsequent,same bass, I have to turn the gain up to nearly full to get it to clip.

Fourthly ,the amp was superbly packaged, but when I tilt it tiny things rattle about inside.

And then there's the relatively high noise floor. The mid control affects it too.seems to be frequencies in between high mid and treble controls.

Hi Downunder,

Yes  a Barefaced Big Baby.And yes, sorry it is termed a 'compression  driver ' .I dont know the difference.it mentions a crossover but I thought that's just a matter of choosing at what freq the compression drive takes over.

Form what I have gathered since ,it may be that I assumed turning the CD full up ='flat' but apparently it could actually be that the CD adds relatively MORE treble than 'flat'/equal strength to the woofer.if you see what I mean?

Anyway I am reliably informed that speakers can't hiss..only amps.

Beedster- I hate them too ! And I didn't expect it from an amp this new.

It is second hand.it was advertised as being "in full working order" 

I dont know if excessive hiss counts as NOT in full working order or not.

Anyway a speakon cable is due to arrive today (been using a 1/4 I  jack speaker cable) so fingers crossed that gets rid of it.....

.