agedhorse

Does the position of the ground switch on the DI out make any difference?

is the power source itself really earthed? This is by far the most common cause of noise. Just because the other amp was ok doesn’t rule this out because the internal architecture is different.

Most IEC cables are molded assemblies, it’s easier to maintain safety certification under the components program.

Did you try both positions of the ground lift switch?

I’m assuming that the monitor’s input is line level… is the monitor earthed? Is the amp earthed? This is important.

Since I have yet to see a bad DI in a ShuttleMax amp ever, let’s be sure it’s not something external to the amp. 

Set the DI to pre mode, line level, plug your bass in, be sure the mute switch is off. Check that your powered monitor is properly configured and you should have sound. No other controls on the amp will have an effect. 
 

In pre mode, the level may be a little lower than in post mode depending on how you have the amp’s controls set. 
 

Now, switch to post mode, set the eq to noon (flat), set the tone shaping filters off, select channel 1, bring the channel 1 volume control to 1:00 and slowly bring the channel 1 gain control up. You should have sound. 
 

If you don’t, can you confirm

that you are using an XLR to XLR cable and that it’s properly wired? Is there a selector switch on the monitor between mic and line that might also switch the monitor’s inputs? 

19 hours ago, Jaybeevee said:

I think in this case it does. it is apparently a different approach to that used in most amps. This is a point made by the builder leading me to understand that the pot position does relate to the power being delivered. 

Good idea, but I have returned it now. I wait and see what comes back

This is knowledge above my pay grade, but in terms of the pot used on the master, the builder specifically talks about this aspect and that the power delivery from the amp is via a linear (not sure of the technical terms) pot, and the user can expect to run the master at a higher setting than would be normally expected.

The position of the control is only one factor in the output power an amp delivers, but is interactive with everything else in the signal path.
 

If you turn the bass volume down by 6dB and increase the amp’s master volume by 6dB, the amp delivers exactly the same power that it did before. This is an example of the position of the master not dictating the power that the amp delivers.

14 hours ago, Bill Fitzmaurice said:

It's an issue, but not one necessarily caused by the pot. The total voltage gain from pickup to speaker starts with the pre in your bass and ends with the output stage of the amp, with every gain and EQ stage in the chain making its own contribution. Google 'gain staging'.

That said, you've got the effect of the pot backwards. Assuming you have a linear pot wide open versus at half the attenuation at the halfway point is -3dB. That's audible, but just. It's not half volume, which is -10dB. A log taper pot at half is -10dB compared to at full. Therefore the linear pot goes louder earlier in its rotation, not later. Some amps did so on purpose, so that someone trying one in a shop would be impressed at how loud it got at, say, a setting of 3. They wouldn't have been able to realize in a shop that anything past 4 didn't get any louder. 🙄

For clarification, a linear pot at 1/2 rotation is 1/2 the input voltage or 6dB of voltage attenuation which is 1/4 the power. 
 

Log pots are available in various taper rates or laws, this affects the output versus rotation curve and is part of the “user interface experience” (for lack of a better term).

2 hours ago, BassmanPaul said:

@Downunderwonder I hope you're keeping your feet dry my brother. 

Yeah, and I thought we got some rain... nothing like you guys!

Knob position has nothing to do with how much power is being delivered. This misunderstanding may be part of the problem. 
 

is the clip LED indicating input/preamp clipping or power amp clipping?

5 hours ago, andy67 said:

I'm sure the Bugera BV1001T is a copy of the Streamliner, @agedhorse will definitely know

Cosmetic copy, features copy, intended to look like a Streamliner but an entirely different circuit.

Too much reading DIY service posts on the internet?

1 hour ago, Downunderwonder said:

I am guessing all of the above means aux out and aux in are not a line loop?

There is a line level aux in, no effects loop.

The owner’s manual with block diagram is available on the website.

On 18/01/2023 at 08:06, MartinB said:

Looks great! The ability to pre-set the contour on each channel independently seems useful, along with the adjustable HPF.

It's nice to see top jacks, but it's odd that the input is at the top-left when you're facing it - that's not where you want it if there are other pedals in front.

Since this came up on the TB forum also, let me provide the answer that I provided there.

On the Pre-DI, there's a LOT more going on internally so the left to right signal flow matching the left to right feature architecture which makes more sense, otherwise every signal would have to cross over at least once and in some cases twice. This applies to both the jacks and the controls working together with the signal path rather than against it. As the gain increases (there's over 40dB of available gain), and as the number of amplification stages increases, the opportunities for noise and cross talk multiply exponentially. This is why ALL consoles and channel strips follow this format... the jacks in the same order as the controls and the controls in the same order as the signal flow for performance. This is a very quiet pedal compared with the average pedal.  In another life, I designed pro audio consoles, and Genz Benz (Jeff's earlier company) started out as a pro audio company, and the designer of this product (Scott) is also a pro audio guy as well as an accomplished bass player. I was only responsible for most of the mechanical and PCB layout on this pedal.

Since these are top mount jacks, it doesn't really matter from a wiring perspective as it does with side mount jacks (which I do not care for, especially) when there are more than 2 jacks).

I would suggest cleaning up the wiring and whatever crossover it’s supposed to have back to factory condition and listen to it before assuming anything. You might be pleasantly surprised.  

Basic electrical engineering absolutely links voltage to power. Since (solid state) amps are generally considered an ideal voltage source, it’s also an ideal power source. 
 

While a speaker has a reactive component, when the capacitive and inductive regions are averaged out with the DCR of the speaker, the net result is an average or nominal impedance.
 

The amp must provide voltage x current to drive this load which is power. In the inductive regions the current lags voltage and in the capacitive regions the current leads voltage. 

Regardless of phase angle, the amp must be able to deliver both voltage and current, this is something an experienced power amplifier designer has to deal with.

A 500 watt, 4 ohm single driver compared to a 300 watt 8 ohm driver is likely to have a lower sensitivity, quite possibility 3dB lower, which would make the 8 ohm speaker (slightly) louder at 300 watts than the 4 ohm speaker at 500 watts.

50 minutes ago, umcoo said:

I'd be interested if you manage to get this resolved. I have an old Peavey valve amp which is making a similar noise, and previous techs have not found any issue with it. Rather frustrating.  

Have you confirmed (beyond any doubt) that the problem is actually with the amp?

I see a fair number of claimed problems end up being misdiagnosed as an amp problem when in fact it ended up being something else.

4 hours ago, Chienmortbb said:

Yes, as a battery depletes, its internal resistance rises.

 

Correct, I used to align CRT TV monitors, the kind used in TV studios. We would often get a 1.5Kv (1500 volt) shock from part of the line output circuit. I hurt, drilled a small hole in your finger and gave your nervous system a kick up the ..... (insert slang or expletive to your taste). Although it was 1500V, it was a very short duration pulse and there waa very little curret, around 1mA or 1/1000th of an amp. Funnily enough, the jolt to the nervous system meant you felt more alive for the rest of the day. However one word of caution. If you put your hand into a valve amp, put the other hand in your pocket. Do not make a circuit with your heart in the middle.

 

Oh, yes. Bleeder resistors are useful and will discharge the cap after switch off, but they are a compromise.

At a high enough voltage, wounds become self-cauterizing… 

The main tradeoff with bleeders is the loss of efficiency as voltage increases.  This is an import consideration in small Switchmode power supplies meeting the EU’s eco-directive.

7 hours ago, Bill Fitzmaurice said:

Not that I recommend it, but if you connect the terminals of a 9V battery, the small type, with a screw driver you'll get a small spark. Do so with a 12v car battery and the screw driver will suffer serious damage. It can even get arc welded to the terminals. The difference is due to the ampere capacity of the two. Consider a taser. They run at 30 to 50k volts. They tend to be non-lethal because they have very low ampere capacity. A static shock you receive on a dry winter day can be an upwards of 75,000 volts, but the current is so small that all you might feel is a slight annoying zap. Like most electricians I seldom bothered to turn off the breaker to swap out an outlet or switch, and as a result got zapped dozens of times over the years. Smart? Maybe not, but that's what we do. I once stuck my finger in the wrong place in a Fender Bassman and got the full 470v. Unpleasant, but not injurious. Still, that experience educated me to the value of using a bleeder resistor to drain the caps before messing around. 😳

With the battery examples, the amount of current delivered to the load is a function of the open circuit voltage the internal resistance of the battery, and the resistance of the load (which in this case is 0 ohms). The 12V car battery has an internal resistance of about 0.02 ohms, the 9v battery has an internal resistance of ~5 ohm. It's not the capacity, but the internal resistance that limits the current. Generally, higher capacity batteries rated for higher discharge rates have lower internal resistance.

The current delivered to the short circuited 12V battery would be 12V/.02 ohm = 600A

The current delivered to the short circuited 9V battery would be 9V/5 ohm = 1.8A

Some folks are more tolerant to getting shocked, but some are not tolerant at all. Because of this variability, the safety recommendations are absolutely valid and are also "best practice" in the service field. While bleeder resistors are required for all amps with an IEC60065 or IEC62368 safety rating, a wise and experienced service tech will ALWAYS verify that there is no voltage present before attempting service.

Do you know what the biggest danger from shock is? It's either falling off of a ladder (in the power field) or getting knocked off your stool as the amp falls on you after you react to the shock. Once you have a tube amp fall on you, you may wish you were dead. 

13 hours ago, Bill Fitzmaurice said:

Not necessarily lethal, and it's not the voltage that kills, it's the amperes. Still, getting zapped with even 450v isn't a pleasant experience. One thing to do is to turn the power and standby switches on, with the amp unplugged, before removing the chassis from the case, especially the standby. When the standby switch is off the power supply caps will hold their voltage for a long time. With it on they'll discharge, albeit slowly.

It's the voltage across the body resistance that causes the current to flow. 450 volts can easily cause enough current to flow through the body to kill (if you are moderately unlucky). The power supply has plenty of current available (>100mA) so yes, it is dangerous.

Since this is a newer version (designed by Matt Wilkins, he worked under the VP of R&D at the time who was a good friend) which is safety approved to IEC 60065, there are bleeder resistors within the power supply that will safely discharge the power supply when power is removed regardless of the position of the standby switch (I verified this, it applies to all factory stock Fender Bassman 300's). This doesn't mean that the bleeders haven't been damaged, or some hack tech removed them because of some cool trick they heard about on the internet, so a professional tech will ALWAYS verify that the voltage has been discharged before doing any work. 

On 21/12/2022 at 19:17, Bill Fitzmaurice said:

Clean everything with contact cleaner, including the pots, tube sockets and tube pins.

No, please don't do this, it's a common cause of additional damage to amplifiers. It's probably the quickest way to ruin a set of pots, and likely not the cause of the original problems anyway. When I was working for Fender, I saw the results of "magic cure-all spray" and is always cost the customers more (and if the amp was under warranty, this damage was not covered). The authorized service centers hated working on such amps because there was so much to clean up after.

Read the manual and learn how it works before you damage something. 

I think you will find that the smaller the box and the greater the expectations, the more difficult and expensive the project will be.

The advantage of buying already well designed speakers is that the while you are paying for the designer's experience and knowledge, you are also indirectly paying for a number of prototype builds that may have been much poorer and "scrap worthy" than the finished product. 

Respectfully, I understand the desire to build your own, but you are comparing to a very high quality and expensive speaker. As a professional designer, I know how hard it is to get results like that without churning through 6 or 8 prototypes, and the cost of custom drivers also. Stock drivers are not intended for this type of product, which is why custom drivers are used. My coworker is the engineer who designed the entire KRK monitor line, I know how much work that was to extract that much performance in such a small, reasonably cost effective package.

I disagree, an accident or momentary lapse of good judgement will put the 4 ohm cabinet at greater risk. 
 

This doesn’t mean you CAN’T damage the 8 ohm cabinet but it will be much harder to do.

3 hours ago, lemmywinks said:

Will be fine, you're better off with an 8ohm as that means you can add an extra cab if the opportunity presents itself. With 4ohms if you need more volume you're stuck really.

 

You're no more likely to blow your cab with a 4ohm load than you are with 8ohms, similarly you can blow a cab with less power than it's rated for. If it sounds like it's struggling then turn the volume down or roll off a bit of low end. Unfortunately the myth that a 4ohm load means you amp will be pumping a ton of extra power to the cabs is one that refuses to die on forums, same with using watts to rate power handling.

 

No, this is not true.

Overpowering is by far the greatest cause of speaker failure.
 

Power (watts) is absolutely correct in describing power handling, once you understand what it means. 

In this case, the “myth” that a 4 ohm cabinet will draw more power from the amp is absolutely correct for virtually all solid state amps as they are turned up.

To the OP’s question, the 8 ohm 210 is a MUCH better and safer choice with no downside and many upsides.

Start here with the owner'smanual:  https://manualsbrain.com/en/manuals/1111847/

On 11/12/2022 at 06:18, Sparky Mark said:

Because its electronic design isn't based on the Streamliner, it's based on the Ampeg PF800.

 

The MOSFET preaamp version appears to be based around Ampeg products, I'll let you guys determine the basis of the tube preamp model...

14 hours ago, Phil Starr said:

I'm going to play devil's advocate for Bugera/Behringer/Music tribe here.

 

I'm pretty sure the amplifier section of the Bugera is 'borrowed' from Behringer's class D PA amps, specifically the iNuke. I've got both here so I ought to take a look   There was a lot of online 'debate' between Uli Behringer and the designers of the Peavey IPR series PA amps about copyright so it is a moot point about how original their design is but I think they will have simply stuck a bass pre-amp onto their existing power amp to create the Bugera. 

 

Behringer have form in recycling their own designs and I've come across their 300W class D/100W A/B combination in a range of different PA speakers and monitors. Again to be fair this is common across many manufacturers who use essentially the same power amp across a whole range of active speakers throttled back to match the drive units.

 

I've also recently acquired a SansAmp to go alongside my Behringer BD121, there is a generic similarity in the sound but it just isn't the same. It's way easier to dial up a pleasing sound with the Behringer which also doesn't have the same range of adjustment the SansAmp has. I wouldn't say either is 'better' and one is definitely a tribute act to the other but it isn't a straight copy. 

 

Any commercial designer would be a fool not to look at what their competitors are doing. It would be a real arrogance not to monitor the world around them. The boutique speaker makers have stimulated the big makers to look at making their own lightweight speaker cabs and if GRBass start to take significant market share then expect a rash of 'me-too' plastic bass cabs. If I were chief designer for Behringer/Music Tribe I'd be pretty much doing the same thing, reverse engineering everything I could find, taking the best bits from everywhere then bringing them together in a design I'd hope to have maximum appeal to everyone. I'd imagine all the big manufacturers have had a look at the insides of all their competitors products and keeping a wary eye on what the market is doing. (OK maybe not Gibson  ) Ultimately if we see further it is because we stand on the shoulders of giants and we all benefit from the copying of good ideas and the dropping of poor ones. There's a problem in plagiarism if it starves the means to continue to innovate but IP is a double edged sword if it retards the spread of good ideas. Where would all us covers bands would  be if Mick Jagger had never heard the Beatles and thought 'I want a slice of that'

You make some good points, yes we do stand on the shoulders of those earlier designers but while we are doing so, most of us are careful (respectful) not to stomp on their heads.

I have talked with other designers (including one who was responsible for some of the Peavey class D designs) about the ethics of (and the differences between) learning from other designers and simply copying. Most designers have surprisingly high morals and take pride in developing new approaches while refining long standing circuits to improve performance and reliability.

There's general agreement among designers that the customer will accept a "cheap copy" if the price is low enough. The pedal world is a good example of blatant copying (including PCBs). If there's enough of this, it will affect those companies that are currently bringing new approaches and new ideas to the players, ultimately the investment required to develop innovative new products will dry up and many new ideas simply won't make it to market.

2 hours ago, Chienmortbb said:

This is not a trick question, as I am torn on this. Apart from the cosmetics, what do you consider Music Tribe have copied from the Genz Benz? On another point for everyone. Did Genzler play on Mercedes Benz's reputation with his choice of company name?

Cosmetic, materials, layout plus feature set, even down to the fonts and legend on the back panel. If it wasn't intentional, it's an unbelievable coincidence... 

The Benz is actually a play on the word "bins", which was the term used here in the states to describe bass cabinets... bass bins, which comes from the fact that Genz Benz originally stated as a pro audio cabinet and rack company. I started out designing pro audio products for Jeff, then we branched out to bass cabinets and later amplifiers.  The Genz part is obviously from Jeff's last name, and was also a nickname.

What are bass bins?

The term 'bass bin' was used primarily in pro-sound before the advent of sub woofers to denote the cabs used to handle the lowest frequencies, down to 40Hz or so.Sep 6, 2012 (from Google)