obbm

Move It - Cliff and The Shadows

There are very few power amps that bridge into 4-ohms. Most QSC do however. I used to have a PLX1602, it was excellent and bridgeable into 4-ohms. 2U x 19-inch.

[quote name='Bobby K' post='779474' date='Mar 19 2010, 09:28 AM']Can anyone give me an answer on this.. i'm leaving for Glasgow imminently Sorry to be a pain...[/quote] If 1048 is 8-ohms and 1153 is 8-ohms then using them together will be 4-ohms.

I use an Epifani UL212 2x12 that is rated at 4-ohms with an Orange all-valve head. It is very light and managable. There is also the Genz Benz NEOX 212T which is also a 4-ohm cab. Without looking inside you wouldn't know but some of the older 4-speaker cabs used 16-ohm drivers in series parallel to make them 16-ohms. They can be rewired to be 4-ohms. Yet again Trace did make a 4-ohm version of the 1153 called the 1154 IIRC. You could simply swap the driver in your cab for a 4-ohm unit.

[quote name='Bobby K' post='779272' date='Mar 18 2010, 11:13 PM']what do you mean? Do you mean it would be better to use the top section of the head (the GP11) as opposed to the valve input section. Sorry if that sounds confusing...[/quote] I didn't mean to confuse. The GP11 is all solid-state, the direct input on the VA350 chassis is valve all the way but has no tone controls IIRC.

It's not really a power problem, more to do with providing the correct anode load for the output valves so they work correctly. The reason that the output transformer has a speaker impedance selector is so the anode load always remains the same. The 8-ohm 1153 will work, maybe not optimally, however it will put a strain on the output valves and could well shorten their life. A matched set of 6 KT88s are expensive. BTW I think you'll find a lot of solid-state in that pre-amp.

[quote name='Musicman20' post='777337' date='Mar 17 2010, 01:18 PM']Can you go out from an output of the Sansamp BDDI or Aguilar Tonehammer into headphones? I would really need wireless though...I could not deal with another cable to the pedal especially to my head. Ill see how this new band goes first...they dont play silly loud, so I can hear myself even DI'd with BDDI.[/quote] Nope. Those outputs are either instrument or line level. You need to think of earphones/ headphones as very small loudspeakers, consequently you need a very small power amp (headphone amp) to drive them.

[quote name='Jamesemt' post='777012' date='Mar 17 2010, 09:12 AM']I currently use the ACS in ear custom mould ear Plugs and they sell earphones which replace the filters. If I buy those, connect to a suitable output on my amp and buy an inline volume control for the earphones ...erm is that it? How do you go on with the wires? Feed them down the back of your shirt? Is it really that simple? ACS want £120 for the earphones that work with their moulds - anything cheaper that's compatible? I've been using the custom moulded plugs for about a year so am used to wearing them ( sounds weird without them tbh)[/quote] Not quite. You must not connect the headphones to any speaker output from the amp. You need to use a line-out however the signal is not suitable for driving headphones/earphones so you'll need a personal headphone amp such as the Rane PM50, PM351 or similar from ART. The alternaive is to go wireless. I have a set of ACS T3 custom in-ear phones. Whilst they are great for listening to my ipod they are not much use with the bass as they can't drive the low frequencies loud enough for me. They just distort. Expensive ipod phones. Before you shell out £120 on the earphones make sure that they can handle the bass frequencies. Get ACS's confirmation in writing so you have some leverage to get your money back if they don't do it for you. I have a pair of Sony in-ear phones that are 10 times better with bass than the ACS ones however they do don't fit the ear mounds. One day I'll sort it.

[quote name='Nostromo' post='774619' date='Mar 14 2010, 07:55 PM']Hi obbm Thanks for your concise advice. If you were me, would you bother to change it ? . . . . . I've been trying to work it out, and I reckon the amp has done about 2500 to 3000 hours work probably nearer 3000 ? . . . mainly running in mono mode into a 4ohm load so getting warm. Cheers,[/quote] Firstly how you run the output stage has no bearing on the pre-amp valve, it's just a stage in the pre-amp. To give you an idea there are valves made in the 1950s and 1960s that are still performing well today after years of use, in fact some are highly desirable. If the amp is reliably delivering the sound you had when you bought it then don't mess with it. If you are unsure then you could always get another valve and try it - I do it occasionally - and if it's better then you've cracked it. If there is no change the at least you have a spare for the future.

Pre-amp valves need no setting-up or adjustment. With the amp switched off and disconnected from the mains, remove cover unplug old valve plug-in new valve replace covers job done Just because it is old and has been used a lot doen't mean it's worn out. These types of valves usually go on for decades.

Paul bought a cable for his new wireless system. Perfect transaction.

That is very nice.

[quote name='thebassman' post='768299' date='Mar 8 2010, 06:20 PM']I see they do the muting connectors. Does anyone know if they work with stingray 5 basses. The neutrik site says they do not work with some active bass guitars.[/quote] Works fine with my SR5. Just a slight click as the pre-amp is energised. I suppose with a big rig that might be a loud click. Never had the chance to try it though.

[quote name='Mr. Foxen' post='767060' date='Mar 7 2010, 05:15 PM']Shouldn't that be impedance then, since you are specifying frequencies?[/quote] Theoretically it should be but because the inductive and capacitive components are minimal, it is the resistive component that has the major influence.. There is an interesting paper on speaker cables [url="http://procosound.com/downloads/whitepapers/Understanding%20Speaker%20Cables.pdf"]here[/url]

My thoughts on the matter: [quote]In order to get the best performance from a solid-state bass amp/speaker set-up you need to have a high damping factor. A low damping factor will give a woolly sound whereas a high damping factor gives tighter control of the driver and will give much clearer low frequencies. This is especially important at frequencies around the driver’s resonant frequency, which for a bass is usually in the order of 40 – 45 Hz, well within the usable frequency range of a bass. The resistance of the speaker cable directly affects the damping factor and needs to be as low as possible. Heavier gauge cables have a much lower resistance and therefore help to achieve this. They are also more than capable of handling the high transients produced by a bass amplifier. The problem is not so prevalent with guitar amps as the resonant frequency of many speakers is below the guitar’s frequency range. That being said it is still important to use a good quality, low resistance cable and not an instrument cable as the there are still significant voltage and current transients.[/quote]

[quote name='freelancesam' post='766555' date='Mar 6 2010, 11:48 PM']if i bought one of these [url="http://cgi.ebay.co.uk/PEAVEY-SPEAKON-TO-JACK-CABLE-x1_W0QQitemZ130371286248QQcmdZViewItemQQptZUK_Computing_CablesConnectors_RL?hash=item1e5abbf4e8#ht_500wt_1182"]http://cgi.ebay.co.uk/PEAVEY-SPEAKON-TO-JA...8#ht_500wt_1182[/url] and cut the jack off, would that work?? or am i missing the point? The impedance on the cab says 4 or 8 ohms[/quote] You are switching to bridged mode in order to extract more power. That cable would work however you would undo all that you've done by switching to bridged mode as the additional power would be strangled by that small cross-section cable. If you are trying to extract 800-watts then you need a short high-capacity cable.

[quote name='misrule' post='766335' date='Mar 6 2010, 06:49 PM']+1 -- OBBM does great speaker cables. I've got two. Cheers Mark[/quote] Thanks Mark Badass and I are in communication.

Back in the day, when I were a lad, there were no such things as bass amps, only amps. All the top bands used Marshall stacks so play away and enjoy. As you said just make sure you have appropriate speakers. The only difference is that the EQ controls will be voiced for guitar but that's not really a problem if you like the sound you're getting.

Sheet of MDF and a circular saw?

Alternatively you could consider one of these: I believe that they come with either Speakon or Jack. The WT800 needs an 8-ohm cabinet to work bridged. What is the make of your 4x10 and what is the impedance?

[quote name='Bankai' post='765677' date='Mar 5 2010, 10:20 PM']Ah. So would a US spec rack case be alright?[/quote] I'm can't be certain. It would be best to take your brackets along and try them with any case you are thinking of buying.

[quote name='Bankai' post='765651' date='Mar 5 2010, 09:49 PM']Cheers. So in summary the screws take 2U space but in reality there's a bit of space both above and below the unit.[/quote] Nope. You need 2U space but you will never get the screw holes to line up with the fixings on European spec rack strip. The best solution is to find a case with sliding nuts so you can move them tyo where the holes are.

[quote name='Bankai' post='765615' date='Mar 5 2010, 09:01 PM']Just got a Little Giant with a mind to rack mounting it yet it's not a standard 1 or 2U size.[/quote] Correct. The fixing holes in the brackets are not in the right place either. See page 8 of [url="http://basschat.co.uk/index.php?showtopic=13645&st=140"]this thread[/url]

Somehow I also missed this one. It's looking good. I became a member of the Shuker P5 club a few months ago when I acquired "Alice", the PJ5 that OHM had made. In fact I'm playing it right now and wondering what it would be like with flats.