Trace VA350 and speaker compatibility question

[Bobby K]

Hello again guys

I've managed to get hold of a lovely old Trace Elliot VA350 amp, the one with the GP11 and valve preamps.

Just wanted to ask if I could use it safely with a Trace 1153 speaker?

The amp is 350 watts and the impedance switch on the back of the amp is switchable between 2 and 4 ohms - it's set on 4.

The 1153 speaker is only rated at 200 watts and is an 8 ohms.

Can I use the amp with the 1153 on its own, or would I have to use the 1153 in conjunction with another speaker?

I've got the output power selector on the back of the amp set to "low" - it's got low medium and high settings - but it's bloody loud enough on low (I tested the amp through a friend's 1153 and 1048 speakers together)

Sorry to bring up the old impedance/wattage issue but I can never get my head around it

Any answers would be most appreciated....

[obbm]

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.

[Bobby K]

[quote name='obbm' post='779250' date='Mar 18 2010, 10:51 PM']BTW I think you'll find a lot of solid-state in that pre-amp.[/quote]

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...

Also, would using the 1153 in conjunction with, say, a 1048 (4 x 10) make it a lot safer for the amp?

How about using the 1048 on its own with the amp?

Edited March 18, 2010 by Bobby K

[obbm]

[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.

[Bobby K]

[quote name='obbm' post='779285' date='Mar 18 2010, 11:23 PM']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.[/quote]

Yes, that's what i thought and I intend to mainly use the solid state input (GP11) not the direct valve input.

So, if i input through the GP11 only, using the 1153 on its own, will the issue regarding the strain on the output valves still remain? If I used a 1048 on its own, would that be ok?

Sorry to harp on..

[Musky]

Another VA350 owner.

Sadly whichever preamp you use, you'll still be risking the power amp running at 8 ohms. It's the power amp that connects to the speakers, so that's what will 'see' the load. The VA350 pushes its valves pretty hard in standard form, so you really don't want to strain them further. You might like to do a search for posts by Oxblood, who bought a VA350 power section and did some pretty major work on it. He also lovingly detailed all that work and his findings.

You'll have to go to finnbass for the conclusion though.

[Bobby K]

[quote name='Musky' post='779312' date='Mar 18 2010, 11:52 PM']Another VA350 owner.

Sadly whichever preamp you use, you'll still be risking the power amp running at 8 ohms. It's the power amp that connects to the speakers, so that's what will 'see' the load. The VA350 pushes its valves pretty hard in standard form, so you really don't want to strain them further. You might like to do a search for posts by Oxblood, who bought a VA350 power section and did some pretty major work on it. He also lovingly detailed all that work and his findings.

You'll have to go to finnbass for the conclusion though.[/quote]

Ok, thanks for that Musky.

Am i right in thinking then that if I ran the VA350 through [b]two[/b] 8 ohm cabs, the impedance will then become 4 ohms and thus eliminate the risk to the power amp?

I don't really have the capability to transport around two cabs plus the beast that is the VA350, if I'm being honest.

Would be a lot easier for me to be able to run it through just one cab. I'm now assuming that that one cab would need to be a 4 ohm cab..

Am I correct?

[Musky]

[quote name='Bobby K' post='779318' date='Mar 19 2010, 12:02 AM']Ok, thanks for that Musky.

Am i right in thinking then that if I ran the VA350 through [b]two[/b] 8 ohm cabs, the impedance will then become 4 ohms and thus eliminate the risk to the power amp?

I don't really have the capability to transport around two cabs plus the beast that is the VA350, if I'm being honest.

Would be a lot easier for me to be able to run it through just one cab. I'm now assuming that that one cab would need to be a 4 ohm cab..

Am I correct?[/quote]

Running a single 4 ohm cab would certainly be the easiest option (especially since I can't think of any cabs that are rated at 2 ohms ). Another option would be a pair of lightweight 8 or 4ohm cabs. Overall weight would probably be comparable to a single standard cab. Or if you can find a two speaker cab that is wired in series, rewire it for parallel.

[obbm]

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.

[bumnote]

Hi Bobby

Is that the VA on ebay that completed yesterday or the day before?

[Musky]

[quote name='bumnote' post='779418' date='Mar 19 2010, 08:34 AM']Hi Bobby

Is that the VA on ebay that completed yesterday or the day before?[/quote]

I just had to do a search for that one. £62!

How to screw up your chances of maximising your sale price in one easy lesson! Congratulations are due if you did manage to score that one Bobby.

[quote]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.[/quote]

I forgot about that option - it would work with a more common 8 ohm cab rewired for 2 ohms as well.

Whatever cab you end up with you just need to bear in mind that Oxblood ended up measuring the output on his VA350 at 470w - it's a lot more powerful than the rated output would suggest.

[Bobby K]

[quote name='Musky' post='779452' date='Mar 19 2010, 09:05 AM']I just had to do a search for that one. £62!

How to screw up your chances of maximising your sale price in one easy lesson! Congratulations are due if you did manage to score that one Bobby.



I forgot about that option - it would work with a more common 8 ohm cab rewired for 2 ohms as well.

Whatever cab you end up with you just need to bear in mind that Oxblood ended up measuring the output on his VA350 at 470w - it's a lot more powerful than the rated output would suggest.[/quote]

yes, it was the one on ebay. I needed it as a matter of emergency, so contacted the seller and arranged a buy it now, outside of ebay (tsk tsk, I know)

As it stands, i've got a gig in Glasgow tonight, armed with the VA350 and the 1153. Don't know if i should use it now. The gig the night after is in Newcastle, where we'll be picking up a 1048 (bought on ebay too from someone else) - I'm guessing it's fine to use the 1153 and 1048 daisychained with the VA350? those cabs are both 8 ohm yeah?

* I say daisychained because there's only one speaker out on the VA350

Edited March 19, 2010 by Bobby K

[bumnote]

I saw that as did a friend, we were both going to bid and then it disapeared

nice score

Edited March 19, 2010 by bumnote

[Bobby K]

[quote name='bumnote' post='779462' date='Mar 19 2010, 09:20 AM']I saw that as did a friend, we were both going to bid and then it disapeared

nice score[/quote]

Sorry guys...

Got it for 300 in the end. Had to get it from Hull yesterday!

[Bobby K]

[quote name='Bobby K' post='779463' date='Mar 19 2010, 09:22 AM']As it stands, i've got a gig in Glasgow tonight, armed with the VA350 and the 1153. Don't know if i should use it now. The gig the night after is in Newcastle, where we'll be picking up a 1048 (bought on ebay too from someone else) - I'm guessing it's fine to use the 1153 and 1048 daisychained with the VA350? those cabs are both 8 ohm yeah?

* I say daisychained because there's only one speaker out on the VA350[/quote]

Can anyone give me an answer on this.. i'm leaving for Glasgow imminently

Sorry to be a pain...

[obbm]

[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.

[Bobby K]

[quote name='obbm' post='779476' date='Mar 19 2010, 09:31 AM']If 1048 is 8-ohms and 1153 is 8-ohms

then using them together will be 4-ohms.[/quote]

I thought so obbm, thanks very much for the reply!

Phew, for Newcastle at least

[Bobby K]

Ok guys, the VA350 shook newcastle to its foundations last night with those two 8 ohm cabs

Now then, I'm quite interested in musky's suggestion earlier about rewiring an 8 ohm cab to 2 ohms. My band now hates me because we're carting around two bass cabs and it would be more practical to just carry the one.

The Trace 1048 cab i've got is 8 ohm and looks like an older one (no wattage info etc on the rear socket plate, tolex covered, not carpet, with the red stripes accross the front)

Not sure of the wattage, but just wanted to know if the rewiring to the correct impedance for the VA350 can be done and what the implications/ramifications of doing so are. Is it easy to do and as a great man once said
[i]Is it safe??[/i]

I'm guessing it might be more practical to just buy a 4 ohm cab but I'm skint after buying the VA350!

Edited March 21, 2010 by Bobby K

[Musky]

Yes it's safe, very safe - so safe you wouldn't believe it.

The main problem you have is not knowing the actual wattage of the cab, and the fact that even in the 250w mode the VA350 might be delivering well over 300w [i]clean[/i]. The simple answer is to use your ears - if the the cabs are starting to distort, turn it down. From the [url="http://wiki.basschat.co.uk/info:amps:impedance_and_wattage#you_can_use_any_power_ouput_amp_with_any_power_handling_cab._if_any_of_these_combinations_makes_bad_sounds_then_turn_down_and_or_stop_cranking_the_bass_eq_excessively_or_damage_may_occur"]wiki[/url]: "You can use any power ouput amp with any power handling cab. If any of these combinations makes bad sounds then turn down and/or stop cranking the bass EQ excessively or damage may occur."

Edited March 21, 2010 by Musky

[Bobby K]

So I'd need to know the wattage of the cab first. Is it simply a case of taking the drivers out and looking at the figures on them?

When you say [i]250w mode [/i] do you mean when the output power selector switch is on [i]low[/i]?

[Musky]

[quote name='Bobby K' post='781776' date='Mar 21 2010, 04:41 PM']So I'd need to know the wattage of the cab first. Is it simply a case of taking the drivers out and looking at the figures on them?

When you say [i]250w mode [/i] do you mean when the output power selector switch is on [i]low[/i]?[/quote]

Strictly speaking you don't [i]need[/i] to know the power rating of the cab, so long as you use your ears for signs of it starting to complain. Even if the cab is rated at 320w like the later 1048's, you could still push it to it's limits (or past them) with say an amp rated at 300w if you like distortion and boosting the bass. And if you do like distortion, that can mask the sound of the speakers complaining. But it won't hurt to look in the back of the cab anyway, just for a bit of peace of mind. Or you could have a word with Merton - he's quite up on old Trace gear and might know the power rating.

250w is the rated output of the VA350 (AFAIR) on the medium setting, although I'd expect that to be quite conservative.

Edit: I just took a look on harmony central to see if anyone had left a review for an older cab, and someone mentioned that they used Celestion C100h speakers, rated at [i]32 ohms[/i]. That might put the kibosh on any idea of using this cab as a standalone.

Edited March 21, 2010 by Musky

[Bobby K]

[quote name='Musky' post='781985' date='Mar 21 2010, 07:37 PM']Strictly speaking you don't [i]need[/i] to know the power rating of the cab, so long as you use your ears for signs of it starting to complain. Even if the cab is rated at 320w like the later 1048's, you could still push it to it's limits (or past them) with say an amp rated at 300w if you like distortion and boosting the bass. And if you do like distortion, that can mask the sound of the speakers complaining. But it won't hurt to look in the back of the cab anyway, just for a bit of peace of mind. Or you could have a word with Merton - he's quite up on old Trace gear and might know the power rating.

250w is the rated output of the VA350 (AFAIR) on the medium setting, although I'd expect that to be quite conservative.

Edit: I just took a look on harmony central to see if anyone had left a review for an older cab, and someone mentioned that they used Celestion C100h speakers, rated at [i]32 ohms[/i]. That might put the kibosh on any idea of using this cab as a standalone.[/quote]

Thanks again Musky.
As far as power rating of the cab goes, i'm fine with the using my ears thing. I know when to back off on the power if the speakers grumble.
I'll definitely need to look inside this cab because the original drivers have been replaced. I can tell this because the discs in the centre of each speaker (are they the voice coils?) are [b]silver[/b] instead of black. you may have seen this very cab on ebay last week. I think a lot of buyers were put off because the speakers looked different. I got it for 137 quid in the end and it sounded fine in conjunction with the 1153.

I'll look at the back of one of the drivers and see what's on there and report back if that's ok?

[Bobby K]

[quote name='Bobby K' post='781776' date='Mar 21 2010, 04:41 PM']So I'd need to know the wattage of the cab first. Is it simply a case of taking the drivers out and looking at the figures on them?

When you say [i]250w mode [/i] do you mean when the output power selector switch is on [i]low[/i]?[/quote]

Ok then. I've now removed the drivers from the cab...

I was very dubious about these from the start, but imagine my horror when I looked at the back of one of the drivers and saw the words [b]McKenzie Disco Series[/b] on the back of the magnet!

These it turns out are PA/disco drivers and most certainly are not bass drivers!

Gutted, but you live and learn eh?

Thankfully, the cab itself seems to be a genuine 1048, so I'm now thinking of turning the cab into a 2 or 4 ohm version by getting the correct [b][i]bass[/i] [/b]drivers.

I'll have a look around the forum but in the meantime, can anyone recommend some decent ones that won't break the bank...

Looking forward to getting closure on this [i]enclosure[/i] issue!

Edited March 23, 2010 by Bobby K

[Bobby K]

Would Celestion BL10-200's be suitable replacements?

Would be getting them wired to 2 ohms of course...

Edited March 23, 2010 by Bobby K