Ampeg SVT-II & Trace Elliot cabs STUFF ARRIVED!

[Rattanee]

Bulgarian speakers might be very cool.
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That is like nuclear-reactor type power handling lol, but I'm not sure it'd work with this size cab? I might have a look at modeling it's behavior based on the thiele/small data on that enclosure, but would possibly not go as low as I'd prefer.

I also just got a reply from my friend who does custom voice coils, he'll have a look but can probably replicate them if the old coils didn't damage the cone.

Still, it'd be nice to have an alternative.

 

[Wood and Wire]

Ok, that makes sense, as I mentioned the other Celstion 10" drivers were for the 200 Watt cabinet.

You obviously have the 300 Watt version (just checking my maths... 75 x 4 =... Yep, 300, I think).

They're 8 ohm Celestions, wired together in pairs (series to make 16 ohms), and the pairs in parallel (to make the total load 8 ohms).

If you're having to replace the lot (assuming you like how the other Trace cabinet sounds), then it might be more cost effective to find an identical Trace cab for sale, and pass the dud along to someone who has a use for it.

Alternatively you could get 4 of the drivers that Trace Elliot used on the next revision of that cabinet :

The Celestion CT10T-80

They're absolutely compatible, have very similar voicing (perhaps slightly more focused), and only 5 Watts more powerful a piece - making the cabinet 320 Watts.

Their 32 ohms each, so wire them in parallel, for an 8 ohm load.

They crop up quite often (NOS) on eBay, or alternatively, Watford Valves has them for £48 each :

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I've never used that company, so you'll have to do your due diligence in that respect.

I'd still recommend contacting Celestion for advice.

If you're tempted to go with something else entirely, be that Eminence, or whatever, of course all the usual caveats apply re. the cabinet, and you have the added complication of making sure they compliment the other Trace cabinet, when combined.

Good luck!

 

[Wood and Wire]

Oh, and by the way, for anyone who wanted to know :

Apparently the 3rd manufacturer that Trace used for their 15" drivers, was Precision Devices.

It turns out I did run in to one once (without realising it at the time).

So, if you're wondering what 15" a Trace 1518 cabinet has :

If the frame is circular, with 8 bolts ; it's a Celestion.

If the frame is octagonal, with 4 bolts ; it's a Fane.

If the frame is circular, with 8 (if I remember correctly, possibly just 4) clamps ; it's a Precision Devices.



I don't know exactly what drivers were used in the small format 15" combos, and cabinets, or the 2x15 cabinets (1528 & 1524) - it depends on the vintage, but in almost every case they're Celestions.

Basically, everything from SMX era onwards is a Celestion 15" driver (even if it uses 4 clamps to attach to the baffle), and will probably have the small dust cap with Trace Elliot written on it.

If it's a small cab, or combo, from the Series 6 era, it's probably a Celestion 15".

If it's a 2x15 from Series 6 or earlier, they're most likely Celestions, but could be Precision Devices (would be great if anyone on here has one, could take a driver out and confirm).

So don't jump to the conclusion that because your 15" driver has a circular frame, and is held on by clamps, that it's made by Precision Devices (if your cabinet is Series 6, or later, it's a Celestion).

 

[Rattanee]

...

Thanks for the info, I was looking at a pair of those newer celestions locally as well, but there's only two and 32 ohms are not too easy to mix and match... To boot, I'd prefer the 8 ohm speakers, because I could add a switch to change the cab to 2 ohms so I could use a single cab with the Ampeg (2 or 4 ohms output) for small gigs. I guess I'll measure the cab innards and just start modelling speakers in that volume enclosure, see if anything comes up with a decent frequency response.

What has me a little surprised is that the cabinet itself is in fact not made of plywood, but MDF! On the other hand, I love the tolex coating, that thing looks cool, and indestructible (there are only two small scars nothing major and you can tell that these cabs have gotten around during their life).

 

[Rattanee]

One more thing. Anyone knows if the SVT-II PRO knobs work on the non-pro? I just like the looks a lot better, and they seem to be machined aluminium instead of cheap plastic. Also, for some reason cheaper?

 

[Wood and Wire]

Yeah, I think the mark V range was the last time they used plywood for the cabinets, until Peavy took over, and reintroduced it.

There may have been some early Series 6 that were ply, and I have a feeling there may have been an 8x10 variant that was ply, under Gibson, for the V-type range, but I'm not certain.

How are you liking the combination of the SVT with the working Trace cab?

 

[Rattanee]

Yeah, I think the mark V range was the last time they used plywood for the cabinets, until Peavy took over, and reintroduced it.

There may have been some early Series 6 that were ply, and I have a feeling there may have been an 8x10 variant that was ply, under Gibson, for the V-type range, but I'm not certain.

How are you liking the combination of the SVT with the working Trace cab?

I'm about to find out... the cab is 8 ohms so I can't use it alone with the SVT (2 or 4 ohm output). So far I just tried the cab with a poweramp with the bass plugged directly into the unbalanced input. It was very quiet, but clean. I just finished fixing my Tech Graphic 625's power-amp, so I'm going to give the trace a go with that first. If I like what I hear I will buy a two-pole switch to install into the cab for switching between 2 and 8 ohm wiring and try it with the SVT.

 

[Wood and Wire]

I've no idea which particular Celestions Peavy were using, in the recently discontinued Trace 4x10.

By all accounts, those cabinets sounded really good, and authentically "Trace", but I have a feeling they had a different internal volume, and the drivers were definitely much more powerful - so they may not be compatible with your existing cabinet, or safe to partner with the working one, without risk of inadvertently pushing that too far.

Obviously, the best way to judge the cabinet is in a band situation - you may find you don't like the slightly nasal character of the Trace cabs on their own, but that's what really helps them work in a full mix, or band.

 

[Rattanee]

I honestly wouldn't call them too nasal hehh. With the Tech Graphic head, with very little added in the 40 and 60 hz area, it sounds pretty damn good! They are obviously tuned for 4 string basses though, as the open E and A sound goddamn amazing even without EQ, but for the B I need to boost low end a little. I'll see how they work in a band situation on Thursday, but so far I'm okay with them, though in a band setup, they will probably be a little dark for my taste, then again a little EQ will probably fix that.

I also took the speakers out of the busted cab to test individually. One of them sounds good, the other three are rattling like hell. On the upside, my friend will fix them with new-wound coils (to spec) for about $10 each, provided there is in fact no damage to the paper under the dustcaps. Fingers crossed, cause I kinda like the sound of these boxes. Reminds me of Ampeg (even though I tested with the Tech head!) Or maybe I just have Ampeg on my mind

Oh and I think I know why the cab got fried. Previous owner was using jacks for connecting the enclosures... Let's just say I thought I failed in fixing the Tech head when I first tried the box... then realized the jack for the speaker was not exactly making good contact. Get a cab disconnected during a louder concert, that's going to cause some smoke from the other cab!

 

[Wood and Wire]

Just be aware, if you decide you use the XLR connectors, that Trace used an alternative wiring scheme - it's detailed on the connection plate.

Glad to hear you're getting along with the sound of the cabs so far.

 

[Downunderwonder]

I'm about to find out... the cab is 8 ohms so I can't use it alone with the SVT (2 or 4 ohm output). So far I just tried the cab with a poweramp with the bass plugged directly into the unbalanced input. It was very quiet, but clean. I just finished fixing my Tech Graphic 625's power-amp, so I'm going to give the trace a go with that first. If I like what I hear I will buy a two-pole switch to install into the cab for switching between 2 and 8 ohm wiring and try it with the SVT.

you can play the SVT through an 8ohm cab without concern so long as you keep the volume down. It will wear on the tubes if you crank it.

 

[Rattanee]

Just be aware, if you decide you use the XLR connectors, that Trace used an alternative wiring scheme - it's detailed on the connection plate.

Glad to hear you're getting along with the sound of the cabs so far.

Yeah I actually popped off one plate to see how exactly it's wired, but I'm actually considering swaping the connectors to Neutrik speakons and thus eliminate any and all connection issues.

you can play the SVT through an 8ohm cab without concern so long as you keep the volume down. It will wear on the tubes if you crank it.

Really? I thought it would overheat the output transformer? Better safe then sorry

 

[Downunderwonder]

Yeah I actually popped off one plate to see how exactly it's wired, but I'm actually considering swaping the connectors to Neutrik speakons and thus eliminate any and all connection issues.


Really? I thought it would overheat the output transformer? Better safe then sorry

really. Search 8ohm SVT. It's surely not recommended for the reason given as tubes are replaceable for lots less than the transformer. But at low volume for a taste of the sound I wouldn't worry.

 

[JimmyM]

Really? I thought it would overheat the output transformer? Better safe then sorry

Bill Hughes, the engineer who co-invented the SVT, says that they're so overbuilt that they will easily withstand a 2:1 impedance mismatch. It is not current-day Ampeg's official company line, and I don't like the slight hit the sound takes when you do it (extra compression and slightly less tubiness), but I've done it many times on gigs where backline is provided and never had a problem.

 

[Rattanee]

Awesome. It's making me want to get a 8x10 though...
I really like the sound, though there are some oddities. Like the ultra low feature seems to compress the sound... It feels like it's extending the low-end further, but also compresses the signal at the same time.
Also, am I right in thinking I can use the Pre-amp out as a tuner out, or is that affected by the volume control as well? I could use the balanced out with an adapter, but I'd prefer to have that for larger stage scenarios.

 

[JimmyM]

Awesome. It's making me want to get a 8x10 though...
I really like the sound, though there are some oddities. Like the ultra low feature seems to compress the sound... It feels like it's extending the low-end further, but also compresses the signal at the same time.
Also, am I right in thinking I can use the Pre-amp out as a tuner out, or is that affected by the volume control as well? I could use the balanced out with an adapter, but I'd prefer to have that for larger stage scenarios.

I don't know the answer to that one. Never tried it.

 

[anderbass]

Awesome. It's making me want to get a 8x10 though...
I really like the sound, though there are some oddities. Like the ultra low feature seems to compress the sound... It feels like it's extending the low-end further, but also compresses the signal at the same time.
Also, am I right in thinking I can use the Pre-amp out as a tuner out, or is that affected by the volume control as well? I could use the balanced out with an adapter, but I'd prefer to have that for larger stage scenarios.

Ultra low switch on my SVT-II basicly just cuts mids. it sounds pretty cool playing solo, but you'll probably discover your clarity is lost playing in a band mix.

Your Preamp out & Balanced out jacks both go mute with the amps volume knob turned off, but you could try plugging your tuner into the bright input jack.

 

[Rattanee]

So... could someone with tube-knowhow chime in on this?

Basically, amp has no noise, bass sound is... well... no better way to put it... It has balls. It is pure greatness, and even without EQ to boot! Friggin awesome.
But two songs later, I end up cranking the volume a litte higher, and during the third song, volume is gone. Even on full volume, all I get is a weak fart out of the amp. I had a look, at the endstage tubes, and I found it a little odd that the two outer tubes on each side had blue glow, but the middle two did not(or just very minor. I could not tell if it was just reflection). So I turn it off, switched over to my Tech head, played rehearsal. Out of curiosity, I plugged the SVT back in afterwards, and it fired up fine again with great sound and no noise at all.

I am well versed in more modern electronics, but no experience with tubes. My understanding was that when tubes start going, they'd start humming bad, or turn microphonic before actually dieing completely? Soo... am I looking at bad tubes, or should I just be hunting for a contact fault somewhere ?

 

[JimmyM]

So... could someone with tube-knowhow chime in on this?

Basically, amp has no noise, bass sound is... well... no better way to put it... It has balls. It is pure greatness, and even without EQ to boot! Friggin awesome.
But two songs later, I end up cranking the volume a litte higher, and during the third song, volume is gone. Even on full volume, all I get is a weak fart out of the amp. I had a look, at the endstage tubes, and I found it a little odd that the two outer tubes on each side had blue glow, but the middle two did not(or just very minor. I could not tell if it was just reflection). So I turn it off, switched over to my Tech head, played rehearsal. Out of curiosity, I plugged the SVT back in afterwards, and it fired up fine again with great sound and no noise at all.

I am well versed in more modern electronics, but no experience with tubes. My understanding was that when tubes start going, they'd start humming bad, or turn microphonic before actually dieing completely? Soo... am I looking at bad tubes, or should I just be hunting for a contact fault somewhere ?

That is the case sometimes but not every time. Personally, I think you may be looking at a bad tube or two, but I'm no expert.

 

[bobyoung53]

Hey guys,

I just struck what I think is a pretty damn awesome deal on a complete bass amp rig. The setup is an Ampeg SVT-II (non-pro) with two 1048 Trace Elliot cabs (no tweeter), a Korg DT-1 tuner, a rack for the head and tuner, and road ready containers for both cabinets. I got it cheap, though there are a few problems that I will need to address, which I would like some advice with. (Mind you I will only recieve the rig in two weeks or so as it is abroad, but my friend already picked it all up so it's just a matter of time till he comes home

There are two problems with the rig:
1, The seller told me the tubes are not 100% in the head anymore, so I would like to know if there's a method to test the endstage tubes properly in this head. Is it set up the same way as multi-6l6 tubed amps, where you can pull out tubes in pairs and the amp will still work albeit with reduced output power? The pre-amp tubes are no problem I have a bunch of those laying around that I can play with.
There is also the trivial issue of the volume pot's knob missing. Is there a source for authentic replacements? Otherwise the head looks good, has all the eq pot caps and whatnot.

2, There is a dud speaker in one of the cabs. Can anyone tell me what the original speakers are in these cabs, or if there is a source for legit up-to-spec new cones for these speakers?

And the bonus question:
I have not heard these cabs before, but with no tweeter, I might want to add a midrange horn to them to brighten their sound a little. These are the version with the broad, slot port in the center, so I was thinking of popping one into the middle there, calculating the change in the surface area of the port, and re-adding that surface area somewhere else. Do you think I could get away with that, or would the volume taken away by the horn affect the sound in a significant manner ?

Thanks for any help guys!

One triplet side ( 1,2 and 3 tube) is one half of the push pull and the other three (4,5, and 6) are the other half, you could possibly take one tube out of each side but I wouldn't, but definitely don't run it with only one side of three tubes in it. You can buy set a sextet of matched 6550's for less than 200 bucks online. I doubt you have a tube problem at least a power tube problem (endstage tubes), that's a strange one to me. It sounds like something is opening when it gets warm. I would have a tech look at it, there is really high voltage in that amp, up to 700 volts. Those amps have kind of a safety valve in them for the power tubes, they have a big resistor wired in series with each plate of each 6550 which takes them out of the circuit if they fail, I think they're 10 ohm 10 watt resisters and when the tube gets old they draw too much current and the resisters open. I bought one that had 3 or 4 of them open and it sounded like your description but it didn't change as it warmed up, sounded like that right when you first turned it on.
@beans-on-toast will probably know what's going on with that thing.