VTypeV4

Cool..

It's difficult to say whether I can hear any differences when operating different loads on any of my amps as any difference can likely be attributed to the change of speakers. Plus I expect the freq range of the amp to be greater than that of any speakers I have at home..

TruVox will be a black pressed frame with a red label on the magnet.. I think it's the TF1520 unit.

Merton, for the MK1, I'm not sure, let me know and take some pix as I'd be interested to see..

When I had trouble with the BG12S flapping in my 712SMC, Trace Elliot udgraded it under warranty to a Q12 (2025?) 200w unit and that never gave any trouble. I expect the rest of the Q series were equally up to the job and judging by the age of the MK1 Commandos, it's where I'd put my monies on..

I remember reading something about windings on secondaries causing a head ache for designers for use at 8 ohm due to a potential imbalance.?

I think it was something to do with two sets of windings in parallel driving current into one another potentially causing output losses and errors?

.

Cheers Man.

Cheers Umph,

You say 'how it's wound' can you expand a bit more on that? For example, guage of wire, distance between windings, thickness of insulator, density of iron core?

Nope, not at the time..

I always find it fascinating how much each component contributes to a particular sound, you know how it is man, I can't help it!

An X of mine had the 1x15 MK2 model and was great. It never saw much hard work but at rehearsals and home use it always came up trumps on the occasions I used it.

It's possible that MK2 came with a different 15" speaker as they came with a TruVox series Celestion whereas the MK1s pre-date this driver so it was probably a K or Q series unit in those..

I owned a Commando 10 for a time and it was a belting little amp and I only paid £50 for it!

Use the 'Pre-out', it might solve your problems..

As far as I'm aware, there were never any made in the USA, all Trace stuff has been made in the UK. The confusion usually stems from the company being owned by Gibson from 1997 to the early 2000s..

As for the Commandos, they're a geat amp with plenty of bang for buck. From my experience there has only been two series of Commandos: The very early models were the green pimply finish and a round punched (like the TEK series) which were 1 x 12" and 100w but there's not many of those about..

Most commonly see are:

Green carpet finish, diamond punched grill 100w 1 x 12 and 1 x 15 models (as per the above pic)

and the later models..

Black Leatherette finish, gloss finish diamond punched grill in three models: Commando 10 (1x10 65w) Commando 12 (1x12 100w) and Commando 15 (1x15 150w).

In all fairness, I've never played a bad one although the green framed Celestion BG12S 100 in the 12" models was a known weak point (also in the 712SMC) in the earlier 12" models. The 15 inch models are great whether it be an early or a late model and will happily show a Peavey TKO a clean set of heels!

Hope that helps, Matt

I was wondering how much the frequency response of a valve amplifiers' output transformer changes with respect to output level?

Looking at typical specs, most output transformers are referenced at low level, usually one watt (not unlike speakers) but i was wondering how much these deviate by the time they're at rated power / half power or whatever. I assume high quality transformers maintain their low level characteristics as the power rises better than cheaper / lower spec units? For example, I expect my Leak output units to be a smoother response curve than the one in the Linear L30..

I appreciate that difference in designs, Class A, Class A/B, Single ended, Push-pull, Ultra-Linear etc designs will also dictate the overall response and of-course coupling of the appropriate load on the secondary etc. My question is aimed at the output transformer itself assuming all other parts to be an 'ideal world scenario' including any distortion whithin the amp, not the coupling device..

Many thanks, Matt

[indent=1]What a lovely thing..[/indent]

The Warwick amp is solid state (transistor) amplifier so running it without speakers will not harm it. It's largely only amps with a valve output stage that can be harmed by not connecting speakers..

Nice enough valve but not a patch on the Siemens smooth-plate IME..

[url="https://soundcloud.com/vtypev4/bautostringer07-master"]https://soundcloud.com/vtypev4/bautostringer07-master[/url]

For those of a disco feel..

Most certainly sounds like a fried coil thats split and is now rubbing against the magnet gap.. Postage will be heavy on those units, I have a pair of DL12s (300w) loaded in a 2x12 that weighs an absolute ton..

It's an early '90s 1048.. I think this design came in about '91 and continued in green furry carpet from '97 and the last few were in black leather until production ceased around 2001ish..

The 32ohm Celestions were standard issue in this cab although I have seen some with 8 ohm also. The one I had a few years back had the 32 ohm variants although I don't thinks there's much difference between 'C10T' units and Celestions' (at the time) BG10 80.

Don't think they're worth much these days but still a solid and good sounding if not slightly vintage by todays standards.. Mine had the HF component and was designated 1048H as I prefer an extended HF response.

Hope that helps.

6V6, When you're inputting the data for the speaker make sure you've got the correct parameter value/scaling. For example Vas can be measured in Litres, Cubic Cm, Cubic M, Cubic inches or Cubic Feet.

I've never used WinISD but I've put data into Eminence designer before and it's thrown up errors becuase I didn't check..

Hope that helps..

Thanks anyways Bert..

I'm gonna put it in my 1x15 Ashton cab and see how it performs in a reasonably large vented box vs the small sealed WEM.

Truth is, I'm not expecting miracles or 35 Hz (which would be a miracle!), just a pleasant and warm sounding speaker to use at home or to do a bit of old school recording with an SM57. I paid next to nothing for it but think it's;s a really cool looking old thing that could be put to good use.

Here are some pix I did of the repair job..

[IMG]http://i778.photobucket.com/albums/yy70/VTypeV4/Celcoil1_zpsd3204df8.jpg[/IMG]

[IMG]http://i778.photobucket.com/albums/yy70/VTypeV4/CelCoil2_zps861f06e2.jpg[/IMG]

[IMG]http://i778.photobucket.com/albums/yy70/VTypeV4/Celcoil3_zpsd4a4a3ad.jpg[/IMG]

[IMG]http://i778.photobucket.com/albums/yy70/VTypeV4/Celcoil4_zps3c55f509.jpg[/IMG]

I was surprised by how deep the voice coil iss, I expected it would be really short being only a 50w speaker. I guess the paper former is the limiting factor..

[quote name='Mr. Foxen' timestamp='1360886928' post='1978084']
"Equivalent" doesn't mean much, this kind of dates from when everyone 'knew' a 15" speaker had a sound from it being 15", so equivalence might be no more than that.
[/quote]

Ok man, cheers..

Not meaning to Hijack my own thread but..

I read on another forum that the G15C was Celestions' lower power equivilant of the JBL D/E140..

Does this sound likely or simply hearsay?

I could do that.. I have an EV SRO 15L with an EVM-L recone kit which is in fine fettle and there's plenty of data on those..

Thanks Mr F, I'll have a think.

[quote name='Mr. Foxen' timestamp='1360718463' post='1975505']
If you use a high pass filter its safer. But simultaneously saying they don't know the properties of the speaker and also making recommendation as to what to do with it doesn't fill me with confidence.
[/quote]

Thats a fair point, I hadn't considered that..

It sounded OK in my WEM cab so maybe something of that description is in order but just a little larger voulme wise? I was thinking somewhere between the size of a Trace Elliot 1153 and a 1518..

I guess without data other than Fs (55Hz), and a guestimated Xmax of around 3mm it's gonna be a case of build it and see?

Thanks Mr F and not meaning to contradict but..

I got this from Dr Decibel at Celestion..

[i]Hi Matthew[/i]
[i] Sorry we don’t have parameters for these things. Try downloading Audua’s Loudspeaker Workshop which will teach you to measure the parameters of your speaker. You will likely end up with a box between 75 and 100 litres tuned to around 45Hz using two 100mm diameter vents 300mm long. That’s a good practical size for a 15”. Remember its getting old now so be a bit sympathetic if you hear it struggling!![/i]

[i]Regards[/i]
[i]Doc[/i]


My plan with the vented box is to give an extended low end a little but also give the unit a slightly easier life within it's operating parameters. I don't plan to gig the box particularly or even work it hard, it'll probably be used for recording too being driven by a 60w valve amp at little above bedroom level..

It was on my understanding that a vented box was easier on a drive unit of any description when operated above Fb?

I have a vintage G15C that was bought from eBay for next to nothing although after a few weeks use it developed a slight coil rub. I have since removed the magnet and re-aligned it and now the speaker works great without complaint.

Does anyone have the T/S specs for this unit? My plan is to put a custom built enclosure around the unit and plan to go down the vented box route to extend the low frequency response a touch. I expect originally it would have been put in a smaller than ideal sealed enclosure.

It'd be great if anyone could help.

I have also emailed Celestion and am awaiting a response from them.

Many thanks, Matt

[IMG]http://i778.photobucket.com/albums/yy70/VTypeV4/Cel1.jpg[/IMG]

For easy reference, this is the drive unit in question..

[quote name='BassPimp66' timestamp='1359884543' post='1961442']
Hmmm, good old Torque 100 W, 15"? Yup, this was made everything sound like s***
[/quote]

My friend Mick had the 200w version of the 1x15" combo when he upgraded from a Laney BC120. He had a really soft / warm sound as he played in a blues band and just used the soft bit of his thumb to play the strings. It had a Celestion speaker and he was very pleased with it at the time and from what I remember, it was quite good at this particular task. It was a massive improvement over the BC120 which really wasn't great. Not sure the Torque would suit my sound tho..