LesterPTelestrat 10/10/2017 7:09 AM
16 or 8 ohm Replacement Speaker
I'm looking at replacing the speaker in my Marshall DSL 15c with a Celestian Greenback and am wondering if there is any recommendations one way or the other regarding a 16 vs. 8 ohm speaker. The stock Marshall speaker is a 16 ohm speaker but there are 2 additional 8 ohm jacks if I want to go that way. Just curious if the 8 ohm might be more efficient? I won't be running any additional cabs, just the internal speaker so no need to be concerned about pairing.
 
pdf64 10/10/2017 7:42 AM
There should be no noticeable difference in performance between the 8 ohm and 16 ohm versions of the same speaker type.

In the future, you may find that running the amp with an extension cab would be useful. If so, a 16 ohm speaker in the combo, and a 16 ohm extension cab, would make for a perfect match with the 8 ohm outputs on the amp, as together they create an 8 ohm load.
Whereas pairing an 8 ohm combo speaker with any impedance extension cab would result in a total load somewhat under the 8 ohm minimum you have available, thereby reducing power output and tube life.
 
olddawg 10/10/2017 5:01 PM
How many hrs do you have on the amp? Speakers usually need to be broken in. If you haven't played a lot of hrs at high volume the stock speaker may just be stiff. I'm not sure how much improvement you will get vs the cost and trouble with this amp.
 
J M Fahey 10/10/2017 5:51 PM
Just checked.
You have the cheapest Celestion there, a small magnet G12E(conomy)60, the latest reencarnation of G12L35 .
Any "real" Celestion will be better, a G12H30 would be perfect there.
8 or 16 ohms is the same, see what you can get.
If not, one of the "good" Eminence.
 
Steve A. 10/11/2017 2:17 AM
If you plan to reuse the speaker with a solid state amp some time in the future with many SS amps you will get twice as many watts from an 8 ohm speaker than one that is 16 ohms. Since we generally don't get to test out speakers with our amps I figure that if it doesn't work well with one amp it might work better with another one...

I played a DSL15C for a few years but never did get around to doing some needed mods to it (at least for my taste - I play mostly traditional blues, rock and country from the 50's through the 70's... no heavy metal shredding for me!)

If you compare the schematic to that of the DSL40 you'll see that they used the more distorted OD2 mode for the dirty channel. It looked like it would have been fairly simple to convert it to the less distorted OD1 mode. I also wanted to rewire the tone stack and switches more like an older Marshall.

Warehouse Guitar Speakers make great Celestion copies at a great price. It used to be that their shipping charges were a real deal killer but many of them are now available through GC or Musicians Friend with free shipping... Woohoo!

Steve A.
 
J M Fahey 10/11/2017 3:57 AM
Agree and add: 8 ohms is usable with way more amplifiers out there.

That said, a few have only a single 16 ohms tap, including a °!"#$%&/*?=)(/&% Crate "Vintage something" with only a 16 ohm tap.
Customer killed its speaker (it had a killer sounding but feeble paper voice coil) and I should hand wind a new one, annoying because it uses very thin wire which must be wound **perfect** , each turn exactly side by side with its neighbours, two perfect layers, magnet gap is *very* narrow.

Our pickup friends use far thinner wire, but they scatter wind and only pot coil after it is assembled, while I canīt let just one wire cross over another, also leave no gaps at all..

Whatīs the point? ... 8 ohm speaker users live a simpller life
 
LesterPTelestrat 10/11/2017 7:46 AM
I was seriously considering the ET65 from Warehouse but for the same price on MF they had an Eminence Cannabis Rex. I've had a good relationship with a Eminence Rajin Cajin in a Marshall Mini Cab in my DSL15 so thought I'd go with the 16 ohm version of the Cannabis Rex. Now I'm kicking myself for ordering the 16 ohm version since none of my other amps are rated for 16 ohms. I'm sure I could run a 16 ohm speaker in my Blues Jr, or DRRI though.... any real reason I wouldn't want to do that if I don't like it in the DSL15?

PS, I bought the amp used so not sure how many hours are on the stock speaker. I just know that the gain channel sounded awful with the stock speaker. When I hooked up my Rajin Cajin it sounded 100% better. I then installed the Jensen C12k that I had pulled from my DRRI a few years ago and that actually sounds really good. I'd keep it in there but want to re-install it in my DRRI. So I needed a new speaker for my DSL15.
 
J M Fahey 10/11/2017 8:50 AM
Quote Originally Posted by LesterPTelestrat View Post
thought I'd go with the 16 ohm version of the Cannabis Rex. Now I'm kicking myself for ordering the 16 ohm version since none of my other amps are rated for 16 ohms.
Not everything is lost.
Put the new speaker in the DSL and use it.
Make a simple (a little plywood, glue, nails, not even painted if you donīt want to) extension cabinet, same width as DSL, less tall, just enough to fit the speaker, and leave it there.
For regular use play with the combo alone; if in a larger place or wanting a "larger" sound or if you want to spread thge sound (combo pointing at you, extension pointed somewhere else) you use both, each in one of the "8 ohms" labelled jacks.
I'm sure I could run a 16 ohm speaker in my Blues Jr, or DRRI though.... any real reason I wouldn't want to do that if I don't like it in the DSL15?
You *can* if absolutely needed, but not recommended: a not so good or efficient speaker, and to boot impedance mismatched?

Edit: now I think you are talking about the Cannabis and not the old Celestion.
IF you donīt like it, now you have *two* 16 ohm ugly ducklings: make a compact 2 x 12" 8 ohms cabinet, which at least will be more usable, and very probably will sound much better than each alone.
ALL speakers have ragged uneven frequency response, full of peaks and holes.
Using 2 different ones will make each other compensate most of them if working together in same cabinet, sound will be smoother to begin with.

Only problem is than now you will have an excuse to buy a head to drive it
 
LesterPTelestrat 10/11/2017 8:54 AM
Good suggestions Juan, thank you.
 
LesterPTelestrat 10/11/2017 3:04 PM
"Only problem is than now you will have an excuse to buy a head to drive it"

And the cycle repeats.... I have one of my amps and speaker cab for sale now, but I priced it high enough where I hope no one buys it. :-0 )
 
Steve A. 10/11/2017 9:57 PM
Quote Originally Posted by J M Fahey View Post
Agree and add: 8 ohms is usable with way more amplifiers out there.
That said, a few have only a single 16 ohms tap, including a °!"#$%&/*?=)(/&% Crate "Vintage something" with only a 16 ohm tap.
I had always heard that with most tube amps you could safely mismatch speaker impedances by "twosies" — like connecting a 4 or 16 ohm speaker to an 8 ohm tap. Yes, it would not be the correct load on the power tubes but it should be "good enough for rock'n'roll" and should not damage the speaker or OT. Reality check: Do amp techs today still believe that or have they learned otherwise?

Solid state is an entirely different matter. The new Vox palm-sized MV50 Clean microamp is rated at 50W into a 4 ohm load, 25W into an 8 ohm load and 12.5W into a 16 ohm load. On many solid state amps they warn you not to plug in a load of less than 2, 4 or even 8 ohms as that might overload the output transistors or module.

Vox MV50 Clean Head review | MusicRadar

Question: I put a 4 ohm GWS ET65 into my old EVJ cab specifically to use with the Vox MV50 Clean to get the full 50 watts. I would also like to use it with my ZT Lunchbox 2 amp which is not to be connected to a load under 8 ohms. I was thinking of adding a switch to the 4 ohm EVJ cab to wire in a large 4 ohm resistor array in series to bring the total load up to 8 ohms. Any suggestions on the wattage resistors to use? The ET65 is rated at 65 watts.

https://www.ztamplifiers.com/store/p...hbox_Amplifier

I was thinking of using 4 resistors wired like a 4Ũ12 speaker cab — 2 strings of two 4 ohm resistors wired in parallel, wired in series. Doing that will of course reduce the total output of the Lunchbox but it is advertised at having 200W (!?!) but the designer Ken Kantor agrees that it is actually more like 65 real watts.

[img]http://music-electronics-forum.com/attachment.php?attachmentid=45282&d=1507781462[/img]

Steve A.

[ATTACH=CONFIG]45282[/ATTACH]
 
glebert 10/11/2017 10:22 PM
I'll bite on the threadjack: On the ZT, the external speaker and the internal can be driven simultaneously, correct? Are they wired in parallel? What is the internal speaker impedance? If it is 8 ohms or less and the external speaker is in parallel it seems as though disabling the internal speaker via the back panel switch should allow you to drive an external 4 ohm load. Or does the speaker switch kill internal and external? I've never worked on a "big" lunchbox, only the Jr, which doesn't have an external speaker out.
 
J M Fahey 10/12/2017 5:22 AM
Personally Iīd have an 8 ohm extension cab which covers most bases and accept the micro VOX, which looks like a grown manīs toy to me, to put out "only" 25W.
And of course will work well with the small but "real" Lunchbox which:
* is usable on its own, it has its own speaker
* is a Rock amp, it has its own quite acceptable distortion
* has "some kind of" Reverb (I guess they call it "ambiance" or similar)
* the minimum usable configuration is smaller and lighter than the VOX option, where you also have to carry the cabinet ... and pedals.

Only problem is that itīs "yesterdayīs paper", all excitement worn off years ago, while the VOX is the exciting new toy

Nothing against, itīs a Human trait to constantly become bored with what we have and search for something "different", even if inferior quality.

Only explanation for Hugh Grantīs having become bored stiff with having filet mignon for dinner every night and having cravings for a corner stand $1 burger instead.

[IMG]http://assets.nydailynews.com/polopoly_fs/1.76408.1318373182!/img/httpImage/image.jpg_gen/derivatives/gallery_1200/gal-cheat-hugh-grant-jpg.jpg[/IMG]
 
glebert 10/12/2017 8:54 AM
And then build another 8 ohm extension box with a parallel jack so you can run 4 ohms for the Vox. More gear!
 
Steve A. 10/12/2017 7:26 PM
Quote Originally Posted by glebert View Post
I'll bite on the threadjack: On the ZT, the external speaker and the internal can be driven simultaneously, correct? Are they wired in parallel? What is the internal speaker impedance? If it is 8 ohms or less and the external speaker is in parallel it seems as though disabling the internal speaker via the back panel switch should allow you to drive an external 4 ohm load. Or does the speaker switch kill internal and external? I've never worked on a "big" lunchbox, only the Jr, which doesn't have an external speaker out.
Half a hijack... I did ask if it was okay to just use an 8 ohm speaker connected to the 16 ohm output of the OP's DSL15C. ("I plead half guilty, your honor!")

The internal speaker in the Lunchbox 2 is disconnected when an external speaker is used. I was thinking that connecting a 4 ohm load to it would be safe as long as I didn't crank the volume up too high... true or false?

I picked up a Lunchbox Jr. a few years ago when GC was selling them for $99... I started using it a lot about 6 months ago but managed to screw up the speaker so it has a nasty buzz to it. Does the amp come apart like the LB2 by prying off the front panel bezel and removing the speaker? I was thinking of adding an ext. speaker jack until I can get around to replacing or repairing the speaker...

Quote Originally Posted by J M Fahey View Post
Personally Iīd have an 8 ohm extension cab which covers most bases and accept the micro VOX, which looks like a grown manīs toy to me, to put out "only" 25W.
But I do have a larger Egnater 8 ohm extension cab with a WGS ET65-8 speaker in it. I also have a Vox AC4C1-12 rewired so that I can use the 16 ohm speaker (replaced with a WGS ET65-16, of course!) as an external cabinet which is what I had been using with the MV50 for a measly 12.5 watts. Yes, I do like those ET65's...

I had the old EVJ cabinet around and decided to put a 4 ohm ET65 in it to use with not just the Vox MV50 amp but with other solid state amps as well.

"A grown man's toy"?!? Well, all of my guitars and amps are a grown man's toys. Unlike the Lunchbox amps the Vox MV50 amps have a tube preamp, using the Korg Nutube 6P1 dual triode.

Nutube ? English | korgnutube.com ? English

Be sure to try out at least one of the the MV50 amps if you get a chance — the Clean is one of the nicest clean amps I've had the pleasure of playing and I am sorely tempted to add the MV50 AC to my garage full of grown man's toys (with the Gain and Volume controls it adds the distorted rock sounds the MV50 Clean lacks.)

Steve A.

P.S. I've posted extensively about the Lunchbox amps and how the designer Ken Kantor is a genius who figured out how to get really nice authentic guitar amp tones from a digital processor. Unlike everyone else (as of 2009) who wanted to emulate anywhere from 6 or 8 to dozens of different amps, Kantor focused on capturing the magic of various classic amps in his R&D facility in Berkeley.

In my 50 years of playing electric guitar there have been some amps which have been really fun to play and quite a few that haven't, and that has not depended on whether they were tube or solid state. I never could put my finger on what quality made them great but I now think that latency and response has a lot to do with it... it responds to your playing right now!

He devoted so many bytes on the ROM chip which programs the microprocessor to get a great amp tone that there weren't enough left to create a decent reverb so he eventually renamed it "ambience" which when turned up a little bit gives the amp the sound of an open-backed combo amp.

[The Lunchbox] is a Rock amp, it has its own quite acceptable distortion
As mentioned above so does the MV50 AC (and the MV50 Rock, too.) I opted for the MV50 Clean because it has separate bass and treble controls and I can get all of the dirt I need from pedals.

BTW the Lunchbox originally did not distort at all when you turned up the gain which beta testers complained about so Ken added discrete clipping diodes to the SMT circuit board (which made them easier to clip out, thank God!)

In a thread on the Gretsch forum in 2009 Ken offered to make a custom ROM for someone who did not like the midrange boost in the stock LB2 and I was the first person to respond so he burned a ROM for me with a more even frequency response and he used that ROM in the custom Lunchboxes he built for Wilco, etc., and was also used in the subsequent batches.

I also had him show me how to cut out the clipping diodes and he gave me a defective board to practise on (I was going to add a switch to add them back to the circuit — I guess I could use a double throw center off switch to toggle between germanium or silicon diodes, or none at all!)

I bought a second Lunchbox 2 when it was on sale at GC for $99 (to play in stereo!) but I haven't cut out the clipping diodes which reduce not only the clean headroom but the overall power as well.

I guess we are back to a full thread hijack... Go Ken Kantor, go ZT Amps! Go Korg Nutubes! Go WGS ET65's!

Steve A.
 
pdf64 10/13/2017 5:38 AM
Quote Originally Posted by Steve A. View Post
I had always heard that with most tube amps you could safely mismatch speaker impedances by "twosies" — like connecting a 4 or 16 ohm speaker to an 8 ohm tap. Yes, it would not be the correct load on the power tubes but it should be "good enough for rock'n'roll" and should not damage the speaker or OT. Reality check: Do amp techs today still believe that or have they learned otherwise?...
Yes, I think that guideline is probably generally ok if used with caution, with the proviso that it's not a copper bottomed guarantee / applicable to every tube amp.

When working as intended, many guitar amps push their tubes beyond at least one of their limiting values; if cranked into a load that's too far off nominal, the limits can only get stretched so far before the stress damages the tube, with possibly significant potential for catastrophic failure / collateral damage.

Beam tetrodes with reasonable operating conditions tend to be fairly resilient (what's the Marshall's HT?), so I think the DSL15 (with 6V6) should be ok into a load impedance down to half nominal.

I would be more reticent if it was pushing pentodes hard, eg claiming 20W from a pair of EL84.