Old diesel 2x10 bass cab questions

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THB_bassman

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I just got one of these to use with my old diesel 1x15 cabs. I'm not sure the age of it, it has black leather-like covering, not quite the same texture as the tolex on my other Mesa/Boogie cabs.

I have a couple questions for you with more knowledge of these.

First, the knob on the back for the horn adjustment seemingly does nothing. Turning it full right, full left, or in the middle makes no difference to the sound of the cab. I have looked inside, at the wire connections and it's all solid. I removed the knob/pot assembly and using an ohmmeter read across the two leads which go to the speakers. There is no change in the reading. Are there known to be problems with this unit, or are replacements available?

Next, the speakers themselves. I think they are original EV 10s, but the only markings I can find on the two speakers are the numbers:
1810-2596 stamped on the magnets. Can anyone confirm these are EVs?

Third, the jack plate. This one has (one) 1/4" jack in it, has "8 ohms" printed on it and a decal (sticker) which says "4x10 BASS, COMBINED POWER CAPACITY 600 WATTS". Strange decal to have on a 2x10 cab.
This makes me think that parts were changed at some point, or else the cab was simply made with the wrong decal and has gone unnoticed for years.

Any information is appreciated.

http://i63.photobucket.com/albums/h133/THB-bassdude/mesa2x10.jpg
http://i63.photobucket.com/albums/h133/THB-bassdude/mesa2x10plate.jpg
 
the sticker may have been a factory misprint, or a repair that utilized a 410 jackplate as a replacement. probably the former. the first thing you need to do is figure out whether the problem with the horn is with the horn or the crossover. disconnect the leads to the tweeter and use your multimeter to measure the impedance across the two leads on the tweeter. if you don't get continuity then the tweet is toast, you need a new diaphram for the tweeter. probably not too hard to get or very expensive. if you get a reading the the tweet is probably ok and you need to look at the crossover. look for a fuse mounted somewhere on the board. some crossovers had tweeter protection fuses. if the fuse is bad then replace it. if that's not it or you don't have a fuse, you might have bigger problems with the crossover that i can't diagnose without having the unit in my hands.

as far as the components being from a 410 this won't be a problem as long as the cabinet is wired for the same impedance. (8 ohms) i feel that it probably is as most 210's are 8 ohms (especially older ones) if your cab is 4 ohms and the crossover is designed for an 8 ohm load that will throw the crossover frequency off. check this anyway, even though i'm 99% sure you have an 8 ohm cab.

another thing to consider. if you are running a very treble muted sound. say flats on a p-bass, you may not be giving the tweeter enough signal for it to be heard and make a difference in your sound anyway. try cranking the treble and turning the tone knob all the way up on your bass and see if the attenuator knob for the tweeter works.

out of all the possibillities my first best guess would be a blown tweeter diaphram. this is a common problem, and an easy fix.
 
Thanks for the detailed reply to my questions.

I tend to agree with you that the "4x10 BASS 600 WATT" sticker was a mistake from the factory, since there's really no reason to change the jack plate itself...unless the whole cab was on fire, which it is clear to see it wasn't. Contacting Mesa, they replied that the EVs in that period were 150 or 200 watt speakers, so the max on this cab should be 300-400 watts. No problem with that, but I'd sure like to have the proper decal on the cab for future reference.
A minor detail to be sure, but I'd like it to be as original in appearance.

I removed the tweeter as you suggest, and it does read continuity, and it is labeled as 150 watts 8 ohms.
so I will go on to looking at the crossover parts. I don't think there's a fuse here. (see pic),

http://i63.photobucket.com/albums/h133/THB-bassdude/crossover.jpg

I don't know what these little pieces are, but I can read continuity through each of them. Is it safe to say they're OK?
I hope that you're right about 8 ohms, that would be each speaker is 16 ohms, (wired parallel) correct?

Funny you'd mention flats on a p-bass...that's exactly what I'm using here. I will do as you suggest and see if the tweeter is actually working after all.

I really appreciate your insight and help with this. I'll finish putting it back together and get back here for an update.
 
i'm no crossover expert (when i build one i use a calculator and go by the scematic) but my guess is that that crossover is just a high pass on the tweet. iow the 10's are running full range. this isn't necessarily a bad thing, but it simplifies things a bit (if i'm right)

the 10's are not low passed so they reach up pretty high on their own. add this to your sound preference and i'm not surprised the tweet isn't adding much. the good new is that the high pass crossover is only dependant apon the the tweeter impedance for it's crossover frequency, so it won't matter what impedance the 10's are wired at. however you should probably check this so you can match it to your amp. (again 99%sure you have an 8 ohm cab) borrow a bass with roundwound strings and test the tweet again. a pop or two with the tweeter cranked should make it very obvious.
 
The tweeters in my PH1000 and in my Diesel 2 x 10 are both blown...
The PH1000 tweeter by myself (And my ex Ampeg SVT III Pro) and the 2 x 10 tweeter was broken when I got it.
I can't say I miss them, don't like the sound at all... (based on prev exp. with the PH1000)
If you really want the tweeter back and play at high volumes, you might also want to replace the crossover... (not an expert here either btw)
 
replacing the crossover would be a good option, if, the cab wasn't meeting his tonal rquirements. my best guess is that the existing crossover is a 12db highpass at 3000-4000hz for his setup i think he would prefer the stock configuration. for more agressive techniques (slapping and such) a player might appreciate a two way crossover, probably about 3500hz with at least an 18 db slope. this is a more audiophile type sound, probably the last thing a p-bass groove player wants.
 
Boogafunk said:
, so it won't matter what impedance the 10's are wired at. however you should probably check this so you can match it to your amp. (again 99%sure you have an 8 ohm cab) .

Thanks again for the reply.

I have assembled it and tested it again, and it does seem to be working. I cranked the treble on my amp and you can hear the "hiss" get louder as the knob on the cab is turned. It is true that I really don't need to use it, but I was curious if it was working or not...plus, I always learn stuff by messing around and asking questions.

I don't know how I can determine the actual impedance of the speakers. Is there a way to measure?
It is very important that the cab is not 4 ohms or I'll wreck my amp, an old GK 800RB. I'll be hooking this cab to the100 watt -8ohm minimum- amp on the GK.
I am about 99.9% sure that they are the original EVs. They are not marked, as far as I can see.
My two 1x15 cabs are both EV 15L and they're not labeled either, but I've had them since new, and so I know they are 8 ohms each.

Thanks...again.
 
This is a copy of a post I left on the TalkBass forum.

********

I am way late to this party. Sorry, but just discovered it using Google.

I am unable to see the original eBay auction, obviously. However, there is currently (March 2014) a similar speaker for sale on eBay:

http://www.ebay.com/itm/29107849450...eName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Some info:

  1. Mesa/Boogie did use two Electro-Voice 10-inch speakers (in some or most Diesel 2x10 cabinets).
  2. The Mesa/Boogie Diesel cabs I am familiar with are 8-ohm devices.
  3. If wired in parallel, two 16-ohm speakers will give a total resistance of 8-ohms (and two 8-ohm speakers a total resistance of 4-ohms, etc.), I believe.
  4. On the other hand, if wired in series, two 4-ohm speakers will give a total resistance of 8-ohms (and two 8-ohm speakers a total resistance of 16-ohms, etc.), I think. (That's correct, right?)

I currently have in my possession a Mesa/Boogie Diesel Roadworthy cab with two stock Electro-Voice 16-ohm speakers wired in parallel so that it is an 8-ohm device. Therefore, I know that at least one original Electro-Voice speaker model used in the Mesa/Boogie Diesel 2x10 cabs was the EVM10L-16, with a model number of 810-1320. That is what was in my cab.

But experience shows that manufacturers changed parts without notice, so perhaps 1810-2596 or 1810-2595 speakers (which I am unfamiliar with) were also used by Mesa/Boogie. They would have to be either 16-ohm or 4-ohm speakers though, I believe, in order to be hooked up in tandem and give a final 8-ohms, right?

In conclusion, I am unsure how two 8-ohm speakers could be connected to give a final DC resistance of 8-ohms. So if the speakers you are discussing are 8-ohm speakers, I wonder if they are the original speakers that came with the cab. If they are the original speakers, maybe they are not 8-ohm speakers?
 
Additional updated information and corrections:

- The 1810-2596 speaker is an Electro-Voice B-10-16 16-ohm speaker.
- The 1810-2595 speaker is an Electro-Voice B-10 8-ohm speaker.
- I am unable to find an engineering data sheet (EDS) on the Electro-Voice web site for either speaker. However, they are probably intended for bass guitar amplification devices.

Therefore, with this additional information, the use of two 1810-2596 speakers now makes perfect sense in a Mesa/Boogie 2x10, 8-ohm cabinet (if the speakers are wired in parallel).

And you would not want to use 1810-2595 speakers in a 2x10 8-ohm cab, since they would not provide an overall 8-ohm rating.

As stated, my Mesa/Boogie cab came stock with two EV 810-1320 speakers. And other Mesa/Boogie 2x10 cab owners discuss online (e.g., TalkBass forum) also having 810-1320 stock speakers. These are the Electro-Voice EVM-10L-16 (16-ohm) speakers. What is the difference between EV 1810-2596 and EV 810-1320 speakers? (And no, the answer is not just a "1.")

I checked with the seller of the 1810-2596 speaker on eBay and he said it weighed 11.5 pounds. The 810-1320 speaker is an 18-19 pound speaker. Since these 10-inch EV speakers all use the same basic cast-aluminum frame, the difference in weight must be due to size of the magnet (and accompanying rear cover plate).

Since I do not have an EDS with specifications for a B-10-16 speaker, I can only speculate. But if it is similar to or an earlier version of the Electro-Voice 10BX bass speaker (which also weighs about 11 pounds and also has the smaller magnet), then it may have a lower power rating (e.g., 150 watts vs. 200- or 300-watts) and may have various auditory differences (e.g., frequency response range) from the heavier EVM-10L-16.

Does anyone associated with or knowledgeable about Mesa/Boogie know why different speakers were used at different times in the 2x10 cabs, or whether specifications changed?
 
Interesting. I have a 2X10 Mesa Boogie bass cab with a similar label plate 2X10 Bass Power Capacity 600 watts.
This is a ported bass cabinet. Horn has a date of 2002.
The speakers have a label with: 1048 *01603* Made in USA
printed on it. The impedance is correct. If both could handle 300, then it could be a 600 watt cab.
I trying to figure out what the nature of these 10" drivers are as they need to be reconned.
It's a great sounding cabinet, or was until very recently.
 
Interesting. I have a 2X10 Mesa Boogie bass cab with a similar label plate 2X10 Bass Power Capacity 600 watts.
This is a ported bass cabinet. Horn has a date of 2002.
The speakers have a label with: 1048 *01603* Made in USA
printed on it. The impedance is correct. If both could handle 300, then it could be a 600 watt cab.
I trying to figure out what the nature of these 10" drivers are as they need to be reconned.
It's a great sounding cabinet, or was until very recently.
Is this a diesel or powerhouse cab? The diesel's used 3 different speakers through the years iirc.

The 810-1320 EVM 12L started the party, and I'm very late to this party still. One of these days I'll stumble on these. The plates corresponded with 200W per driver.

My RR410 and regular 210 are eden 150W drivers.

There was a 3rd (PAS?) that may be the same one used in the PH line. I can only assume you have the powerhouse 300's:

https://store.mesaboogie.com/products/speaker-12-powerhouse-300-ceramic-300-watt.html
 
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