Hi all,I've got an early mark 1 (a452)that has recently started to do a few weird things and was hoping someone here could give me some advice.The amp sounds really farty ?? and like it has a bad rattle when hitting certain notes.If I play the amp clean,I dont here the rattle so much.There is nothing loose in /on the chassis.I'm thinking speaker,but I dont know.The amp is all original.I normally plug into input 1,vol. 1 on 7-8,gain out,vol. 2 on 4,master on 3 up,i cant run the presence more than about 4 without losing it.If I do have a speaker problem,should I recone? Replace? It has the EVM 12L in it.What other speakers would you suggest?I dont have a tech w/in 200 miles of me that I trust.Thanks for any input/suggestions.
Mark 1 troubles & speaker preferance
- Thread starter nitrohog
- Start date
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MarkPurney
Well-known member
I would do these in order until you find the problem:
I doubt it's your speaker, but if you have another speaker you can try, it's an easy thing to rule out.
Install a new set of power tubes to see if there is any difference.
Take a good preamp tube and swap it into each of the 12AX7 locations to see if anything changes.
Re-tension the tube sockets. Look at where the tube pins are inserted: There is a small piece of metal with two sides that grips each pin. Over time, these can separate so that they don't hold the tube as securely. Use a tiny screwdriver to push these closer together so that the tube has a tighter fit (just don't over-do it).
Using some sort of tool (to prevent burning yourself), apply upward pressure to each tube while playing the "bad" notes to see if the rattling sound goes away when you prevent the tube from vibrating. If you find a tube that changes the sound when you do this, re-check the tube and any solder joints on any of the tube's socket pins.
If it does turn out to be the speaker, the 90W Celestion Black Shadow is probably a good choice. The going rate for a used EVM 12L on eBay is roughly in the $110 to $150 range.
I doubt it's your speaker, but if you have another speaker you can try, it's an easy thing to rule out.
Install a new set of power tubes to see if there is any difference.
Take a good preamp tube and swap it into each of the 12AX7 locations to see if anything changes.
Re-tension the tube sockets. Look at where the tube pins are inserted: There is a small piece of metal with two sides that grips each pin. Over time, these can separate so that they don't hold the tube as securely. Use a tiny screwdriver to push these closer together so that the tube has a tighter fit (just don't over-do it).
Using some sort of tool (to prevent burning yourself), apply upward pressure to each tube while playing the "bad" notes to see if the rattling sound goes away when you prevent the tube from vibrating. If you find a tube that changes the sound when you do this, re-check the tube and any solder joints on any of the tube's socket pins.
If it does turn out to be the speaker, the 90W Celestion Black Shadow is probably a good choice. The going rate for a used EVM 12L on eBay is roughly in the $110 to $150 range.
The symptoms you describe coud be a number of things. First off check all your tubes. Try a new set of preamp tubes and then try the output tubes. I have two Mk I's and have replaced the filter capacitiors. After a number of years they dry out and do not perform at their best (as with any electrolytic capacitor). The amp could sound farty, noisy, mushy bottom end and lack response & "musicality" to name a few symptoms. A rattle sound could be a bad solder joint (I have seen this many times), a bad cathode bypass cap (I had one that made the amp sound like it had a blown speaker). Try hooking the amp up to a different speaker and a different amp with your EV. I love the EV12L. If it is blown you could get it reconed or just get a new/used one. I think they are out of production but during a conversation with Mike Bendinelli he told me that someone recently orderd one from Electro Voice. Are they back in production? Maybe worth a call.
I hope this helps.
I hope this helps.
Boogiebabies
Well-known member
The 12L has been re-issued as a 300W Black Label.
The price is brutal as well.
http://www.samash.com/catalog/showitem.asp?SKU=EEVM12LB
The price is brutal as well.
http://www.samash.com/catalog/showitem.asp?SKU=EEVM12LB
Is the speaker tight to the baffle?
Is the baffle cracked?
btw, EV has been bought and sold several times since the early '80s. 3 personal friends of mine were EV employees in Buchanan, MI. The reissue speakers are not the same as the originals.
Boogiebabies
Well-known member
The new 12L is being made in Arkansas. I would take southern craftsmanship any day. They still take pride in what they do.
At least they are not being made in China !!!
At least they are not being made in China !!!
I tried the amp thru a 4-12 cab,and it was still mushy sounding,hooked the speaker up to my Sound City 120 and it sounds fine.I've swapped the preamp tubes-same thing.The power tubes dont have a lot of hours on them,but I know that doesn't really mean anything.I'm going to try some new tubes Mon. and see what happens.Has anyone dealt with Wells Electronics in Orlando,Fl ? They are the closest Mesa-authorized repair center to me.Thanks for all the feedback,I appreciate it.
