Changing tube to an Art Tube MP

[Vagodeoz]

I have the Art Tube MP and it sounds pretty damm good IMO. However I wanted some advice about changing the tube. Which one do you recommend? And is it worth the investment?

 

[Beck]

The EI ECC83 will be a huge improvement over the Chinese 12AX7 that’s in there.

http://www.eierc.com/rc/ECC83.htm

Their ECC83 is about as close to the original Telefunken as you can get at a decent price. I use it in the PAIA tube pre that I built and moded. It originally had a Sovtek 12AX7, which is not much better in a vocal pre than the Chinese stuff.

 

[cjacek]

Tim, how close will the Art Tube MP, with the tube replacement, sound to the real thing? Is the stock 12AX7 inside the Art Tube MP, the bottleneck, which prevents the product to be a lot more prized?

 

[mshilarious]

Tim, how close will the Art Tube MP, with the tube replacement, sound to the real thing? Is the stock 12AX7 inside the Art Tube MP, the bottleneck, which prevents the product to be a lot more prized?

No. You can improve the tone with a better tube, but replacing the opamps makes a larger difference in cleaning up the mud. ART uses OPA2134 in their MPA Gold range, that's what I had used in the MP I modded.

After that, you are looking at recapping, and the MP uses a LOT of caps for a single channel pre.

The last thing is increasing the plate voltage, that requires reworking the power supply with a voltage multiplier on the plate supply. I didn't do that as a mod, but the MPA Gold has high plate voltage, which makes a tremendous difference in clarity. That's a more advanced mod though.

 

[Beck]

Tim, how close will the Art Tube MP, with the tube replacement, sound to the real thing? Is the stock 12AX7 inside the Art Tube MP, the bottleneck, which prevents the product to be a lot more prized?

Daniel, “The real thing” is a different animal than these budget starved-plate tube pres, but I don’t agree with some purists that say they aren’t real tube devices. The low voltage, starved-plate design is just another way of making it work… the PAIA 9407K in particular is a well-designed device.

Devices like the MP can be improved with higher-grade components. Manufacturers keep the costs down by using marginal parts (and slave labor ). There are just so many hissy, microphonic tubes coming out of Asia, so a tube manufacturer like Ei with better QC will make a difference.

Op-amps will help as well. The BB 2134 is a good choice if you want to try something else, but if the stock amps are NE5532 I tend to like those and leave them in place. Best thing to do is solder in an 8-pin DIP socket so you can try different op-amps. Give the 4580 a shot… I like those for some things.

Also spend a little extra on machined DIP sockets (See photo) rather than the tension type available from Radio Shack. The machined type make the best contact with the pins, short of soldering, and you don’t have to worry as much about oxidation down the road.

You could end up repopulating the whole MP circuit board with new caps and resistors for best results, but a better tube and op-amps will make a noticeable improvement over the stock units.

 

[cjacek]

Thanks Tim

 

[analog aaron]

The EI ECC83 will be a huge improvement over the Chinese 12AX7 that’s in there.

http://www.eierc.com/rc/ECC83.htm

Their ECC83 is about as close to the original Telefunken as you can get at a decent price. I use it in the PAIA tube pre that I built and moded. It originally had a Sovtek 12AX7, which is not much better in a vocal pre than the Chinese stuff.

Can you order these ECC83's directly from EI and if so, will they also fit in the Cheaper ART TUBE MP studio model pre?
A.A.

 

[mshilarious]

Op-amps will help as well. The BB 2134 is a good choice if you want to try something else, but if the stock amps are NE5532 I tend to like those and leave them in place. Best thing to do is solder in an 8-pin DIP socket so you can try different op-amps. Give the 4580 a shot… I like those for some things.

TL072 as I recall. And I don't like 4580 for anything But once you go fast, it's hard to go back . . . you can always hit the tube hard if you want to fuzz things up after the swap.

 

[Beck]

TL072 as I recall. And I don't like 4580 for anything But once you go fast, it's hard to go back . . . .

It's hard to go anywhere once you're self-oscillating.

The 4580 is good for swapping out the ubiquitous 4558 or 4560, and I think it's pretty clean where I've used them... but you know, op-amps are like a religious thing. The 4580 and NE5532 are safe bets for drop-in without worrying about oscillation, or PS issues with a mass swap in a console.

But hey, that's why we put the sockets in first... you can experiment to your heart's content.

 

[Beck]

Can you order these ECC83's directly from EI and if so, will they also fit in the Cheaper ART TUBE MP studio model pre?
A.A.

Ei doesn't sell directly, but their ECC83 is easy to find out there... just google. I don't remember where I bought mine. It's been a few years.

Yes, it will work in any of the MPs. The 12AX7 is a very common tube, used in a lot of amps and pres.

 

[mshilarious]

It's hard to go anywhere once you're self-oscillating.

The 4580 is good for swapping out the ubiquitous 4558 or 4560, and I think it's pretty clean where I've used them... but you know, op-amps are like a religious thing. The 4580 and NE5532 are safe bets for drop-in without worrying about oscillation, or PS issues with a mass swap in a console.

But hey, that's why we put the sockets in first... you can experiment to your heart's content.

I would be wary about dropping in 5532 where there was a FET input opamp. And the capacitance of a socket can be troubling to the truly fast opamps. 5532 is more of an output driver or summing amp from my point of view.

Anyway, OPA2134 is very reasonable and stable. Given the usual precautions with small bypass caps in the feedback loop, I've never had trouble with it oscillating.

Once you reach a certain point with slew rate, further increases will not improve performance within the parameters of frequency and gain. There may be other characteristics of the really high-end opamps that are still desirable for audio. I don't go there myself, it doesn't seem necessary. But I think there is still considerable audible room for improvement over 4580 without getting too crazy.

 

[analog aaron]

So all you have to do is replace the tube and the mic pre will sound better? Is that all there is to it?
Aaron

 

[Beck]

So all you have to do is replace the tube and the mic pre will sound better? Is that all there is to it?
Aaron

In a word… yes. That step alone will show improvement. For one, the stock tubes are cheap and inconsistent. Secondly the Ei is of very high quality. For some, changing the tube will be the first step in a more extensive mod of the device, but it’s an easy and good thing to do even if it’s the only thing you do. A better tube will not fix other issues with a pre, but it will improve the sound in as much as the tube is responsible for the character of the device.

 

[Vagodeoz]

Thanks everyone! I think I will only switch the tube for starters.
I found in musiciansfriend some ECC83 but I'm not sure if it's this, since in the review most people use them for Marshall AVT50.
So can anyone please post a link to where to buy those tubes? (would be nice if they have international shipping)

 

[Beck]

Thanks everyone! I think I will only switch the tube for starters.
I found in musiciansfriend some ECC83 but I'm not sure if it's this, since in the review most people use them for Marshall AVT50.
So can anyone please post a link to where to buy those tubes? (would be nice if they have international shipping)

http://www.tubeman.com/item299.htm

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280152905484

http://www.tubedepot.com/ei-12ax7eg.html
(Out of stock, but check back... these guys do prescreening, which is preferable to buying blind.)

http://www.vacuumtube.com/tubes.htm
(site is a bit hard to find what you want... search the page for Ei ECC83 and it will go right to it)

http://www.tube-shop.com/usa/prod_eielites_detail.asp?ProductID=39&ProcessType=3

Also, back to the op-amp issue... it can be confusing since there are different versions of the Tube MP with different op-amps and different designs. So for anyone stumbling across this forum be careful as it looks like ART changed everything but the name of the MP over the years. It would be helpful to know what op-amps are in the one in link above from Vagodeoz if anyone knows.

 

[Dr ZEE]

Also spend a little extra on machined DIP sockets (See photo) rather than the tension type available from Radio Shack.

Just want to drop my BIG WORD of disapproval for those IC sockets that are available currently at RadioShack. And I mean specifically those sockets, as I can't say much about maybe some different sockets of similar type.
I could write a nightmare novel bigger than Tolstoy's "War and Peace" just about how RadioShacks IC sockets SUCKS

 

[Beck]

Just want to drop my BIG WORD of disapproval for those IC sockets that are available currently at RadioShack. And I mean specifically those sockets, as I can't say much about maybe some different sockets of similar type.
I could write a nightmare novel bigger than Tolstoy's "War and Peace" just about how RadioShacks IC sockets SUCKS

Yeah, they're not good for anything but testing or maybe non-critical for-fun circuits. You wouldn't want to solder them in a critical device you're trying to upgrade. You'll just have to take them back out, and that's when the traces of your circuit board start lifting off, adding a chapter or two to your book.

The machined types are available at Digi-Key, etc.

 

[Vagodeoz]

Thanks all!
A friend is making an order from musiciansfriend, so I could add a tube.
Can anyone please recommend me a model from the ones that sell there? Or I should get one of the other ones?
Living in Bolivia and not owning a credit card, adding this tube to my friend's order would be way easier than buying only a tube from another store, but if you think it's worth it I'll take your word.

 

[Beck]

The Tung-Sol 12AX7 is probably the best of what they have at MF for a mic pre. It will sound better than the Chinese or Sovtek stock tube.

http://www.musiciansfriend.com/product/Tungsol-12AX7-Tube?sku=212231

The Ruby Tubes ECC83 also looks promising, as it's basically a hand-picked Tesla, but chosen for lower gain.

http://www.musiciansfriend.com/product/Ruby-Tubes-ECC83-12AX7A-Preamp-Tube?sku=212034

It's not a bad idea to try different brands and see what you like. At those prices maybe you could buy one of each.

 

[trancedental]

Real Mullards & Brimars, RCA & GE, if you can find them? Look on EBay theres still old ones for sale sometimes cheaper even, & they Do sound better IMO!