[cryoparts]

First off, I have no financial interest in Eastern Electric, Morningstar Audio and don't offer their products for sale.  I receive no remuneration if Bill sells any amps from my recommendations

I have borrowed the Eastern Electric M520 a few times for shows, but have, not until now, put my money where my mouth is, and purchased one.  Well, now I have.  And, I love it.

A few weeks ago, I got one of the Minimax integrated amps pictured below from Bill to run a single driver near field speaker that Whilplash Audio is developing for me. 



The Minimax  is a great piece of gear and I came away mightily impressed (I still own and use it), however, I needed something with a bit more power to test a new 2-way that Whiplash is developing for me.  Enter the M520.



Like I mentioned above, I have used this amp at trade shows before and was always very pleased with the way my room sounded with this amp providing the power.  Well, now that I have had a M520 in my shop for a while, I am even more impressed.  It is very harmonically rich and drives even medium sensitivity speakers with ease to levels that are too loud for me.  The bass is very taut and controlled and the midbass flows really nicely with no boom.  The build quality is very solid and I think the industrial design is really quite attractive as well.  Even the remote is a heavy chunk of aluminum...very cool.

Compared to the plethora of other amps I have one hand, some less expensive, some MUCH more expensive, the M520 acquits itself very well, comparing favorably and bettering some that I have and use.  For the list price of $1799, this thing is a steal, methinks.  Sure, it doesn't compare to the megabuck Sonicweld systems that are my reference, but compared to other real world gear, I heartily recommend this amp.

Overall, this amp is going to be a permanent part of my equipment stable.   If you are in the market for a medium power tube amp, make sure to put this amp on your list!

And, as a bonus, Bill is one of the good guys and a real pleasure to deal with.  He even spent a great deal of time to set me up with some NOS driver tubes and steered me in the direction of some rectifier and driver tubes that will soon be mine and taking a place of honor in the M520.

So, contact Bill and buy one today.  You won't be sorry!   

Peace,

Lee

PS--I forgot to mention that the amp has 3 levels of adjustable feedback and a Pentode/UL switch.  Cool!

[JoshK]

That looks like an EF86 input tube and a dual triode behind it.  Williamson circuit?  Looks like it is a modern version of a Mullard 5-20.

[cryoparts]

That looks like an EF86 input tube and a dual triode behind it.  Williamson circuit?  Looks like it is a modern version of a Mullard 5-20.

Yes, IIRC you are correct, it is an updated 5-20.  Bill can confirm if this is the case.

It uses 12AU7 phase splitter, EF86 input, EL34 outputs, dual 5AR4 rectifiers.

I am soon going to purchase some Mullard 5AR4/GZ34's and some KT-77's to see how/what that changes. 

This 50th anniversary Shugang tube looks mighty sweet too, I was trying to get the manufacturer to sell me a few, but in searching for an image, I just realized that AC member Grant Fidelity is the North American distributor, so maybe I'll grab a quartet of them from him:



Peace,

Lee

[JoshK]

IMHO, before you tube roll the output tube, if you have the filament current available, try the 12BH7A or ECC99 in place of the 12AU7.   This reduces the chance of slewing.

[cryoparts]

Cool. Years ago, I used to have a pair of Quicksilver 8417's that used a 12BH7A, they were nice sounding amps.

After consultation with Bill and going by his recommendations, I have in the M520 now:

EL34's are the winged C's
EF86 are the E80F goldpin substitutes
12AU7's are some nice Australian 12AU7's that he likes in the amp.
Chinese 5AR4's (need to change).

I am looking for some Mullard F31B or F32B date code 5AR4's first, then I will try some different outputs.

Peace,

Lee

IMHO, before you tube roll the output tube, if you have the filament current available, try the 12BH7A or ECC99 in place of the 12AU7.   This reduces the chance of slewing.

[lonewolfny42]

Nice going Lee....the M520 is a very nice, heard it a few times....its smooth.

And Bill , he's great guy...(with some good scotch )...and very fine equipment.

Happy listening....

                         Chris



PS....Looking back....it only took you 3 years to finally purchase...

http://www.audiocircle.com/index.php?topic=21929.msg195392#msg195392

[Bill O'Connell]

Good Morning Gentleman,

  Yes, the circuit is similar to the Williamson but the amp is designed around the Mullard 5-20 circuit.
 For future reference for anybody who owns the amp DO NOT use a 12BH7A or ECC99 as these are not direct substitutes for a 12AU7.You can use a 5814A or a 6189 if you like as a 12AU7 sub but that's it.

 Now that is one pretty 6CA7 I haven't tried them yet but hoping to pick up a quad soon.They'll have a hard time beating out the new Genelex re-issue KT77's though in the M520 but looking forward to hearing them.
 Having had a few amps that use a 6SN7 their new CV181 looks like it might be the real deal also although the CV181 is not a direct sub for a 6SN7 so check with your manufacturer/designer before substituting willy nilly.The Chinese and Russians are making some great tubes right now. Looking forward to the Blackburn factory opening up in April to try out the new Mullard 12AU7,12AX7 and 12AT7 tubes. From exchanged emails they are quality controlling the heck out of them so that we all can benefit from quiet, ruggedly built great sounding tubes

[cryoparts]

Yeah, I'm a little slow...  And, I had used the amp once before that, earlier that year at the LSAF.  Good things come to those who wait, right?   

Peace,

Lee

PS....Looking back....it only took you 3 years to finally purchase...
http://www.audiocircle.com/index.php?topic=21929.msg195392#msg195392

[cryoparts]

Hi Bill,

For future reference for anybody who owns the amp DO NOT use a 12BH7A or ECC99 as these are not direct substitutes for a 12AU7.You can use a 5814A or a 6189 if you like as a 12AU7 sub but that's it.

Thanks Bill!

Now that is one pretty 6CA7 I haven't tried them yet but hoping to pick up a quad soon.They'll have a hard time beating out the new Genelex re-issue KT77's though in the M520 but looking forward to hearing them.

I'm going to try the Genelex KT77's soon.

Peace,

Lee

[cryoparts]

Now that is one pretty 6CA7 I haven't tried them yet but hoping to pick up a quad soon.They'll have a hard time beating out the new Genelex re-issue KT77's though in the M520 but looking forward to hearing them.
 Having had a few amps that use a 6SN7 their new CV181 looks like it might be the real deal also although the CV181 is not a direct sub for a 6SN7 so check with your manufacturer/designer before substituting willy nilly.

The El34 does look good, doesn't it?  Here is a pic (from Grant Fidelity website) of the CV181 that Bill mentions:



Maybe "iGrant" will pop in and tell us about these new tubes.

Peace,

Lee

[cryoparts]

Sorry, double post.

[iGrant]

Now that is one pretty 6CA7 I haven't tried them yet but hoping to pick up a quad soon.They'll have a hard time beating out the new Genelex re-issue KT77's though in the M520 but looking forward to hearing them.
 Having had a few amps that use a 6SN7 their new CV181 looks like it might be the real deal also although the CV181 is not a direct sub for a 6SN7 so check with your manufacturer/designer before substituting willy nilly.

The El34 does look good, doesn't it?  Here is a pic (from Grant Fidelity website) of the CV181 that Bill mentions:



Maybe "iGrant" will pop in and tell us about these new tubes.

Peace,

Lee

I can tell you what I know so far. I only have about 60 hours on the Shuguang Treasure Series CV181-Z and I'm impressed so far. I've known about these tubes for quite a while as we have worked closely with Shuguang on some other projects and changes are talking place at Shuguang as the audio dudes are getting more control over the companies direction. Shuguang spent a small fortune and about 3 years worth of time tweaking these to where they are today. All testing was done by the audiophile community in China and Shuguang has chosen Grant Fidelity to launch them the way we are outside of China, trying to get feedback from the western end user. I have over 10 new tubes just launched, so getting time on them and getting my thoughts out too is nice problem to have

We are offering a trial pair/quad at a discount to those that want to do some testing and write about there results. If you don't like them after 21 days, send them back for a refund!!!

The goal with these tubes is not to have the best tube out there, there is no such thing. It is to get a decent supply of excellent tubes into production that will allow you to save your favourite NOS for special occasions, if the Shuguang Treasure Series or TJ Full Music tubes just happen to be better than your NOS in your system, great bonus eh

The other bonus is that hopefully these tube will halt or slow down the ever increasing prices of NOS tubes. I can't afford WE NOS 300B's !!, 2 years ago I could.

Technically the tubes are premium internal matched at the factory for export and have 60 extra processes in the construction of the tube over a standard Shuguang. All the builders and testers need over 30 years of experience to work on the Treasure Series. I have no concerns over quality and we do offer a one year warranty. Sound?, only time will tell.

I've tried the CV181-Z in RITA as the pre-amp tube, excellent, but with RITA we still think she would sound good with coke bottles and as driver tubes in our A-348, I've compared then with RCA 6SN7 Grey Bottles and much prefer the SG CV181-Z. My NOS collection has dwindled to about none now as I'm going with our tubes. In our forum I will continue to share my thoughts on these tubes as I get more time on them and will also be getting others to post there. I will try and keep audio circle up to date too.

Cheers,
Ian

[JoshK]

They look nice.  I like the black glass, not just for looks.  But they are priced beyond my threshold for pain.  There are still a lot of NOS tubes in each category for less.

[cryoparts]

Ian,

Sent you a PM on the 6CA7-Z, I would love to try out a matched quad.  I could compare them to the winged C's, the Genalex and anything else that New Sensor imports.

Peace,

Lee