musiclover101,
If you look back a few responses, you will find Scott Frankland's contact info. He is the "F" in MFA. Give him a call. He is very accommodating and may supply that schematic. I spoke to him a short time ago, so I believe he is still in business in San Jose, CA. |
I know this thread is old but I’m looking for a schematic for my magus mag a2 . I’m new and don’t even know what caps are « coupler caps . This Magus is labeled the ‘ tweekers dream ‘. If and one has some close ups of one of these lol done I’d really Appreciate it . Thanks in advance |
Thanks, Triode 12 for the info. Sorry for the delay but I don't browse the forums as much as I used to. |
Although you need to have balanced XLRs to us it, the BMC MCCI is far and away the best phono stage. I still remember the shock that I had when I first heard this piece after the twenty or so phono stages that I have had. Nothing was even close. Read Michael Fremer's rave review. |
Tonykay,
This is Scott's contact details.
Scott Frankland Assoc.
706 Charcot Avenue
San Jose, CA 95131
408-432-1500 TEL
408-432-1501 FAX
audioeng@pacbell.net |
Joemarsh, you said you had your MFA upgraded by Scott Frankland in 2003. Do you know if he is still in business, or some way to contact him? |
Hhi, I had my Magus A upgraded in 2003 by Scott Frankland. I'm happy to share the upgrade list with you offline. I had all the capacitors upgraded, the RIAA curve reworked, jacks upgraded etc.
Now while i did not do scientific listening tests, i have loved this component forever. I bought it for 600 originally and it is the only component that i have not changed out. Synergistic with a Koetsu, Shelter, and Madrigal. If I had all the money in the world, I would get a Wavestream Kinetics phonostage. |
Some of the Magus preamps had a step in the EQ curve (at 50KHz) that results in the phono sounding bright. Its easy to fix it as it involves removal of a couple of EQ parts. |
Heres on Liberty B2B-1And yes I do make them :-) Good Listening Peter |
The main issue that I see with your system is that the Koetsu Black is too good a cartridge for the Rega P5 - it is starting to show the shortcomings in the arm. This is a common mistake made by many folk on this forum. Its like putting NASCAR tires on a tractor and expecting it to go round a racetrack.
I own a Koetsu Black - have had 2 plus Koetsu Red's Onyx's etc - they sound best with tube preamps loaded at 47k exactly as Allen Wright suggested.
The EAR 834 has a natural easy sound and you would not be disappointed. However my suggestion would be to get your Magus serviced and get the coupling capacitors upgraded - this will get a big improvement out of the existing preamp.
The passive linestage in the MFA should not be a problem with dynamics because the valve power amps you are using have a very high input sensitivity. |
This is of high interest to me as I also have an aging Magus and have contemplated getting it upgraded by Scott Franklin as far back as 2005 given my attachment to the unit. I have however not proceeded as I'm not certain the upgrade cost will better a Rogue Ares for not much more, or perhaps an ARC PH6 or PH8. Admittedly the ARC units exceed the upgrade cost of the Magus. Any comparative audition experiences with these units? |
i have been happy with my magus a-2 for 22 years. great phono section & tube rolling allowed. my mods from bill jones, former builder of moore/franklin's luminessence amps. i use sumikos black bird mc but that's 2 mv. |
The next logical step.
http://www.canuckaudiomart.com/view_images.php?cfid=649021019&image_id=3418154
Still one of the best sounding phono stages. The only rub is their age. If I were to consider this I'd call Scott Franklin, show him the link and get an idea of the cost of updating before making an offer. |
Tube rolling is the way to go. I've had a Magus longer than any other component in my system by far (21 yrs). Older tubes such as Mullards or Amperexes will dramatically change the sound in the phono and line stage vs any newer production tubes. The only weakness of the Magus in my opinion is that it is hard on NOS and used older 6DJ8 tubes in the line stage. It tends to chew up roughly every other older tube I have used but the results are oh so worth it! Those that do last more than a few mins or hours can last for years. No such problem in the 12AX7 and 12AT7 tubes in the phono stage. Another option would be to have the Magus upgraded by Scott Franklin (the F in MFA). He does reasonably priced servicing and mods which I have had done and highly recommend. |
The 834p is a wonderful smooth phonostage. I have also found the Whest phono stages-especially used- are a great bargain -detailed,usical and highly revealing. The whest .20 in my opinion sounds better in my system than did the EAR. You cN also improve the EAR greatly by modifying it |
Newbee, I agree with you on the speakers. Once I bought the Audiokinesis Jazz Module I found they immediately clicked with my amp, more so than any other amp/speaker combo I have had. I also found that changes further up the chain made less of a difference, especially cables. Maybe I'm fortunate not to have to load down the cartridge and perhaps I should grateful for the amp/speaker/room synergy as a result. |
A PS. A new revelation that aught to really impress Allenwright. Another phono pre of his design was just advertised for $925 (not mine) and it comes with 100 and 470 ohm loads!. Go figure. :-) |
Hi Clio, I've been fortunate (or cursed perhaps) with an old ARC SP10 which allows loading on the fly. Obviously I've had many cartridges, TT's, etc to play thru it. That is where I'm coming from.
IMHO a system is successful only when you have found synergy from source to speaker. To me the speaker is the anchor and once you have identified a speaker that works for you you can address the other components. The problem, as I see it, with running a system with any cartridge arbitraily loaded at 47K, is that the result is not necessarily optimum depending on the rest of your system.
As you have noted, you prefer 75K and 100K. I have used 10K with some old Grado's, 2K with some Gliders, etc, even an old Accuphase and Grace and only the Grace sounded good at 47K. All have been chosen for tone and clarity using the pre-amp, amp and speakers on hand at the time they were used.
I would agree with anyone who believes that changing the load that a cartridge sees is more a tonal change and 'clarity' sets in somewhere between 'muddy' from loading down too much to 'excessively bright' by not loading it enuf, also subject to ones personal aural preferences.
The problem with Herron's, and probably Allen's, views on an absolute load of 47K is that you are likely to have to change out other components every time you change your cartridge, or only buy cartridges designed to work optimally at 47K. (Of course if you have tubes everywhere you can probably just fiddle with those and get a pretty good result.
Now, the reason I post on this subject (other than my originals to the OP) should be obvious but I'll clarify. Look at the OP's problems and his first response as well.
Of all the solutions at hand the cheapest and easiest way to solve the problem (if it worked) was to load the cartridge. If it don't work you just pull the plugs. He could have several sets made at different loads to play around with as well. Cheap.
Or he could have changed some tubes in his pre-amp. This is also very cheap UNTIL he identifies a tone he likes and tries to duplicate it by getting some high quality NOS with a similar tone.
Lastly he could buy Allen's designed phono pre on sale for 1650, buy a high quality line stage to match, probably at least 2000, and hope it works! Unless he is sonically clairvoyant I doubt that he'll get it right the first time out.
He mentioned the EAR phono stage with its passive VC, thinking that he could bypass the MFA Magus. While that phono stage is good enuf, and he can fiddle with loads and tubes, a nice combo I think, and if he were to get it modded it would be even better (so I'm told) it would still be passive and miss out on the dynamics a good active line stage adds, which I think is essential to enjoying vinyl sound. Because of the cost and uncertainty attendant to getting new electronics I though he might satisfied HIS needs in an easy and economical way by exploring loading and tube changes. Was I wrong?
Frankly I'd be interested in seeing more possible and practical solutions for the OP's dilemma, than just Allens promoting his own design and overbroad dis'ing cartridge loading without any specificity.
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Actually, many other phono stage manufacturers incorporate that provision. Are they doing this just to accommodate a bunch of deaf, dumb, or lazy audiophiles? My guess is they just may be but it would be economic suicide if they went public with it. Then again it may be to offer people options to tailor the sound which as we know in this hobby is a preference among audiophiles. IIRC, the original Herron phono preamps just had the 47k ohm provision. Which led me to ask Keith why and elicited the response I got from him regarding the negatives in loading down the cartridge. FWIW I have also loaded my B&O MMC-2 at 75k and 100k ohms. I like 75k best. |
Allen, How ironic. That JLTi phono stage is advertised for sale today on the 'Gon. Interesting that the manufacturer must have deviated from your design. It has provision for loading built in.
Actually, many other phono stage manufacturers incorporate that provision. Are they doing this just to accommodate a bunch of deaf, dumb, or lazy audiophiles?
Perhaps you just have problems with the 100 to 500 ohm comments. Would something between 500 and 10K ohms be a better match considering the actual cartridge and the voicing of the pre-amp being used by the OP? Or is your advise generic? |
I agree with Allen. Its one of the reasons I went to a moving iron cartridge. You don't load it down. At one time I had a discussion about this with Keith Herron and he also agreed about the negative aspects of loading down the cartridge. So between Allen and Keith you have a pretty credible point of view. |
I build the JLTi phono, which someone recommended - way better than the EAR in my opinion.
But I disagree with the advice about loading your MC cart with between 100 and 500 ohms - that will just suck the life out of it. Loading down a MC is a very poor way to shift the tonal balance of a system, better to find what is causing the problem than bandaiding it and killing your dynamincs at the same time.
Regards, Allen |
First thing to do is get the impedance load between the cartridge and the pre-amp matched. The Magus has a nominal impedance of 47K which is fine for most MM cartridges but not for most MC cartridges which run best somewhere between 500 and 100 ohms.
Find out what the manufacturer recommends for the load of the cartridge. Then find a techie who will make a couple of male RCA plugs with resistors with the load values - then plug them in. You'll note the proper female RCA's on the back of the Magus right next to the Phono RCA's. That what they are for and that alone could solve your entire problem (well most of it anyway). And it is highly recommended in any event. Either that or get a MM cartridge. A MC cartridge with a 47K load will more often than not sound bright and thin.
Re tubes - I'm not enthused by EH 12AX7's at all and warm they are not. Unfortunately the tubes I use are practically unobtainable now. NOS Mullards should/could work well but are spendy. Before you go that far I'd buy some new production JJ's for all tube positions and see if that tone would work for you. If so at least you have a benchmark for further exploration if you want to fine tune it further. And these four tubes would cost less than $60 total.
Re VTA, save that for last unless you can find out what exactly that cartridge likes. Some cartridges like to be set up so that the rear of the arm is a degree or so lower than the cartridge. Another fine tuning thing - but don't get to anxious about it, as different records will sound different depending on their thickness, and how they were initially cut. Also the shape of the stylus plays a big role in the sensitivity of it to VTA as well.
BTW, I know some will disagree, but using a phono pre with a volume control is similar to using a standard phono pre with a passive volume control. Even though using a phono pre w/VC may avoid a couple of issues of the latter you still loose the dynamics that an active pre-amp will add.
As I mentioned before, this little Magus is a fine unit! Just learn how to use it. Getting vinyl right ain't a Sunday walk in the park :-)
Hope that helps a little bit. |
Audio Research PH5 is very good. This might work for you as well. |
Grinnell, I've seen those come up from time to time and they've disappeared too fast for me to snatch one up. I also wasn't sure that they would best the Magus.
Newbee, I was thinking of a phono pre that had volume controls that can run directly between a source and an amp. I've read about a couple that are out of my price range that I think can do that, including the Aesthetix Io-VC and the Manley Stealhead V2. I thought the EAR 834P could do the same, but I could be wrong. I'm pretty new to the audiophile obsession.
I haven't done any tube rolling yet, and I don't know anything about tubes, but it sounds like that would be a good way to go for now. The Magus started making a windy/rushing noise a couple months ago, so I retubed it, which took care of that problem completely. I used basically the same tubes that were in the Magus when I bought it from its original owner, so this is what's in it now:
1 Electro-Harmonix 12AT7
2 Electro-Harmonix 12AX7s (Gold)
1 GTE Sylvania Jan 6DJ8
Would the Mullards be warmer than the EHs?
And yes, the Koetsu Black is an MC cart; I think it's output is something like .25mV, but I can't remember off the top of my head. As you probably know, the Koetsu carts are supposed to sound a little thicker than others, especially in the bass (although Koetsu lovers seem to debate this). I do think the cart has deepened the bass and made it stand out a little more than other carts I've used (Denon 103R, Dynavector 20xl).
I don't know much about setting VTA on my TT. I think it might be difficult with Regas in general, because there's no VTA adjustment nut (not sure what to call it) on them. I use one Rega shim between the tonearm's base and the plinth to raise the tonearm so that it's perfectly horizontal when the Koetsu cart is on it. Maybe that's not what you mean by VTA though? I know enough to know that it's a complicated issue.
Thanks again for any insight you all can offer.
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You won't beat the Magus easily. It's awesome. A nice Audio Research could be an upgrade.
Upgrading the tubes to NOS can make a huge difference too. |
for 1 to 2k....no. the magus still is incredible. |
I have a Magus also so I have a few questions for you to consider before you get another pre-amp.
1) You are using a MC cartridge (I assume - I don't know the Koetsu Black). Have you used resistors to match its output impedance (plug in types)? If not that could be your problem.
2) Have you played with the phono and output stage tubes in the Magus? Perhaps all you need is something warm in the line stage tube - try a cheap new JJ 6dj8 for example, and or some Mullard 12AX7's in the phono stage. That would warm it up in the highs and fill out the bass.
3) Have you optimized VTA on your turntable? That could be also be a cause or solution to your problem.
That Magus is a nice little pre-amp...........:-) BTW, you say you want a dedicated phono stage. What will you use for a pre-amp to drive your amps? |
If you don't want to go tubes the JLTI ( Vacuum State ) is tubelike ( with exc. bass ) in sound and a great Phono amp in your pricerange...... |
What about looking for a Wright phono? |
