19 June, 2014

Letter from NYC (35) 2014 (7): The BIG Shindo Monbrison Report

Pics show unit of reader AA. Click to enlarge.

Letter from NYC (35) 2014 (7): The BIG Shindo Monbrison Report
Review: Shindo Monbrison (old version), Part I 

Addendum (10/28/17): Part II (vs Manley 300B preamp) and Part III (large phonoamp and preamp comparison) have been published.

Revised 30/06/14 New Info from reader PR added.

It is amazing that, aside from a brief mention in my 2011 retrospective, I have not written more about the Shindo Monbrison, one of my reference preamplifiers. I am glad finally I am redressing the problem. Since that post, I have received some feedback from readers, so first some consolidation, and revision of what I had posted before, then some new material.

My Shindo Monbrison I actually acquired this older version (serial number 153) in 2010!. The fellow who sold it to me claimed it was the unit reviewed in 6moons , and it certainly looked the same on the outside. Contrary to the seller's statement on the unit's health, all the tubes that came with the unit were almost completely spent. Fortunately the ECL84/6DX8 used in the linestage of my unit were inexpensive and available on Ebay, while I already had good EF86's (used in the phono stage) in stock. After re-tubing, the sound was, as I wrote, "...quite dramatic, with great presence, a good match for horns."

Tube Compliment - Mystery?

Initial Assessment I had no problem with 6moons reviewer Jules Coleman's sonic assessment, but it did seem to me he made some mistakes in describing the tubes and what they do (his description in italics, my comments in bold face):
  • "...Beginning on the left immediately behind the power switch, there is a chamber that holds the power transformer, a 6X4 rectifier, a 6BM8 pentode/triode voltage regulator and a smoothing capacitor bank..." Correct.
  • "...Along the rear behind the input jacks is yet another chamber running left to right that houses the ECC82 twin-triode line stage tube, another 6BM8 for line stage voltage regulation, two EF86 mesh plate phono tubes (one per channel), another 6BM8 for phono stage voltage regulation..." The 1x ECC82 and 2x EF86 are correct, but they are all positioned closely together by the PHONO inputs, so I think the ECC82 is NOT for the line stage, rather for the phono section. And the 2 other tubes are ECL84, not 6BM8/ECL82. Also these 2 ECL84s are close together and clearly far away from the other 3 phono section tubes, so both are for the LINE section, one for each channel (see pic above).
First Reader Feedback Soon after my post reader Ron from Germany was very nice in sending me emails (Jan 2012) on this old version:

"...I listen with this preamp (comparable "old" version) very happy for quite a while...The tube compliment of the latest version of the old casing version should be 2x EF86 Phono; 1x ECC82 / 12AU7 Line; 2x ECL82 / 6BM8 Line; 1x 6X4 / EZ90 Rectifier; 1x ECL82 / 6BM8 Regulation...I thought the actual (current) Monbrison with "window" in the front panel uses ECL94 not ECL84? I don't now if they are exchangable. All the old Monbrison I saw here in Germany and that are used by the people I know, all use ECL82. Only the very first Monbrison units have a completely other circuit with usual double triodes..." 

My Reply "...I thank you so much for contributing! These rare gears and old versions need more info. I wrote an addendum in my article:

Addendum 09/01/12 Reader Ron from Germany was very nice in sending me an email on this old version: "...I listen with this preamp (comparable "old" version) very happy for quite a while...The tube compliment of the latest version of the old casing version should be 2x EF86 Phono; 1x ECC82 / 12AU7 Line; 2x ECL82 / 6BM8 Line; 1x 6X4 / EZ90 Rectifier; 1x ECL82 / 6BM8 Regulation. Maybe the previous owner changed tubes by himself..."
So, it could be that Shindo changed something here or the previous owner had had his unit modified. Now, this raises the question on why mine uses the ECL84/6DX8 (close to the current version's ECL94) instead of ECL82/6BM8 (both are similar triode-pentode tubes, but they have different pin-outs). It is possible Shindo changed from ECL82 to the similar ECL94 because the former got more expensive and the latter is still quite cheap. At the least, re-wiring of the tube sockets would be necessary for proper operation. When I get back I'd check the soldering. Shindo is well known to change parts without notice and for variations between units. The mystery shall not be solved in a while.

P.S. I did check after I got back to NYC and my unit showed NO sign of rewiring.

Second Reader Feedback Then I got emails from reader AA in Bangladesh (Feb 2012):

Email 1 "...I have bought a pre-owned Shindo Monbrison...looks like to be the exactly the same version you have. And you are absolutely right that 6moons was wrong about the tube complements, and its good to know your one and my one is not one off. My one uses the following tubes:
2 x Tungsram EF83 mesh plates - EF86 is a direct replacement and will provide more gain;1 x Philips 6189W (12AU7 / ECC82); 2 x ECL84 (unknown brand); 1 x Brimar 6X4;1 x ECL82 (unknown brand).
Most of the tubes in my pre-amp is also spent. The phono tubes are extremely microphonic and has hum/noise. One of the ECL84 is meshed and provides less gain then the other causing channel imbalance.
Could you kindly let me know what tubes (brands) originally came with you Monbrison? and which ECL84 and EF86 you have installed now?..."

My Reply "...It is wonderful to receive your mail that clears up things! I'd like to ask you for permission to post your comment as well as the pics in the article...

I am not sure what brand of ECL84 and EF86 they were.
Not Tele for sure. Likely German RFT or Siemens.

The line ECL84 is not demanding. Any brand will work well. I got some Mullards (labelled RCA/GE) for nothing and they are fine. The phono EF86 demands more. I have some RFTs and they hum a little in my system, but then my speakers are >100 db.

Email2 "...I have ordered the following tubes from ebay: 2 x Valvo EF83; 2 x Valvo EF86; 2 x Telefunken ECL84; 1 x Telefunken ECL82; 1 x Siemens EZ90

Since my pre came with Tungsram EF83 mesh plates installed, I'd like to see what difference it will have with EF86. Studying the tube data, the tube pinouts are exactly same and the 86 should provide more gain.

I have seen another Monbrison series II got sold on ebay.de recently (highest bid 3900 Euros) and could clearly see pair of Siemens ECL84 installed. Also I have seen someone in Germany selling NOS unplayed backup set of tubes for Shindo Monbrison (but the seller's advertisement was expired dated 2011):Valvo ECL 84; Tungsram EF86; Telefunken.ECL82; RCA 6X4; Tungsram ECC82.

So I'm guessing, Siemens and Telefunkens being German and having a reputation of being very accurate and clinical, were used in the ECL 84 and ECL 82 positions. But the ECC82, I'm preferring a 1960s Mullard and the EF86 probably needs to be also very high quality and preferably a mesh plate. Also note the new Monbrison uses a Telefunken ECL94S which seems to be a fantasy tube relabeled ECL80 series by Ken Shindo.

BTW, I think all Shindo Monbrison series II has the same tube complements and 6moons was responsible for making people believe otherwise. Unfortunately I am afraid your German friend was wrong as well in reporting other Monbrisons using 3 x ECL 82.

...As much as I love this unit, its a bit frustrating with the hum and channel imbalance issue. I am waiting for the tubes that I ordered, and then I should be able to report back in details..."

I think Reader AA's emails strengthen some of my beliefs - at least our units are the same! I'd love to hear more from him! Or from ANY Shindo Monbrison user for that matter!

Third Reader Feedback Then I got emails from reader PR in the UK (Jun 2014):

"...I have recently bought an old-style Monbrison, serial number 160. I can confirm the valve complement to be: 1x 6X4 (Philips); 1x ECL82 (Mazda); 2x ECL84 (Philips); 1x ECC82 (no markings, brand unknown); 2x EF83 (Telefunken)...Works well ..."

This again agrees with what reader AA and I have! PR's unit also has serial number very close to mine.

Short Note on Monbrison (?Current Version) 
The next and ?current version of the Monbrison not only has a different look, but also different tubes. Jeff Day at 6moons reviewed it, listed the tube complement ("...two Telefunken ECL94S, two 12AU7, two 12AT7 and two 6X4WA..."), but unlike the previous review by Jules Coleman avoided remarking on what the tubes do. The dagogo review provided more details: "...The power supply is tube rectified, in this case with two 6X4 tubes where the old Monbrison had only one. The preamp is equipped with 4 line inputs and two phono inputs; one phono input is for MM cartridges and the other for moving coil, utilizing custom amorphous core step up transformers. There are a total of four twin-triode tubes in the phono stage, one pair in each channel, and the linestage tubes are genuine NOS Telefunken ECL94S’. These are the tubes on display in the ‘window’ on the front of the Monbrison..."

Research on earlier Monbrison 
For this article I re-researched the Monbrison. There is not much still but When I did an image search I uncovered some interesting things. Most intriguing is a French thread - I can read a little French so was able to find some info and translate it here:

Imagepic borrowed from thread
homecinema-fr thread on Shindo This is a long thread, but around page 24 (on my computer) muse92 posted both pics and tube compliment of his Monbrison. You will notice from the pic that the positions of the line and phono tubes are very different. His tube complement is "...2 x 12AX7 JAN Philips; 2 x 12AU7 Mullard; 1 x 6X4 USA; 1 x  6BM8/ECL82..." He thinks "...the 2 x 12AU7 are for the line section and the 2 x 12AX7 for the phono section..."

muse92 also asked what is the tube complement for the "1st version", as he has read (just like us) contradictions on the internet.

To which riesling replied: "...Il s'agit d'un Monbrison produit très probablement avant 2000, donc dans la version précédant celle avec les EF86 dans la partie phono.Il possède un transformateur en entrée et un transformateur Lundahl en sortie.Le 6X4 et le ECL82 (ou 6BM8) règlent l'alimentation.Les ECC82 (12AU7) sont dans la partie line (donc CD), les ECC83 (12AX7) dans la partie phono..." Basically he confirmed what muse92 said, that "..It is a Monbrison probably before 2000, so the version before the one with the EF86 in the phono section. It has a transformer input and a Lundahl transformer output.The 6X4 and ECL82 (or 6BM8) regulate power supply. The ECC82 (12AU7) are in the line section (ie CD), the ECC83 (12AX7) in the phono section..." riesling again: "...On peut appeler cette version la première version, celle avec les tubes EF86 la deuxième version. La version III est celle avec la fenêtre et le bouton vert (la dernière à être commercialisée en Europe). Le modèle actuellement vendu en Asie et aux Etats-Unis (fenêtre et bouton noir) est alors la IVe version..." "...We can call this version the first version, the one with the EF86 tubes the second version. Version III is the one with the window and the green button (the last to be sold in Europe). Then the fourth version is the model currently sold in Asia and the United States (window and black button)..."

Then there were some musings on the sonic differences between versions. Both persons knew someone who preferred the older versions, but let us not go further.

My Summation on the Tubes in the Various Versions of Monbrison
  • Variations Typical of Shindo san, the long-running Monbrison has had many iterations. Keep in mind Shindo has also been known to one-off modify/add/subtract features for clients.
  • Power Supply In my version (also the one that readers AA and PR have) and the version before mine (perhaps the one muse92 has) 1 x 6X4 does the rectification and 1 x ECL82/6BM8 provides regulation. The next (?current) version doubles the 6X4 and dispenses with the ECL82 regulation.
  • Line Section In my version 2 x ECL84 are used. In the next (?current) version 2 x (similar) ECL94S do the same job and are displayed in a window. In the version before mine (muse92) 2 x ECC82/12AU7 are used.
  • Phono Section In my version, the phono section uses (likely definitely) 2 x EF83/86 (still not sure which one is stock) and also uses (I judge likely, by topography) 1 x ECC82/12AU7. The next (?current) version uses 2 x ECC82/12AU7 and 2 x ECC83/12AX7. The version before mine (muse92) uses 2 x ECC83/12AX7.
  • ?Possible Variations/Reader Ron in Germany As mentioned above, Ron had a unit very much like mine (and AA's), except that in his opinion: (a) the 1 x ECC82/12AU7 is for the line section and (b) 2 x ECL82 are used also in the line section instead of the ECL84. After reflections and subsequent info from AA and my research info from the French thread I have my doubts: (a) the usual line section does NOT need that many tubes; the ECL82/6BM8 is a triode-pentode with high gain, so I don't think the ECC82/12AU7 is needed; (b) the ECL family tubes look alike, and can be easily mistaken; (c) since I haven't found anything else that corroborates Ron's assertions, and since no pics show anything like he described, for now, grateful as I was for his response, I have to discount his assertions. That said, I do think it is not impossible that certain units in Germany were wired for ECL82/6BM8 (different pinout from ECL84) and I'd love anyone to have such a unit to come forward with some pics! But until then, I have deleted the addendum to my original post, and THIS post represents my current thoughts. The only other source that reported so many ECL82/6BM8 is the original 6moons review by Jules Coleman cited above, but I do think he was seriously remiss in multiple ways.
My Sonic Impressions
  •  Having spent so much time on structural matters, I shall be brief. What I said before,
    "...quite dramatic, with great presence, a good match for horns...", sums it up. If you look, I have two reference systems, with two different preamps, but I can tell you the Shindo Monbrison is my favorite. It sounds big and airy, goes to the heart directly, without fuss, and partners well everything I throw at it. The phono section in particular is versatile and exemplary. If you need more description, I'd urge you to read Art Dudley's various comments on Shindo in Stereophile; he can say it better than I can.
  • Good as it is, I do think (as does Dudley) the Lundahl SUTs in the Shindo can be bettered (as related in my article on Cinemag). So, the tubed MM section is the star.
  • Original tubes frequently have an oval silver label with "SLC" inscribed on it. These are good tubes.

  • The tubes, especially the EF86's, can be noisy (maybe EF83 would be better?) and need some care (as AA also experienced).
  • It gets very hot; I keep the lid open.
  • Dudley thinks Shindo preamps are best placed on a wood platform, without any tweaks, but my Monbrison distinctly benefits from placement on Vibrapods (link here) (perhaps because my shelf is far from sturdy).
Postscript: This article is long in the making, but I hope I have finally added something to the Monbrison literature. I bet there may be future revisions. I'd love to hear from other readers and owners. I envision a Part II, where I'd attempt to contrast the Shindo with my Manley 300B preamp - they are very different!


    1. AnonymousJune 29, 2014

      Dear John,

      In the meantime I got the information, that the early models of the pentode/triode tube units had been sold with ECL82 and Shindo later switched to ECL84...I assume due to availability issues. Also the ECL82 made quite a price jump when the DIY crowd and also some manufactures "discovered" NOS ECL82.

      Best regards


    2. Any comparison with EAR 912.....

    3. Dear Dr. John,
      As a long time user of Shindo gear, I would like to share my experience regarding the tube assortment of Monbrison.
      You are lucky that your sample had original tubes, even if they are spent. It is very important to stick to the exact tube types, year and brand in order to enjoy the true Shindo sound. I have made numerous tube substitutions over the years and managed to get many good "sounds" out of Monbrison or my Cortese amp, but I never surpassed the sound of the original tubes. It is very strange thing that happens when you finally correctly match the tubes and a very special superior sound comes out of these machines. I wouldn't worry about the specific version of Monbrison I have, each one of these machines is differently made not only in the tubes they use but also to the rest of the materials. They share though the same sound.
      I would suggest to try to restore the tube compliments to the originals, which is a project in itself and also check the fuses and their polarity, they should be brand "littelfuse".

    4. Thank you Nikitas, I do believe the original tubes, which are not that exotic, are very good and tested and true. As you said, it is not a good idea to second-guess the designer, especially one of Shindo san's caliber!

    5. AnonymousJuly 04, 2017

      Love your blog! how do I send private email?

      1. Thx. Since there is no mention of hifi, I'd have to ask you to provide some info before going further. My email can be found in the sidebar.

    6. There is no such valve as an ECL94. In the European valve designation system the "9" would mean the valve has 7 pins. There is no way of making a triode pentode with only 7 pins. And you will not find an ECL94 in any Telefunken catalogue