Tuning in:
Marantz 10B Modifications and Alignment
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Restore, Modify or Upgrade?

What a formidable question or dilemma to answer! I have been interested in collecting, refurbishing, restoring and upgrading electronic gears and vintage audio equipments since about 20 years, and several times I have asked this fundamental question myself.

In such a long period, I have been lucky enough to meet several experienced technicians and skilled engineers who have been involved in state-of-the-art industrial research and design for years in the late 50s and 60s. From these dignified old guys, but not only, I tried to learn how to design, or better how to compromise. But being so seriously interested in old equipment, I knew what were the original goals and achievements in professional tube equipments (and I mean those of correct design), and how to be successful in restoration, maintenance and upgrading existing ones.

I was also lucky enough to inherit two huge technical libraries from an industry R&D laboratory and retired senior designers. These were full of scarce and very precious publications, and you well remember that in the late 80s the Web was still to come, and with it almost forgotten books and papers (Radiotron Designer’s Handbooks, complete Philips, Mullard and FIVRE data sheets – and I mean ALL – plus annuals of Proceedings of I.R.E., A.E.S. publications and Brüel-Kjær or Hewlett Packard journals).

I thus have had the opportunity and the privilege to discuss many aspects in tube equipments, with people that were used to study on those papers, also contributing to their writing! OK, maybe they were neither of Saul Marantz or Peter Walker caliber, nor demitted only to audio (at least for work). But, most important to me, they have been married for a lifetime with electronics and tubes; and I mean tons of tubes.

Very soon I started to collect audio equipments while being also interested in modern so-called hi-end systems, thereof the restoration process was born automatically. Since I was interested in getting usable items with decent specifications, I started to consider how to do the job: strip it all and rebuild with new parts, or simply clean and keep them with minimum changes on the shelf? It depends on the final destination, and very personal taste and philosophy.

If you want to use a piece of equipment that has been designed at least 20 years ago you have to consider at first its value. Sometimes it's a complete waste of time or money, trying to make poor or mediocre systems perform better. You cannot get a Ferrari simply by changing the color or the tires! I am concerned when I see old commercial grade amplifiers and receivers heavily tweaked and modified in order to get spectacular sonic results and so on. They were meant as good commercial grade systems, but specs were on the lower side even when they left the shop. Thus getting a slight improvement can be impossible or too expensive.

It's always a matter of balance and careful compromise. No one is used to make miracles on earth, as the saying goes here in Italy. Except Mr. Berlusconi, of course!
On the other hand, if the original design is good or outstanding, and likely to offer very well results even today, or has no commercial equivalent, a complete restoration and cautious upgrade is well worth. The Marantz 10B, along with a few other items from McIntosh or Leak and Quad here in Europe, they ALL do deserve utmost respect and a few upgrades to perform better than new. Improved parts that simply were not available in these days, can really make the difference, especially after an accurate alignment – and this is not easy, although the most important.

But, and I insist, never stress the original design and carefully evaluate if a simple restoration will make substantive justice without impairing the item value. Changing a few capacitors and resistors is quite different from tearing out nickel-plated RCA plugs, the original power cord or substituting tube types.

Very recently I had to restore a poor McIntosh MR71 tuner, seriously abused with new holes on the chassis and a DIY variety output stage (oh, what an expert technician did the job with glue and surplus capacitors, even being paid by the lucky owner!). Do you imagine how much this restoration back-to-original did cost? How many hours of bench work? The owner spent quite a lot to have it ruined and restored again!

Also, stay away from a too fashioned, new looking item: I would never buy a black painted QUAD II with an IEC supply connector and WBT gold speaker terminals! Apart from that, it's also true that with no service or alignment at all, and the more complex and expensive the apparatus is, all the bigger will be the delusion. Always keep this aspect seriously in mind when buying vintage HiFi, considering all the so-called hidden costs.

Giacomo Pruzzo, © March 2011