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The Manley-Modjeski Letters (Redux) Part 1

In the Roger’s Corner article that appeared in the May 2025 edition of The Muse, we presented a copy of a letter to the editor Roger sent to Stereophile. At that time, I thought I found a piece of historical documentation related to the Manley-Modjeski letters published in Stereophile in 1990 and 1991. While technically related, this letter was not part of the series of published letters in the infamous “debate” between the two audio industry luminaries. In addition, I lamented that I could not reference the original letters, including the letter written by Kevin Hayes that at a time not so long ago could be found on the Valve Amplification Company (VAC) website.

Since I have been using Artificial Intelligence (AI) to do research for a tape head preamplifier project, I thought maybe AI could help me find the Manley-Modjeski letters. My query started by searching for the letter written by Kevin Hayes since it was the only one that appeared online as far as I knew. If it existed, I was hoping ChatGPT could locate an archived version of the VAC web page. Although that effort was unsuccessful, as an alternative, ChatGPT recommended tracking down old hard copies of Stereophile. When I asked ChatGPT to identify specific monthly issues, the response was: “Vol. 14 No. 6 June 1991, Letters to the Editors section.” Doing a search on eBay yielded a lot of nine magazines from 1991, one of which was the June issue. So, I purchased it and excitedly awaited its arrival. Imagine my displeasure when I read the Letters to the Editor section of the June issue only to find no evidence of the Manley-Modjeski letters. However, there was a letter from a famous jazz pianist praising the Tice Clock and the vast improvement it made in his system. Turns out this is the same jazz pianist who owned a Music Reference RM-9 amplifier and scolded Roger for making him take off the bottom cover to change fuses. Roger would later make the output tube fuses accessible from the top plate. The jazz pianist was Keith Jarrett. I admonished ChatGPT for its error and the response was an apology and admission of failure with no alternative suggestions. Note that the Stereophile magazines of today are nothing like those I acquired. Each issue in the lot was like a paperback novel with 250 pages or so of content. As the June 1991 issue was still in my hands, I continued reading it. Now imagine my surprise when I reached the Manufacturers’ Comments section and found not one, not two, but three of the Manley-Modjeski letters, including the one from Kevin Hayes. From these letters, I identified the monthly issues where the first series of letters were published in 1990. So again, off to eBay where I located and purchased those issues.  Now on to the letters. In Part 1 we present the first three letters in the series. For those of you who wish to research this topic on your own or acquire the Stereophile monthly issues where the letters appear, here is a list for you:

1. VTL, Chinese Tubes, Money, & Criticism: Written by David Manley. Stereophile Vol. 13 No. 2, February 1990, pgs. 215 – 217
2. Music Reference/RAM Tube Works: Written by Roger A. Modjeski. Stereophile Vol. 13 No. 9, September 1990, pgs. 219 – 221
3. Manley and Modjeski: Written by David Manley. Stereophile Vol. 13 No. 12, December 1990, pgs. 259 – 264

David Manley wrote what became the first Manley-Modjeski letter after reading the “…interesting review of the fine Modjeski RM-9 amplifier,” by Dick Olsher (DO) in the December 1989 issue of Stereophile (Vol. 12 No. 12, p. 105). While commenting on DO’s review, David Manley referred to the fact that with the RM-9, “…it seems possible to nimbly exchange EL34s with Chinese KT88s at will.” However, he cautioned against doing this with Vacuum Tube Logic (VTL) amplifiers. Fair enough, if VTL amplifiers are designed for a specific tube type and the designer indicates only that tube should be used, so be it. Well, Roger had a different opinion and made that clear in his response, which is a combination of facetiousness, facts, and pot shots refuting some of David Manley’s claims. 

David Manley did not take kindly to “…the overriding tone of Roger Modjeski’s tasteless letter.” Also, “Since the gloves are off,” he fired back with his own pot shots further escalating the “debate.” When it came to matching wits with his peers, Roger could get under their skin and he certainly got under David Manley’s. In addition to their audio engineering expertise, both men promoted their knowledge of vacuum tubes. Roger’s expertise was born out of years of research in the late ’70s and early ’80s resulting in him building the first computer tube tester. David Manley grew VTL into a leading manufacturer of tube equipment and supplier of vacuum tubes. While playing those cards in his letters, he could not resist throwing some shade at RAM Tubes by calling them a tube re-brander. 

So let me clarify a few things, given this is Roger’s, and not David’s, Corner. Roger considered himself a researcher and educator. From his days at Stanford right up to his death, that is who he was. Every product Roger manufactured was born out of his curiosity to do something that had not been done before. So, Roger would conduct his research, write his own tube circuit applications, and build prototypes until he was satisfied his goals were met. This process often took years. Only then would Roger consider bringing the product to market and only in small to moderate volume. Here are a few examples:

1. RM-4 Pre-preamplifier: The first tube head amplifier for moving coil cartridges using the 6922/6DJ8 family of tubes that prior to this was rarely used in audio.
2. RM-9 Power Amplifier: The first power amplifier capable of being 9, and later 15 amplifiers in one. With its flexibility to use EL34, KT88, and 6550 tubes (and later KT66 and KT77) along with three gain/feedback options, one could make a strong argument this was the amplifier of an audiophile tube roller’s dreams.
3. RM-10 Power Amplifier: The first amplifier to produce 35 watts per channel using a pair of EL84/6BQ5 output tubes per channel. The norm prior to this was half that power rating for the same number of tubes.
4. RM-200 Power Amplifier: A hybrid amplifier using a JFET input and tube output section. In addition, the only tube amplifier at the time (and possibly even still today) that could increase power as the load impedance dropped. Roger was also able to get 112 watts per channel into an 8-ohm load (145 watts into 4 ohms and 125 watts into 2 ohms, 1-ohm stable) from a single pair of KT88 or 6550 tubes per channel without running the tubes “hard” (tube life rating was 10,000 hours).
   

Until recently, RAM Tubes supplied tubes for these products as well as provided tubes and testing services to the audio community in general. David Manley boasts about VTL sales and the relationships with tube manufacturers and distributors, but it is a little-known fact that AKG contracted with RAM Tubes to supply computer-tested, extremely-low-noise 6072A tubes for their microphones. Sure, they were rebranded GE Five Star tubes, but it says a lot that AKG bought them from RAM Tubes and not VTL, or any other US tube manufacturer/vendor. On top of tube research there were tube factory tours and tube consulting engagements (e.g., Ei and Emission Labs). As such, Roger deserved his props as a vacuum tube expert. After his role as an educator, I think he would have appreciated recognition for his vacuum tube expertise more so than his audio engineering expertise. As I researched and wrote this article, I read the letters several times and continued to be in awe. While Stereophile still accepts contributions from audio industry resources for its Letters to the Editor and Manufacturers’ Comments section, I do not think we will ever see an exchange like this between two audio industry luminaries again. Sure, some exchanges like this from audio designers exist on the audio forums but they are hardly the same. There is a big difference between posting online and getting your letter published in Stereophile. It says a lot about Roger and David Manley that they took the time to write about and defend their design philosophies and knowledge of vacuum tubes. Sure, they beat each other up and Kevin Hayes tried to be the peacemaker, but in the end, I wonder if Stereophile ever regretted publishing the letters. Regardless, here they are for you to read. Just click the link to access the first three letters in the series.

The Manley-Modjeski Letters