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[Doug Fowler]

Ye Olde Music Shop, located in the small village of Marissa, Ilinois. was opened in late 1966.  By 1970, Ye Olde had become one of the largest Sunn amplifier dealers.   The first Sunn amplifiers actually had Dynakit amplifier circuits using KT 88 and EL 34 tubes.  They were far ahead of anything on the market at the time but they really had no power house PA systems.   Ye Olde Music had been making huge strides in the serious sound reinforcement market with multi kilowatt systems doing many Midwest and regional tours.  I had suggested that Sunn should get into the large PA market but they really had no idea of a direction and asked if I would help design the first packaged Sunn PA system.
 
Working closely with their engineering department, the first 8 channel Coliseum mixer was handbuilt.  That mixer was used on several of our local shows and was far ahead of anything available. The sound touring division became Heil Sound and this handbuilt Sunn mixer was creating quite a stir in the market.  It headed out on a tour with Chaka Khan and Rufus.  In the middle of this Midwest tour,  Heil received a call from the management of The Who.  They wanted this new powerful sound system they had heard about for their next date in Boston for the "Who's Next" tour.
 
This system was a complete Sunn system, which included he hand built portable console and an additional production Sunn Coliseum console,  16 fiberglass horns (Heil built) with JBL 2440 drivers,  and 16 Sunn front loaded 15" cabinets loaded with JBL D140s. 
We added four JBL sub woofers and  32  JBL 075  ring tweeters.  This was a monumental step forward in the concert scene.  The system did two years of the "Who's Next" tours here in the US, the UK and Europe. 
 
During the second half of the US tour, I designed a very special Sunn system for John Entwhistle.  Using electronic crossovers driving a three way system, this new approach to bass guitar for John's style of playing changed the direction for bass guitar rigs.   The first system was brought to the Cow Palace for John direct from Ye Olde Music Shop in Marissa and remained with John for at least a decade later. 
 
Sunn gained huge respect and remained a leader to many leading artists during the 1970's.

[Art Welter]

This system was a complete Sunn system, which included he hand built portable console and an additional production Sunn Coliseum console,  16 fiberglass horns (Heil built) with JBL 2440 drivers,  and 16 Sunn front loaded 15" cabinets loaded with JBL D140s. 
 
Sunn gained huge respect and remained a leader to many leading artists during the 1970's. [/i]

Doug,

In the 1970s there were dozens, perhaps hundreds, of fiberglass horns made by Recchi Engineering around Minneapolis, sold primarily through Freedom Electronics.

They were all copies of the 1" and 2" JBL radials of the time, though the throat undercut was poor, resulting in poor dispersion on the 2" 90 degree horns. They all were made with rounded "lips" to make them stiff enough for the thin fiberglass production, and easy to screw into flat front boxes with removable covers.
They appear identical to the Heil labeled horns.
I had heard Recchi Engineering (the spelling may not be correct) made the horns for Heil, as well as what were known as the Heil "Troffs", short horns loaded with your choice of 12" or 15" speakers.

Anybody have the inside story?

Art

[Tom Danley]

Ye Olde Music Shop, located in the small village of Marissa, Ilinois. was opened in late 1966.  By 1970, Ye Olde had become one of the largest Sunn amplifier dealers.   The first Sunn amplifiers actually had Dynakit amplifier circuits using KT 88 and EL 34 tubes.  They were far ahead of anything on the market at the time but they really had no power house PA systems.   Ye Olde Music had been making huge strides in the serious sound reinforcement market with multi kilowatt systems doing many Midwest and regional tours.  I had suggested that Sunn should get into the large PA market but they really had no idea of a direction and asked if I would help design the first packaged Sunn PA system.
 
Working closely with their engineering department, the first 8 channel Coliseum mixer was handbuilt.  That mixer was used on several of our local shows and was far ahead of anything available. The sound touring division became Heil Sound and this handbuilt Sunn mixer was creating quite a stir in the market.  It headed out on a tour with Chaka Khan and Rufus.  In the middle of this Midwest tour,  Heil received a call from the management of The Who.  They wanted this new powerful sound system they had heard about for their next date in Boston for the "Who's Next" tour.
 
This system was a complete Sunn system, which included he hand built portable console and an additional production Sunn Coliseum console,  16 fiberglass horns (Heil built) with JBL 2440 drivers,  and 16 Sunn front loaded 15" cabinets loaded with JBL D140s. 
We added four JBL sub woofers and  32  JBL 075  ring tweeters.  This was a monumental step forward in the concert scene.  The system did two years of the "Who's Next" tours here in the US, the UK and Europe. 
 
During the second half of the US tour, I designed a very special Sunn system for John Entwhistle.  Using electronic crossovers driving a three way system, this new approach to bass guitar for John's style of playing changed the direction for bass guitar rigs.   The first system was brought to the Cow Palace for John direct from Ye Olde Music Shop in Marissa and remained with John for at least a decade later. 
 
Sunn gained huge respect and remained a leader to many leading artists during the 1970's.

Hi guys
In the 70’s I built a number of 200W Sunn amplifiers using the output transformers purchased as a service part for the 2000s amp (they were $32 back then, equal to  5 or 6 tanks of gas for my 64 Chevy).    These were simple amplifiers with 4 6550’s (KT-88’s if you had the extra coins) for output but could easily deliver the rated 200W and THAT was a lot of power in the day. 
I still have a couple of the output transformers somewhere, the rest of the transformers came for Fair radio.   
At one point I had the seemingly  bright idea to make a 400W 2ch amp and to reduce the arm stretching properties of even a single channel amp, I used a Voltage multiplier I saw in a QST magazine used in a 1kw RF linear amplifier.
This was a good weight savings BUT meant the chassis was tied to one side of the AC line and being in the days before 3 pin AC receptacles, one needed to be REAL careful about outlets where what should have been the return was actually the hot side.   The only other issue aside from the electrocution risk and the turn on surge which required a big negative TC thermistor from a color TV was the heat 8 6550’s put out, as this eventually was my “stereo” too, I found one was able to warm the bedroom where I lived with it.
Anyway, the Sunn stuff was great! I played through a couple 2000s amps rented from a music store in the city, that’s what got me going building the power amp part.
Thanks for the fond memory jog.
Best,
Tom Danley

[Bob Leonard]

That's a lot of 6550's Tom and I'm reminded of the old Fender 400 series amps. The problem was always properly biasing that many bottles, the heat, and of course the transformers needed to properly power the tubes. And damned straight about Sunn amplifiers. Some of the best made amps I've ever worked with or on.

[Tom Danley]

That's a lot of 6550's Tom and I'm reminded of the old Fender 400 series amps. The problem was always properly biasing that many bottles, the heat, and of course the transformers needed to properly power the tubes. And damned straight about Sunn amplifiers. Some of the best made amps I've ever worked with or on.

Hi Bob
Your right, each tube had a pot to adjust and each tube made a lot of heat haha.

With the kluge amps I made, there were several transformers in addition to the output, one for filaments, one for the negative bias and so on, such is the way when you used parts from Fair radio, taken from something else.  These were an armload!    That’s why the Cockroft Walton voltage multiplier “seemed” like a great idea at the time. Oh well.
After writing, I remembered that in the old Servodrive days at an AES or some other trade show in the 90’s, I met the guy who ran the company.   
A quick search with my not very close phonetic spelling and I found him.
He looks older here than I remember from back then  but hey so do I .
Best,
Tom

http://www.conradamps.com/About_Conrad.html 

http://www.eurotubes.com/SUNN-113ws.jpg

http://www.eurotubes.com/SUNN-126ws.jpg

[Bob Leonard]

The value of the amp Conrad signed just doubled. My first amp was a tube stereo I modified in 1962, and my second amp came from the RCA tube manual and materials my father brought home. I went through the same thing with transformers, still have 1-200 chunks of iron in the basement, and I guess that's why I must like the big iron.

The most powerful tube amp I made was for my HAM rig. 2000 watts with the key down all day long. It used a pair of IMAC 4-400s and I hand formed all of the coils for the inductors using 1/4 copper tube tuning them with a grid dip meter along the way. The power supply was 25amp 5V for the filaments, and 3750V at 3amps for the plates. Caps were oil filled and all rated at 5KV. I eventually sold the linear, but have many fond memories of the time I spent building it.

[Tim McCulloch]

Ah the old days... dip the grids, peak the plates.  Lowish power college radio back in a former century.

[TrevorMilburn]

If it hasn't been mentioned already, there is loads more info on the Heil system and other stuff from the Who here:http://www.thewho.net/whotabs/gear/pa/pa7374.html

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