NAD 7130 Receiver

Another NAD receiver arrived yesterday, this 7130 model runs at 30WPC and has both a MM (Moving Marnet) and a MC (Moving Coil) phono input, something you rarely see in a model of this power level.

I did clean out the inside and all the pots and switches.

I have yet to mate this with either the NAD Model 20's or the NAD Model 30's but will do so in the near future.

Most reviews seem pretty positive on this unit and  have always liked  NAD's stuff. Clean and simple.

Technics SU-7300 Integrated Amplifier

This nice little 41WPC Technics amplifier found its way to me today, a beautiful silver faced unit with a veneer wood case. A nice feature is the VU meters that have a low level and a high level. got to love the old analogue VU meters

A phono pre amp with a 78db signal to noise ratio make it very sensitive to the pick up on the phono cartridges.

These were built in the Golden Era of HiFi between 1976 and 1978.

More info can be found on the Stereonomono site.

This unit matches up nicely with the Mission 717 speakers.

Open Baffle Electro Voice SP12 B speakers

This is the open baffle system that I have been listening to as of late. These beautiful condition Electro Voice SP12B 12 inch full range speakers.

Extremely efficient and without a crossover connected to a single ended tube amp, these speakers project a huge sound stage that has got me hooked.

I would like to get two more of these and make a new baffle for them, so two speakers in each baffle.



 

Dynaco A25 Speakers

My second set of Dynaco's after the A35's is the smaller brother the A25.

I enjoyed the A35's when I had them and found them best suited to a Solid State amplifier, these A25's I feel are the same. They do  not pair up well with tube gear.

There is plenty of information on these speakers and they were proven to be wildly popular in the 70's for good reason.

These have wonderful SEAS drivers in them and are extremely well built with a mid century modern wood finish.

Klipsch Tangent 30 Speakers

I came across my first pair of Klipsch speakers today, the Tangent 30.

The Tangents were Klipsch's mass market speakers for those who could not afford the Heritage line.

This speaker uses two 8" woofers in a sealed box and a horn compression tweeter. Super efficient at 96db these will work well with my tube amps. The cabinets are well built with real wood veneer and weigh in at 45lbs each.

So far I have had a few songs on these and I like what I hear. Granted I am a fan of horn tweeters mow. The dual 8" woofers have pretty good, tight bass response.

The Tangents were built between 1989 and 1991 and the focus was on clear sound, which when paired with a tube amp, these are very clear.

Mission 717 Speakers

Always a soft spot for early Farad Azima and brother Henry Azima Mission speakers.

This pair of white faced Mission 717 came up locally and I could not resist buying these beauties. The white faced with the Mission logo are my favorite generation of Missions.

This matched pair was in exceptionally good condition and just needed a light sanding to the cabinet and a coating of really nice wood oil.

The drivers for this pair are made with Franch Saire woofers and Audex tweeters. The woofers will never need to be re foamed.

There is a great article at audio4maniacs on the history of these white baffled Missions and it is worth reading to see what Henry and Farad where shooting for in the development of this speaker line.

I have had two other pairs of the white baffled Mission 700 speakers and I like these much better due to the French drivers.

Here is the original brochure form the 80's on these speakers.

At 92db sensitivity these are good for the tube amp.

I like early Mission loudspeakers and have had many over the years. They are very alive and musical with great dynamic range.

I have had a lot of speakers over the years and Missions are one of my favorites, there is something about them and I love having them.

Clements 300SI Redeux

Another pair of Clements 300SI or Spacial Image came my way today, my first experience was from a reader of this blog that had a pair and wanted to see how they sounded versus the NAD Model 30's.

His pair of speakers are in this write up here.

This is the pair I picked up today which look like an earlier version than his.

These are a little pair of speakers has a huge sound from a little 6 1/2 inch woofer that uses a transmission line enclosure. Bass is really deep for such a diminutive size.

The imaging is pretty impressive with a large spacial sound stage.

These need to be run with a solid state amp and I have them hooked up to a Harmon Kardon HK 395i 35WPC receiver. Both the SE tube amp and push/pull do not run enough power to get the best out of these little speakers.

These are nice Canadian audiophile speakers that really fly under the radar except for those in the know.

Tannoy Oxford Gold Open Baffles

I decided to open baffle this pair of cabinet distressed Tannoy Oxford Gold's. The original boxes were definitely worse for wear and often I found the bass boxy if not boomy due to the ported design of these speakers.

I opted for a really nice 9 ply with Cherry wood veneer. I also decided to invert the tweeter under the woofer like early Mission 700 or 717 speakers.

This is the finished result.

Sound wise these speakers no longer sound confined to the box, bass is much tighter and cleaner but not as low as when in the box. The mid range is more open as the woofer seems to handle most if not all of the mid range frequencies.

Aesthetically these speakers are my best project to date, I love the look of them and the pictures on this site do not give the speakers real justice.

JVC R-S5 Receiver

Early 1980's 27 watts per channel silver faced JVC receiver arrived today in mint condition.

This looks like it as in between the JVC JR-S300 and the JVC R-S33 class A receiver.

At 27 watts per channel perhaps build quality and sound was more important then gizmo's and gadgets as per the other two JVC receivers listed above.

This unit is pretty simple and clean looking. Best of all is the 90db sensitivity to the phono section.

Full specs are as follows courtesy of HiFi Engine

Specifications

Tuning range: FM, MW
Power output: 27 watts per channel into 8Ω (stereo)
Frequency response: 20Hz to 20kHz
Total harmonic distortion: 0.03%
Signal to noise ratio: 90dB (MM)
Speaker load impedance: 4Ω (minimum)

The Journey to Open Baffles and Tube Amps

This blog is a journey into the wonders of hi fidelity. As I travel this path it opens up more and more.

My first memories of hi fi was my dads dynaco tube amp that he built with a pair of AR3 speakers. He had a cassette deck and I used to listen to Simon and Garfunkel Bridge Over troubled Waters over and over through a set of headphones.

My first real stereo was a JVC PC-11, half boom box half component stereo. It was around 20WPC and was pretty cool at the time.

Later I bought a Pioneer turntable to go with this system.

My first set of speakers was a pair of Mission 700S and  we had that connected to a JVC JR-S301 and then some sort of Sansui amp. Both the JVC and the Sansui were great at frying the Vifa tweeters in my missions at that time. Heavy fingers on the volume.

My first decent receiver was a Harmon Kardon HK 380i, a step up in sound and lots of head room. I stopped blowing tweeters.

Next came a Rotel RA-840B amp that ran 40WPC, I chose this over the AR Cambrige A60, although in retro spec I should have bought the AR.I had the Rotel for many years and just recently sold it in the past couple of years.

My next great pair of speakers was a pair of Energy 22's which I had for at least 20 years of which has seen some time on this blog.

It was the first tube amp that really sent me down the rabbit hole. The fidelity you get from 1 or 2 watts per channel can put the biggest monster receivers to shame.

Since being bitten by the tube bug, I have not really cared for solid state stuff and pretty much pass over most of it unless there is an end game for the stuff I pick up.

The tube amp has opened the door to speakers and their design.

In my journey I have found that the early well designed speakers from KLH or EPI with minimal crossovers are the best, after all in is signal in and signal out. Keeping the path of least resistance is the key.

When running a tube amp, speakers need to be over 90db in efficiency and the higher the better.
Another thing I found is horns in the mid range and tweeters give incredible clarity of which paper or domes can not. Some can come close.

Now I am finding that open baffle speakers are really clean in sound and the reason speaker were ever put in a box was to make them a piece of furniture that a wife could like. The bass in an open baffle is really clean as if the box imparts plenty of resonance, colouration and a myriad of other problems.

Open Baffles need a special room or space to work properly. A few things I have discovered in the open baffles is Alnico drivers work best, minimum of a 10" woofer is needed, a 3-5" full range is optimal for the mid range, preferably open in the back to get the proper refraction. I tend to like a horn tweeter to top the music off.

Of the open baffles that I have built to date this Foster Open Baffle is stunning in its' sound. I had to tame the tweeter down a bit with a resistor. The little Foster 8F3 full range is spectacular, a massive open sound stage is presented while the bass is really articulate, tight and clean with the 25E33.

So as the journey continues I have decided to sell off many of my boxed speakers and will concentrate on building what I think from my ears and years of experience some vintage cool efficient open baffles.

Stay tuned I have about six unique designs in my head and the drivers to create the path into this wonderful hobby.

I leave you some things to read and ponder.

Linkwitz Lab conclusion on OB versus box speakers.

Hawthorne Audio on the Art and Science of Open Baffle speakers.

Speaker Projects.

Good luck on your journey and I hope if you read this far try a tube amp some day and if you get the chance a really nice pair of open baffles.

Realistic Minimus 1 Speakers

Another pair of speakers that I picked up today is this set of Realistic Minimus 1. Realistic used really nice Foster/Fostex driver in the early days. This pair uses a 5"alnico full range driver and a nice cone tweeter.

This pair will be cannibalized for their driver and put into an open baffle system.

Coral 10L-17 Woofers

I picked up this set of Coral 10L-17 woofers today in mint condition. These 10 inch units will be used in a future open baffle project. Older Alnico woofers tend to be really efficient and have really nice bass tone.

I have discovered that Coral's, Foster and Fostex drivers are really efficient and work really well in open baffles.

Akai/Foster Open Baffles

Last week I picked up this pair of Akai SW-135 speakers that has Akai branded Foster driver in them.
In the original box these speakers are not much to listen to, in fact they are boxy and not to open on the sound stage.

I promptly removed the drivers and went down to Makers Lab to start my project.

This is the finished product and I think this forth rendition of my open baffle experiment turned out really well.

Once again with open baffles there is a really open sound stage, the three drivers are all designed to work together with minimal crossover which is a 16uf cap for the mid range and a 2.2uf cap for the tweeter.

Bass is exceptionally strong, tight and articulate in these speakers, mid range is nice and smooth and the highs are perfect for a cone tweeter, not as strong as in the horn tweeters.

Best suited with a single ended tube amp versus the push pull tube amp. I am going to keep an eye out for the vintage Akai speakers as they can be had for next to nothing and they have really good alnico drivers in them.

Next open baffle project Akai SW-135 Speakers

Just picked up this pair of Akai SW-135 speakers for the next open baffle project. These seem to have Foster or Coral Alnico drivers, perfect for open baffles.

The cabinets have been gutted and speakers are in perfect condition.

Foster Open Baffle Speakers

The latest open baffle speakers I have put together is a 3 way Foster driver speakers. The donor driver came from a pair of Noresco NEC-571  plus a horn tweeter that I picked up from a set of Zenith Allegro speakers.

This project turned out to be spectacular with the push/pull tube amp, almost in the league of openness and fullness as the Speakerlab Super 7's, almost. The Super 7's are really an amazing loudspeaker.

 The original Noresco speakers used a 10" Foster 25E33 alnico woofer with a massive magnet assembly crossed over to the Foster 8F3 three inch full range speaker. The original crossover was used as the crossover point between the woofer and the full range driver is around 650hz.

A foster horn tweeter was included to handle the high end as I found the 8F3 seemed to roll off in the highs.
A 2.2uf cap was used with a crossover point at 9000hz, it seems to have added the high end depth and sizzle that I like.

This combination came out way better than expected. Bass is full and clear, the mid range from the 8F3 is luscious and smooth, very deep and wide. the horn tweeter takes care of the highs in spectacular fashion.

Before I started this project I had an idea as to how this set up would sound, but it came out way better than I expected.

If this is what open baffles are supposed to sound like, then I am a believer now.

Aesthetics came out beautifully with the dark mahogany veneer.