Noresco 2570 Receiver

Re branded for the Canadian market, this Noresco 2570 is a Rotel RX-402 from the 1974-1976 era.

Conservatively rated at 25WPC into 8 ohms this little receiver sports a robust power supply with a hefty transformer and two Elna 6800uf filter caps. It is unusual to see such large caps in a 25WPC receiver. Rotel rated the RX-402 at 40WPC into 4 ohms which this unit easily sounds like.

The build quality is exceptionally clean on this unit. With such large capacitors for its' rated WPC the sound is very robust with the loudness switch off, similar as a tube amp.

My first foray into Rotel was back in the early 80's with the purchase of my first budget audiophile amp the Rotel RA-840BX amplifier. I had this unit for over 25 years and was a formidable, over built 40WPC unit capable of driving any speakers I could throw at it.

 
So far I have paired this unit up with the Mission 770 Freedom IV's and this unit does everything right, tight full bass, clear mid range and nice sparkling highs. I always opt to run these units without the loudness switch on as it gives a proper indication of how robust the power supply is.

(The difference with tubes vs. transistor amps is tubes give you a full sound stage at low volumes where as transistors usually sound best when they have some power coursing through them, Tubes sound amazing from the 1st. watt all the way through to they peak out. Transistors usually do not give you that fullness until 5-10 watts per channel.)

This unit was in exception condition, super clean on the inside, the wood case was immaculate, only one bulb needed replacing although the stereo indicator bulb will not work even though I soldered in a new bulb. The silver brushed face plate is blemish free. Once apart I cleaned all the pots and switches.

Noresco is probably a brand that gets ignored in the used market which is good for anyone wanting a fantastic Rotel receiver that was built with quality first. Unlike those who clamor over the same era Pioneer, Marantz, Sansui and Kenwood should find incredible value in either the Noresco line or Rotel's of this era.

Clements 300si Speakers

A friend of the blog was kind enough to stop by one evening with his pair of Clements 300si speakers. He was originally interested in the NAD Model 30's and felt that the Clements infinite baffle design had just as much bass as the NAD's. The Clements had pretty solid bass right down to the 40hz level from a 61/2 inch woofer, pretty impressive for its' size. The Clement's gave the NAD"s a run for the money in the bottom end.

We ran the speakers through the Creek 4040s2 which did not match well with these speakers. We switched up to the Yamaha CR-400 and the sound was night and day. The Yamaha opened up these speakers, the detail in sound with the Clements and Yamaha was a better pairing..

We finally switched to the tube amp and these sounded good at first with the speakers near the wall I knew they could sound better if we brought them in to within 4 feet.

Now we were enveloped with sound, Clements are not the most efficient at 88db's so we had to push the tube amp a little herder.

All I can say is WoW! for such a small speaker these had an incredible smoothness, from solid clear bass into the luscious mid range and sparkling highs that were never harsh or shrill.

Up close the speakers enveloped you into their sound stage, left right, front and back it was like being in the room with the musicians. We listened to about 4 hours worth of music and my friend has just reached out for some tube amp advice, he was taken aback with the silky sound of the tubes, they paired very well with the Clements although they do not go earth shaking  loud, which is perfect when kepping other happy.

This speaker reminds me of the sound of the Paradigm Control Monitors I had at one time, incredibly polite, smooth, a very nice speaker and worth seeking out when they come up for sale.

TubeCube 7 tube amplifier

I picked up this little desktop tube amp for my son's Christmas present this year, replacing the Realistic System 11.

This fully assembled unit was well packaged and the fit and finish is really nice. It feels like a solid little amp in your hands.

I am just listening to my Electrohome Marseilles tube amp for the past few months as my only source of amplification. I was pretty excited to see what this 3.5 watt would sound like in a comparison. I burnt the amp in for 12 hours before giving it a serious listen.The Tube Cube 7 can be found on the Tube Depot site and runs for $179.95 with free delivery in the USA.

I first had a listen with the stock Chinese Sino EL84's with the Sino 12AX7B connect to a pair of Tannoy Oxford Gold's. The Tannoy's are very efficient so it was best suited to the 3.5 watts per channel.

The sound was very clear and transparent in the mid range and high's. The midrange and highs were not warm even having a bit of shrill at times. Although imaging side to side was excellent, back and for depth of the sound stage was not as deep as the Electrohome.

I also tested the TubeCube 7 with the Sound Dynamics Concert 500's, these are another efficient horn loaded speaker that pairs really well with tube amps. The sound was a bit better in the bass along with the same traits in sound as with the Tannoy's. Last up were the NAD Model 30's of which this little unit was striving to drive with clarity, the bottom end was very muddy.

I opted to replace the Sino tubes over to J/J EL84's and a J/J 12AX7B

The change over in tubes had an instant impact on the sound this little amplifier could achieve, it was like a veil was removed from the sound. Back where the sweet luscious mid's and high's with the bottom end filling out. The Tannoy's had their shine back, the warmth was there along with the depth of sound, next was the Sound Dynamics, where the bass was clearer and much more refined. Any shrill associated with the original Sino tubes was gone.

Overall this is a pretty cool entry into tube amps for a small space, we still have them hooked up to the Minimus 11 speakers. When trying to fill a larger room with bigger speakers this little amp tries and does a surprising good job, I found this amp best suited for a smaller office or bedroom. The output transformers are obviously not as robust as you would find in higher power units, I found it shy on the bottom end.

My wish list that I had for this amp is a headphone jack being a priority, it would be great to listen to through headphones. Two inputs would be nice too, but I would take the headphone jack first.

I would recommend one of these units as a starter into the tube world. I had mine shipped to a US address which help keep the cost down with the exchange rate.

The TubeDepot will also supply better tubes for this amp which I would step up to the J/J tubes all around.

The TubeCube 7 can be found here and the tube upgrades here.

Tube: Shuguang EL84 2pcs, 12AX7B 1pc

Power Output: 3.5W+3.5W @ 8 ohms

Frequency Response: 30-40Khz (+-1db)

Input Sensitivity: 500mV

Signal-to-Noise Ratio: -80dB / 3.5W

Residual Noise < 1mVac

Input AC Voltage: 100-250Vac

Power Consumption: 38W

Input Impedance: 50K ohms

Output Impedance: 8/6/4 ohms (Japan Z11-EI48*24 Output Transformers)

Dimensions: 130mm (w) x 130mm (d) x 130mm (h)

Weight: 2.6KG

Input: RCA Jacks

Output: Banana Jacks

AC: Standard IEC Jack with Fuse protection (2A Fuse)

Color: Black

 

Braun L830 Speakers

Another fine example of Deiter Rams iconic Braun L830 speakers, if you ever get a chance to audition a pair of these wonderful speakers do so. The detail and depth of sound is like the finest set of headphones on your ears.

This pair was full re capped with Solen polyester caps and new speaker terminals added.

The clarity of the mid range dome is unreal and the dome tweeter sparkles while the 10" woofer takes care of the bottom end with plenty of oomph..

Tannoy C-10 Speakers

Another set of speakers showed up this week, Canadian made Tannoy C-10, manufactured under license by API, the same makers of Energy, Mirage, Sound Dynamics, ESM, Image, DB Plus, and probably a few more.

These Tannoy's use a 10 inch woofer pair up with a Vifa dome tweeter, the crossover is a simple first cross on the woofer and a second cross to the tweeter. This pair needed a new 6.8uf Solen cap installed as no signal was getting through to the tweeter. New foam surrounds were also installed as the old set had sen their day.

This is my second pair of Canadian made Tannoy's, I had a pair of Tannoy C-6's a few years back.

I am impressed with this Tannoy offering from API, the bottom end is full and with any Vifa tweeter the upper mid range and high end is crisp and clean.

At 92db sensitivity these Tannoy's run well with a tube amp and sound right at home with the rest of my speaker collection. They are non fatiguing with a great open sound stage. the imaging, although not as precise ad the Tannoy Oxford Gold's is pretty good, API really do make good consumer orientated speakers.

Sound Dynamics 500 Concert Monitors finished.

The Sound Dynamics 500 Concert Monitors were finished this week but not without a bunch of extra delicate work.

I choose to use black foam surrounds as I like the look better than the red foam that were original.

The crossover got two new Solen caps in 3.3uf and 4,7uf value. The build quality is pretty good as there is a brace from the front baffle to the rear baffle.

I was all ready to audition these speakers through the tube amp only to find out the right tweeter was non functional. These horn tweeters with the black face are hard to come by and I did not want to buy a silver one from Ebay as they would not match.

I opted to take the horn tweeter apart and carefully remove the old voice coil. I found a donor voice coil from another pair of tweeters kicking around.

It was a very delicate operation to get the two very thin wires from the new voice coil to attach to the leads on the tweeter. Once I got them soldered I used model glue to attach the new voice coil to the diaphragm.
After several attempts I got the tweeter centered and working.

I really like these speakers when paired to the tube amp, I believe the sensitivity is north of 95db @ 1 watt so they sound nice and full when powered by the tubes.

Aesthetically I think they are gorgeous, the bottom end is full and the compression horn tweeters are spot on.

Sound Dynamics 500 Concert Monitor

These speakers followed me home today, Sound Dynamics 500 Concert Monitors. I am happy to have another pair of these wonderful speakers that match up very well with my tube amp.

I sold off my Sound Dynamics 10S a while back and kind of regretted it since. I am happy to have an updated pair of the same speakers fall back into the rotation.

Of course this pair will get re foamed with black foams instead of the orange originals as I like the look of the black foams. Also new Solen caps will be put in place along with new speaker terminals.

These 500 Concert Monitors are the later version of the 10S, they still have the 10" woofer and horn loaded tweeter, they come in a mirror image set and the cabinet is just a bit smaller.

I really look forward to listening to these speaker again.