Zenith 5L29 Single Ended Tube Amp

 

Winter is coming and I finally got around to doing a bit of work on this Zenith 5L29 single ended pentode tube amp. I won this on Ebay about a year ago and it sat in storage. I finally have the time and space to work on tube amps again. 

This little guy is probably maxed out around 5-6 watts per channel. This unit comes with bass, treble, bass boost and volume. It runs two EL84, 12AX7 and a 6FQ7 with 5Y3 rectifier.

So far I just added the speaker terminals along with new RCA input jacks and CL90 inrush current limiter to bring the voltage down a bit from the wall socket. No cap work has been done on it yet.

This is a great little single ended unit and sounds great in my office with a not very efficient pair of Monitor Audio MA-9 speakers.

These are worthy little amp if you can pick one up, super easy to get up and running as a stand alone amp.

November 3, A little update, this little amp sounds fantastic and has really grown on me. I do not use the Bass Boost switch as it takes away the detail of this amp, I may just rewire this circuit out of the amp period.

Loving this amp, what more can I say.....

Pioneer SX-3700 Receiver

 

Fun, this Pioneer SX-3700 receiver showed up for me this week, the last of the silver faced Pioneer before the full digital champagne series that followed.

This SX-3700 was rated at 45WPC and had a mix of digital and analog tuning, best of all it had the Fluroscan meters so you could watch your music as you listened to it, as was all the rage in the late 70's and early 80's receivers.

 This unit is in pretty good shape over all and is missing the original on/off power switch knob. I had an older spare Harman/Kardon one kicking about and stuck it on. 

Nice sounding unit for a solid state receiver and if you search the audio threads some think it was better sounding than the generation proceeding this one. I have been noticing these silver faced units are fetching a premium these days.

I will probably keep it in rotation for a bit and let it go to a new owner. Let me know if anyone is interested.

 

Boston Acoustic A150 Speakers

 Finally, I get to show case these speakers and have a listen to them in a nice new big space.

I picked these up pre Covid days and they sat in storage for a long time, I got around to re foaming the woofers in the spring and now I get a chance to listen to them.

A very nice sounding speaker that I am running off the Single Ended tube amp. The bass is nice and deep with no sloppiness, with a mid range driver the mids are clear, the dome tweeter takes care of the rest. Not as nice as lets say a Braun or NAD three way but a very pleasant speaker.

This pair has immaculate cabinets and grills that perfect. I always liked how flat and thin these speakers are. Very nice vintage speakers that are well worth searching out.

Monitor Audio MA9 Speakers

I picked up this pair of Monitor Audio MA9 speakers over a year ago and just got them up and running again.

 

 

There is a back story to these speakers that needed to be addressed. One the previous owner seemed to have driven these speakers beyond there output and basically burnt the voice coil on one of the Dalesford woofers, it had a crackling sound.

The closest speaker I could find with the parameters is a pair of Visaton WS-17E woofers, these are also the closest to the same basket shape of the original Dalesford woofers. The mounting holes were just off by millimetres and a small amount of filing was needed to get them installed.

 

 Another issue I found was a cold solder on the crossover which I re flowed with solder.

Another issue was the cabinets needed a good sanding as these speakers are a beautiful wood veneer that you do not find as much these days.

The sanding went smoothly and I added Circa 1850 Terra Nova NaturOil to the veneer and did these ever turn out nice.

 

I am now enjoying these speakers and I am blown away by how nice my first introduction into Monitor Audio products, even if this pair is from 1979.

I find the Visaton woofers sound super nice and the Seas tweeters are superb. This is a great bookshelf speaker, imaging is great and bass is nice and full for a small enclosure

Acoustic Research AR 18S

 Another project as of late is this pair of Acoustic Research AR 18S speakers. I got this pair way back in November 2019 and finally got into the re foaming mode. 

This being the third pair of 8" 2 way speakers featured recently on this blog. Much like the EPI 100's that use well matched woofer and tweeters that need minimal crossovers, these speakers use a simple 1st order 5uf cap to cross the tweeter, allowing the natural roll off of each speaker to due the rest of the work.

Since these have a smaller cabinet the bass is nowhere near as deep as the PSB Avante or the EPI 100's, everything above 80kz through the mid range and upper range is just as good as the PSB and EPI's. Same goes with the imaging, these have a very nice sound stage and are super pleasing to the listener.

 

 

 

 

Sansui AU-2900 Integrated amplifier

Sansui AU-2900 integrated amplifier, I picked this unit up a few month back and have finally gotten around to having a listen to it.

These units are from the golden age of Sansui and this unit is the entry level unit at 15WPC. 

I always like the low wattage units and this one sounds really open for solid state. I am really surprised by the sound, coming from a tube amp connoisseur. 

This unit is missing a silver cap for the tuner button, outside of that is is pretty rock solid and a really nice build. 

I was thinking of selling this one but I might keep it for fun.

PSB New Avante

Another pair of speakers I have been looking forward to listening too that have been is storage is this pair of PSB New Avante. I always wanted a pair of these speakers when I was younger and never got a chance until now to listen to them. 

Wow! these are nice open speakers. Very nice and now I can hear why these got great accolades back in the early 80's. Well worth fining a pair if they come up locally for you.

It would be super cool to have the original speaker stands with these.