Sherwood RX-4109 Receiver

[johnda]

Leroy, you're bad! Sorry, I couldn't resist! Whatever floats your boat, Leroy, life is too short. My low cost Yamaha RS201 does sound clearer than the RX 4109 that I still have, but it's $50 more. My RX 4109's never sounded dull, though. I still think the RX4109 is the best $100 receiver out there. Perhaps you got a bad sample, who knows, but in any case enjoy your new baby!

 

[Brian]

I actually suggest buying a refurbished unit. It will mean the unit was looked at by a human, repaired, tested and confirmed to work. It must likely will also have been updated to reflect production changes addressing reliability shortcomings. Most new off the production line units get not much more than a quick turn on it assure the lights work and it makes noise and then packed. QC has become a thing of the past with most companies that die risk analysis. As production is automated, provided the component parts sampling shows a high likelihood of being in spec then the completed unit has a high probability of working. Then the simple final QC will pick out another % leaving, in theory a very small number of units that are down so it is less expensive to let these through and do refurbs than expend the money in QC investment. Of course this is all predicated on the unit being decently engineered and decent parts spec'd that is where most of the problems really arise and no QC nor repairs can address.

 

[johnda]

Right, Brian

I have also purchased refurbed gear and never had a problem. I picked up a Sony digital camera with a Zeiss zoom lens for less than half the cost of a non-refurbed unit. Works great!

 

[icenine]

Listening to my Sherwood RX-5502 right now. I play it a few times a week. It is a pretty good match for my nightstands, Altec Lansing Santana IIs



I only paid about $20 bucks for it. I got some sort of gift credits for longevity at my part time job so the credits made the receiver pretty cheap. It does not sound like my NAD, but then again I have not hooked up JBL 4406s or Snell Type III Series E to them yet either.

 

[Degajoe]

Sherwood RX-4109

Back in 2010 in needed audio for a tv monitor I was installing in a lake house I use for vacation rentals. I picked up the 4109 on sale a rat shack with a pair of Yamaha NS-6490 (6 ohm by the way), set it up and never looked back. July of this year, I rented the house for 2 years to an Army Colonel and he wanted it unfurnished. A few weeks later I set this little system up behind the bar in my basement, hooked up an old ipod classic with a monster cable and it rocked the house. Sounded fantastic to my undiscerning ear, I loved it.

I played it in that configuration for a few weeks. (I had an Onkyo SR8440 with some old Pioneer surround sound speakers on the other side of the bar that I never turned on again.) I dug an old set of Kenwood JL-1103Rs out of my shop, moved the RX-4109 in to the old Onkyo location, hooked up both the Kenwoods (8 ohm) and the Yamahas (6 ohm) And was impressed.

I had used the kenwoods (which I got for free from a buddy when I helped him move years ago) with an Onkyo TX82 I bought new in the early 90s. They sounded very boomey even at moderate volumes and I never liked them. (The TX82 sounded great with the Cerwin Vega AT-10s that I had in the 90s.)

The Sherwood sounded so good, I have since bought an old Pioneer PL-A25 turntable (1974?),pulled out the old vinyl, and installed a yagi in the attic!

The Sherwood has never clipped, cut out, shut down etc. It plays all day at 12 to 14 on the volume as my office is in my basement and the radio is on all day. At night and on weekends I regularly crank it up to 30 or 35 for extended periods with no issues.

 

[Michael Powers]

Interesting...

Back in the day... (70's - Early 80's) people in the trade often talked about the "reletive strength" of RMS Watts delivered by various Hi-Fi Manufacturers.

Tis started in sorta fun, but soon became a serious discussion. It was compared to the same situation found in automotives, especially in the muscle car era. Clearly some manufacturers horsepower was based on smaller horses than others.

In Hi-Fi we had similar ideas. McIntosh fans rejoice, Mac and Marantz (pre 83) and Crown were considered far and away to have the "healthiest" "watts". Many clinic's in my store, (Marantz Clinics) confirmed that perception. The next down the list were Dyna, Bedini, Accuphase, SAE, GAS, Phase Linear and Kenwood (!), Pioneer and Luxman, bringing up the rear believe it or not were Onkyo and Yamaha in addition to less "serious" equipment.

There was no trickery in these tests/clinic results. Most of the equipment belonged to my shop (55gal drum of motor oil with massive resistors in it for Power Runs) etc. Typically a Crown DC300 would put out 250+ rms per channel at rated spec's. A Mac 240 tube (we called em "twin 40's) easily put out 55 per chanel into 8 ohms, and a Marantz 500 (250x2) once cooked along merrily at 520x2 into 8 with no signs of stress other than the fan kicking into high speed.

Over the past 3 decades I've often been asked to help "set up" new systems for folks. Lots of chip amps, and 5.1 receivers sometimes into vintage squeakers. I have NOT been impressed with those receivers. A suprise though, Onkyo and Yamaha seem to be the best vs. their "rated" power now.

Flame an old mans memory if you like... but I'm not gumming my food yet, those are accurate memories.

No flame(s), but I was wondering where you thought (1970's) Harman Kardon fit in....

 

[captincork]

upgrading speakers

I have been using the RX4109 for about 6 months with a pair of bookshelf speakers and have so far enjoyed it thoroughly. However, I think I am ready to upgrade to some tower speakers and have been looking at the Pioneer SP-FS52-LR. Everything I have read about these speakers is pretty positive and I listened to them at best buy and they definitely sound better than my dinky bookshelf speakers. My problem is that I don't entirely understand how ohms work. Would the 4109 run the Pioneers without a problem? If so, could I hook the bookshelves up to the B speakers and use both A and B together?

Thanks for the help!

 

[jazzwolf]

I've had the 4109 for over 2 years and it's been a nice little workhorse and I've never had any of the problems that I've read online. For under a hundred dollars I don't know of any receiver that can give you the value and it even has a phono preamp. I don't think it's really 105wpc because I have a Marantz PM5004 which is rated at 35wpc and it blows the Sherwood away easily in volume.

 

[hnash53]

I'm curious about those Pioneer speakers too...

I have been using the RX4109 for about 6 months with a pair of bookshelf speakers and have so far enjoyed it thoroughly. However, I think I am ready to upgrade to some tower speakers and have been looking at the Pioneer SP-FS52-LR. Everything I have read about these speakers is pretty positive and I listened to them at best buy and they definitely sound better than my dinky bookshelf speakers. My problem is that I don't entirely understand how ohms work. Would the 4109 run the Pioneers without a problem? If so, could I hook the bookshelves up to the B speakers and use both A and B together?

Thanks for the help!

I'm curious about those speakers, too!

I think you might find an answer to your question about the 6 ohms in some of the Amazon reviews of those particular speakers. There are about 700+ reviews to choose from on Amazon! I'm pretty sure I read that there is no problem running those 6 ohm speakers with an 8 ohm receiver. Or... post this question in the General Discussion... I'm sure others will be able to answer it for you.

My opinion is that the Sherwood will have no problem with those speakers.

 

[johnda]

Sherwood recommends that speakers less than 8 ohms impedance not be used. It is possible that you can get away with 6 ohms, but the receiver may run warm and have a shorter life span. I would stick with 8 ohms myself.

 

[Pete B]

I'm very interested in the RX-4109 and found William's teardown page quite interesting. The outputs, 2SD1510 and 2SB2510 transistors, are made by KEC and I've had trouble in the past getting data sheets on their parts. I think that there is also a 2SD1510 from Panasonic that is an entirely different part and I hope that the cross to the NTE part is rather to the Panasonic type and not the KEC part. 65W parts in an amp like this are just too low and I think that part is a TO220 whereas in the picture the outputs look like a TO3P or one of the other larger plastic types. Most TO-220s are only good for 80W at best.
Sanken makes some excellent power darlingtons in the TO3P case, here is a 125W version that would be excellent in this amp, I'd rather see 150 to 200W devices but I don't think that's going to happen with a plastic darlington part.
It would be excellent if the KEC parts were clones of these Sanken parts, 2SC3284, but I have no way to know:
http://www.semicon.sanken-ele.co.jp/sk_content/2sc3284_ds_en.pdf

The die size is a good way to get an estimate of the power and if anyone has blown outputs from one of these amps I'd be willing to cut them open and take a look at the die - I have done it before with similar parts:
http://s150.photobucket.com/user/BASCON07/media/SANKEN/OPEN.jpg.html

 

[Pete B]

Here is the KEC web page:
http://www.keccorp.com/

Could not find the parts until I searched by Darlington devices and found KTD1510:
http://www2.kec.co.kr/data/databook/pdf/KTD/Eng/KTD1510.pdf

And KTB2510:
http://www2.kec.co.kr/data/databook/pdf/KTB/Eng/KTB2510.pdf

These are very conservatively rated at 100W, since if you look under the safe operating curve they will take their full power around the amp rail voltage, 2A at 50V for the full 100W rating. Most power devices take about half of their rated power at higher voltages. These really act more like 150 - 200W parts in amplifier applications - very nice. They do look as if they are copies of the Sankens with their excellent 50 MHz Ft. Most similar US made parts have 4 to 6 MHz Ft.

 

[Pete B]

Thinking about this more, doing a bit more research and seeing that the outputs fail fairly often reinforces the fact that the output devices are undersized. They really should be 15A minimum, 20 better and 200W especially if you plan to use nominally 4 ohm loads. Really, a pair (four total per channel) of 200W devices should be used for good drive with margin into 4 ohm loads. Granted it is rated in the manual for 8 ohm only but there is no excuse for the output protection not working and it failing with shorts or low Z loads.

The outputs could be doubled up, but I'm not sure that it is worth the effort.
Here is a suitable device from OnSemi, 15A 200W but it is not a Darlington so drivers would have to be somehow rigged up:
http://www.onsemi.com/pub_link/Collateral/NJW3281-D.PDF

That the outputs fail further suggests that the output protection doesn't actually work.

Looking at the service manual there are a few things that I don't like. The VAS is undersized, in my opinion, such that I'd expect it to blow if the outputs were shorted and the volume turned up. There is no protection transistor on the VAS which is common when a low power VAS is used. I'd like to see a device with 10 times the rated collector current there running at about 4 times the idle current of the existing design.
Edit: Some protection (current limiting) is provided by R318 in the emitter path of the VAS and it might actually save it when cold, but still it is better to design for worst case conditions.
There is output protection and I believe that it is a latching type that on a single trigger puts the amp into protect mode, this is good if it is set at a high enough current level. I think it is since many are able to run the amp into 4 ohms without it going into protect. The odd thing is that the sense for the trigger is on the output device that is passively turned on and not turned on by the VAS which will provide enough current, far more than the passively driven side, to blow the output and itself from what I see so far. Usually, the protection sense is on both output devices. This might be why outputs fail even with the amp having output protection. It would have been far more logical to put the protection on the VAS driven side. It is quite possible that the VAS fails first and then takes out the output stage. I'd really like to take a look at one of these with a failed output stage.

I agree with William that the air flow and heat sink should be better. If you look at the last Figure on the last page of the transistor specs, it shows that at a case temp of 75 deg C the KEC outputs must be derated to 60W from their 100W nominal rating, so keeping them cool is very important:
http://www2.kec.co.kr/data/databook/pdf/KTD/Eng/KTD1510.pdf

 

[Bassblaster]

i get this is a few years old but i had to throw my 2 cents in

i got my RX-4109 on Ebay for $12..yes $12. the guy listed it as "speakers and headphone doesn't work"
i got it and i shit you not the only problem was the speaker switch was off. that was back on 09 and it is still pounding today, listening to it as i type this.

 

[Danddd]

We have had one in our kitchen since, I want to say 2008. Runs small Pioneer speakers in the kitchen on top of the cabinets and some older outside Advent speakers. And at the same time on a lot of spring through fall occasions. Never an issue. Just a great entry level workhorse.

 

[DarkAudit]

i get this is a few years old but i had to throw my 2 cents in

i got my RX-4109 on Ebay for $12..yes $12. the guy listed it as "speakers and headphone doesn't work"
i got it and i shit you not the only problem was the speaker switch was off. that was back on 09 and it is still pounding today, listening to it as i type this.

Okay, you got me beat. I got my RX-4109 for $15 at an estate sale in 2013. Worked well for me for a few months until that SA-600 popped up on Craigslist. I've since passed it on to my sister along with my spare SL-D2 turntable.

 

[johnda]

My last 4109 was my gift to our friends. The speakers I gave them were the AR215 PS and I added the system to their Samsung HD 60" TV. Sounds great! Unfortunately her husband passed away last November but she is still enjoying the system.

 

[ChiHawks7]

I'm still a noob audiophile here, so I'd love some help on my system. I recently got a RX-4109 off of Cash Converters here in Spain, now I need a proper speaker pairing. I already had some Kenwood bookshelf speakers. Luckily I just educated myself about impedance since these speakers are 4 ohm speakers. I've only had the Sherwood for about a week and haven't blasted anything yet so the amp should be fine, but I've probably listened to a few hours of music at low-medium volume. I've since come across these Skytronic bookshelf speakers for 35euros. They're rated 6 ohms...would that be safe? Thanks.
https://www.amazon.co.uk/Skytronic-SHFB55B-Passive-Bookshelf-Development/dp/B005DWVX4M

 

[Bassblaster]

I'm still a noob audiophile here, so I'd love some help on my system. I recently got a RX-4109 off of Cash Converters here in Spain, now I need a proper speaker pairing. I already had some Kenwood bookshelf speakers. Luckily I just educated myself about impedance since these speakers are 4 ohm speakers. I've only had the Sherwood for about a week and haven't blasted anything yet so the amp should be fine, but I've probably listened to a few hours of music at low-medium volume. I've since come across these Skytronic bookshelf speakers for 35euros. They're rated 6 ohms...would that be safe? Thanks.
https://www.amazon.co.uk/Skytronic-SHFB55B-Passive-Bookshelf-Development/dp/B005DWVX4M

Depends on how loud you play music.. the Sherwood is only rated for 8 Ohms but at lower volumes it will do 6 Ohm and its a little risky but also 4 Ohm. but it has over current protection so dont worry too much

 

[ChiHawks7]

Depends on how loud you play music.. the Sherwood is only rated for 8 Ohms but at lower volumes it will do 6 Ohm and its a little risky but also 4 Ohm. but it has over current protection so dont worry too much

Would you say the Skytronics would be safe bet until I come across something perfect? I mean they have to be better than the Kenwoods right?