henry4841

Really nice and cool looking. Eye candy.

I have built all that have been published and many of the Zen versions as well. Recently had 7 complete ones running. Not at the same time of course.

? At least that is my understanding for many years of what it means. If not explain your understanding of what A/B means. "Starts at class A then transitions to class B at some point depending on how the amp is bias'ed." Yes, that is what I have been taught. In A you do not have a transfer of the voltage swing from one transistor to another. In B one transistor handles the positive swing and the other transistor the negative swing. My understanding of what A/B means is both transistors in and A/B amplifier handles both the positive swing and negative swing at lower levels then being not biased high enough converts over to B at some point. A/B's run cool at low volumes and heat up at higher volumes. Class A is biased pretty much at the best working level (high)of a transistor all the time and handle both swings at the same time. Once a Class A amplifier reaches it operating temperature it does not change it's temperature no matter the input signal strength.

With our speakers many class A/B amplifiers never leave class A average signal. Maybe on peaks if you push it hard. That is essentially what class A/B means. Starts at class A then transitions to class B at some point depending on how the amp is bias'ed. Diy'ers can bias an A/B amplifier higher to stay in class A longer. To lesson the crossover distortion in B you have to use a relatively large amount of feedback compared to feedback in a class A if used at all. Just technical stuff that really does not mean how good an A/B amplifier will sound. The one I am listening with now is superb sounding and I have a lot of class A amplifiers.

Class A is more linear and most serious audiophiles will prefer Class A. The problem is the heat. If you want 100 watts from one you will need air conditioning and a fork lift to lift the thing. That is the reason those that are sensible buy in the 25 watt range. More power generally means better bass whether A, A/B. or D. I have always favored Class A but that being said I am right now listening with a 150 watt Class A/B amplifier and loving the sound. All classes can sound outstanding when used by a good designer. The circuitry and designer is the determining factor on how an amplifier will sound. That and of course how much is spent. In theory and on paper Class A is the best. In reality they all can sound outstanding

Beautiful wood. Maple?

I thought that is what the PS section looked like. Old school and it worked in the past so should work now. I have done the same thing on some of my builds years ago. Many say that way improves the sound. Using motor run caps, excellent quality film caps, instead of electrolytic's is always a good thing in my book.

Wow! Be sure and post picture in my topic of pictures of tube amplifiers. Let more see what excellent work you have done. Also I would like to know more about your build, choice of transformers and what kind of PS section did you choose. Is some of that iron chokes on the PS? Are those big caps motor run ones.

Let's keep this thread running. I am sure there are lurkers that have tube amplifiers who have never posted. Now is the time to just post a picture and join in. I just like the looks of tube equipment glowing in the dark when listening to music. Romantic as well for you younger members.

Very nice. They do not make them as they use to applies to 70 receivers. Especially a Marantz. Very desirable piece. The 70's receivers may not sound as good as modern higher end equipment but certainly good enough for a pleasant listening experience. I have a Wayne Colburn designed linestage and diyaudio Honey Badger 150 watt per channel amplifier that sounds a lot better than the old Kenwood but there is nothing wrong with the sound of the Kenwood. The diyaudio Honey Badger is designed to compete with A/B amplifiers costing in the thousands and Colburn is the linestage designer for Passlabs to give you some perspective. The Kenwood is perfect for a second system for bedroom with decent small conventional speakers or a primary amplifier for those on a budget with Klipsch speakers. And certainly looks a lot better than my builds. My Kenwood restoration is coming along. I did find that one of the push buttons needed cleaning as well. Should have done them when I did the pots. Found a few more small issues to address but nothing major. Working and play nicely now.

Maybe they are picking just on me.

I have that to happen as well but I never use to have this many be so slow. Waiting on two to show up late right now.

I have two packages right now, one from Amazon and one from Ebay, that tracking says arriving late after posting an earlier estimated time of delivery. I had one last month from Amazon with same notice that did arrive but a week or 10 days later than estimated delivery date. Seems to be a trend for some reason.

Anyone else noticed the time it takes for you to get mail and packages now. I buy a number of items online every month and many have been very late getting to me. Way beyond the expected delivery date. You think all this talk of mail in ballots has something to do with it?

Both are excellent equipment. It will be hard to find someone who had the same gear at the same time to compare. You are probably on your own for which is better for you. Both your gear and the Pioneer could do with a refurbish but that can get expensive depending on who does it. I have been watching some of this guys videos and you may want to watch it to get and idea on what he thinks of it. https://www.youtube.com/watch?v=fjTjAwaopXk&t=5s&ab_channel=xraytonyb

I wouldn't touch it believing it would degrade the sound.

The phono input is much more susceptible to hum, noise. Not unusual to have hum when volume turned wide open. Will never be used that way so no problem. In general only very expensive, in my world, equipment will be totally quite on the phono stage with knob turned wide open.

First listen to them with music. My guess, unless something wrong, is 85% of volume is way too much. Where your volume control is at has absolutely nothing to do with gain. Chances are you will never listen to more than 25% of the volume control. If so that is where you need to listen for hiss.

Arcing on turn on is never a good sign.

I cleaned the pots on my Kenwood with CRC Electronic cleaner first working them back and forth then gave them a small shot of Deoxit D5 and it appears to have fixed the drop out of one channel. The seller said the sound would always drop out on one channel after about 20 minutes and I have run it with no problem for a few hours with no dropouts. As stated previously those wafer selector switches are known to give problems. Glad I do not have to take the selector switches apart to clean as you sometimes have to do. The tuner works amazingly well, very sensitive, with a slight problem with the stereo light on the panel. Someone has wired it to stay on all the time. I will need to investigate that further. Also the Speaker selector switch is not working correctly. You have A then B then both and reverse but changing it has no effect. The A speakers still stay on and do not go off. That and recapping appears to be all that is needed. The PS caps measure slightly high in circuit which is a sign of going bad but the ESR is really low. If I decide to keep it myself I might just leave them alone and just replace the ones on the boards. Sounds really good on a pair of test speakers. Gonna recap before listening with my LS.

I recently bought 3 vintage Kenwood Receivers from the 70's to do complete restoration on. I popped the top off of the Kenwood KR5400 yesterday and it looks as though it was well made with quality parts. Big transformer and Elna caps. I like the looks of the vintage receivers compared to the ones being offered. But then there is not a lot of demand these days for stereo receivers. Is there anyone else that likes those old stereo receivers? I may later one post some pictures and what I did on the restoration on one of them. The KR5400 was sold as one channel cutting in and out and I believe from just a quick inspection it is the wafer switch control. They are notorious for dropping out sound. It could be something else but I believe that is all that is wrong after turning it multiple times and both channels are working now. I may just have to recap and clean everything, spit and polish. We will see.

I'm sorry to say but it takes me back 40 years looking for things you can only find only on the Darkness on the Edge of Town, on suicide machines. If anyone every ask if you have ever smoked a joint you can always just say I went to college back in the 60's, 70's. Now over 70 don't even drink regular coffee, decafe.

It was that kind of night.

I have found that a preamp, linestage, is not need with our speakers. I just use a quality buffer with no gain for volume control mainly where I can use a sub when there is not a sub outlet on the amp. If anything a pre with gain will more than likely, depending on amplifier, give you no control over volume. In other words off and then too loud with just a slight turn. If your amplifiers do not have pots just use a passive linestage or buffer. Just what I have found and I have numerous quality linestages. They all will contribute their tone to the sound as well.

How many watts does it make being PP?