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Never had tubes. Need advice.

ssmith3046 said:
My 500C was restored by a pro ( not me ) and I've used it everyday for years with no problems. Love it.
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I think I am leaning towards a restored 500C. Seems to be a lot of love here. I am not technical enough to do a restore on my own. There are probably several definitions of "restored" out there. What do I need to watch for and ask questions about when a restored unit comes up that I am interested in?
 
gbroot said:
I think I am leaning towards a restored 500C. Seems to be a lot of love here. I am not technical enough to do a restore on my own. There are probably several definitions of "restored" out there. What do I need to watch for and ask questions about when a restored unit comes up that I am interested in?
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At the very least I'd want all electrolytic and paper capacitors replaced. Preferrably all of them, but ceramics in the radio section are ok. Then all levels checked, especially bias, and anything that looks worn out replaced. If the amp has been well taken care of it should not need a whole lot more. With TLC they can last another half a century. Watch out for too much voltage in your house - these were made for 117V and many homes now have 125V+
 
Just out of curiosity: Why are you wanting Tubes?
After fooling with this 'stuff' for 40 years I've come to the realisation that the Best of Tubes and the Best of Solid State are darned near Identical soundwise.
May not have been true 15/20 years ago.. but certainly is Now :-)
Converse of that is that less than the best.. of either type... remains as crappy.
Argue /flame if you must.. but It took me 4 decades to come to that epiphany.. Hopefully yours will take less time :-)
G'luck
 
gbroot said:
I think I am leaning towards a restored 500C. Seems to be a lot of love here. I am not technical enough to do a restore on my own. There are probably several definitions of "restored" out there. What do I need to watch for and ask questions about when a restored unit comes up that I am interested in?
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I believe the Fisher 400/500/800 are a good value and demand will increase.
 
I've had a number of 'friends' ask me this $1K question.....and I usually tell them to find an old Dynaco ST-70 in working condition....usually around $500.....and then couple that with a working SS pre-amp at around $100 or so. This will puts you at only a $600 investment.....and time to 'ponder' about what you want to do next. You already have some good speakers......and while not as efficient as some that I personally recommend (Klipsch KG-4 @ about $250, Forte @ about $400, and Chorus at about $500....all at over 90 db) you will have GREAT sound with this combination....and money in your pocket to continue to 'invest' in your system. I've played around with 'better' CD players....but am now planning my move 'back' to vinyl. I'd be there already were it not for structural problems with my home involving bouncy floors and no good place for a TT. But, I'll solve that eventually. But all the advice aforementioned.....the Asian units, the Fisher 500Cs, and the Scott 299 C or D.....all 'good' choices. I just like the idea of 'beginning' in tubes with separates in the power and pre area. Keeps the 'options' open. And...the ST-70 is perhaps the most 'versatile' of all tube power amps ever built. More up-grades than Carter's got pills.

Good luck..... WC
 
If we are talking about tube amp combined with modern affordable speakers, 50 W requirements is reasonable. Most speakers you can buy today for under $2000 are designed for high power solid state amplifiers. Usually they make 85..88dB per watt. If someone want 50W per side of REAL power (under 1% THD), it means a quad of KT88 per channel in output stage. Usually it also means monoblocks rather than stereo amplifier. With $1000 in hands one will likely need to look at used market of modern Chinese tube electronics.
 
I'm not sure of the 'math' here....but I once read where difference between a 30 watt amp and a 60 watt amp was only about 3 db when it came to actual sound pressure levels. Needless to say, I'm taking this comment out of text....and I really don't recall if it was relative to a specific speaker set-up or not. But, I do seem to recall that I've heard similar comments made after that. I've compared 'volume' levels between my 60 watt Dynaco Mk III monoblocks, the ST-70 at 35 WPC....and even some smaller 15 WPC EL-84 amps......and unless REALLY pushing it.....even the smaller amps sound great through my Forte IIs. I'm thinking a set of KG-4s, a Scott 299D or a Dynaco ST-70 w/ a Pre-amp, could all be bought for under $1000. A great 'start' in the tube arena IMHO...... TSD
 
I remember reading that amps operate at about one watt except at peak times when the source sends a particularly strong signal that requires higher wattage so as not to distort. Don't know if this is true.
 
Most posters in this thread know this but have not mentioned it I will.

Every 3db at one watt of efficiency is a double of sound.
A double of sound by wattage of the amplifier will require 10x the power.
A decrease in thd of 1% or less in some systems can double output db.

So op this would mean the benefit of going from 25w to 50w is not actually worth the cost in most cases when you can gain the db for cheaper with the right speakers.
 
Just wondering about the 50W requirement: what size is the room you will be using this amp in? If it's not that big, you should not exclude 6BQ5 amps like the Dynaco ST35, simply because these tubes sound so good. I have amps running 7591s, 6L6s, 5881s and EL34s, but the 6BQ5s sound best (to me). Just another 5c contribution.
 
One of my favorite amps is a little single-ended Magnavox console amp....the model escapes me at the moment...but it was an 'integrated' stereo amp when used in the console......and is now 'converted' to being just a power amp. Uses 2 EL84s for outputs, 1 6EU7 for the driver, and a 6CA4 Rectifier tube. I believe this little amp puts out a whopping 6 watts. But, though modest in power output, it can drive my Cornwalls to some pretty substantial sound pressure levels before I hear the distortion setting in. As long as I keep it beneath that 'peak' level....the 'quality' of the sound is really stunning with this little guy. I believe Redboy here on AK built a 'clone' of a similar amp using about the same configuration. If one can live with only 6 watts of power....this is a GREAT little amp to enjoy 'tube' sound...... WC
 
bare said:
Just out of curiosity: Why are you wanting Tubes?
After fooling with this 'stuff' for 40 years I've come to the realisation that the Best of Tubes and the Best of Solid State are darned near Identical soundwise.
May not have been true 15/20 years ago.. but certainly is Now :-)
Converse of that is that less than the best.. of either type... remains as crappy.
Argue /flame if you must.. but It took me 4 decades to come to that epiphany.. Hopefully yours will take less time :-)
G'luck
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I'm thinning the heard a little bit in order to try out tubes. Just have never had tubes and want to see what the fuss is all about. Will keep a good bit of my ss gear though.
 
I wonder how many folks who recommend vintage tube amps over new tube amps have actually owned a variety of both?

With efficient speakers it also comes down to choosing between push pull tube amps vs single ended tube amps.
 
I have both 'new' and 'vintage' Tube amps.......and your comment is actually pretty insightful. So much so that it begs an entirely new thread on the subject. I have a VERY humble opinion, and that is that at a certain point a 'newer' design can actually be so 'modern' and take advantage of all the newer technology available so as to actually 'design out' all the 'flavor' of a vintage tube amp. I found this to be very true of my Jolida amp...where ..... simply put: I just didn't 'feel' it! I also have a massive set of Antique Sound Labs DT805 Explorer amps......and to me, there's a sense of 'sterility' associated with these amps that is NOT there when I simply replace them with a set of old Dynaco Mk IVs. So......if one is making a decision to move from SS to Tubes.......the question of 'vintage' vs 'modern' is, to me, equally important. This is one reason I recommended the separation of power amp and pre amp. This permits some additional versatility in the process. I'll be interested to see what other comments this thread brings to the table. WC
 
While I've had Fishers, an HH Scott, an ST70 and a Prima Luna Prologue they were all push pull tube amps. My new gear consists of SET amps which I much prefer with HE speakers. The oldest amp circuit is the single ended triode yet I see few if any vintage examples. The oldest SET amp I've heard were some Wright mono-blocks from the early 90's. You can't compare vintage to new unless it's apples to apples.
 
Not to belabor this, but when it comes to SET amps......most are in the lower power range...simply because the design of single-ended really came 'earlier' in the scheme of things than did Push-Pull......and then after the Ultra-Linear versions. My ASL 805s are one of the few SET amps that I'm aware of that are 'modern' in construction..... and also have comparable power to some of the push-pull amps of both modern and vintage variety. The 805 develops appx 45 watts of single-ended power, vs most 'modern' or vintage type SE amps using 300B or other tubes where only 3 or 4 watts are produced. So, a lot to consider in all this....... Comparing tubes to solid state is just the beginning. Then comparing SE to PP, ultra-linear to NON-ul, and then you get in to comparisons of power supply types....like Tube rectified vs SS rectified. The list goes on........ Gotta start somewhere...... WC
 
Sounds like my new 3.5 watt 2a3 SET is vintage.

So what became of the old 2a3 SET amps?

I can buy their NOS tubes but that's it.
 
Wharfcreek said:
One of my favorite amps is a little single-ended Magnavox console amp....the model escapes me at the moment...but it was an 'integrated' stereo amp when used in the console......and is now 'converted' to being just a power amp. Uses 2 EL84s for outputs, 1 6EU7 for the driver, and a 6CA4 Rectifier tube. I believe this little amp puts out a whopping 6 watts. But, though modest in power output, it can drive my Cornwalls to some pretty substantial sound pressure levels before I hear the distortion setting in. As long as I keep it beneath that 'peak' level....the 'quality' of the sound is really stunning with this little guy. I believe Redboy here on AK built a 'clone' of a similar amp using about the same configuration. If one can live with only 6 watts of power....this is a GREAT little amp to enjoy 'tube' sound...... WC
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I bought one of these amps off of barter town for $200. Every capacitor and resistor was replaced and a volume control, on/off toggle switch, new speaker binding posts and a light for when the power is on was added to it. In addition, the power transformer was painted red, a red piece of metal with a magnavox logo from a console and wood sides were also added.

For $25 the seller would throw in some pedestrian tubes but since I has a set of Mullards I passed on the seller's tubes.

I think this amp only puts out 3 wpc but with Klipsch Cornwalls it plays very loud and only seems strained when I play metal at ear bleeding levels.

One of these amps is great way to get into tubes and they come up on barter town quite often. I put a wanted to buy post in barter town and received offers the same day.

BTW, the PP version of this amp puts out 15 - 17 wpc and is way more than enough watts with Klipsch heritage speakers for instance.
 
Poultrygeist said:
Sounds like my new 3.5 watt 2a3 SET is vintage.

So what became of the old 2a3 SET amps?

I can buy their NOS tubes but that's it.
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vintage tube architecture, sure.

There probably just weren't very many SE 2A3 amps made when that was a current production tube. It dates to the early 30s, and was largely extinct from current production by the late 30s. Even if you were to find such a beast from that time period, it probably wouldn't be designed or capable of reproducing the frequency range a more modern 2A3 amp can. The best radios of that time period also typically ran a push-pull amp anyway. My own Scott Allwave 15 from 1934 used a pair of them with a transformer phase splitter. For what it is it sounds quite good, but its not really capable of giving a 20-20k response.
 
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