Jump to content
The Classic Speaker Pages Discussion Forums
npt3

Good Tube Amps (integrated or not)?

Recommended Posts

npt3    0

I have a pair of Allison 3s, and AR3as that I recently restored. I am driving them (not at the same time!!) with an HK3485 (2x120W) receiver. I like the HK unit a lot, but have been thinking about tube amplification. I'd probably go with a power amp (remove the jumpers from the receiver and use it as a control unit).

That said, I don't even know where to start. What's a good match for my speakers in, say, the $1 to $2000 range? Vintage units are OK. Can I even get something good in that range?

Share this post


Link to post
Share on other sites
JKent    0

dynaco ST-70

these go for ~$500 on ebay

a pair of dynaco Mk III mono amps ($??)

There’s an ebay seller who sells something he calls a dynaco ST-120 tube amp kit. It’s an “upgraded" ST-70. Looks pretty. He also sells a mono block kit.

Anything McIntosh that fits in your budget

Fisher

I’m told H-K and Marantz stuff tends to be a bit flakey. Many love them but I’d stay away.

Scott made some nice stuff

there are new tube amps coming out of China but you’d have to do some research.

Sherwood was known for its tube tuners and receivers but also made tube integrated amps.

Remember that any vintage tube amp will need work—now or in the future. The availability of parts and service is important. My tech (Bristol Electronics in NJ) is an authorized Mac service center, but there are “some” parts even he can’t get. And Mac is still in business! I think Mac is the best choice at the high end and Dynaco is a good choice at the lower end—they made millions of those, and the “new” kits being offered look interesting.

You want at least 60wpc RMS IMHO. Your Allisons are 4 ohm and require a min 30wpc but more is better. The AR3a will probably like 60.

nb: I am not using a tube amp now so this is not 1st-hand info. I used to have a little dynaco ST-35 that drove my AR4x's to rock levels with just 15wpc (at a cost of $40 for the kit!). Now I'm using a Fisher tube tuner but it needs work again so I use the FM in my Mac (solid state) receiver. I DO love the little KLH Model Eight tube radio :)

Kent

Share this post


Link to post
Share on other sites
soundminded    0

I have a pair of Allison 3s, and AR3as that I recently restored. I am driving them (not at the same time!!) with an HK3485 (2x120W) receiver. I like the HK unit a lot, but have been thinking about tube amplification. I'd probably go with a power amp (remove the jumpers from the receiver and use it as a control unit).

That said, I don't even know where to start. What's a good match for my speakers in, say, the $1 to $2000 range? Vintage units are OK. Can I even get something good in that range?

Tube equipment is expensive. Good tube equipment is very expensive. And good vintage tube equipment that has been restored is usually exceptionally expensive. AR3a's published ads stated they require 25 wpc RMS. That is very modest by today's standards, not so modest by the standards of the early to mid 1960s.

Dynaco Stereo70 (35WPC) is about the smallest amplifier practical. Paired with a Dynaco PAS3X it was probably the most popular choice for driving thes speakers with a tube amplifier. MacIntosh MC225 is too small. MC240 and MC275 are out of your price range. For a preamp, the C-22 was excellent but the price is through the roof. However the MX110 and MX110B are MacIntosh tuner/preamps whose preamp is similar to C-22 at a fraction of the price. One of the great bargains of a lifetime I missed was an opportunity to buy one in excellent condition for $75. Marantz tube equipment is also out of your price range. The 7 and 7C preamp alone are more than you want to spend. The matching power amps were TOTL competing head to head against MacIntosh and are also very. So are Harman Kardon Citation I, II, IV and V. They are in a niche collector's market with a following. Separate amps and preamps from Fisher and HH Scott were very good but the tube receivers were mostly not powerful enough. Perhaps the Fisher 500C would be adequate. HK also had a cheaper line, the Award Series. The only models of potential interest are the A700 integrated amp and TA7000X receiver both 35 WPC. The A500 and TA5000X are not powerful enough for AR3a. Eico and Heathkit may have had some separates that qualify. I'd avoid Bogen, Pilot, and Sherwood. I'm not aware of any Sherwood tube amplifiers powerful enough although there might be one or integrated amps that qualifies.

One problem you won't have with a tube amplifier is the low impedence of AR3a. All tube amps except for the very rear OTL types have output transformers with 4 ohm windings to connect to.

There are other tube amps out there, lots of them but they all seem expensive. Conrad Johnson and Audio Research seemed to be in the vanguard of the "tube revival" after solid state equipment had become established as the norm and the standard. That's my walk through nostalgia land and the audio landscape of my youth for today.

Share this post


Link to post
Share on other sites
JKent    0

Your inquiry got me thinking about my ol' dynaco ST-35. It was designed by Ed Laurent and introduced in 1963.

In the August, 1985 issue of Audio magazine Bascom King wrote this of the Mark Levinson ML-9: “Surprisingly, it sounds similar to the Dyna ST-35, which is a highly musical-sounding little amp (when its ceramic input-coupling capacitor is eliminated).” The Levinson was a $3,000.00 amp at that time! I knew nothing about capacitors at the time, but I wrote to Mr. King and he was kind enough to reply with a very clear copy of the schematic, with notations showing how to modify it. Nice guy. This was pre-email and he took the time to make some notes by hand and mail me the schematic.

Anyway, dynaco tube equipment is still very popular, and I came on this site

http://www.tubes4hifi.com/bob.htm

They sell brand new dynaco clones for prices within your budget. I know nothing about this outfit or their products, but they’ve been in business 23 years. I’m very tempted to get one of their kits myself! There’s just something about tubes....

Kent

Share this post


Link to post
Share on other sites
ar_pro    0

I wouldn't overspend - the Dynaco solution is excellent, and falls well within your stated budget.

If you can solder, you can make any needed repairs/updates to the Stereo 70 yourself - it is very easy to work on, there are tons of resources for this model, and you'd be hard-pressed to find a better-sounding vintage tube stereo amplifier, UNLESS you're able to afford McIntosh.

Short of a garage-sale find, though, all of the vintage Mac tube amps are going to far exceed your price range, and they might require expensive servicing.

But the more-recent iterations of the MC275 are amazingly affordable, and the 275 is a phenomenal match with the AR-3a, tube amplifier-wise.

So, I'd tread water with a nicely rebuilt Stereo 70, and save my pennies for the MC275.

Share this post


Link to post
Share on other sites
ssmith3046    0

This is a timely thread for me indeed. I'm waiting for delivery of a little Fisher X-100-C integrated tube amp that I'm going to use to set up a vintage tube system. I have quite a bit of vintage solid state gear so this is my first excursion into tubes. I'll probably set this one up in my bedroom. I was glad to hear JKents remarks that he used to drive a pair of AR-4's with a 15 WPC tube amp. I have a pair of AR-4a's and AR-6's just sitting idle that I want to try out with the Fisher ( it's rated 25 WPC ). I have a pair of AR2-ax's but I don't think I'll try those on the Fisher.

Share this post


Link to post
Share on other sites
soundminded    0

This is a timely thread for me indeed. I'm waiting for delivery of a little Fisher X-100-C integrated tube amp that I'm going to use to set up a vintage tube system. I have quite a bit of vintage solid state gear so this is my first excursion into tubes. I'll probably set this one up in my bedroom. I was glad to hear JKents remarks that he used to drive a pair of AR-4's with a 15 WPC tube amp. I have a pair of AR-4a's and AR-6's just sitting idle that I want to try out with the Fisher ( it's rated 25 WPC ). I have a pair of AR2-ax's but I don't think I'll try those on the Fisher.

Back in the bad old days, amplifier power meant different things depending on who was advertising it. Dynaco, Marantz, and MacIntosh used RMS as we understand it today. (even this is an oversimplification but it is the most conservative commonly used rating) But many others including Fisher, Scott, Harman Kardon, advertized IHF (Institute of High Fidelity) power. This was based on the peak of the sine wave, not on the area under it as RMS power is. It is inflated by about 25%. Worse was EIA (Electronics Industry of America)power which was much higher yet. This was often used by manufacturers of mass produced console stereos. Some of the worst and most unscrupulous manufacturers even rated their amplifiers according to how much power they drew out of the wall outlet. All this changed in the mid 1970s when the FTC stepped in and set up standards that had to be followed. This included a 1/3 power preconditioning and power bandwidth. Under the new FTC rules, even Dynaco Stereo 80 dropped from 40 wpc to 30 wpc.

Share this post


Link to post
Share on other sites
soundminded    0

Thanks soundminded. That's interesting news. So if Fisher advertised 25 wpc by the standard I'm familiar with it would be closer to 18 or 19 wpc.

Could well be. You'd have to go back to the original advertisement and read the fine print in the specs carefully. For example, HK A500 was advertised as 25wpc...IHF. Actually it tested about 17 or 18 wpc RMS. This is about what the Dynaco SCA35 was capable of. AR3 was often demonstrated with Dynaco Stereo 70 and PAS3X by AR itself. It was adequate and worked well. A pair of Mark IIIs would probably have been even better. The design criteria Hafler used for his products was to make them outstanding performers, easy to build, and easy to obtain consistent performance even when built by amateurs from kits. Also to keep costs low to be competitive. As a result, a very large number of them were built and are still around in the market, usually selling for much more than they originally cost. It is not surprising that even today, there are copycat clones, I think many from China.

Share this post


Link to post
Share on other sites
rrcrain    0

In the arena of new tube equipment, take a look at what Rogue Audio makes. They are strictly a U.S. manufacturer making excellent tube equipment across an impressive price range. Whether or not the make something suitable to you is up to you but their products are excellent, current and under warranty.

Share this post


Link to post
Share on other sites
Mexicomike    0

You might check out an old Moscode 600 if you can find one on ebay or wherever. It was a 300WPC tube front end/MOSFET back end that, IMO, sounds really great. It was designed by George Kaye in the mid '80's for New York Audio Labs (reading about NYAL history and it's founder, Harvey Rosenberg, is an adventure in itself). BUT, the view's of this amp are extremely polarized; people either love it or hate it. THere seems to be no middle ground. It's an amp that, if you blind a/b it, you will probably be able to pick it every time. Some folks would say that's good, others say the opposite.

But it's extremely musical (some say "colored") and if you run across one it's worth listening to. I used to to do the "amp of the month" kind of thing when I was a totally nutso audiophile and the Moscode 600 put an end to that. I have not purchased a new amplifier since I bought it in the late 80's. Currently I run my LSTs with either the Moscode or a McIntosh 7270 (solid state) amp. The Mc setup LOOKS a lot better - the Moscode is rather industrial looking - but the Moscode TO MY EARS sounds better. I'm not exactly recommending it because you might hate it but if you have the opportunity, give it a listen.

Here's a pic of one:

http://www.moscode.com/george_kaye/images/m600_trans_517.jpg

Share this post


Link to post
Share on other sites
sofaman    0

Hope it's not bad form to revive an old thread with a similar question.

A little over a year ago, I bought very nicely restored AR 2ax's from Classic Speaker Pages occasional poster Crunkarelli.

These were the first vintage addition to my system. I love them. Now, as the OP here asked, I'm thinking of going tube amp.

My present power source is a simple 2 channel reciever: Onkyo TX 8522, 100 watts X 2. It powers the speakers fine. Nice clean modern power. Nothing to complain about.

But am I missing more of what these speakers can deliver with tubes?

There's a Sherwood S-5500 I've found that I'm considering. It's fully restored by NOS Valves (excellent reputation from what I've found.) But I"m not sure it has enough muscle to move my ARs. It's rated at more like 25-30 watts, rather than the suggested 60 that is recommended for AR3as. Am I right to assume that's a good ideal number for the 2ax's?

I'm not looking for huge volume. Rather enough power to reveal nuance. Opinions appreciated.

Share this post


Link to post
Share on other sites
tysontom    0

Most of the Dynaco tube amps, particularly the ST-70 and the Mk III versions, held up well under the FTC-mandated measurement standards. Either of these amps was very capable of driving AR speakers well, especially the more powerful, but less clean, Mk III. These amps also had close to 3 dB headroom, too, meaning that the Mk III could easily be driven to peaks of 120 watts before clipping on short-term peaks. AR used the Mk III to power the AR-3 in all of the early live-versus-recorded concerts and the 1910 Nickelodeon demonstration, and the amp always performed well. Mk IIIs were also used to power two AR-3s—mounted on the roof of the AR Music Room in New York's Grand Central Terminal—to high output levels playing Christmas music for the entire train station.

One good way—back in the old days—to see how good or bad your amp performed was drop by McIntosh Amplifier Clinic. Many McIntosh dealers conducted such clinics, run by McIntosh Labs between 1962 and 1991, and anyone was invited to bring in their equipment and have them tested by Mac's traveling field engineer, David O'Brien. McIntosh had nothing to hide and the company feared no one, and they loved to test "brand x" amps and watch them fall by the wayside under the duress of max-output power into 8 ohms or 4 ohms. While these clinics were difficult to run and costly for the company, they were a boon to the reputation of the company and to sales.

I took my old Dynaco Mark III amps in for testing, and they performed reasonably well (see image Dynaco), but they did not quite meet the Mac minimum-guaranteed performance standard (a faint red line close to the bottom showing around 0.25% harmonic distortion from 20-20kHz). Nevertheless, the Mk III could easily meet its rated power. It clipped at about 70 watts. Dave O'Brien was reasonably impressed by the performance of the amp as it was comparable to the performance of McIntosh's MC 60 amp. About a year later I took in my fairly new AR Amplifier, and it did extremely well, easily surpassing the difficult testing standards (see image AR Amplifier).

--Tom Tyson

post-100160-0-34928200-1329010097_thumb.

post-100160-0-18931200-1329010199_thumb.

Share this post


Link to post
Share on other sites
oldguide    0

I have been building and modding Dyancos for many years and would offer a few bits of advice. My current AR setup is an AR PAS 3x, totally gutted and rebuilt, with a QSC power amp. The QSC was Tom Tyson's idea and I like it a lot.

Buying vintage Dynaco equipment is not for the faint-hearted. Assume that anything you buy will need to have something done to it. I have not tried the new kits, so cannot comment on them other than to say I have seen the schematics for some of them and they make some modifications to the originals.

THE best place for advice on Dyancos is run by Joe Curcio, who also sells some Dynaco parts, upgrades, etc. That site is Dynaco Doctor at:

http://www.audioasylum.com/cgi/etv.mpl?forum=dynaco

Of the "upgraded" Dynacos, the consensus leader in that department is Bob Van Alstine. His stuff isn't cheap but its quality is outstanding.

http://www.avahifi.com/index.php?option=com_content&view=article&id=251&Itemid=172

Share this post


Link to post
Share on other sites
philcryer    0

there are new tube amps coming out of China but you’d have to do some research.

I'm currently running a pair of Antique Sound Labs, Wave AV-25 DT http://www.divertech.com/aslwaveav20dt.htm tube monoblocks, with a McIntosh 6100 pre-amp to my AR-4x's, and I'm loving them. ASL are designed in the US, but built in China, and while the build quality isn't anything to write home about, I think they sound great (disclaimer: these are my first tube amps). They certainly fall in your price range too, put them on your short list.

Funny, I just read about a vintage Dynaco today, looks very interesting.

Share this post


Link to post
Share on other sites
rl1856    0

Restored Dynaco MK III pair and a Conrad Johnson PV5 would be a very good match for you. There are many Conrad Johnson stereo amps with sufficient power that would be within your price range. You may be able to find some Audio Research preamps as well. With an upper limit of 2k, there is a lot of equipment out there.

Eico made a 6550 mono amp (HF60 ?) that should be in the $1200-1500 range fully restored. This would be another good match.

Among new amps, Jolida and Rogue have several choices in your price range, unless you want to roll the dice and import something directly from China.

Yours is a nice problem to have.

Best Ross

Share this post


Link to post
Share on other sites
ironlake    0

I just picked up a marantz receiver that had been all redone for my ar4's. It only has 26 watts per channel but my gosh it will kick the heck out of the new 100 watt sherwood rreceiver I have. The marantz is solid state but has a super smooth sound, almost tube like to it and 26 watts is enough to really fill up the living room with rich full sound on the 4,s. I know they are not tube but the ads for the old marantz solid state talk about their tube like sound and they are right. This receiver was made in 1977 and was used by a church only on sundays for music before service so it is spotless. Spent 100 bucks at a vintage service center to put it in tip top shape and it should last for quite awhile.

Share this post


Link to post
Share on other sites
JKent    0

I'd avoid Bogen, Pilot, and Sherwood. I'm not aware of any Sherwood tube amplifiers powerful enough although there might be one or integrated amps that qualifies.

Sherwood, built in Chicago, (not the new stuff) made excellent affordable products. Their tuners were outstanding. They did produce some tube monoblocks (S-360) but I'm not familiar with them. The S-5000 would deliver 36 watts per channel at 8 ohms--more at 4 ohms and could be bridged so a pair would give 72wpc into 8 ohms. That would be more than adequate. http://www.romeroy4u...ml#anchor325901

But I think if I were in the market for tube gear I'd go for one of those brand new Dynakit replicas like this: http://www.tubes4hifi.com/bob.htm#ST120

Kent

Share this post


Link to post
Share on other sites
fran604g    0

I'm with Kent on his suggestions.

I own a TAD-60 and really happy with the performance with my 3a's, they come up for sale occasionally and I've noticed the price seems to be dropping on the ones I've seen sell over the last couple of years. A bit obscure, maybe, but the neat thing about them is the variety of output tubes it will support. Mine can be biased for 6550's, KT88's, KT90's, EL34's and their variants. The model that was sold later than mine could also use 6L6's.

If I didn't have the TAD-60, I would absolutely buy a kit from Bob Latino, great reviews and that VTA-120 looks VERY interesting. :)

Plenty of power for the AR3a's, IMO.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×