[Dmason]

I will agree with that.

The ClariT, known for its "speed," has company. My 45 SET amp uses OPT with Ni/Permalloy laminations, and demonstrates the same agility/FR as the ClariT. It only looks "old."

I have heard similar circuits in c.1920's Western Electric 45 amps sounding just as lithe. I am surprised the audiophool bonanza didnt start back then.

[TheChairGuy]

The Rectifier and voltage Regulator tubes never made it here on Friday.....FEDEX re-routed them God-only-knows-where.

But, the Odyssey Khartago Mono's arrived.  I set them up Saturday morning.

Three notes - game over.

Never have I heard more of everything I've been looking for for many years.  It's still quite obviously stiff legged (needs weeks to break in according to Klaus), but all those things I suspected were room interaction/poor configuration, lousy midrange for the cheap Peerless woofer in my Linaeum, inadequately designed crossover, my ears/hearing, my various moods and level of tiredness - are now rendered largely irrelevant.

Friggin' amazing   The soundstage is so wide my speakers seem like they were splayed a part another couple feet from the 6' they are now.  The integration of woofer and tweeter is the most seamless I have ever heard in my room/office.  All this, and it is still stiff legged.

Not that the Dukane are slouches - and I am holding out the possibility that my tastes might change and they might be even more appealling to me in the future.  They are keepers (maybe a biamp future?) and will probabaly improve further when I relieve those tired last tubes and insert fresh.  As well, change out the power cord to something a bit fatter.

The Dukanes are quite easy to listen to, by a slight margin as good as the Khartago stereo I just sold.  I think much of it's virtues, other than abundant power to hit crescendo's, are it's monoblock status.  I will never even consider anything but a true dual mono (with separate power supplies) or monoblocks of any iteneration in the future. It's simply theory that does translate in real world instances - even at lower volumes.

No matter what, that woofer needs control - and I think that's only something a 100 amp SS amp-lifier can do.  The clarity is actually eery....Ben Harper (thanks again for the CD-R, WolfyChris!) sounded like he was here a few minutes ago; his (or somebody's in the band) acoustic guitar is singing - I can see his fingers strumming across the strings and up and down the neck.

With it's signifant damping of the woofer, it's probably a high feedback device...theoretically, that being 'bad'.  Somehow, that just does NOT translate in the real world in this case      

[Dmason]

.....on the other hand, there IS something to be said for increased power, damping factor induced driver control, turning the driver into a musical beam weapon. Fascinating comparison. I still somehow "know" I likely would prefer the sound of mono beam-power tetrodes with impact.

The Too Bad Factor

---Too bad they couldn't make Jumbo sand amps sound like 2 watt ambrosia factories, dimensionally sparkly, harmonically restorative soul-injectors, yet with the iron grip that also does sooo many good things---

Enjoy the Sand Storm, Msr. Auteur, ...oh yes, one of my cherished posessions is a Hafler 9505, a 250 watt A/AB amp, which because its intended market was the studio crowd, went almost unnoticed by the audiophool-escenti. It was my favored result with the B200, which LOVES power and glory. The most "fun" amp was a Carver Pro 250 watt T amp.

[zybar]

The Rectifier and voltage Regulator tubes never made it here on Friday.....FEDEX re-routed them God-only-knows-where.

But, the Odyssey Khartago Mono's arrived.  I set them up Saturday morning.

Three notes - game over.

Never have I heard more of everything I've been looking for for many years.  It's still quite obviously stiff legged (needs weeks to break in according to Klaus), but all those things I suspected were room interaction/poor configuration, lousy midrange for the cheap Peerless woofer  ...

Gotta love it when Ben is playing in the room for you...  

If the system is cooking, "God Fearing Man" can give me goosebumps and put me into a trance!      

Enjoy John.

George

[TheChairGuy]

Compelling, that's what these tube amps are.

I rolled in the new OD3 Regulator and 5U4 Rectifier tubes in yesterday...and chopped off the IEC from the 14ga. cheapie cords supplied with the Odyssey Mono's. 6 hours later, the tubes are settling in a bit (seems to take tubes more than 10 hours to settle in from the thin sound they have in the beginning).

I think the old tubes were more tired, than these being any step-up in aural tube delights.

Unfortunately, a hum is quite evident from both channels and that means it's 99% likely a capacitor issue. Until that is squared away, and it is properly biased, a fair comparison cannot be made vs. the Khartago Mono's.

Both have effortless power, and a very easy, all day listening personality (needed here 10 hours a day).  The Odyssey's are about 500 hours shy of full break-in from what I'm told...and the Dukane's need new caps (and probably would benefit with changes to certain key wiring points and resisters).

The Dukane's are also using 20 year old (softwired - no rca's on the golden oldie, only screw terminals) Monster Cable Interlink Reference A's I had lying around (versus awesome Revelation Audio Labs silver cryo cable), Kimber 4TC (vs. the amazing Alpha-Core MI-2) and cheapie 14ga Chinese cords (vs. LAT International AC-2's)...in addition to the tired internals.  I hope the dang cords on the Odysseys' are better as the purchase prices in total are probably $750.00 vs. $100.00.

So, for the Dukies to be compare favorably to the Odyssey's is quite amazing to me right now  

Sheet - I'm having fun      

[Scott F.]

Hey CG,

When you take the Dukanes in for service, have the tech put in the JJ PIO power supply caps. They are very nice sounding. They aren't Black Gates but they'll let you keep some of that vintage sound you like so well. Be sure to bypass them with a good cap (insert your favorite cap here).

Also have the tech install a decent pair of RCAs and low mass binding posts. You want the signal as pure as possible. Then do some Sonicaps as coupling caps. They aren't overly expensive at about $6 each and sound pretty darned good. They have decent resolution and will sound much better than the mylar caps that are in there now.

I can't tell from the pics but if you have the old selenium rectifiers in there, get those changed out pretty quick. If one of those lets loose, bye bye Dukies. When they replace those with Shottkeys, you'll need to replace the first B+ resistor for something with a higher value (the new recitifiers are more efficient).

Be very selective replacing those old Allen Bradley resistors. They sound as good as Tantelums (some people like me think they sound better). I'd leave them unless your tech says they absolutely need to be replaced.

I think I found the schematic to your amp, maybe. Heres the link;
http://www.triodeel.com/du1a475.gif
Take a peek at it, if it is, I may be able to make some more specific recommendations for your tech.

When you get that thing restored, you won't believe how good it will sound, honest.

[TheChairGuy]

Cool Scott - thanks for the info.

I bought a service manual on ebay for it(with schematic)...it's the model under the one on Triode Electronics site, the 1A435 (50 watter).  I think the 1A475 is the 100 watt version of it.

The 50 watts these guys put out are plenty - no sense of dynamic compression noticed.

The tech stuff you mention are barely understood by me   but I'll print out for the tech that brings this up to spec. Okay, so who out there knows of a good tube tech in San Fran area?

Interestingly, it's not 'vintage/warm' I'm hearing....it's powerful, like a good SS amp with some neato tube magic thrown in.  It's just plain good stuff  

[Scott F.]

After looking at that schematic, if your 1A345 is the same basic design (it should be close), I noticed you have a single silicon (selenium) rectifier in it. Its RC1 on my schematic. Its followed by a 1k5 resistor (R14). Have your tech measure the voltage with the diode in place down stream of R14. Note the voltage. Then take and replace the diode and remeasure the voltage. He should be able to calculate the new resistor value to maintain the same voltage. Use a power film resistor (caddock would be great) in its place. It will run you about $7 for the resistor (I know thats expensive but its only one resistor).

Where your final output signal from teh tubes feed the transformers there is an RC circuit (R23 R24 C10 C11) and there is a lot of switching going on for the 25 and 70volt PA connection. You should be able to eliminate some if not all of this (assuming the output tranformers will let you, your tech will know).

Unless I missed it, I don't see a bias pot for your tubes. That means you've got a fixed bias (done with a fixed value resistor). This is a good thing.

Tell you what, when you get the schematic for your amp, scan it and send me a copy (if you don't mind). That way I'm not making assumptions on what could be a completely different amp

As for a tech in the Frisco area, you should be able to take it to a shop that sells guitars. Any good tech that works on guitar amps (tubed Fenders and such) can find his way around your amp. Be prepared to get some strange looks and comments when you specify the exact parts (Sonicaps or whatever). They don't get the whole audiophilia thing. I'd come with printouts from the places you want to source your parts from.

[Dmason]

I like, and was hoping for the fixed bias point. Looks like this opens up the possibility of some extremely sweet tubes, the NOS 6L6, which is a direct cousin of these, also something like the newly redesigned JJ KT66, others, and really a pallette on which to experiment. You could even try some 1625, once we know the V'ages.

John, you really scored a nice unit.  Once you bring er up to snuff, it should wipe the floor with about anything you put up against it. IMO.

[TheChairGuy]

Thanks guys - dumb luck found 'em I think  

I was just surfing ebay, thinking about tube monoblocks to try cheap...and these had reasonable price tags and about 15 minutes to go on them.

From the ad that caught my eye:

THESE AMPS SOUND AS GOOD AS ANY POWER AMPS IVE HAD IN THE PAST AND PRESENT.DYNACOS,HEATHKITS,HARMON KARDON,ETC.IVE BEEN RUNNING THESE AMPS THROUGH MY PRESENT SYSTEM USING DYNAUDIO AND ALTEC DRIVERS,TUBE CD PLAYER AND A LUXMAN PREAMP.

BEEN RUNNING THESE FOR A MONTH NOW.I CAN TELL THE DIFFERENCES BETWEEN THE GOOD THE BAD AND THE UGLY.WHILE THESE AMPS ARE'NT THE PRETTIEST,THEY HAVE GREAT TONAL CHARECTERISTICS:SMOOTH,SILKY HIGHS AND A OPEN MIDRANGE.THE TUBE COMPONENTS ARE;1-5U4 RECTIFIER,1-OD3 VOLTAGE REGULATOR,2-12AU7 AND 2-6CD6 OUTPUT TUBES.ALL TUBES AND CAPS HAVE BEEN CHECKED AND REPLACED WHERE NEEDED.

ONE OTHER GOOD THING ABOUT THIS AMP IS THAT THE TUBES ARE INEXPENSIVE TO REPLACE WHEN NEEDED.THIS AMP IS RACK MOUNTABLE AND HAS A VOLUME POT MOUNTED ON THE UNDERSIDE OF UNIT.

Too bad he didn't hear the hum beforehand, or he would have likely replaced the bad caps, too.  Oh well, you buy vintage, you buy some vintage problems, too  

[TheChairGuy]

Scott,

The schematic is very large (fold out)...I'd have to go to Kinko's to downsize it  

Meanwhile, while writing this...the hum turned into coma for one amp...the humming bastard as it turned out.  So, to play stereo (always nice), I now need to fix for sure.

John / TCG

[Scott F.]

Ultra bummer.

Hopefully it was only the cap and maybe a resistor that let loose. If it was a tranny, thats a different story altogether. Don't forget that if you change a cap or resistor you need to change the matching cap or resistor in the other amp too. Otherwise you could end up with a sound mismatch between the amps. Who knows, maybe you'll get really lucky and find out it was only a weak fuse  

[TheChairGuy]

Ultra bummer.

Hopefully it was only the cap and maybe a resistor that let loose. If it was a tranny, thats a different story altogether. Don't forget that if you change a cap or resistor you need to change the matching cap or resistor in the other amp too. Otherwise you could end up with a sound mismatch between the amps. Who knows, maybe you'll get really lucky and find out it was only a weak fuse  

They needed to be worked on anyhow. They are 45 years old, that's pretty much a necessity - I'm just glad I was able to run them for a while, and re-tube them to know they are worth fixing  

It's not the fuse, and it's only the voltage regulator and rectifier tubes that aren't lighting up, so I have high hopes that it's a fixable-without-much-cost situation.  It's not the tubes as they were changed out...and the hum was there with the old tubes in place, too.

I wrote a couple local guitar amp guys to see if they worked on audio amps, or knew of someone that did.  One of them is Torres Engineering, a pretty well known local outfit  

[Dmason]

iwould contact Guitar Centre as well. Theirs is generally considered a "good gig," for technicians. They see PP tetrodes all day long.

[nodiak]

TCG, appreciating the ride via your journal here, and penpals too, nice. A couple years ago I acquired a free Hammond organ w/100 watt tube (M2 model iirc ?) amp, we enjoyed it in the home, then passed it on for others to enjoy. I didn't get it at the time, but that may have been quite an amp worth removing from the organ and keeping, and looking for another. It had buzzes and pops but played, could've been repaired/upgraded as you're doing. I think I'll be wiser now.
All ears, Don

[Dmason]

The amp in the old M series spinet Hammonds is PP-EL84, one channel only, so I am grateful that you left it where it was. With the EL84 amp, I have always thought the M series gave up very little to the mighty B3, C3, and A100's, which have two channel PP-6550 in the older ones up til the '70's. My C3 is 1957. The difference between the M2 and M3 was that the M2 lacked the 2nd and 3rd percussion tabs, which provide that percussive attack at the beginning of the note heard used by Jimmy Smith, or Keith E. Useless for jazz or Emerson type rock organ, but great fun.

Ass-Tray Auteur.

While you are at it, I would suggest [nudge nudge] you splurge abit more down the road, and get a quartet of 6L6. Trust me, PP6L6 has the least of the tetrode edge when used with more sensitive speakers. Once you tune er up, and add some truly tasty tetrodes, I think you shall be amazed. This was the hugely kharmic thing in this purchase: a whole panoply of bottles you can push in and they will work VERY well. I have PP6L6 in my Leslie organ speaker, {those things with the rotating horns] and hearing albums in mono thru em is a true enlightenment. Early Genesis thru a Leslie...  Gone over at Guitar Centre, by the way, the tech here liked it and its owner enough to throw in a pair of NOS 6L6 Sylvanias he had kicking around for a more appreciative home than some run of the mill  Marshall head or whatever. PP tetrodes are the unsung musical monkeys out there.

[Listens2tubes]

Once upon a time the Parts Connection offered a parts upgrade kits for my vintage Dynaco Mk.IV monoblocks. The kit included Holco resisters and Silver Mica, Multicap PPMFX and Solen(to shunt quad cap sections to gnd) caps. Plus 2 ft of Teflon 20Ga. wire- To rewire inputs to board & outputs to tube sockets. And 5ft of Wondersolder. Over the next weekend I broke out the soldering iron and when the smoke cleared I had much improved my 30+ year old amps. Quieter backround, sweeter highs, smoother mids and tighter bass. Point is, you can learn what you need to do from the people here on this and other similar forums. And using a soldering iron is a matter of practice and common sense. The end result is satisfaction that can't be described. 

[TheChairGuy]

Scott/Good Doctor, et al,

I'm getting the Dukies checked out and updated this week...found a local McIntosh service place that said that these would be well worth working on as they were originally 'commercial' amps - built to higher spec than most. World of Sound in Mill Valley, CA (www.worldofsoundmarin.com) .

They looked at 'em yesterday and said they are in good shape.  He suggested doing little, than more, if I like how they sound already.  The 'cause of the 'pfffft' on one side was a blown coupling cap.  They suggested changing out all the little caps, put strain reliefs on all the wire ends (no rca's or even soldered power cords on these old dudes  ) and re-bias and check everything again.  They said if the old selenium rectifier blows - it'll smell with no long term effect to the amp (just have to change rectifiers then).  And, I was told to keep the power supply caps - they work and apparently the overall sound of the amp is okay to yo as you're considering updating it - you can always get tweeky later.

I like their pragmatic replies.

For $400 or so - I'll be picking them up in a week 

[Listens2tubes]

So....have them back yet?

[TheChairGuy]

No, not yet - I wish tho, man 

The coupling cap values are 'odd' I was told and they had to order them from a different source than usual - they tell me.  I suspect said supplier is a bit slower than normal sources, too (perhaps further away out of California)

I didn't think to ask if they were paper-in-oil, teflon or what....were all coupling caps of that era (1960) oil caps?  If so, and the fact that they are weird values, it's probably gonna' be oil caps.  He said they were fairly pricey (even by McIntosh standards???), too.

I need to call them tomorrow and see how they are faring.  I'm using a lovely 10watt 6v6 integrated mono's, but they are about 10watts shy of driving my 87db speakers fully (tho, they too have tired caps as they of the same vintage as the Dukies)