Monitor 7's on old tubes - anyone else?

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JayMX
JayMX Posts: 435
in Vintage Speakers
I came into this near mint 1962 HK TA500x, a pair of Jensen H-222’s and a very nice (but dusty) Garrard Type A II turntable last weekend (Pickering model 380 red cart 😁). A little elbow grease and the HK is sounding pretty sweet on the Jensen's. Still has one channel that’s a little lower in output, but the tubes all appear to be original, so they may be a little long in the tooth...

So tonight, I figured it was time to move to the 8ohm taps and try some monitor 7’s. Oh my... I’ve been sitting here with Norah Jones in my garage for an hour or more. What a fantastic pairing. This ol tuner might just stick around. Anyone else have experience with a combo like this or this tuner?

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Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (3x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • verb
    verb Posts: 10,176
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    Nope. But love the setup! Very cool!
    Basement: Polk SDA SRS 1.2tl's, Cary SLP-05 Pre with ultimate upgrade,McIntosh MCD301 CD/SACD player, Northstar Designs Excelsio DAC, Cambridge 851N streamer, McIntosh MC300 Amp, Silnote Morpheus Ref2, Series2 Digital Cables, Silnote Morpheus Ref2 Series2 XLR's, Furman 15PFi Power Conditioner, Pangea Power Cables, MIT Shotgun S3 IC's, MIT Shotgun S1 Bi-Wire speaker cables
    Office: PC, EAR Acute CD Player, EAR 834L Pre, Northstar Designs Intenso DAC, Antique Sound Labs AV8 Monoblocks, Denon UDR-F10 Cassette, Acoustic Technologies Classic FR Speakers, SVS SB12 Plus sub, MIT AVt2 speaker cables, IFI Purifier2, AQ Cinnamon USB cable, Groneberg Quatro Reference IC's
    Spare Room: Dayens Ampino Integrated Amp, Tjoeb 99 tube CD player (modified Marantz CD-38), Analysis Plus Oval 9's, Zu Jumpers, AudioEngine B1 Streamer, Klipsch RB-61 v2, SVS PB1000 sub, Blue Jeans RCA IC's, Shunyata Hydra 8 Power Conditioner
    Living Room: Peachtree Nova Integrated, Cambridge CXN v2 Streamer, Rotel RCD-1072 CD player, Furman 15PFi Power Conditioner, Polk RT265 In Wall Speakers, Polk DSW Pro 660wi sub
    Garage #1: Cambridge Audio 640A Integrated Amp, Project Box-E BT Streamer, Polk Tsi200 Bookies, Douglas Speaker Cables, Shunyata Power Conditioner
    Garage #2: Cambridge Audio EVO150 Integrated Amplifier, Polk L200's, Analysis Plus Silver Oval 2 Speaker Cables, IC's TBD.
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  • VSAT88
    VSAT88 Posts: 1,227
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    Well folks here may call loco on this but oh well. I have enjoyed many a time my Fisher 500C receiver with my SDA 2b speakers as well as other Polk audio M5's M7's and M'11's . Used a rebuilt Dynaco ST 70 with some of them as well. Liked that too. I no longer have the 7's 5's 11's or the Dynaco but the Fisher and the SDA 2b's aint going no where.
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  • teekay0007
    teekay0007 Posts: 2,289
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    JayMX wrote: »
    Oh my... I’ve been sitting here with Norah Jones in my garage for an hour or more.
    Well, send her home! Tell her I'm getting hungry...and it's almost bedtime. ;)
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  • audioluvr
    audioluvr Posts: 5,432
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    JayMX wrote: »
    I came into this near mint 1962 HK TA500x,

    Nice!
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • xschop
    xschop Posts: 4,684
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    Double like. Still have my eye open for an old HH Scott tube setup. Will you rebuild the unit?
    Don't take experimental gene therapies from known eugenicists.
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  • BlueBirdMusic
    BlueBirdMusic Posts: 2,076
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    All BEAUTIFUL!!

    Original tags on the Jensens?
    "Sometimes you have to look to the past to understand where you are going in the future"


    Harry / Marietta GA
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  • Gardenstater
    Gardenstater Posts: 4,182
    edited October 2020
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    Too cool. At first I thought it was two tuners (receivers actually), one stacked on top of the other. 30W per channel. There may be a schematic for download here:

    https://www.radiomuseum.org/r/harman_ta_5000xta5000.html

    The only experience I've had with a receiver was my old Technics SA500 and I'm sure it doesn't hold a candle, being solid state and no tubes.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • mhardy6647
    mhardy6647 Posts: 33,030
    edited October 2020
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    That is nice stuff :)
    Although those Garrard changers make me nervous. I think I'd rather adjust a bank of Weber carbs on a vintage British sports car than work on one of those! ;)

    I - typically - want to offer a completely solipsistic response to the thread title. :blush:

    Long, long, long, ago -- when I spent a bolus of real money (to me, at any rate) on eBAY and bought, and rehabbed, an EICO HF81 -- I tried the amplifier on pretty much every pair of loudspeakers in the house. The HF81 is a great sounding push-pull EL84 stereo integrated that makes pretty much any loudspeakers sound great -- but, for whatever reason, it didn't mate well at all with my Monitor Series model 7As. The sound was thin and kind of shrill -- and the latter characteristic, in particular, is not a hallmark of the "Monitor Series" of the late 1970s.

    I never repeated the experiment, nor do I have any insight as to why that would have been the case. It might have been worth trying different output taps on the OPTs on the EICO, come to think of it (and more than 20 years later!). :p

    EDIT: The separate AM & FM tuners were configured to permit reception of the early (pre- FTC licensure of "MPX" stereo FM) "AM-FM simulcast stereo" broadcasts. We don't have any of those any more ;) but the AM tuner section of this receiver should be of notably higher audio (and maybe also radio) quality than the average "modern" receiver AM section.
    Post edited by mhardy6647 on
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  • mhardy6647
    mhardy6647 Posts: 33,030
    edited October 2020
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    Oh, and... :)

    The only "problem" with some of those lower-powered h/k components was that they used weird output tubes. I have an h/k receiver (very low end... a kit model, in fact) that used 7408s (which are actually "just" 6V6 variants, fortunately). I think (???) that the TA500(x) might use 7355s? They're not easy to find , and the one "modern" replacement (last I knew), the Russian "7591XYZ" is probably as hard ($$) to find as are NOS 7355s. Just a thought.

    The output may be one of the preamp or driver tubes (are they 12AX7s?) -- or bad coupling capacitors. I would definitely recommend replacing all of the coupling caps if they haven't been done in the last 20 years or so (i.e., if they're original).

    Also, be wary of the P/S multi-section electrolytic cans caps. :( They're way past their EOL if they're original. One can source more or less exact drop-in replacements, but they're kind of pricey. Some folks re-stuff the orignal cans with modern electrolytics (which are usually small enough to permit that) or just add modern ones underneath -- or go with modern replacements like F&T in place of the cans.

    My rule of thumb (which comes with NO GUARANTEES!!!) -- if you run the amp for a while (say 1/2 hour) and the cans are cool/cold to the touch (and, of course, there's no P/S hum on the audio output)... they're probably fine. If they're warm or hot --they're bad. :|

    Sometimes a nearby component may heat them by radiation, but it's usually pretty to tell.

    My apologies to @JayMX if all of this is old news to you (and/or if the h/k's been rehabbed sometime in this century ;) ).

    EDIT:

    1) The titular h/k of this thread does have some nice, beefy looking output iron in it! Many of the low powered h/ks tended to have kind of wimpy (dare I say anemic? B) ) output iron.

    2) Gary Kaufman's synopsis of the 7355 :)
    The 7355 is essentially a 6L6 electrically, with a 7591 pinout in a 6V6 bottle :)

    Even if you re-pin the socket as a 6L6 you'll still have the problem of bottle size. Admittedly 5881's are the correct size - but they aren't any cheaper than 7355's.
    source: https://antiqueradios.com/forums/viewtopic.php?f=15&t=184303

    PS That forum thread is well worth a look, as it has some tidbits of info about the TA500x, a receiver with which I personally have zero experience.

    PPS Threads like this one give me the itch to start playing with some of the electrically unrestored dowagers lurkin' around here... :)



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  • pitdogg2
    pitdogg2 Posts: 24,559
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    I see the tubes Mark mentioned out on ebay some are new production Soviet Tung -Sol
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  • mhardy6647
    mhardy6647 Posts: 33,030
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    pitdogg2 wrote: »
    I see the tubes Mark mentioned out on ebay some are new production Soviet Tung -Sol

    Oh, that's interesting -- I did try to disclaim that I wasn't up to date on the 7355 supply... but I didn't try very hard. :p

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  • JayMX
    JayMX Posts: 435
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    @mhardy6647 - always a pleasure to read your discourses. 👍🏻 As you know, I’m a relative tube-noob, so I’m just fooling around at this point. Not sure if I will keep and rework or build a wood box for it and resell. As it stands I believe it to be 100% original, never serviced afaik. I was just so enamored last night that I thought I’d share. Good times. Got some studying to do it seems. Thanks all!
    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (3x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • pitdogg2
    pitdogg2 Posts: 24,559
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    mhardy6647 wrote: »
    pitdogg2 wrote: »
    I see the tubes Mark mentioned out on ebay some are new production Soviet Tung -Sol

    Oh, that's interesting -- I did try to disclaim that I wasn't up to date on the 7355 supply... but I didn't try very hard. :p

    As you know tomorrow may be a different story. I've lost count on how many times there's a plethora of tubes one week and for the next 3-8 months none to be found.... anywhere.
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  • dromunds
    dromunds Posts: 9,981
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    Good output iron. That's key. I have a pair of rebuilt 1950s Heathkit W5-M tube mono blocks that have Peerless output iron and they make my Monitor 7's SING!
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  • lavane
    lavane Posts: 8
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    I recently picked up a pair of monitor 10's and they play nicely with my VTA ST-70 35wpc PP tube amp. I have a Dynaco clone ST-35 17.5wpc tube amp on a switch with the ST-70, and the smaller ST-35 does a decent job as well all though not as loud.
    I was a bit worried the Polk's wouldn't mesh well with tubes, but they do. Plus with tube amps i have 4,8 and 16 ohm taps i can use to help dial them in. Output transformers are much more forgiving when connecting, say a 4 ohm speaker to an 8 ohm tap. One tube amp I have sounds best with 8 ohm speakers connected to the 4 ohm taps.
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  • pelhamplace
    pelhamplace Posts: 111
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    I’m looking at local garage sales to find some monitor 7s that I can pair with a Fisher 500c or Scott 299c.
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  • lavane
    lavane Posts: 8
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    I'm currently using a pair of monitor 10's with a VTA Dynaco ST-35 UL PP amp and the 10's sound wonderful with it. This amp is a 35wpc amplifier and can still drive them stupid loud.
    I would think the 7's would work just as well with tubes. I had the same question before I bought the 10's. Glad I bought them. They also sounded good with my little 17.5wpc Dynaco ST-35 PP amp. It just couldn't push them as hard.
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