So...now I own a tube amp...what do I do?

Pycroft
Pycroft Posts: 1,961
edited June 2010 in Electronics
HI all...

I just bought a Dynaco ST-70 and am loving it. I have only good things to say. I just want to know the rules...you know...that everyone knows and expects everyone else knows...well I don't know those.

For example, I found out from George once I started in the 2 channel realm, that I had to turn on components in certain order - Preamp, CD Player, then amp, and turn them off in reverse order.

With my tube amp, I'm finding it's throwing off LOTS of heat, which I know is normal. Is there some rule regarding play time with it? Is there some rule when using both Tube amp and Preamp....anythign I should know?

Just general guidelines, rules, suggestions would be helpful. NOTHING is too simple.

James
2 Channel/HT:
Sony SS-M9 P's (ES version)
Sony SS-M1CN Center Channel
Polk RT800 Surround Speakers
Odyssey Stratos Dual Mono Amplifiers
TAD 150 Signature Tube Preamp
Harman Kardon HK354
Sony SACD Player
Post edited by Pycroft on
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Comments

  • joeparaski
    joeparaski Posts: 1,865
    edited June 2010
    Didn't the amp come with a manual and a rulebook? :D

    Joe
    Amplifiers: 1-SAE Mark IV, 4-SAE 2400, 1-SAE 2500, 2-SAE 2600, 1-Buttkicker BKA 1000N w/2-tactile transducers. Sources: Sony BDP CX7000es, Sony CX300/CX400/CX450/CX455, SAE 8000 tuner, Akai 4000D R2R, Technics 1100A TT, Epson 8500UB with Carada 100". Speakers:Polk SDA SRS, 3.1TL, FXi5, FXi3, 2-SVS 20-29, Yamaha, SVS center sub. Power:2-Monster HTS3500, Furman M-8D & RR16 Plus. 2-SAE 4000 X-overs, SAE 5000a noise reduction, MSB Link DAC III, MSB Powerbase, Behringer 2496, Monarchy DIP 24/96.
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  • tonyb
    tonyb Posts: 33,077
    edited June 2010
    Give your amp lots of room to breath, the heat is normal, you'll love it in the winter.
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
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  • mhardy6647
    mhardy6647 Posts: 35,193
    edited June 2010
    The only really hard and fast rule: Do NOT turn on/run the ST-70 with no speakers connected to it! There is a pretty good chance of destroying (open-circuiting or shorting) the expensive to replace output transformers and/or killing the output tubes. Other than that, don't sweat the small stuff. Feel free to use a small fan to circulate air over the amp, but it was designed for convective (passive) cooling. Run it without the cage if at all possible (although it's not even likely that you got it with a cage...); keep pets, children, and idiots away from it, as there is access to HV above-board on an ST-70.

    EDIT: the stuff that should get hot (seriously hot), the output tubes, the rectifier, and (possibly) the power transformer.

    If you don't have a manual for it... you do now:
    http://www.curcioaudio.com/st7_mnl.pdf

    Finally, enjoy the heck out of it!
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  • mdaudioguy
    mdaudioguy Posts: 5,164
    edited June 2010
    Apparently you're supposed to listen to some tunes and then post about how good everything sounds! Enjoy! :)
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  • mhardy6647
    mhardy6647 Posts: 35,193
    edited June 2010
    Turn off all the lights and play Warren Zevon's great song Carmelita...

    I hear mariachi static on my radio
    and the tubes they glow in the dark...

    DSC_9987.jpg
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  • Pycroft
    Pycroft Posts: 1,961
    edited June 2010
    The amp did come with the cage. I will take it off and check it out. I've read that the stock st-70 was muddy bass. This Welbourne mod I believe has improved the bass, it sounds even better bass wise than my Carver TFM35x, which I didn't expect. The mid seems a bit fuzzy, but highs are just as clear and natural. That's only with 3 CD's and 1 LP listening. I will continue going. I did get the tip of not turning it on without speakers hooked in from Face, so I'm good :)

    I'm guessing it's made to withstand the big heat? Is there a listening limit I should set? Also, I think I've read that I should give it time to warm up before listening? Should I turn on for 10 minutes before listening, or does it not matter?

    Thanks everyone. I'll post pics soon!

    James
    2 Channel/HT:
    Sony SS-M9 P's (ES version)
    Sony SS-M1CN Center Channel
    Polk RT800 Surround Speakers
    Odyssey Stratos Dual Mono Amplifiers
    TAD 150 Signature Tube Preamp
    Harman Kardon HK354
    Sony SACD Player
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  • mhardy6647
    mhardy6647 Posts: 35,193
    edited June 2010
    The mod would be expected to improve the bass. The midrange should be 'to die for', though. Which speakers are you using? If they're too insensitive, you may be driving into nonlinearity (compression, if not clipping as you're used to hearing from soiled state amps). This could easily result in midrange mushiness or other unpleasant distortions.

    I listen as soon as sound starts to come out...

    (EDIT: The amp in the photo I posted above is only about 1 watt per channel and is quite picky about speakers)
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  • Pycroft
    Pycroft Posts: 1,961
    edited June 2010
    I'm not sure mushy is the word. I usually test bass with the track: Another One Bites the Dust by Queen. it's got a solid and consistant heavy bass sound. It's more like a balanced focus. It used to be quite balanced, but there's a part of the song that has mid range, and it's even a bit overpowered by the bass - it could be that the mixing of the track is off a bit. I've listened to some Jazz, and some acoustic guitar (Coltrane, and Dave Matthews Tim Reynolds LIve at Luther College) and no problems with the mids.

    Speakers are in my sig - they are a bit difficult to drive - 86 db at 8 ohms I believe, but this amp SHOULD handle it no problem I think.

    James
    2 Channel/HT:
    Sony SS-M9 P's (ES version)
    Sony SS-M1CN Center Channel
    Polk RT800 Surround Speakers
    Odyssey Stratos Dual Mono Amplifiers
    TAD 150 Signature Tube Preamp
    Harman Kardon HK354
    Sony SACD Player
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  • mhardy6647
    mhardy6647 Posts: 35,193
    edited June 2010
    If you turn the sound down a little bit and it sounds better... you've found the problem.
    On the other hand, the track in question is not the best sounding in the world - I do know it well.
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  • zingo
    zingo Posts: 11,258
    edited June 2010
    All the heat is fine and it's made to handle it. I have a quad tube, EL34 amp as well and it gets toasty!

    I usually give my tubes at least 10 minutes to warm up and regulate before listening to them; some people prefer more or less.
    Jake
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  • HB27
    HB27 Posts: 1,518
    edited June 2010
    Tube rectified tube amps are great. Remember to follow the 5 minute rule on rectifier tubes.

    ALWAYS wait 5 minutes betweet turn on and turn off. IF you turn your amp on and off quickly you can blow an expensive rectifier tube.

    KEEP BIAS SET for optimum tube life. Mullards in these are famous for lasting 40 years and still test and sound as new. 1.56 as stated on bias socket. OR if modified follow instructions given by the person that modded them.

    Rolling tubes will tune your ST-70 to your liking and matching your gear.
    The Mullard XF2 are impossible to beat in the Dynacos. The 7199 (mod dependent) are crucial for for sound quality. Good NOS tubes are reasonable and I prefer the old yellow labeled Raytheon for excellent music in them. The GE, RCA, etc sound good also.
    The 5AR4/GZ34 rectifier is a great tube. Mullard again if at all possible but there are some good re-issues that are stable and have a good tone to them. YES, the rectifier tube can have an effect on tone. I feel an arguement coming on here.

    Heavy speaker wire does help as do your ICs.
    AS stated above always keep speakers or dummy loads connected to protect your transformers and output chokes.

    Keep away from your thermostat. LOL!

    As far as the cage is concerned it was designed with cage installed and should be used if you have kids or pets.
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  • hearingimpared
    hearingimpared Posts: 21,136
    edited June 2010
    Pycroft wrote: »
    HI all...

    I just bought a Dynaco ST-70 and am loving it. I have only good things to say. I just want to know the rules...you know...that everyone knows and expects everyone else knows...well I don't know those.

    For example, I found out from George once I started in the 2 channel realm, that I had to turn on components in certain order - Preamp, CD Player, then amp, and turn them off in reverse order.
    With my tube amp, I'm finding it's throwing off LOTS of heat, which I know is normal. Is there some rule regarding play time with it? Is there some rule when using both Tube amp and Preamp....anythign I should know?

    Just general guidelines, rules, suggestions would be helpful. NOTHING is too simple.

    James

    James just to nit-pick a bit; you should always turn your source on first then the preamp then the amp follow the same in reverse order to turn them off.

    Now for the turntable!:D
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  • george daniel
    george daniel Posts: 12,096
    edited June 2010
    Congrats-- do not become obsessive about bias,, check it ocassionaly and enjoy the music. I have a fried who is a walking ST 70 information/tweaker/tube encyclopedia,based upon years of experience-I'll pm you his contact info--you'll enjoy this. :)
    JC approves....he told me so. (F-1 nut)
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  • cnh
    cnh Posts: 13,284
    edited June 2010
    Now all you need is to start the "rolling".....tube rolling that is...these guys 'swear' by it. Chinese tubes, Russian tubes, and the even better tubes. I'm not a tube man...but I love to hear all the 'jargon' the boys throw up. And believe me, I've heard JARGON from every Hard Science on earth after a year here!! I am jargon laden....from circuits, to lasers, to various forms of radar, to GPS architectures, to satellites, to rocketry, physics, biogenic manipulation, search algorithms, nano-carbon tubes....on and on...and I must say if I could grasp even 50% of all that I'd be the next Einstein? lol

    Sometimes I think I should just throw out a Chinese presentation just to confuse 'us' ALL.

    cnh
    Currently orbiting Bowie's Blackstar.!

    Polk Lsi-7s, Def Tech 8" sub, HK 3490, HK HD 990 (CDP/DAC), AKG Q701s
    [sig. changed on a monthly basis as I rotate in and out of my stash]
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  • Pycroft
    Pycroft Posts: 1,961
    edited June 2010
    The amp came with the tubes - and apparently they were good ones! I don't have details because I haven't opened it up, but apparently Face bought them on recommendations from Jesse I believe. Maybe Mike can chime in, because even if I look at them, I'm not sure I'll know what I'm looking at. I don't even know the difference between a rectifier tube and the other tubes - I do know there is a size difference though.

    James
    2 Channel/HT:
    Sony SS-M9 P's (ES version)
    Sony SS-M1CN Center Channel
    Polk RT800 Surround Speakers
    Odyssey Stratos Dual Mono Amplifiers
    TAD 150 Signature Tube Preamp
    Harman Kardon HK354
    Sony SACD Player
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  • wayne3burk
    wayne3burk Posts: 939
    edited June 2010
    Hey,

    If anyones got a spare ST-70 they wanna loan me -- let me know

    j/k (not really)

    -- wayne --
    Yamaha RX-V2700, EMI 711As (front), RCA K-16 (rear), Magnavox Console (Center & TV Stand), Sony SMP-N200 media streamer, Dual 1249 TT =--- Sharp Aquas 60" LCD tellie
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  • madmax
    madmax Posts: 12,434
    edited June 2010
    Do not lick, fondle or play with the tubes while hot and do not move the amp until the tubes cool down.
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
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  • Pycroft
    Pycroft Posts: 1,961
    edited June 2010
    Is it normal to hear a crackling once it shuts off? It's hard to explain...almost as if the tubes are shutting themselves down.
    2 Channel/HT:
    Sony SS-M9 P's (ES version)
    Sony SS-M1CN Center Channel
    Polk RT800 Surround Speakers
    Odyssey Stratos Dual Mono Amplifiers
    TAD 150 Signature Tube Preamp
    Harman Kardon HK354
    Sony SACD Player
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  • HB27
    HB27 Posts: 1,518
    edited June 2010
    It could be tubes. The old Dynacos can have a bit of noise to them if not gone through.
    IF it's both channels identical it's going to be hard to run down.
    IF only one channel wait until it's cooled down and swap one pair of tubes from left to right channel at a time
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  • Pycroft
    Pycroft Posts: 1,961
    edited June 2010
    The crackle isn't actually from the speakers, but rather the tubes themselves.
    2 Channel/HT:
    Sony SS-M9 P's (ES version)
    Sony SS-M1CN Center Channel
    Polk RT800 Surround Speakers
    Odyssey Stratos Dual Mono Amplifiers
    TAD 150 Signature Tube Preamp
    Harman Kardon HK354
    Sony SACD Player
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  • hearingimpared
    hearingimpared Posts: 21,136
    edited June 2010
    Pycroft wrote: »
    The crackle isn't actually from the speakers, but rather the tubes themselves.

    You mean like the sound the oven makes when it is cooling off and the metal is starting to shrink . . . that kind of noise?
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  • madmax
    madmax Posts: 12,434
    edited June 2010
    Pycroft wrote: »
    The crackle isn't actually from the speakers, but rather the tubes themselves.

    Thats normal. I've had several that crackle and always look forward to hearing it after a nice listening session. All part of the beauty of the tube enviroment. I can hear my 300B tube preamp do it through the speakers as it warms up too. ;)
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
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