Topic: How do you maintain a tube amp?

[muypogi]

I'm currently in the process of saving up for an AMX amp, and I'd like some tips on how to maintain it.  I've used SS amps exclusively, so I've have no idea on how to maintain them.  I've auditioned the KT88 75-watter, so I'd like some tips on:

1) Daily use tips?

- How long do you need them warmed up?
- Do playing stuff almost immediately harm the tubes, or do they just sound bad?
- Do you need an electric fan focused on the amp?

2) Tube replacement

- Can you replace the tubes yourself? Any special tools?

Any body tried these out: http://www.euroaudioteam.com/en/kt88diamond.php

- What is biasing?  Do you need to do this often?  Are there "self-biasing amps"?
- Life span of tubes?

3) Any idea if this product would be any good?

http://www.euroaudioteam.com/en/eatcooldamper.php

Thanks!

[alexg]

I'm currently in the process of saving up for an AMX amp, and I'd like some tips on how to maintain it.  I've used SS amps exclusively, so I've have no idea on how to maintain them.  I've auditioned the KT88 75-watter, so I'd like some tips on:

1) Daily use tips?

- How long do you need them warmed up?
- Do playing stuff almost immediately harm the tubes, or do they just sound bad?
- Do you need an electric fan focused on the amp?

I was advised by one of the tube masters in the Philippines, that 5 minutes of warm up is enough.

He also told me that you really do not harm the tube when you play stuff after five minutes, they just do not sound at their max potential.

You do not need an electric fan to cool down the amp.

2) Tube replacement

- Can you replace the tubes yourself? Any special tools?

Any body tried these out: http://www.euroaudioteam.com/en/kt88diamond.php

- What is biasing?  Do you need to do this often?  Are there "self-biasing amps"?
- Life span of tubes?

yes you can replace the tubes yourself.

You only need to bias when you replace your power tubes, I then re-bias mine every month. There are tube amps that are auto-bias.

Life of tubes depend on your usage (how loud you listen). Pre-amp tubes usually last 10,000 hours, I was told, and power tubes, on the average, around 4,000 hours.

I have not try these KT88 tubes (I have a KT88/6550 push pull amp), but trying vacuum tubes on your amp is quite exciting.

3) Any idea if this product would be any good?

http://www.euroaudioteam.com/en/eatcooldamper.php

Those dampers might be useful if you have microphonic tubes (I have a pair of 6688 that are quite microphonic). But usually, you really do not need dampers.

Hope this help.

[mrquery]

sir muypogi ot po,

Like you I'm in the process of saving for a tube amp. And as much as I wanted to answer your question on tube amps I'm afraid all I can do know is to ask you more questions.

I went to phasetron last monday 02-April and audition their tube amp, unfortunately i was not able to find a kt88 base integrated amplifier. What i heard instead was a sonata 70 integrated amplifier which uses an el34 tube. For my newbie pair of ears the sonata was great for music with a sweet sounding highs and magical mids. Although I wanted to hear the kt88 for the second time since I fell in love with the musicality it produced when I heard it the first time.

Would you know how much is the kt88 based amp of amx, in addition would you know where can I audition one. Thanks for the input in advance and will keep an eye on this thread. 

[alexg]

I went to phasetron last monday 02-April and audition their tube amp, unfortunately i was not able to find a kt88 base integrated amplifier. What i heard instead was a sonata 70 integrated amplifier which uses an el34 tube. For my newbie pair of ears the sonata was great for music with a sweet sounding highs and magical mids. Although I wanted to hear the kt88 for the second time since I fell in love with the musicality it produced when I heard it the first time.

I have a KT88 amp that I built myself, and I can switch between KT88 and EL34 tubes. The KT88 will give you more bass but is a little forward. I like the mids and highs of the EL34, but the bass is a bit shy. KT88 tubes cost almost double that of EL34 (a quad of 6550/KT88 is PHP10,000, a quad of EL34 4-5,000). Overall, I prefer the KT88 over the EL34.

[mrquery]

@ alexg,

thanks for the input alexg, i know that you do build tube amp as I read them on the thread posted here. while the kt88 is said to have more bass compare to el34, i wonder if an upgraded el34 tube would have the same bass as kt88. (upgraded in terms that it would use mundorf cap, Sovtek / Telefunken  / Mullard 12AX7, etc...)

currently i am fixated on buying cayin tube amp for its craftmanship, aesthetic presentation and remote capability, but is also lacking funds for them.  im afraid remote capability would be compromise for now since i am on a tight budget.
 
would you mind posting a picture of your kt88 amp. in addition would a well built amp would cost around 30+K as per your Audiospace 8i Mark III?

@ muypogi,

what particular kt88 amp did you auditioned? i read from the amx thread that you asked for a kt88 amp with particular specs below:

Thanks for the reply.  So how much for these particular specs:

1) Integra 150 (remote volume and source selector)
2) KT88 tubes
3) no loudness control
4) tone controls, preferably one on each side of the central volume control
5) tube cage, can be slid out (forward) for serious listening; sliding action, no screws (pwede patong lang), but secure enough so that young fingers don't get to touch hot tubes; can be metal or wood (like the old Fisher amps)
6) max dimensions are: (W and D) 435 and 290mm
7) hopefully between 20-30k pesos
Kaya kaya remote turn on rin, or is this asking too much?

any feedback here, is this on production? how much will this cost?

[butchoy8701]

I'm currently in the process of saving up for an AMX amp, and I'd like some tips on how to maintain it.  I've used SS amps exclusively, so I've have no idea on how to maintain them.  I've auditioned the KT88 75-watter, so I'd like some tips on:

1) Daily use tips?

- How long do you need them warmed up?
- Do playing stuff almost immediately harm the tubes, or do they just sound bad?
- Do you need an electric fan focused on the amp?

Hi Muypogi,

   I agree with Alex with the warm up sequence but based on my experience, 10 to 15 mins is required for you to hear the tubes at its full potential.  Mas bumibilog ang tunog ng tube habang umiinit.    No need for fans just make sure it's well ventilated. And oh, don't turn on your amps without any load, this is a sure way of damaging them. 

2) Tube replacement

- Can you replace the tubes yourself? Any special tools?

Any body tried these out: http://www.euroaudioteam.com/en/kt88diamond.php

- What is biasing?  Do you need to do this often?  Are there "self-biasing amps"?
- Life span of tubes?

Yes, you can remove it yourself by slowly moving the tube from side to side until you completely remove it from its socket.  No special tools required.    You would need a VOM to bias your power tubes when you replace them.

[butchoy8701]

@ alexg,

thanks for the input alexg, i know that you do build tube amp as I read them on the thread posted here. while the kt88 is said to have more bass compare to el34, i wonder if an upgraded el34 tube would have the same bass as kt88. (upgraded in terms that it would use mundorf cap, Sovtek / Telefunken  / Mullard 12AX7, etc...)

currently i am fixated on buying cayin tube amp for its craftmanship, aesthetic presentation and remote capability, but is also lacking funds for them.  im afraid remote capability would be compromise for now since i am on a tight budget.
 
would you mind posting a picture of your kt88 amp. in addition would a well built amp would cost around 30+K as per your Audiospace 8i Mark III?

@ muypogi,

what particular kt88 amp did you auditioned? i read from the amx thread that you asked for a kt88 amp with particular specs below:

any feedback here, is this on production? how much will this cost?

Hi Cris,

       Have you tried listening to 6550 tube?  EL34 's are known for their good mids and highs but the 6550 will definitely give you better bass.  I personally like the 6550 than el34 but some might disagree with me because we do have different preferences.   The KT88 tubes are forward sounding compared to 6550 again, this would all boil down to preference.  Changing the preamp tubes will give you better sonic improvement (e.g. changing them to NOS), hehehe  just my two cents.

[Le_Stat]

And you thought your tube pins were clean.   

This does a very amazing job for contact cleaning, even those RCA inputs too !

For tube sockets, I recommend the Electra brand sold in SM Ace Hardware since it disintigrates as soon as it hits the item.  No greasy feeling.

[butchoy8701]

Hi Andrew,

You're already a marketing guy hehehe just kidding...Contact cleaners are good especially for PC's (OT)...

[mrquery]

hello nino,

i am surprised that you preferred 6550 than el34 since i know you are currently using an el34 base amp.  honestly i haven't compare el34, kt88 and 6550 amps. but like the idea of having an amp that can switch to el34 to 6550 as i read from the caying thread (tube rolling ata tawag dito if im not mistaken)

honestly i plan to go for an mt-35 kc yung lang kaya ng budget ko for now (ni-aawitan ko si sir nadb for this).

nino since you have fully upgraded your rig with mundorf caps, 5751 kna din ba for 12AX7s? would you say that el34 have fuller body? baka you can spare some time for me to audition? hehe, i went nadin kc sa spectra last monday kaso when i ask to audition the cayin mt amp sabi saken ng attendant hindi pa daw kasi na warm up yung amp (and he did not turn it on), so hindi nko nag-insist.

[butchoy8701]

hello nino,

i am surprised that you preferred 6550 than el34 since i know you are currently using an el34 base amp.  honestly i haven't compare el34, kt88 and 6550 amps. but like the idea of having an amp that can switch to el34 to 6550 as i read from the caying thread (tube rolling ata tawag dito if im not mistaken)

honestly i plan to go for an mt-35 kc yung lang kaya ng budget ko for now (ni-aawitan ko si sir nadb for this).

nino since you have fully upgraded your rig with mundorf caps, 5751 kna din ba for 12AX7s? would you say that el34 have fuller body? baka you can spare some time for me to audition? hehe, i went nadin kc sa spectra last monday kaso when i ask to audition the cayin mt amp sabi saken ng attendant hindi pa daw kasi na warm up yung amp (and he did not turn it on), so hindi nko nag-insist.

sent you pm Cris...

[mrquery]

pm replied 

[mrquery]

sir nino, congrats sa upgrade and thanks for your input also, don't forget to post pictures of your rig.

Sobrang ot na toh, but i was curious to your suggestion that my dvd player and wharf 9.2 makes my setup bright. I changed my dvd player to sony cdp-m33 which was seating on our garage and it got a huge difference from my previous setup, mas kumapal sya and much body. anyway just sharing my thought  , hehe! im thinking tuloy nah cd player muna ang i priority koh, tsk... tsk... so little money so much to buy 

[Le_Stat]

wow upgrade na ba si butchoy?  A70 na ba?

[muypogi]

Wow nabuhay yung thread ko.  Kala ko hanggang 2 posts lang. . .

There hasn't been a KT88 amp in Phasetron for sometime.  The particular one I auditioned was purchased already.  Edwin (of Phasetron) and Sir Andrew (Mr. AMX himself) says that they're building some KT88s now.  My particular amp isn't done yet, since Sir Andrew had to design a tube cage and I asked for tone controls as well.  From what I gathered, they ran out of remote control units, and they're just waiting for the shipment of a new batch.  Already cleared up my VISA card for when the amp's available at Phasetron.  I think the cost for the KT88 with remote is more expensive vs the EL34 and 6L6 amp currently on display in Phasetron.  You can PM sir Andrew for the specific price of my amp.  Wag mo lang akong unahan ha. . .   

Actually, I took my father-in-law to listen to some tube amps last Sunday.  Naunahan pa akong magkaroon ng AMX amp.  He purchased a 35x2 EL34 (Sonata 70) amp last Monday and we're currently listening to it now.  Made an audition CD that spans classical, alternative, accoustic, rap, and pop.  The Sonata was able to play them competently.  And quite loudly as well.  Sobrang lakas at the 10-12 o-clock region.  Can't wait for my amp though.

My father-in-law went for the AMX since a similar output Cayin amp (being sold in Spectra Park Square 1) was P10k more expensive.  Maganda rin yung tunog and the amp looks more refined than the AMX, but in the end my biyenan decided that the AMX amp was of better value.  Not to knock Cayin amps, but for the same (or better sound) at P10k less, the AMX was a no-brainer.

I decided on the KT88 since I play different types of music so an amp that can play anything would be what I need.  I think you can replace the KT88 with 6550 and KT90.  Not sure about EL34 for the AMX amp.

[alexg]

@ alexg,

thanks for the input alexg, i know that you do build tube amp as I read them on the thread posted here. while the kt88 is said to have more bass compare to el34, i wonder if an upgraded el34 tube would have the same bass as kt88. (upgraded in terms that it would use mundorf cap, Sovtek / Telefunken  / Mullard 12AX7, etc...)

currently i am fixated on buying cayin tube amp for its craftmanship, aesthetic presentation and remote capability, but is also lacking funds for them.  im afraid remote capability would be compromise for now since i am on a tight budget.
 
would you mind posting a picture of your kt88 amp. in addition would a well built amp would cost around 30+K as per your Audiospace 8i Mark III?

Mundorf caps will not give you the bass nor the other preamp tubes and driver tubes used on an EL34 power amp compared to a KT88/6550. Compared to the KT88 the EL34 does not have as tight bass as the KT88/6550. Electrically they are very similar, some amps whose B+ voltage is lower can use EL34, but those with higher voltage, such as the AudioSpace 8i will burn EL34 tubes.

Cayin have two KT88 models, one model with the lower power, you can substitute EL34 tubes but the other model with higher power, the amp will burn EL34 tubes in no time.

My DIY KT88 pix are in this forum and the picture of my AudioSpace is in: http://www.audiospace-hifi.com/detail.asp?LangId=175&subcatid=0&private=&catid=2270&PageNo=7&PageSize=1

I bought the AudioSpace for 39K used (demo unit), this model retails for 59,000. I was selling this unit for 30K because I like my DIY KT88 better, and my brother bought it from me.

KT88/6550 amps are not on the cheap side, if you do not have the budge, EL34 are a bit cheaper.

[mrquery]

@ alexg,

thanks for the your reply i now know the sound difference between el34s and kt88/6550 and how much the price range for company manufactured tube amp. i think its time for me to go the real world and do more audition myself.

@ muypogi,

last monday ka pala nasa phasetron, i wish nakasabay kita para i got a chance to audition with you. kc when i was there i only audition 2 tracks, my feet was in a hurry to go kc baka mapagastos ng wala sa oras although my ears wanted to stay more. 

IMHO indeed the sonata 70 was a great buy for the price and the sound from which i could not ask for more ,other than a remote  . let me know on the update of your custom kt88 amp and will keep watch of this thread.

[muypogi]

@ alexg,

thanks for the your reply i now know the sound difference between el34s and kt88/6550 and how much the price range for company manufactured tube amp. i think its time for me to go the real world and do more audition myself.

@ muypogi,

last monday ka pala nasa phasetron, i wish nakasabay kita para i got a chance to audition with you. kc when i was there i only audition 2 tracks, my feet was in a hurry to go kc baka mapagastos ng wala sa oras although my ears wanted to stay more. 

IMHO indeed the sonata 70 was a great buy for the price and the sound from which i could not ask for more ,other than a remote  . let me know on the update of your custom kt88 amp and will keep watch of this thread.

Actually, we auditioned it last Sunday.  Bumalik yung biyenan ko Monday without me.  Nagulat nga kami ng wife ko na bumili na siya.  If you don't have the budget to spend for a KT88, then you can probably  specify a Sonata 70 with a remote for the volume.  Pwede naman custom amp order.  Konti lang yata yung additional.  My custom KT88 amp will cost upwards of P30k last time I checked. 

Baka gusto mo pumunta ka pag dumating na amp ko? I'm not sure yet when it will arrive, but I will definitely test it out first before paying for it.  Let's hope its soon. . .

[butchoy8701]

sir nino, congrats sa upgrade and thanks for your input also, don't forget to post pictures of your rig.

Sobrang ot na toh, but i was curious to your suggestion that my dvd player and wharf 9.2 makes my setup bright. I changed my dvd player to sony cdp-m33 which was seating on our garage and it got a huge difference from my previous setup, mas kumapal sya and much body. anyway just sharing my thought  , hehe! im thinking tuloy nah cd player muna ang i priority koh, tsk... tsk... so little money so much to buy 

I'll try to post my set-up when i'm ready...

[muypogi]

sir nino, congrats sa upgrade and thanks for your input also, don't forget to post pictures of your rig.

Sobrang ot na toh, but i was curious to your suggestion that my dvd player and wharf 9.2 makes my setup bright. I changed my dvd player to sony cdp-m33 which was seating on our garage and it got a huge difference from my previous setup, mas kumapal sya and much body. anyway just sharing my thought  , hehe! im thinking tuloy nah cd player muna ang i priority koh, tsk... tsk... so little money so much to buy 

Actually you can do what I did and save the trouble of getting a dedicated CDP.  I bought an Apple Airport Express, which is a WIFI router and hotspot, print server, and music server all in one.  Though the music server function works only via iTunes (which is a free download anyway), it works in PCs as well. 

What I did was to rip all my CDs into 192kbps AAC format (superior vs MP3) and connect the Airport via a high-quality 3.5 plug to RCA cable to my amp's RCA jacks.  Viola!  You can stream music wirelessly from your laptop to your Hifi!

If I'm not mistaken, last year's HIFI Show featured such a setup, but with a tube amp.  When my AMX comes, I'll have the same setup.

Music quality is quite close to CD, though CDs are still better-sounding.  But the convenience of having your music collection in a single place, plus having the ability to play it wirelessly through your Hifi (while surfing the web).

[muypogi]

@ alexg,

thanks for the your reply i now know the sound difference between el34s and kt88/6550 and how much the price range for company manufactured tube amp. i think its time for me to go the real world and do more audition myself.

@ muypogi,

last monday ka pala nasa phasetron, i wish nakasabay kita para i got a chance to audition with you. kc when i was there i only audition 2 tracks, my feet was in a hurry to go kc baka mapagastos ng wala sa oras although my ears wanted to stay more. 

IMHO indeed the sonata 70 was a great buy for the price and the sound from which i could not ask for more ,other than a remote  . let me know on the update of your custom kt88 amp and will keep watch of this thread.

@mrquery

My custom amp is in Phasetron already.  I'm picking it up later today, so anybody who wants to listen to it before I pick it up is welcome (para ma-break in yung tubes).  Sir Andrew also made another KT88 amp that's exactly like mine, save for the chrome finish on the body and transformers and the tube cage on mine.  He fitted EH KT88 on the new amps, and they have remote volume and source selection.  Amp also has tone controls and a handy bias meter built-in, so you don't have to use a voltmeter to set the bias.  You just select the tube (via a rotary selector), and use the built-in meter, so potentially, you may not need matched quads for the amp.

[Superman]

post pics please CONGRATULATIONS!...

[muypogi]

post pics please CONGRATULATIONS!...

As requested, posted the pics in a new thread (para hindi OT).

[mrquery]

hello gurus,

another question on how to maintain tube amp, actually i think my question applies to all amp ss/tube.

well, i have a habit of listening to music before hitting the sacks and usually i leave my amp turned on. Because this doesn't have a sleep function i plan to load the amp into a timer plug socket with a built in timer ,timer ac plug nga syempre may timer obvious  . I will then set the plug into the desired sleep time to turn off.

Now if the amp is turned off this way, will this be a great threat to my amp? masisira ba sya kaagad, yung tubes kaya? my amp specs below as a basis for this question:

cayin A-50T with tube complement of:
4 Svetlana EL34
2 Westinghouse 12AX7
stock 12AU7

thanks - cris

[alexg]

hello gurus,

another question on how to maintain tube amp, actually i think my question applies to all amp ss/tube.

well, i have a habit of listening to music before hitting the sacks and usually i leave my amp turned on. Because this doesn't have a sleep function i plan to load the amp into a timer plug socket with a built in timer ,timer ac plug nga syempre may timer obvious  . I will then set the plug into the desired sleep time to turn off.

Now if the amp is turned off this way, will this be a great threat to my amp? masisira ba sya kaagad, yung tubes kaya? my amp specs below as a basis for this question:

cayin A-50T with tube complement of:
4 Svetlana EL34
2 Westinghouse 12AX7
stock 12AU7

thanks - cris

I do not think this will harm your amp.

The power switch on the amp just cuts off the power from the wall.

[mrquery]

good day alex,

its really good thing that there are such people like you who patiently answer dumb questions such mine 

i just thought kc (like in computers and other electronic devices which usually use Automatic Voltage Regulator) na electronic products need protecting from wall sockets with electric current na pabago bago ng voltage. And i just thought na baka cutting off the power from the wall would post a threat sa amp, hehe... mahirap na i want to enjoy the music coming from the amp in many many years pa

appreciate any input on my question on theory or in practical application

anyway, regards and more power to pdvd community