Topic: Newbie and Not-so Noob Thread: Questions (FAQ) on anything Tubes

[oweidah]

baka may extra ka pang 1pc, let me know

superman,

sensha ubos na. got them for 285php@ and sold at 1k@ lang- hind presyong ginto. (hukay tayo ng ginto sa bundok diyan then itubog pins ng matsus***a bka tumaas ang market value? )

[Superman]

THANKS!

[Bogsle]

I would just like to ask what is the similarity and difference between a Single Ended Triode (SET) and a Single Ended Pentode (SEP)?

I read somewhere that, "In a single-ended triode (SET) vacuum tube electronic amplifier the entire audio signal waveform is amplified by the power triode".

Is this the same with a SEP, in which a single pentode vaccum tube amplifies the entire audio signal waveform?

Pardon the ignorance.

Thanks in advance.

[Bogsle]

I would just like to ask what is the similarity and difference between a Single Ended Triode (SET) and a Single Ended Pentode (SEP)?

I read somewhere that, "In a single-ended triode (SET) vacuum tube electronic amplifier the entire audio signal waveform is amplified by the power triode".

Is this the same with a SEP, in which a single pentode vaccum tube amplifies the entire audio signal waveform?

Pardon the ignorance.

Thanks in advance.

It's okay. I think I already have something here: http://www.stevehoffman.tv/forums/archive/index.php/t-16372.html

Thanks anyway.

[ATJr.]

nice read, answered your questions too.....

i remember growing up in the 1960's we had an admiral 21inch BNW tv set. my father replaced the original speaker with a jensen 8incher in its own baffles and i would say the sound rocks...

it used a 6AQ5 single ended pentode audio amp, with no global feedback...millions of these SEP amps sold....(inside TV's of course.)

triode or pentode? they have their own sets of colorations, it now boils down to your prefferences, both are capable to give you listening pleasure with the right set of speakers...

[oweidah]

it used a 6AQ5 single ended pentode audio amp, with no global feedback...millions of these SEP amps sold....(iside TV's of course.)

triode or pentode? they have their own sets of colorations, it now boils down to your prefferences, both are capable to give you listening pleasure with the right set of speakers...

sir tonyT

uy 6aq5-  7pin pentodes eto balak ko ipa-diy single ended amp. kasi walang makuha cheap 6bq5/el84. parang 6v6 daw ito.

-------

sir bogsle

sampol schematic diagrams in case u may wana diy

- http://www.diyzone.net/diy/references/tube/6aq5cathodefollower.pdf

-http://www.nijnkonijn.nl/machmat/schema/power/se/6aq5.gif

[wraith]

new question sirs:

What audible differences can be expected when comparing a Directly Heated Triode preamp versus an Indirectly Heated Triode preamp?  Let's say a 300B preamp vs. a 6SN7 preamp.

Hindi pa kasi ako nakakarinig ng DHT preamp, so I'm curious.  Thanks.

[ATJr.]

uy 6aq5-  7pin pentodes eto balak ko ipa-diy single ended amp. kasi walang makuha cheap 6bq5/el84. parang 6v6 daw ito.

Yung 6bq5 meron sa southern, TRIGON ang brand, 300 each, or contact gerry, minature seven pin sockets are available in ongpin...

 

[s2kov]

meron ba trigon el34 dun?

[ATJr.]

me nakapagsabi sa akin....

[arnoldc]

new question sirs:

What audible differences can be expected when comparing a Directly Heated Triode preamp versus an Indirectly Heated Triode preamp?  Let's say a 300B preamp vs. a 6SN7 preamp.

Hindi pa kasi ako nakakarinig ng DHT preamp, so I'm curious.  Thanks.

I made a DHT preamp using 01-A, and compared to my Western Electric 407A preamp, the 01-A brings out more soul to the music, the transparency is captivating. But of course, it is still subjective.

Just one comment on those commercial "DHT" preamps that has IDHT in the circuit, to sayang lang. Nag DHT ka pa kung lalagyan mo din ng IDHT. But still kanya kanya pa din yan. Basta ako pure, unadulterated DHT rules. 

[oweidah]

Yung 6bq5 meron sa southern, TRIGON ang brand, 300 each, or contact gerry, minature seven pin sockets are available in ongpin...

 

tnx.
puro exotic tubes ang na k gerry. ganda nung horny 829b 832 

[ATJr.]

oweidah,

a push-pull 6AQ5 is a good idea, i built my first push-pull amp in 1968 using tv vertical output tubes, the 6EM5, simmilar to that of a 6973, you may also try 6GK6 a pentode with 13watt plate diss. as compared to 6BQ5's 12watts, they are simmilar except for pinouts. Last time i checked, the GE brands are still available at Pacific electronics for 250 a piece...

[oweidah]

oweidah,

a push-pull 6AQ5 is a good idea, i built my first push-pull amp in 1968 using tv vertical output tubes, the 6EM5, simmilar to that of a 6973, you may also try 6GK6 a pentode with 13watt plate diss. as compared to 6BQ5's 12watts, they are simmilar except for pinouts. Last time i checked, the GE brands are still available at Pacific electronics for 250 a piece...

tonyt,

tnx for the suggestion. actually tinkered with the idea when mang ben told me that instead of looking for common commercial tubes to use in a (pa-)diy project there are plenty of other lesser known tube types that can be used. among them is the 6aq5 (vice 6bq5), 829b, etc which he has.

[markmlists]

samut saring tanong...

Mayron pa bang triode na can output equal or more power than the 300b?
Ang 1626 of the famed darling amps ba puedeng gawing preamp?
May linestage/preamp schema ba for 10-y/01-a na nasa public domain (ala linux)?

Thanks

m

[oweidah]

samut saring tanong...

Ang 1626 of the famed darling amps ba puedeng gawing preamp?

Thanks

m

congrats! mukhang may new darling ka ah!

eto ba?
http://www.audiohobbyist.com/projects/1626.htm

[ATJr.]

samut saring tanong...

Mayron pa bang triode na can output equal or more power than the 300b?
Ang 1626 of the famed darling amps ba puedeng gawing preamp?
May linestage/preamp schema ba for 10-y/01-a na nasa public domain (ala linux)?

Thanks

m

300b is more powerful that the 1626, besides, the former is a DHT while the latter is not. yes pwedeng gawing preamp yan...

stand-tuned we will dissect triode common cathode circuits and their use as preamps...

it does not take a genius to work on tubes... in my days, a high-school student of about age 17 works on a 5 tube ac/dc reciever as a first project....compared to a triode preamp, that reciever is more complicated...

[arnoldc]

The original "Darling" was designed by Bob Danielak, and uses 8532 high tranconductance single triodes to drive the 1626 to put out a measly, but glorious 0.75watt.

Markmlists, I have a 01-A preamp, pure DHT. I also have a 10Y/VT25 preamp, again pure DHT. They're going to a nice chassis I recently salvaged.

[markmlists]

Thanks Sirs Oweidah, Tony and Arnoldc.

Sir Oweidah, di kaya ng speakers ko yang darling as an amp (low sens) hehe but ang ganda nung pinost mo.

Thanks for the work you put in for all interested Sir Tony.

Sir Arnold, nakita ko sa ws. Congratulations!
Mukang mahirap gawin (or ipa commission to do) since other members mentioned that dht's pose unique design or implementation issues (though Im not sure what or why). Also, the scarcity of schemas on the net pertaing to dht preamps or linestages are indicative na either mahirap nga ata gawin or copyrighted designs or only a few very skilled diyers (like yourself) attempt to do them. BTW, mas maganda ba tunog nung 01-1 vs the 10y since you have both?

Thanks!

[arnoldc]

Copyrighted? I don't think they can copyright something that exists already. I will post my 01-A linestage brew sa Wiredstate.

Between 01-A and 10Y, hmmm, depende sa iyong mood. At this time I would say the 01-A has a slight edge on transparency vs. the 10Y. I like them both, maybe because of the Thoriated Tungsten and I'm trying to make my preamp switchable kasi ayaw ko ng dalawang chassis, pero may mga challenges pa.

[markmlists]

Thanks! I look forward to it.

[dudong]

> as for me, i thank God for spin, mang ben & gerry.   
 
where are they located? contact numbers please...


> Yung 6bq5 meron sa southern, TRIGON ang brand

where is southern located?

tia.. more power 

[tedgat]

Do I need to bias my power tubes every time I change them? Is there such a self biasing amp?

[alexg]

Do I need to bias my power tubes every time I change them? Is there such a self biasing amp?

Yes and yes.

[muypogi]

Yes and yes

On biasing, I noticed AMX amps have RCA jacks on the tube platform itself.  You connect the voltmeter there I suppose?  Is it hard to bias tubes?  Any idea on what meter to purchase and how much?

[alexg]

On biasing, I noticed AMX amps have RCA jacks on the tube platform itself.  You connect the voltmeter there I suppose?  Is it hard to bias tubes?  Any idea on what meter to purchase and how much?

I am using a digital multimeter (Fluke 111, sells for around 10K).

Am not familiar with the rca jacks on the AMX, but on other amps, there is a probe socket on top of the amp for the + and - probes, and a trimmer pot to adjust the bias.

On some other amps, you have to remove the bottom plate, put the amp on its side and do the bias. On these amps, you are better off taking it to a technician to have it biased.

It is quite easy to bias tubes with the bias adjustment on top of the amp. On my audiospace, I just needed to turn the volume control to 0, remove the input (CD or other sources) and turn the trimmers so that my multimeter reads 0.3VDC.

[tedgat]

can anybody share a DIY baising for amx kt88 set

[arnoldc]

On biasing, I noticed AMX amps have RCA jacks on the tube platform itself.  You connect the voltmeter there I suppose?  Is it hard to bias tubes?  Any idea on what meter to purchase and how much?

RCA jacks?  There are more appropriate test connectors for that. Even the lowly Dynaco does not use RCA jacks.

I was able to buy a Radio Shack branded Tenma for 4K. It has super features- the normal AC,DC volts/amps, resistance, diode, continuity, and has capacitance, frequency, and temperature (probe included). It's also True RMS meter, with manual (important) and auto-range functions, plus sample/hold. Sayang sarado na mga Radio Shack...

If you have the moolah and want a reputable one, the Fluke 87 will be more than enough. This is an investment when one goes the DIY route.

But for biasing lang, there are cheap digital multimeters at True Value and Ace Hardware, tig P500 lang. Pwedeng pang test ng battery, he he he. Or ng bias 

@tedgat, why do you ask that? Isn't the bias range part of the AMX manual? It should be!

[tedgat]

I'm planning to have a stock of tubes ?I just want to know if i will decide to repace,will it be a plug and play ?that's why im asking. thanks

[arnoldc]

precisely. amx should come with a manual that specifies the bias range. do you know if it's fixed bias or cathode bias? (may adjustment ba o wala)

kung may adjustment, basahin mo ang manual and look for the recommended bias voltage.

kung walang adjustment, then it's cathode biased and no need for adjustment.