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    Building, troubleshooting and testing of these amplifiers should only be
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6V6GT and 6L6GT

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Dear all,

Now I'm considering to choice between 6V6 and 6L6 for my new amp, they are very common and easy to have in my county rite now.

I've got a pair of SE-OPT; pair of 12ax7 (5741); Power Transformer 110~530-0-530.

After analysed their technical detail, I guess that B+ is 250V, so 6L6 will get more power than 6V6; But this is just only the number and the most impotant is quality of sound. Pls, tell me about your feeling about those power tube; anything about your experience when building them.

Thanks for your attention and looking for your response,

Cominup
 
Yes, both are really great tubes. But before I recommend one over the other, I too would like to know the primary Z of your transformers. A 6V6 will not be happy with less than 10K on its plate at 250V, while a 6L6 does great in SE at about 5K.

( For an experiment, triode-strap a 6L6, you'll only get about 1.4 watts, but the sound is to DROOL over :D )
 
Oh Man,

It's so confusing then I've already bought a pair 6V6 and 6Pi33C (~6L6; but cheaper 4 times).

I'm planning to built two amp. One uses all Russian tube (6H2Pi and 6Pi33C) and another uses all American tube (GE 5741; 6V6). Russian tube ofcouse will be more powerfull than American. But another matter, I've got only one pair of OPT!!!! :hot:

It's really confusing another time, dudes!!!! In my mind, I love to build American first, I feel that it more matches with my OPT.

About OPT, it comes from 2nd Japanese amp and one exprienced man said that it full enough to use with 6L6 :rolleyes: I dont know how to check them!!! If you know, could you teach me how??? It's so kindly!!!
Impedance: OK, I'll check tonight soon,
UL tap: means????,
Current rating???etc....

Could you tell me more detail, dude???

And then, I've read on http://www.triodeel.com/6l6gc_p1.gif, there are some term I do not understand:

1. AF Amplifier Class A1: AF what stands for?
2. Different between Fixed Bias and Cathode-Bias
3. Triode connection: it means 6L6 pentode becomes triode, its'n it? In this case, how about the effect??? Warmer, finer or noiser?
4. I noticed that when +B is at 250V, 6L6 seem working very well, is it true?

OOOOHHHHH!!!!! Tooo much question guys!!! Its overflow to write Eng.

Well, C u guy tomorrow, OK!

Cominup
 
cominup said:
Oh Man,

It's so confusing then I've already bought a pair 6V6 and 6Pi33C (~6L6; but cheaper 4 times).

Great! IMO, 6P3C sound better than 6L6G. Keep in mind the plate rating for 6P3C is 25 watts, same as 6L6G, not the 30 watts of 6L6GC.


UL tap: means????,

Ultra Linear. A tap on the primary at ~40% up the winding. You tie it to your screen. Has added benefits like 2/3 the power of pure-pentode operation, but 2/3 the sound clarity of triode-strapping.


Current rating???etc....

Know the watt rating and physical size of the core? That'll give us a clue.



1. AF Amplifier Class A1: AF what stands for?

Audio Frequency


2. Different between Fixed Bias and Cathode-Bias

Fixed bias means the cathode is either directly grounded or grounded through a low-ohm (10 ohms typical) resistor and a variable negative voltage is applied to the control grid (g1) through the grid-leak resistor (typically 33k to 220k, depending on amplifier class).

Cathode bias means the required bias voltage is developed across a high-ohm (typically ~500 ohms, 5 to 10 watts) resistor inline with the cathode and bypassed by a largish capacitor (typically 470-1,000uf) and the grid-leak resistor is grounded.


3. Triode connection: it means 6L6 pentode becomes triode, its'n it? In this case, how about the effect??? Warmer, finer or noiser?

PRO:
More linear reproduction, sounds much more "tubey" than pentode or UL.

CON:
Lower power out, less power sensitivity, less efficient.

Personally, I'll take a triode-strap over pentode or UL anyday ;)


4. I noticed that when +B is at 250V, 6L6 seem working very well, is it true?

Perfect for a 6P3C ;)

Rule-of-thumb: American tubes can handle higher voltages and less current and Russian tubes higer current, but lower voltages. This is thanks to the Russian typically using larger cathodes than Americans.
 
all of you are cool guys!!!!

Thanks to all,

I'm so excited to build this amp. Rite now, I've still got some problem with power supply (I'm buiding a pre-amp use two 6H2Pi, it works but so hum, the reason is from Power Supply). So after I solve this one, I will begin immediately American amp. But first I should check my OPT to let you know and tell me it's cool enough, OK?!!!

You guys live in US, you are real sleepless guys; What WT is rite now??? Your eyes be like this:bigeyes: Ha ha!!!!!:eek: ;)
 
New world-first for DIY?

cominup said:
I'm planning to built two amp. *snip* But another matter, I've got only one pair of OPT!!!! :hot:
Easy! Adapt an old octal tube socket or whatever to the bottom of your OPT's and then you could plug them into whichever chassis you are using at the time. Or even into another amp you might build in the future. Might look a bit odd but should work just fine.
 
Thanks sch3mat1c,

Incase these OPTs do not fit to 6Pi33C (and 6V6)!!! Could you guess some OPTelse. You know, budget is important to me!

What is the rule to link between tube and OPT? Just only match of resistor or somethingelse??? Some theory question, cuz I'm drilling in this area and get so much challenge.

Cominup
 
You have to understand the loadline. To sum it up, if the plate voltage changes a certain amount, plate current is going to change, and at a rate exactly related to the load on it. This is represented graphically by a line whose slope is equal to the resistance (the slope is actually negative because you are looking at the tube's point of view, which is opposite the load).

For 6V6, AES (www.tubesandmore.com) sells a 5k:8 ohm OPT perfectly suited. I recall Triode Electronics also carries a similar product for slightly cheaper (and I mean cheap here: about ten bucks!). I used one for a 6L6 (check out Revision 3 on my site) and bass response cuts out at high power (it's not made for the beefier 6L6 I used) but otherwise it sounds great.

Tim
 
Hi dudes,

Welcome back DIYAUDIO, I was waiting too much to meet you man.

Rite now, My pre-amp was OK, runs with pair of 6H2P, every caps on signal line is russian oil caps and a pair of film foil. Sound still so high, very littel bass , but have sound of tube, clear, wide. :bigeyes:

My power supply is 5Y3GT-10uF-Self 2H 60mA-47uF//0.47uF-Self 2H 60mA-2200uF//0.47uF. Current be clear suddenly:cool:

So, my next project is using two pair of 6V6GT in parallel to operate mentioned above OPT (2.5K:8Ohms). I got Angela schema and have some considering.
1. THis amp use for guitar! So if use for hi-fi, it'll OK? What change to improve?
2. In case, max OPT current is less than pair of parallel 6V6, they (OPTs) could work fine in small volume level, couldn't they?
3. Is there any other schema useing 6V6 parallel SE?
4. A stupid question: Could you suggest the sound, what will it be??

Thanks
Cominup
 
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