• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Super cheap triode amplifier

Status
Not open for further replies.
Jump to Latest
#41
Original Burnedfingers said:
I question your ability to hear those differences you were talking about considering your Samsung speakers as shown in your You tube videos. I would consider purchasing a set of speakers before you worry about differences between a Hammond transformer and an Edcor.😛
Click to expand...

In some projects I use output transformers made here in Brazil, too.
I made the transformer project and the factory make for me.
This transformers have a good quality.
Brazil export iron M6 to USA and europe.
Here have some of best magnetic irons of the world.
Have a Tessin factory here for produce the M6 lamination, C cores and others cores.
But you do not know, probabily... 😀
 
#45
Mosquito said:
Hi Aldovan,
I have a beautiful set (matched quad) of US made "big bottle" (ST shape) GE 6Y6G
The spec sheet says clearly: max 120V on G2 and 200V on the plate.
Now you're using 270V on the plate in triode mode, ... there is not red plate, or something get stressed? Are the design center specs a bit too conservative?
Thanks
J.
Click to expand...

Yes, the design of this tubes is conservative.
The 12W6GT and 6W6GT support 15W in the plates without red spot in the plate.
I use this tubes with 285V without problem.
And I never use a resistor between the G2 and plate and never burn the G2.
This tubes are robust, are used in vertical deflection amplifier in the old TVs.
This tube support plate peaks of 1200V in triode mode and 195mA peak in cathode current !!!
15W in plate is very soft for this tubes....
But the 6Y6 I never use in this stressed mode.
Probabily support 220 to 250V, but is fine use a 100 ohms resistor between plate and G2.

Aldovan

Aldovan
 
#50

Attachments

  • 6sh5ptwax.jpg
    6sh5ptwax.jpg
    62.9 KB · Views: 566
#51
#52
Tony,

The point I was trying to make is you cannot tell very much about speaker response the lack of detail or any improvements to a circuit when you listening to speakers mounted in a cardboard box.

Aldovan,

Are you talking this transformer?

GXSE10-8-2.5K


10W, single ended tube output transformer for 2.5K Ohms to 8 Ohms.

I have not used this transformer but I do have on hand two Hammond 125ESE's still new and in the box. If I'm going to build this little amplifier I will not depend on it to try to reproduce low frequencies. I will instead hook up a simple little subwoofer. This is why the Hammond 125ESE transformers I have will work fine. They are somewhat limited in their low frequency response and this will mate up fine with a small subwoofer with the frequency at a maximum of 80-100HZ @ 24db crossover.
 
#54
But a sub is for lower frequency...
If you use rhis Hammond transformer you have limited low and high frequency, too.
I use the Edcor GXSE10-8-8k, because the 47 need a 8k transformer.
In some projects I use transformers made in Brazil.
I make the electromagnetic project and a friend make in your factory.
Normally I use big cores for best quality.
My friend use paper isolation and GAP.
I make the GAP adjust with the transformer in the circuit.
Here in Brazil have good core production with iron GO or GNO.

Aldovan
 
#55
Hammond cheap OT's do just fine with even the lowest bass reproduction if you stay under 50% of max rated current. For example the DSE is rated 70mA if memory serves me, and I've found it to have perfectly flat bass reproduction with 25 ... 27 mA bias (for example 71A).

Go parafeed, and you have absolutely no worries even with the smaller cheap Hammonds.

If cost is the main issue, for a cheap amp, I'd definitely go parafeed. A cheap but superb russian parafeed cap is a LOT cheaper than a half-decent OT. So just use a small cheap Hammond and go parafeed, that would be my advice.
 
#56
mach1 said:
Face the bitter truth Aldovan,


You have absolutely no idea how to construct a budget amp. Suggest you take up basket weaving and leave it to the experts 😉.
Click to expand...

I do not understand what you mean by that.
I'm just suggesting a good and inexpensive project. But if you prefer an more expensive project, I suggest that my finished project: 😉
3C24 SE class A2 amplifier (red plates) - YouTube
This sound a lot good, but I lost a big time for obtain good driver for the 3C24 in class A2.
The best results for me is with transistors as drivers.

Aldovan
 
Status
Not open for further replies.
Top Bottom