help to chose Tube for my OPT Hashimoto H-20-14U (20W, 10K/14K Ohms)

[suwaned]

hello..
I have a pair Hashimoto OPT SE H-20-14U (20W, 10K / 14K Ohms), but I am still confused to choose a tube for that.
I expect advice from experienced friends with optimum results
thank you

 

[jazbo8]

See below.

 

[suwaned]

i see, are you have advice another tube? or for the chart what's tube a good choice?

thank you
ed

 

[euro21]

or for the chart what's tube a good choice?

For 10k, I suggest 801a/VT62.
600V B+, 30mA anode current, about 6W output (if you use A2 capable driver).

For 14k try 211 (low anode voltage, low current).

 

[6A3sUMMER]

suwaned,

You might try using an 807 Beam Power Tube in Triode Wired Mode.

Here is a link from this forum: Misty- SE 1625 Triode Strapped- Newest Build

I like that amplifier. I did my own 807 triode wired amplifier, but I did not make the circuit as good as rcollege's version. The 807 is a 6.3V filament version of the 1625 which has a 12.6V filament. Otherwise the two tube types are identical.

 

[VT52com]

14K would be ideal for the 801A or 10/10Y. The induction seems rather low for a 10/80A though, I'd expect 80H there at least. All the induction figures seem low to me really.

If you need power at those impedances, check the 211, but not sure the OPTs will handle 1kV+

 

[FullRangeMan]

I would suggest 813 but its expensive as 211,845, so GM70 or GK71 seems inexpensive tubes and outputing low W may fit this OPT at 10K ohms.

 

[6A3sUMMER]

The transformer specs ought to be checked, before determining the maximum B+ to use.
If an output tube is cut off, the voltage can rise to 2X the B+, even with a load present.

Many of those transmitting tubes generally require voltages of 600, 700, 1000, 1200, etc. to operate very well.

 

[FullRangeMan]

Have read here the GK71 can delivery good sound already at 800V which in Triode may output around 10W or so and delivery the great old fashioned tube sound.

 

[Ketje]

How about an 6HS5 ? Look here,

VinylSavor: Tube of the Month: The 6HS5
Mona

 

[euro21]

The induction seems rather low for a 10/80A though

At maximum power (600V, 30mA op.point, 3.8W class A1 output), the 801a tube output impedance 4k3, the suggested load 7k8 (RCA 801a datasheet).

If you insist minimum 2x load (8k3), at 30Hz (transformer datasheet) the 44H is enough.

BTW most of japan SE transformer inductance is on the lower side.