After a 14 year run, the TSE must DIE!

[lykkedk]

I'am in doubt, what difference the two OPT's will be in real life situ?

The one's i was looking for is claimed to be for 300B's :

TTG-KT88SE - Tube output UL transformer [3kOhm] KT88 / 300B SE
Intended for Single Ended
Core type Toroidal
Ultralinear tap 43%
Nominal Power 40W
Nominal anode current 250mA
Frequency bandwidth (-3dB) 10 Hz - 56 kHz
Secondary Impedance 4 and 8 Ω
Primary Impedance 3,0 kΩ
Turns Ratio (Np:Ns) 27,39:1 (4Ω) , 19,36:1 (8Ω)
Primary Inductance Lp 39,5 H
Primary Leakage Inductance Lsp 10,88 mH
Total Primary DC Resistance 85,4 Ω
Effective Primary Capacitance 7,6 nF

The One's OldHector is using are claimed to be :

TTG-EL34SE - Tube output UL transformer [3,2kOhm] EL34 / 6L6 SE
Intended for Single Ended
Core type Toroidal
Ultralinear tap 43%
Nominal Power 40W
Nominal anode current 100mA
Frequency bandwidth (-3dB) 10 Hz - 56 kHz
Secondary Impedance 4 and 8 Ω
Primary Impedance 3,2 kΩ
Turns Ratio (Np:Ns) 28,28:1 (4Ω) , 20,00:1 (8Ω)
Primary Inductance Lp 51,2 H
Primary Leakage Inductance Lsp 0,73 mH
Total Primary DC Resistance 112 Ω
Effective Primary Capacitance 11,2 nF

I'am pretty sure the smaller EL34 version will work in this amp, but why they are claiming it to be for EL34 / 6L6 and not mention 300B etc.. Or is there something i'am not aware of?

The price difference between them are not much, so it does not matter much (within 12$)
I really hope someone can help me answering this as i am in doubt.

Rgds; Jesper.

PS. : USPS updated the shipping information of my TSE pcb to being on it's way from Copenhagen now

[csample]

The question on the Torodiy output transformers seems general enough that you might also get some information in the "Tubes" forum. I searched there for "Toroidy 300B" and got a few threads including this one that may be of interest (I didn't read the whole thing)

Problem - SE Class A with toroidal OT ?

Chas

[lykkedk]

Thanks all.

I had a conversation with OldHector, which is using the small 100mA OPT.
They seem to work very good, and do not get hot or some.

He asked a quistion simulair to mine some time ago, which was cleverly answered by George (It was a quistion about some other transformer) :

The transformer you listed is optimized for use at 120 mA. This means that the gap in the core (required for SE operation) is a bit wider than the same transformer optimized for 90 mA. As seen in their data, the inductance drops a bit because of the wider core gap. Other than the slight loss in inductance, it will work fine at all currents up to the maximum rating of 210 mA, but it will work best at 120 mA. The loss of inductance may make a small difference in bass response especially when a small tube is being used to drive it. The 6L6 types would be the worse case, followed by the EL34. A 6550, KT88 or 300B should work just fine with this transformer.

Also i see, that the bigger 250mA OPT, has ~20% less inductance, excatly as George described it above.

I did read a lot of stuff about this, all kind's of old stuff regarding anode current / OPT / turns ratio etc..., but it was not clear for me, that choosing a smaller OPT could actually work better (thanks Csample for kicking me in the right direction)

Thanks all.

Jesper.