Choices for a Little amp - Asking your opinion

[Kagliostro]

I'm planning a small amp in the order of around 1W of Power

The originale schematic uses a single 12BH7 with triodes in PP and Is fine for Blues and others Styles (Wangs Mini 5)

Initially I was tinking to follow the project only swapping tubes with tubes I've under hand

So 12AX7 become 6N2P and 12BH7 become 6N6P

After, as I have and want to use a 10W - 10K a-a OT, I've think to other mod, one of it will be to add a pair of EF80 tubes in PP (see Rob Robinette mini amp) this will be used only in alternative to the 6N6P, not in parallel like EL84 and 6V6 in the Mesa Boogie Blue Angel, but in alternative, like in the
Traynor’s Darkhorse DH15H

The EF80 in PP will result, in power, near the 6N6P but obviously has the tone of a pentode, not a triode

One other option will be to use a pair of EL95 pentodes instead of the EF80, this are still small pentodes but will result in a near 6W output, as result it will be nearer to the Traynor where a 12AU7 is used as Power Tube in alternative to 6V6 Power section

The question Is:

Do you think It will be more interesting to have the 6N6P + EF80 tubes or the 6N6P + EL95 tubes ?

Many thanks for your opinion

Franco

[Stevem]

Maybe this.
I have 2 of these and with its 7 watts it sounds like a small JTM45 when cranked thru its 12” driver and yet has nice cleans when needed.

If you don’t build it with the tremolo it will have a tad more clean head room.

[Kagliostro]

Thanks Stevem

I'm not asking about a project

I'm asking about a configuration

What I want to know is if the more people would like a small Power amp (around a 1W of Power) with two final Power options, one being a Triode (6N6P) and the other being a Pentodes (EF80)

Or if the more people would prefer a two Power level (small) amp with a 6N6P Triodes (for the output of around 1W) and with a pair of EL95 Pentodes (for the output of around 6W)

So an amp that has Tiode for 1W and alternatively Pentodes for 1W
or has Triode for 1W and alternatively Pentodes for around 6W

Franco

[Phil_S]

Maybe I don't know very much... I think trying to configure for both 1W and 5-10W could force unwanted compromises.

If I were building a 1W, I'd look at a dual triode power tube like 12AU7 or ECC88. (Not sure what those Russian tubes are but probably OK, too.) At 1W with a dual triode, think about using a self-split configuration so you can skip the phase inverter. Configure the tone stack to dial in the sound you are looking for.

For the 5-10W range, the EL95 is a great option. I built an amp with a pair of these many years ago -- I was able to buy a pair of Telefunken for very cheap so I had to do something with them. As I recall, I liked it a lot. Mine was very Marshall-like but could have built something cleaner and I believe would have been just as good. One great thing about EL95 is that it is a low current tube -- less than 30mA for plate and screen -- so you can use a smaller power transformer.

Anyhow, good luck with your design. I hope it will work well for you.

[Kagliostro]

Thanks Phil_S

Yes a compromise there is and it is in the fact I must use a custom PT (not able to find one that can perform the necessity of this amp

For a better understand of what I'm talking about, here the schematics of the amp on which this project is based and the amp I was thinking about for the Power Section mod

Wangs Mini 5 (credited schematic)

Wangs_mini_5_sch.JPG

Traynor Dark Horse DH15H (Block Diagram & Schematic)

Traynor-DH15H-Block Diagram.jpg

Traynor-DH15H-Schematic.jpg

As you can see the Wangs has a double rectifier, Solid State & Vacuum Tube and since I want keep the Preamp voltages at the same level of the Wangs but the modified Power Section works at a lower voltage (~250V with a load of 10K a-a -- and I've a 10W - 10K a-a OT that I want to use) I must use a custom PT that will have a 190V AC winding and a 50V AC winding to obtain the required levels of B+

One other "compromise" is that a PPIMV must be used because the 6N6P has a 3x times gm than the original 12BH7 tube, this will be a benefit because I'll be able to vary the response of the 6N6P to adapt it to various musical genres (Blues and others)

In the version with both, Triode & Pentode, Power sections the swap between the two will be very sinply, cathodes connected or not connected to ground to perform the swap, look to the Traynor Schematic

About the 6N2P it is very close to the 12AX7 (only it has an internal shield between triodes and filaments are 6.3V only)

12BH7 Datasheet
https://www.r-type.org/pdfs/12bh7.pdf

6N6P (& ECC99, very close tube) Datasheet
https://pearl-hifi.com/06_Lit_Archive/0 ... s_Data.pdf

EF80 Datasheet
https://www.r-type.org/pdfs/ef80.pdf

EL95 Datasheet
https://www.r-type.org/pdfs/el95.pdf

Franco