Has anyone had any experience with these tubes? I am considering them for use in a phono stage, but any information about the audio quality seems nonexistent. I am currently under the impression that the bass would be very soft compared to other DHTs I've tried. Sort of like a 1H4 vs a 26.
I did and wrote about it. Sound is thin, didn’t like it. Go for 2P29L which sounds amazing, no microphonic noise and has low filament current. Great DHT
Ale Moglia
Ale Moglia
Any idea on the electrode capacitances for the 2p29l, Mogliaa? Would it be suitable as a first stage, possibly with a stepup input transformer?
I recently acquired a small boat load of 3A5's (mu of 15) to use in said phono. I'll certainly need a minimum of 3 stages, but I am trying to keep the number of like devices low.
I missed the intended purpose. MU is low. 3a5 is good alternative and has been used successfully in DHT phono stages with higher Mu.
Here is the original from Telefunken, but still no triode data:
https://frank.pocnet.net/sheets/043/r/RV2.4P700.pdf
It supposed to be a low voltage direct filament version of 12J1L:
http://tec.org.ru/_bd/17/1753_121.pdf
https://frank.pocnet.net/sheets/043/r/RV2.4P700.pdf
It supposed to be a low voltage direct filament version of 12J1L:
http://tec.org.ru/_bd/17/1753_121.pdf
I played with this valve back in 2012. Traced triode curves and developed Spice model. This can be useful so here they are:
2Ж27Л / 2SH27L / 2Z27L – Bartola(R) Valves
These are very linear and non-microphonic DHTs, cheap and available!
I just didn’t like them sound wise as Preamp.
You need to play with them and make your own judgement then
Ale
2Ж27Л / 2SH27L / 2Z27L – Bartola(R) Valves
These are very linear and non-microphonic DHTs, cheap and available!
I just didn’t like them sound wise as Preamp.
You need to play with them and make your own judgement then
Ale
From my own experiences with DHT , I believe with cascaded stages and high gain , you may run into issues . Perhaps use a high gm triode as a front end , passive RIAA and a 2P29L final stage
316a
316a
I appreciate it. They're certainly cheap enough. I wonder if the very low filament current is responsible for the "thin" sound you have experienced. I haven't toyed with very many DHTs, but I am assuming the 2j27l has a similar dull sound to the 1H4, which also sports less than 100ma of filament current. I will order some and experiment.
I'd like to stick with 100% DHT front to back. As the sim stands, I've got a 3A5 front end with a hybrid mu follower into a passive RIAA to another 3A5. From here, I'd like to DC couple another gain stage. This will be my first phono preamp, so suggestions are welcome. All filaments will be powered by batteries. This should keep crosstalk between the 3A5 triodes under control. I've gandered at Dmitry's preamp found here:
Phono Preamplifier with 3a5 Directly Heated Triode
My two concerns about it are the paralleled triodes at the input and 3 stages involving the same device. I have yet to hear paralleled triodes not have a smearing effect, and I am leary about the number of 3A5 triodes in succession imprinting too much of their tone on the system.
Phono Preamplifier with 3a5 Directly Heated Triode
My two concerns about it are the paralleled triodes at the input and 3 stages involving the same device. I have yet to hear paralleled triodes not have a smearing effect, and I am leary about the number of 3A5 triodes in succession imprinting too much of their tone on the system.
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