Srellim1 wrote: ↑Mon May 14, 2018 6:11 am
Hey, thank you for the detailed response. This is good information for me. I love my 2 year old AC30HW2X and feel that it is probably a ‘lifer’ amp, however, at times I do wish that I were able get it to sound a bit more open for lack of a more definitive adjective, so I have eyes on the transformers and choke. I don’t know that this is a move that I would like to make just yet as I enjoy the amp a great deal as it is. At this stage it is the germ of an idea and I am attempting to collect as much information as is possible. It would be a drag to go through the cost and hassle if the modification only to find that the difference is negligible.
The 60th Anniversary model is not in my future at this point though the AC15 version is very tempting.
I followed your threads about these amps here and on TGP and appreciate the input. I’m glad that it ultimately worked out for you. That was a serious worst buying nightmare read.
Thanks and you're welcome, Srellim1.
As you know, I've upgraded my AC30HW2X. I've upgraded the speakers, output transformer, choke, and tubes.
Our idea of "open" will likely be different. That said, if I had a completely stock AC30HW2X and I wanted it to be more "open" (by my definition), I would start with the tubes. The AC30HW2X is relatively inexpensive to re-tube, compared to the ones with 6 inputs and Vib/Trem.
At minimum, I'd put nice old tubes in the preamp positions and the Phase Inverter (PI). I also recommend you try a 5751 in the PI and then in V1 for a more open sound. A 5751 is a low gain (70%) substitute for a 12AX7. The AC30HW2X is capable of more gain/drive and volume than I really need from it. I find AC30s more sensitive to tube changes than a lot of amps. If you can get by with less drive and volume, then it's a change worth trying. One 5751 is (typically) enough. I just recommend you try one and find the position that it works best in to your ears. There is no harm in trying.
To put it into simple terms (IMO)… ACs push tubes pretty hard. They are fairly compressed, even when "clean". When that tube compression kicks in, it robs lows and then highs. Meanwhile, distortion adds and increases harmonics. Well, a different set of harmonics form the input. With less gain, there is less compression. With less compression, you have more dynamic range and the frequency response of the input is preserved better. This gives you more punch in the lows and more detail in the highs. It's also harder to play for many people -- it can be more detailed and less forgiving. Of course, you can still get dirt and more volume, they just happen at different parts on the dial and you don't get quite as much distortion/compression/volume at full tilt. But again, an AC30HW2X has more of that than I (typically) want.
Nice old tubes will result in a better tone and the lower gain tube will result in less compression and drive, which will give you a more open sound with more of the input's low and high harmonics.
So, start with 3 good old 12AX7s and a 5751. Then experiment changing them up and find the best combination of tubes to your ears.