100K Plate 1.5K vs high plate version

[jelle]

HRM is a high volume amp IMHO. It absolutely shines at high volumes. The real one I heard certainly did.

Really? Funny that I find the HRM's seem to bloom better at low volumes, which is one of the reasons I like them.

+1. Recently though, I messed with the OD entrance trim and HRM and have been able to get the amp to bloom more consistently at higher volumes. Before the change, it would get harsh at high volume. Also after 2 years I think my speakers are finally broken in!

Cool, what did you do to the entrance and HRM?

[Tonegeek]

Really? Funny that I find the HRM's seem to bloom better at low volumes, which is one of the reasons I like them.

+1. Recently though, I messed with the OD entrance trim and HRM and have been able to get the amp to bloom more consistently at higher volumes. Before the change, it would get harsh at high volume. Also after 2 years I think my speakers are finally broken in!

Cool, what did you do to the entrance and HRM?

The answer to your question is buried in a post i put up last month. I recently edited it an included my HRM changes (measurements, values, etc.) There are some clips, but they are obsolete now since I made these changes. Heres the post:

https://tubeamparchive.com/viewtopic.ph ... highlight=

[greiswig]

I really think the 100K amps sit better in a mix especially with a large ensemble that includes keys, horns, etc. The 220/150 amps are sweeter in your living room at moderate volumes.

I recently changed from a 120k/100k V1, 220k/150k V2 to 100k all around in my D'Lite build. This seems better to me overall, although I do miss some of that buttery quality the OD had at lower volumes.

But I agree that this OD seems to cut better in a dense mix. There's a little bit more snarl and cut to it, and it just pokes its head out more easily without needing to be louder.

Another thing that I find interesting: previously I had battled too much bass, even without the bass jumper engaged across the bass pot and a .001uF OD entrance cap. I had fiddled a fair amount with a number of things, and settled on a switch across that jumper that would accommodate a variety of cabs, (jumpered, 50k, and 66k), and tended to keep it in the 50k position. Plenty of bass with a 150k slope, even with weird cathode bypass values in the few uF range. V2 had 1uF and 2.2uF. Odd values.

The cathode bypass caps, from what Aiken says, result in a shelving HPF, not the same as the OD entrance cap which should be some set db/octave.

At any rate, switching to 100k all around, I now like 10uF on V1 and 4.7uF on V2...same as #124. Not too bassy at all. The jumper switch and the OD entrance cap are the same as previous.

I've had this to one gig and a rehearsal with my R&B band now, and I really like it. I ended up putting in 22uF bypass caps on V1, though, because it actually was a little too thin. Barely audible difference, but it is there and there is a distinct change in the feel. The clean settings are more usable than ever with that change.

Changing to all 100k really took this amp to a different level, one that I like a lot.

[Structo]

Did you ever try the bass pot jumper connected to the PAB relay so that when PAB is not on the pot is jumpered and when PAB is on the jumper is removed?
That's the way I have my amp now and I like that.

I found after the OD entrance mod that I had less bass logically so I went back to the bass jumper, unless it's in PAB then it's off.

Interesting about the 100K plates.
I'm not playing out currently so I have mine with the high plates right now.

What do you have for bypass resistors, 1K5?

[greiswig]

Did you ever try the bass pot jumper connected to the PAB relay so that when PAB is not on the pot is jumpered and when PAB is on the jumper is removed?
(SNIP)

What do you have for bypass resistors, 1K5?

Yes, I have my PAB wired that way. I am using, in essence, both hi-cut and low-cut filters on PAB, making it a very broad mid boost. It's a little weird, but I like it.

Yes, 100k/1.5k pairs on all 4 triodes.