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Two of my best SET's are sounding different. The 500mW WE102D, WE101D, RGN1064 has a nice, smooth sound. But the REN904, RE604, 5R4GY has a "grainy" sound.
I suspect the indirectly heated REN904 is guilty, and thinking of change to a directly heated: Ca, Cf, 3A/110B, WE102D or other.
But first I would like to hear opinions from somebody with experience from this. What creates the "grain"?
Follow Ups:
The question remains. What causes the 'grainy sound'?
ray
Sand.
Beyond a critical point within a finite space, freedom diminishes as numbers increase...as true of humans as of molecules - Pardot Kynes
I use sand in the form of Depletion Mode MosFets for CCS plate loads.
This presents a high impedance load for the tube (triode) and that rotates the load line for the tube towards the horizontal and that lowers the amount of harmonic distortion that the tube produces and that lowers the "grainy sound".
Just saying.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
I use CCS's in everything.
Beyond a critical point within a finite space, freedom diminishes as numbers increase...as true of humans as of molecules - Pardot Kynes
Very neat! Wish my shaking hands and numerious experiments could make it like that!
.
Have Fun and Enjoy the Music
"Still Working the Problem"
Upper order harmonic distortion?Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/07/20
I think I'd go as far as to say that the best DHTs I've used had more clarity and presence, and better instrumental timbre. No idea how the construction achieves this. Thinking here of 300b, 10Y, 46, 26 etc.But this doesn't mean that all DHTs are better - some can suffer from various sonic defects from microphonics to higher distortion in some cases. And they're usually low gain tubes.
I've only used DHTs for the last 12 years but I'm starting to play with a few indirectly heated tubes as drivers for my 300b SE. I've been pleasantly surprised by tubes like EL84 and EL33 in triode, for instance, and intend trying some more like 6V6 etc. These medium pentodes and tetrodes in triode mode outclass all the 6SN7 kind of tubes I used in the past as driver tubes. Useful to have a gain of around 20 or more instead of DHTs mostly being a gain of 11 or less.
Edits: 09/03/20
Now I am changing to C3g in triode coupling. It is a more modern and hopefully better tube than the REN904.
Difficult space for a LL1668 plate choke, may be not important.
Make a great driver tube with a Mu of 30?
Got a mess of them, both Hytron ST and Taylor Globes.
Never found a use for them but, if they are quiet (big if on the globes) they'd be a great driver for an 845, or at least that was my thought at one time.
I used the Taylor globes to drive my 845/211 amp. It was in the same room as Josh's GM100 Monster during one of the shows.
I remember that amp. Built on a recycled chassis from something, right? It sounded good. I had some VT-51, and some 842 for a while. Never got around to building with them, sold most of them to Thomas Mayer. Still have a few I think.
When I first met Josh, that chassis housed his 26 preamp. Then the 801 preamp, which eventually ended up going to you, in a much better chassis if I remember right.
Isn't the plate resistance kind of high?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
but then so is a 6SL7 and some folks use them to drive SET output tubes as well. :-)
But is IS a triode and it IS directly heated.
But I do wish I had a bunch of 842s instead.
Hi,
The Jim Dowdy MQ plate chokes were designed to work well with 841's as drivers.. He posted about them before in the past..
I reckon they're worth looking into.
Sure, you'll get high frequency roll-off... some folks think that is not so bad. Suck it and see.
"Confusion of goals and perfection of means seems to characterise our age." Albert Einstein
Thanks, that was what I needed to go on with this passion.
I have prepared for a C3g (not a DHT) triodecoupled with plate choke acc. to Erwin Wiesbauers C3g-RE604 schematic "Chanchullo".
In the other monobloc I will try Ca acc. to DHT-Rob's Ca-PX25 schematic.
Another superb DHT is 3A/110B which fits in the B4 socket but impossible to find a schematic. My brain is not as before and I depend on schematics now.
Johnny.
Yes !!
Willie
Thanks Willie!
I had prepared to change the REN904 to triodecoupled C3g.(Chanchullo) I have all the parts including plate choke. C3g is very different compared to REN904, and I hoped it would sound better. But, but... Are you sure?
Johnny
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