Emphasising the transients, but making the mediocre listenable

[rick57]

I'm planning a system for which the speakers are pretty well chosen, but the amp is in the short-listing stage.
I decided ~ what the hell - music is my no 1 love ~ to have two systems, one basically for maximum fidelity (or my idea of it), the other for maximum fun.

For the “fun system”: my focus is dynamic response, warmth and effortlessness.

I was researching the best tube amp for about $US 800, to drive 98 db sensitivity cones, with a key test being - *best reproduction of drums.
I thought had a very good prospect - 300B DRDs - until I just read a 300B DRD owner’s comment:

"Awful recordings are almost unbearable to hear".
That stopped my plan in its tracks.

With much of my favourite music, this is almost the *opposite of what’s needed . .

I listen often listen to
- old blues recordings (dynamically very flat, very limited bandwidth),
- FM radio of very mixed sonics.
- garage rock (in parts very distorted, but needs punchy bass and preferably some softening of harsh sounds) and

What do you suggest in a 5 – 10 watt amp that would not highlight - and preferably temper the deficiencies of those kinds of music, while still having really good drumming, warmth and effortlessness??

[rick57]

Yes I know GIGO -
But occasionally I’ve read of systems that strike a more tolerant balance than most. (eg in speaker drivers, as poly cones don’t play every detail, they are possibly better for lesser quality recordings).

I just can’t think of any DIY amps names right now that tend to have that quality.

Unfortunately little of the music I listen to is available re-mastered (eg radio or my sizable collection of less well known artists) . .

Generalisations, but SE ~ more sweetness, PP ~ more dynamic
Maybe as 98 is high efficiency, dynamics will be less of a problem.

So (probably for 8 watts a 300B) SE – with a mild softening of the sound . .

Suggestions on that theme . .

Thanks

[alexistheo]

I suspect one problem with what you are trying to accomplish is that the nature of the "mediocrity" will be different from recording to recording. All bad recordings are not bad for the same reason. Maybe something like an equalizer (the horror!) is what you are looking for?

[rick57]

. . yes an equalizer would help for specific problems.


But for the amp itself – while having the ability to play percussive and other transients well; rather than playing every nuance, a subtle softening of the detail sound . .

CCS/ DRD/ more on OPTs/ less on . ./
certain driver tubes?

Suggestions on that theme . .

Thanks

[tubelab.com]

I have been testing different low cost tubes in my Tubelab 300B amp. set this amp up with a variable power supply, and a set of One Electron UBT3 transformers. When I first got these transformers, I was initially unimpressed, so they sat on the shelf in their original boxes. I had Sovtek 300B's at the time running at 350 volts through custom Electra - print transformers (8 ohm only). I used them for this test because they had 4, 8, and 16 ohm taps, which allowed for testing the various tubes at different loads.

For the first test (the control or reference amp) I used a set of Shuguang 300B's at 400 volts. I was pleasantly surprised. There was quite a bit of punch in the bass that I had not noticed before. Drums, bass lines, and loud rock in general had almost as much life as with the 300B push - pull amp. Turning the power supply down to 350 volts took a lot of the punch away. My speakers are only 86 db Yamaha NS-10's.

I have tried a few different tubes in place of the 300B, and will be trying more over the next few weeks. The results will be placed on my web site as soon as I am completed. The initial results were reported on another thread:

Anyone know anything about a 6AV5GA?

The One Electron transformers are reasonably priced and so are the Shuguang 300B's. I don't do expensive amps, since I build lots of them, I would go broke!

[rdf]

Herb Reichert made explicit reference to this in his 300B "Flesh and Blood" article. Poor material became ‘part of his late night repertoire.’ He also offered suggestions ranging from output transformers to wire for doing this project on a budget.

http://www.audiodesignguide.com/se/fleshblood.html

I know little about the man and less about the success of the design but thought it an interesting read. Another potential starting point?

[leadbelly]

Originally posted by tubelab.com
IFor the first test (the control or reference amp) I used a set of Shuguang 300B's at 400 volts. I was pleasantly surprised. There was quite a bit of punch in the bass that I had not noticed before. Drums, bass lines, and loud rock in general had almost as much life as with the 300B push - pull amp. Turning the power supply down to 350 volts took a lot of the punch away.

Forgive me if this is silly, I am new to this

Would you mind spelling out the B+ 400V -> 350V thing for me? Are you saying that biasing to a bigger B+ yields better punch in general? I am asking in that I keep waffling in how to build my EL84M amp; B+ = 400V with SS diodes or B+ = 300V with tube rectifier.

[tubelab.com]

I am not sure if the increase in voltage was directly responsible for the improved sound, or if the increase in power provided by the increase in voltage was responsible for the improvement. I suspect it is a little of each. Since my speakers are relatively inefficient every little bit helps. I am sure that different results would occur in a different situation.

When I was testing the 6AV5 tubes I kept turning the power supply up until I ran out of knob (it was all the way up), since I didn't worry about frying the tubes. The punch and dynamics of the sound kept improving until the point that the tubes began to overheat. At that point distortion became evident. I was running the tubes at about three times the recommended maximum at this point.

Most EL84 type tubes have a 300 volt maximum rating. I know that most of the vintage American ones will have a short unhappy life on 400 volts. That is the plate to cathode voltage. Total B+ voltage can be slighly higher with cathode bias.

[leadbelly]

Thanks for the reply. I am actually using 6P14P-EV tubes, which can take 500V, rather than true EL84, so you have given me something to mull over

[rick57]

tubelab

Your experiments are *very interesting. I’ll look for further news on your site.
6AV5s - could be ideal for me. Are they hard to find? Do you think the higher volts will cause long term problems for them?
Not a dumpster, but will you compare 6550s/ KT88s?

Do you have any access to some higher efficiency speakers, eg 98 dB, to help identify if the improved sound is due more to extra watts or extra volts?

Rdf

Thanks for the link, I’ll have a read of Reichert’s article. Poor material late night is often it . .