drlowmu's (Jeff's) Amp Discussion
- Thread starter drlowmu
- Start date
Not sure I follow.
Are you saying you plug your source into your power amp?
Please elaborate - beginners are trying to learn from this thread and would appreciate the benefit of your experience.
I use a very well-constructed and thought-out DIY passive attenuator.
Each channel uses two 10K three-turn precision wirewound pots, mounted on a single shaft. The dual pots are wired "opposite" each other on their ends, with both wipers are tied together . This is a 10K L Pad. Short silver wire paths.
What is really funny is, for the better part of two years, as I am developing amps by ear, and I didn't even use the attenuator.
I just used ONE set of interconnects, going " full-bore " into any amp under development. As simple a path as can be,..... often loud !!
There is a degrade going to any extra device between my source ( a Pioneer Elite BPP-09FD Bluray player, 31 pounds...look it up ) and any new amp under development. There is also a audible degrade having to use two interconnects in series, which likewise, I do not like to hear.
Begrudgingly - I will use two interconnects and an attenuator, when not developing an amp by ear.
Yes. A music source, an interconnect, a good DIY passive attenuator, and a final interconnect to the amp, is the "usual" way I chose to do it. My two phono preamps have a volume control built in.
My tube amp is high impedance, over 400K, which helps things.
Jeff
Last edited:
After revisiting this thread of mine today, an addendum needs to be written by me, concerning the use of high efficiency speakers.
I left out some KEY verbiage in all my preceding thread posts, , that can cause people to embark on a less-than-ideal ( in my experience and opinion ) High Efficiency path.
The high efficiency speaker MUST have a large radiating surface.
In my experience and opinion, I greatly prefer a good 15 inch driver, and would never own a single 12 inch woofer.
No matter what the degree of quality inherent in any single-speaker driver, a driver with a 8 or 10 inch diameter cone lacks sufficient radiating area, to meet "my" subjective expectations of optimized fidelity.
The high quality small diameter speaker having a high efficiency rating ( eg: Lowther ) should be avoided. Why ??
Despite it's efficiency rating, the small radiating area will NOT allow the optimal use of a 2 Watt amp. The smaller-driver's-result is unlike a SAME-efficiency-rated speaker system with a 15 inch ( large radiating area ) cone - in an appropriate enclosure !!
A simple two way, with a 15 inch woofer, is my personal speaker preference. No subs either !!
The biggest gains in system fidelity come as a result of the amplifier's total design, ...... and the speaker is secondary. Amps are the real turkeys in audio, in all of my experiences, and in my opinion..
IMO : Seek a 15 inch two way, a good 100 to 101 dB speaker , so you can enjoy the best sounding amps in audio, and the ultimate listening experience.
Jeff
I left out some KEY verbiage in all my preceding thread posts, , that can cause people to embark on a less-than-ideal ( in my experience and opinion ) High Efficiency path.
The high efficiency speaker MUST have a large radiating surface.
In my experience and opinion, I greatly prefer a good 15 inch driver, and would never own a single 12 inch woofer.
No matter what the degree of quality inherent in any single-speaker driver, a driver with a 8 or 10 inch diameter cone lacks sufficient radiating area, to meet "my" subjective expectations of optimized fidelity.
The high quality small diameter speaker having a high efficiency rating ( eg: Lowther ) should be avoided. Why ??
Despite it's efficiency rating, the small radiating area will NOT allow the optimal use of a 2 Watt amp. The smaller-driver's-result is unlike a SAME-efficiency-rated speaker system with a 15 inch ( large radiating area ) cone - in an appropriate enclosure !!
A simple two way, with a 15 inch woofer, is my personal speaker preference. No subs either !!
The biggest gains in system fidelity come as a result of the amplifier's total design, ...... and the speaker is secondary. Amps are the real turkeys in audio, in all of my experiences, and in my opinion..
IMO : Seek a 15 inch two way, a good 100 to 101 dB speaker , so you can enjoy the best sounding amps in audio, and the ultimate listening experience.
Jeff
Last edited:
What's better than just ONE set of interconnects is NO interconnects at all. And, if that sounds impossible, it's not.
Imagine a single-stage RIAA-equalized amplifier, the input of which is connected to the cartridge/tonearm wires and the output of which drives the speakers directly. No need to just imagine it because the great good news is that it's actually doable.
Imagine a single-stage RIAA-equalized amplifier, the input of which is connected to the cartridge/tonearm wires and the output of which drives the speakers directly. No need to just imagine it because the great good news is that it's actually doable.
See this newest post for practical " end-game " available audio equipment, just lovely IMHO :
Synergy: What Speaker-Amplifier combinations work really well?
One of the biggest challenges in the pursuit of good audio quality is equipment matching. I have bought good quality amps and speakers which were reviewed well (subjectively and objectively) from different brands that did not work well together and left me feeling indifferent and even bored...
www.hifivision.com
Last edited:
Hi,
'Like your involvement. Hoorah.
If you had a good room and a full size speaker system, and all amps with LSES power supplies, you will find that ANY form of "negative" or sent-out-of-time feedback circuitry, any forms of " nested " feedback, will be a degrade in dynamics mainly, and musical freedom / timing of the music. Schade, etc. N.G.
I seek / design / build for maximized dynamics.
Example :
If the input - driver tube draws 2 mA. at idle, I would have the B+ SHUNT POWER resistor draw perhaps 4 or 5 times that current, to ground.
Five times 2 mA. is 10 mA. drawing as an added SHUNT current to ground.
If the Ra's B+ value is to become 400 VDC, the R SHUNT value becomes 40,000 Ohms. Power dissipation is 4 Watts. ( I'd use a ARCOL HS-50 chassis mount, 40K to ground..)
Starting in mid 2019, I got better sonic results DOUBLE SERIES SHUNTING the most critical tube's B+ feeds. Locks the circuits down - even better.
Double SERIES :
Imagine starting off first with 420 VDC of B+, add a -20 VDC Dropper R ( simulate dropper's needed Ohms value in PSUD2 ) ,
Use a first SHUNT R to ground ...say a 50 K power resistor with a 50 uF 4 Pin WIMA DC LINK,
PSUD determine a second series Dropper R value to obtain -20 VDC ( to get us to 400 VDC ) , desired as the final B+ VDC
Also apply a second SHUNT R from the second B+ to ground, ..........say 50K / 50 W. .............with a ( 15 to ) 50 uF WIMA DC LINK,
all the above : .....is feeding the top of the Input tube's Ra. Zero lead length of the the energy source to our point of use in circuit.
I use PSUD to see what happens with ripple, and would use as small of a film cap ( 4 Pin WIMA DC LINK ) as I can get away with. Seldom over 50 uF. I apologize for not responding sooner.
SEE IT. Please review my hand drawn schematic in the new 2022 " 6005 TRIPLE " thread. Look beside my L1/C1/L2/C2 ( 6 Ohm Ls ). You can clearly see double series shunting ultra sensitive B+ spots : the Input tube's B+ ( Ra ) and the Tetrode tubes's G2 B+.
Any questions, P.M. or phone me. You may want to start off evaluating just one nice SHUNT section to ground. A-B it on music. Do series later.
Jeff
Last edited:
The prevailing attitude seems to be that, it is better to have more watts and not need them than not have them, then need them. Why be restricted to the kind of speakers one has to use?
saw this too:
Audiogon Discussion Forum
The past 6 - 8 months I have been living with very efficient speakers (~ 109dB/m/w) driven by low-power SET amps. The amps use 300B output tubes for abo...forum.audiogon.com
Amps and not speakers are the qualiity-of-sound limitation with better audio systems. To make the best possible sounding amps, you need to employ actual amplifying devices with the best resulting sound. This will be the smaller tubes, not the larger ones. I don't think it is possible to get a world class result when following the prevailing attitude. It will usually result in a boring and ordinary performance level. Just because something is " prevailing ", does not mean it can not be improved upon.
Jeff
At the risk of sounding elitist, I agree with the sentiment that the majority opinion (prevailing attitude) is often wrong (or boring or worse) in most choices. But I also think that this does not mean they enjoy their music and sound any less than you or I. Statements that use terms like “always” are absolutes and are mostly controversial when used in the context of opinions on preferred SQ.
On the issue of smaller tubes vs larger ones, I don’t have enough experience to compare their sound and make a definitive choice. I have had amps with 12Ax tubes and currently 300B tubes and liked the sound of both (mangoes and coconuts?)
Yes, the quest for improvement is only limited by our imagination, curiosity, wallets and desires.
For excellent sound that won't break the bank, the 5 Star Award Winning Wharfedale Diamond 12.1 Bookshelf Speakers is the one to consider!
