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Bang for the Buck

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Posted on July 10, 2016 at 14:27:22
Triode_Kingdom
Audiophile

Posts: 10049
Location: Central Texas
Joined: September 24, 2006
 OK, here's a hypothetical...

Let's say you have a friend who's skeptical about the advantages of tubes. He's open-minded though, more than willing to consider that there might be something better than the latest sand-based devices. To prove to your friend what those of us here on this forum already know, you want to conjure up the absolute best that tubes have to offer in terms of realism and nuance. Headphone use is permitted for this demonstration, so high amplifier/SPL power levels aren't required, and the associated cost of such isn't a factor. On the other hand, given only the restriction of common availability, expensive tubes, output transformers and power supply topology are welcome.

Because a demonstration like this would require optimizing the entire listening system, many of the questions that come to my mind involve more than the amplifier itself. For example, which headphones are most compatible and lifelike with tube gear? Also, assuming one has a "perfect" tube amplifier and perfect phones, what about the source material? Is there a most appropriate era of music and type of media for this? I know some of the early solid state recordings are truly awful, but beyond that, I'm not sure when the various artists and labels transitioned away from all-tube recordings. I also can't say with authority whether all of them went through that same phase of degradation, or whether more modern recordings and media have entirely remedied this situation. Is it necessary to locate near-mint vinyl from the '50s or '60s to create the best possible source, or will certain contemporary recordings do as well?

Any opinions on this from other inmates would be very welcome. The amplifier especially - because that's what I do - is a topic on which I'd like to hear more. In addition to the fact that perfect amplification is my primary field of endeavor, once the amplifier is optimized in the above terms, other parts of the system are more easily evaluated.

So, if you were asked to assemble the finest possible low-power stereo reproduction system, what would it be?



 

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RE: Bang for the Buck , posted on July 10, 2016 at 15:12:29
Russ57
Audiophile

Posts: 3754
Location: South Florida
Joined: November 16, 2001
 I think cost is always a factor. No doubt you can get a good soilid state amp but can it be done at a cheaper price if wattage isn't a factor?

I have a 6V6 triode strapped amp tha6t I consider very good for the money. The OPT's are hammond 10K's. The voltage gain stage is a 6cg7 direct coupled to a 6cg7 split load invertor. It is very cheap and simple, yet quite good sounding. However it is only good for about two watts in strict class A1.

 

RE: Bang for the Buck , posted on July 10, 2016 at 16:06:32
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 There are good titles, including "Shaded Dog" remasters, on both CD and SACD. I'll try to get back to you with some stock #s. Technology is not (IMO) the real issue. Rather, it's finding technical crew that leaves the musicians' work alone, instead of showing their digital dodads off. "Mr. Reiner, does that meet with your approval?"


Eli D.

 

All 4P1L in filament bias, posted on July 10, 2016 at 16:11:27
andy evans
Audiophile

Posts: 4382
Joined: October 20, 2000
 I've been building amps for years and years, and I've stopped with my current amp because I can't think of any obvious improvements. Topology is 4P1L, plate choke and FT-3 coupling cap into 4P1L into Lundahl LL1682. Everything in filament bias with elaborate choke input filament supplies with Rod's regs, and an elaborate choke input PSU with dual AZ1 rectifiers, all polypropylene caps and shunt regs. The 4P1L tubes are rock bottom prices - at least they were when I bought 150 of them.

Combine this with a Mac based source using Audirvana+ and a really good battery powered DAC, and a pair of single unit columns. In my case Alpair 10s. Very simple stuff apart from all the power supplies.

The particular strengths are voices and grand piano. Opera is a joy - listening to Wagner's Siegfried with Solti as I write.

 

.. "realism and nuance" .......no tube does this better than a DHT..., posted on July 10, 2016 at 18:57:59
drummerwill
Audiophile

Posts: 965
Location: St Louis Mo.
Joined: January 7, 2003

..I found my realism and nuance in music from my all DHT stereo 45 SET amplifier, wired to my 2way Altec/JBL system with modified crossover and wiring.

It takes time and patience to get a simple system to perform, but what you get sounds bigger than you would think !

Have fun
Willie

 

RE: Bang for the Buck , posted on July 10, 2016 at 19:26:56
Michael Samra
Dealer

Posts: 36118
Location: saginaw michigan
Joined: January 30, 2005
 I have a 6V6 triode strapped amp tha6t I consider very good for the money. The OPT's are hammond 10K's. The voltage gain stage is a 6cg7 direct coupled to a 6cg7 split load invertor. It is very cheap and simple, yet quite good sounding. However it is only good for about two watts in strict class A1.

What you have is a typical wide bandwidth,low distortion Williamson circuit..My favorite is the Heath W5m with the 16309 nickel centered Peerless outputs which are 11.9k going into a pair of KT66s or 6L6GCs.

Russ,why not hook your G2s up to a regulated source and I think you will like it and you'll have more power?
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

 

+1, posted on July 11, 2016 at 03:26:28
vinnie2
Audiophile

Posts: 4481
Location: North Carolina
Joined: September 28, 2013
 That reminds me, I STILL have to put the finishing touches on mine! Summer chores just use up too much of my time......

 

RE: Bang for the Buck , posted on July 11, 2016 at 12:59:52
DAK
Audiophile

Posts: 2712
Location: PACIFIC
Joined: August 8, 2010
 can be achieved via single ended pentode amplification. Very simple circuitry ensures the least amount of signal handoffs or connections. The amp is most often 2 stage with a 12ax7 or 12at7 for a driver tube and an el84 for the power tube. The EL84 power tubes are plentiful and excellent sounding. Output will be about 5 watts and one should be able to build an excellent amp for around 200 if you rebuild a vintage console amp from Zenith, RCA, Magnavox, etc. If you build from scratch price will be about 2x more. Other than a once in a lifetime garage sale find i don't think you can beat that for a price vs. sound quality comparison. cheers, Dak

 

RE: Bang for the Buck , posted on July 11, 2016 at 13:41:27
Genp
Audiophile

Posts: 57
Location: Not far from Montreal
Joined: February 19, 2016
 If power is not an issue...A 45 tube based SE amp. Followed by 2A3.
For Hi-Res recordings, I'd have to check (got a Mozart SACD in mind)...

 

RE: Bang for the Buck , posted on July 11, 2016 at 14:48:38
hennfarm
Audiophile

Posts: 535
Location: Oregon
Joined: October 8, 2008
 My introduction to tubes was building a bottlehead FP3 and adding it in front of my then parasound jc1 sand amps. JH

 

RE: Bang for the Buck , posted on July 11, 2016 at 19:17:11
bean
 SE 45 amp can be very cheap to implement; find an old SE 6BQ5 console amp, add a 2.5v filament trans, and modify. I used the JE Labs Simple SE 45 schematic.

 

RE: Bang for the Buck , posted on July 12, 2016 at 04:25:36
PakProtector
Audiophile

Posts: 12366
Joined: May 14, 2002
 EL84/6Pi14's on a 16309 would do very well. Front end of EF184 pentodes, as LTP and E-Linear rigged to the '309's screen taps. Leave the finals as pentodes, with g2 voltage equal to plate voltage. That will make a very fine 10W amp, and be Class A...which leaves the trouble of creating a PS a trivial exercise...:)

Bypass the EF184 g2 node to the cathode, and drop them to around 1/3 of B+. Plate loads for the '184 of around 47k so current to the LTP cathodes is kept out of the 'Needs Heat Sink' regime for their CCS.

Fixed bias on the finals, and use that same supply for the CCS negative rail. A supply of -25V should be more than adequate.
cheers,
Douglas


Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

 

RE: Bang for the Buck , posted on July 12, 2016 at 05:59:54
krankkall
Audiophile

Posts: 296
Location: New Mexico
Joined: April 5, 2014
 Just about any 7 pin based tube amp (12aq5/6aq5 power tubes with 12av6/6av6 or 12ab4/6ab4 driver tubes) will sound good at a VERY modest price.

Steve

 

RE: All 4P1L in filament bias, posted on July 12, 2016 at 13:22:21
Triode_Kingdom
Audiophile

Posts: 10049
Location: Central Texas
Joined: September 24, 2006
 The 4P1L is still plentiful and inexpensive on eBay, certainly passes my test as a "readily available" tube. I've probably read most of your posts on this design, and it's tempting. Complicated though, not as simple as many due to multiple DHTs. Overall, I think it's a good candidate.


 

RE: Bang for the Buck , posted on July 13, 2016 at 13:18:14
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 In production certainly qualifies as readily available. The 2 or so WPC SE, triode wired, 6V6s yield is plenty, for headphones. Only #45 DHTs sound better, in this power range. The "reissue" TungSol 6V6 made by New Sensor is excellent. "Poindexter" is on record as preferring the variant over NOS.

Keeping with the in production theme, use New Sensor's, EH labeled, 12AY7 for the voltage amplifiers.

A total of 3 signal bottles and loop NFB is not needed, with good O/P "iron". You decide whether to cap. or DC couple the 'Y7 sections to the "finals". I'd use high PIV Schottky diodes for B+ rectification, but I appreciate your "hollow state" preference. So, buy 3 specimens of the 100 mA. rated 7Z4 and present your friend with a lifetime rectifier supply. RES shows a $3.00 price per 7Z4. :>D


Eli D.

 

RE: Bang for the Buck , posted on July 13, 2016 at 18:49:01
Triode_Kingdom
Audiophile

Posts: 10049
Location: Central Texas
Joined: September 24, 2006
 " Only #45 DHTs sound better, in this power range."

This is an exercise to produce the absolute best sound at these reduced power levels. In that regard, the cost savings of using a 6V6 in triode VS a geniune DHT wouldn't be advantageous. If it's indisputably better, the 45 would be the one I'd use. I have virtually no experience with "flea-power" amplifiers, so I have to ask - is there a general consensus that the 45 is as good as it gets? Are there other tubes with good general availability that are as good or better?

Incidentally, I'm not sure "in production" is required, as long as the tubes are readily available. I see plenty of 45s and other "obsolete" tubes on eBay, so I think it's OK to include those in the mix.

It also occurs to me that I might have created an unnecessary limitation when I said that the cost of higher power gear could be avoided for this demonstration. Does a 211 or 845 wiggling around at 1/2W output sound better than a 45 working at a higher percentage of its capabilities? Do you think that the best low-power amp might in fact be a humongous DHT operating in the region below one watt? Maintaining a good S/N might be challenging, but again, a fairly exotic power supply is not out of the question.



 

RE: Bang for the Buck , posted on July 13, 2016 at 20:02:54
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 The #45's reputation is sterling. Full power distortion, without NFB, may be higher than you'd like. I don't think you will get anywhere near full power, in a headphone application.

Triode wired 6V6 family tubes are damned good sounding and much easier to drive than the #45. That simplification in the small signal circuitry could easily make the net result favor the 6V6. You can't go wrong using either type.

FWIW, residual hum level is IMPORTANT, in driving "cans". Employing all indirectly heated types could be the best way to go. In a headphone amp, I'd like to see current regulated DC heating of #45 filaments. Take no hum prisoners.


Eli D.

 

RE: Bang for the Buck ...I repeat " for realism and nuance " ..., posted on July 14, 2016 at 15:03:22
drummerwill
Audiophile

Posts: 965
Location: St Louis Mo.
Joined: January 7, 2003


.....a DHT does it better than any other tube !

Have fun!

Willie

 

RE: Bang for the Buck ...I repeat " for realism and nuance " ..., posted on July 14, 2016 at 17:03:51
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 Maybe so, but a triode wired 6V6 is nipping at a #45's heels. ;>) Another good sounding multi-grid tube, when triode wired, is the Russian 6П15П (6p15p), preferably with the EB (ev) suffix. Notice the "12" W. theme. The tubes that were marketed as Svetlana (S logo) SV83 are 6П15П.


Eli D.

 

Oh Eli .....nipping at the heels ! (nt), posted on July 14, 2016 at 18:36:39
drummerwill
Audiophile

Posts: 965
Location: St Louis Mo.
Joined: January 7, 2003

 

RE: Bang for the Buck .... Low power 845..., posted on July 14, 2016 at 19:01:10
drummerwill
Audiophile

Posts: 965
Location: St Louis Mo.
Joined: January 7, 2003
T.K.
Yes this is an option also.. I also built a low power 845 SET stereo amp.... She's a 3 stage, 6SN7 DC 2A3 IT 845 E-P PSSS OPT's, puts out about 4.5 watts/per. Separate Input and output P.S. CLCLC filters in stereo.

How does it sound compared to my All DHT DC 45 stereo amp ?
Well I really like both amps ... the all DHT because of its ability to deliver subtle points in the music...... the L.P. 845 for the depth of the music it can deliver an still give that 45 like clarity .

So that's about an honest personal opinion as I can give.

Have fun !
Willie

 

A Blast From the Past, posted on July 15, 2016 at 14:07:26
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 Follow the link provided below.

As I previously stated, triode wired 6V6 family tubes are damned good.


Eli D.

 

Another +1 for all DHT..., posted on July 16, 2016 at 06:27:31
RPMac
Audiophile

Posts: 377
Location: So. Mississippi
Joined: January 3, 2005
 To my ear, voices are most realistic.

I bought a BottleHead built Stereomour prototype with 3B7 driver which beats my other BH amps that have MQ iron. Digital front end with BH-DAC through Altec 605B open baffle.

 

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