Any tube/valve gear users here?

[howlin' hoosier]

Any of youse mugs into using tube/valve based audio or musical instrument gear? I've got a Musical Fidelity X-10D tubed buffer stage running a pair of Amperex 7308s between my disc player and preamp, and keep a pair of Dynakit MK IV mono blocks in the listening room so they get a monthly workout. Out in the garage, I've got a load of Dynaco gear: a ST-70 that needs a tune-up (gotta figure out what replacement driver board is in it first), my dad's MK II amp and PAM preamp (both need a thorough once over), a couple PAS preamps (one full of Telefunken 12AX7s), a couple FM-3 tuners, and a Fisher 80C mono preamp that had 3 Mullard 10M series 12ax7s (they all test new).

 

[bosshoss]

Yes I am into tubes. I have Coincident Reference preamps and phono amps, and highly modified Audio Research power amps.

 

[Ned]

Yes. a tube fan here as well.

I grew up with my father's Scott preamp & mono block power amps.

Over the years I've owned/bought/sold a Radford preamp, two Marantz 7C preamps, both Audio Research SP3 & SP3A preamps (in the mid 1970's). I've also had a pair of Marantz 10's (they went to pay lawyer's fees in a divorce) several Dynacos & the glorious Julius Futterman handbuilt amp of the mid 1970's. Currently using a Conrad Johnson with matched vintage Blackburn Mullard tubes & a solid state Musical Fidelity dual mono poweramp. I feel the way to go is tube preamp & solid state mono poweramps.

Currently have my eye on a new Audio Research SP-17 if my budget will permit. I have yet to own the elusive (at least here in the US) dual mono Croft preamp from the UK, that is one I'd like to get my hands on.

Ned

 

[howlin' hoosier]

Yes I am into tubes. I have Coincident Reference preamps and phono amps, and highly modified Audio Research power amps.

Do you run NOS tubes? I've tried Russian and Chinese EL-34s and they just don't sound as good as the RFTs I settled on. The Chinese GZ-34s suck - I had one die after a few dozen on/offf cycles. Besides the Amperex 7308s in my buffer stage, my Dynakit MK IVs have Mullard GZ-34s, Sylvania 7199s, and RFT East German EL-34s (the poor man's Mullard). Those RFTs are starting to sneak up in price, so I'm aways on the lookout for more. They've been relabeled for a bunch of different resellers, so sometimes they can be had for under a couple hundred for a matched up quad.

 

[howlin' hoosier]

Yes. a tube fan here as well.

I grew up with my father's Scott preamp & mono block power amps.

Over the years I've owned/bought/sold a Radford preamp, two Marantz 7C preamps, both Audio Research SP3 & SP3A preamps (in the mid 1970's). I've also had a pair of Marantz 10's (they went to pay lawyer's fees in a divorce) several Dynacos & the glorious Julius Futterman handbuilt amp of the mid 1970's. Currently using a Conrad Johnson with matched vintage Blackburn Mullard tubes & a solid state Musical Fidelity dual mono poweramp. I feel the way to go is tube preamp & solid state mono poweramps.

Currently have my eye on a new Audio Research SP-17 if my budget will permit. I have yet to own the elusive (at least here in the US) dual mono Croft preamp from the UK, that is one I'd like to get my hands on.

Ned

Futterman OTL - one of those amps I'd love to hear. Did they warm up the room when you fired them up? Mullards in the CJ amp - that's got to sound great. I keep hoping I'll stumble into a stash of those sometime (ala folks here hoping to find a pile of great 45s). I have a Musical Fidelity A 3CR amp and Adcom GFP 555II preamp - the tubed buffer stage gives things a little liveliness and warms things up a bit.

 

[Ned]

The Futterman amp did give off a lot of heat, but nothing beat the big Audio Research amp of the day - the D150 - that sucker could keep your pizza warm. Pretty good sounding, too !

Vintage Mullards are tough to find "in the wild" here in the US, but the tubes made by GE, Sylvania, RCA, Zenith & so on in the mid to late 1950s are excellent. Vintage radio shows are a good place to score tubes although most dealers are not very particular about testing them. As long as they still light up they figure they are sellable. As you mentioned, the quality of the tube makes all the difference in sound & each company had a distinct sound.

I'm pretty sure the big output tubes used in most vintage amps - the KT 88 are fairly common due to the fact they were used in TV sets to control vertical hold. Remember the days when TV pictures "rolled" - that was due to faulty or aged KT 88's.

Good choice on the Musical Fidelity, mine is the A 3.2 & it is a great match with the Conrad Johnson. Don't ever underestimate the importance of good cables, either.

Ned

 

[howlin' hoosier]

The Futterman amp did give off a lot of heat, but nothing beat the big Audio Research amp of the day - the D150 - that sucker could keep your pizza warm. Pretty good sounding, too !

Vintage Mullards are tough to find "in the wild" here in the US, but the tubes made by GE, Sylvania, RCA, Zenith & so on in the mid to late 1950s are excellent. Vintage radio shows are a good place to score tubes although most dealers are not very particular about testing them. As long as they still light up they figure they are sellable. As you mentioned, the quality of the tube makes all the difference in sound & each company had a distinct sound.

I'm pretty sure the big output tubes used in most vintage amps - the KT 88 are fairly common due to the fact they were used in TV sets to control vertical hold. Remember the days when TV pictures "rolled" - that was due to faulty or aged KT 88's.

Good choice on the Musical Fidelity, mine is the A 3.2 & it is a great match with the Conrad Johnson. Don't ever underestimate the importance of good cables, either.

Ned

Grover interconnects in key places, some good for the money AR cables in others in the hi-fi here.
Wish I could find KT-88/6550s in quantity. I've got a pair of GE 6550s made in Owensboro, KY that I might put to use in the Dynakit MK II mono amp that's waiting for a rebuild. Some legit KT-88s from GEC/Gold Lion would be a great find. I'm about 30 years too late for quantity finds on power tubes like those or Mullards, but I occasionally find small groups of preamp tubes like the 12A** types.

 

[soundog III]

I recently (1/2) packed it in with tubes. This MC2000 was just a bit to finicky / "twitchy" for me. It always needed kid glove treatment, would be another way of putting it.



I have a tube phono pre - amp, so I will be loading an analog stream into the power amp(s) once I decide on which brand to go with. These caught my eye, the XPA-100 in particular:

shop.emotiva.com/collections/amplifiers

www.stereophile.com/axpona2010/affordable_emotiva/index.html

 

[howlin' hoosier]

I recently (1/2) packed it in with tubes. This MC2000 was just a bit to finicky / "twitchy" for me. It always needed kid glove treatment, would be another way of putting it.

View attachment 779

I have a tube phono pre - amp, so I will be loading an analog stream into the power amp(s) once I decide on which brand to go with. These caught my eye, the XPA-100 in particular:

shop.emotiva.com/collections/amplifiers

www.stereophile.com/axpona2010/affordable_emotiva/index.html

What were you having trouble with? McIntosh has a good reputation for being reliable.

 

[soundog III]

I ran it a bit harder than was perhaps advisable. Specifically overdoing P.I.L. Metal Box one afternoon. I could've roasted marshmallows over the KT 88's. Or ribs...

McIntosh charged me $900.00 for a set of new KT 88's.

And I had a few issues with the meter, capacitors and resistors. The first go round I will allow was self inflicted, the second, nope.

 

[howlin' hoosier]

I ran it a bit harder than was perhaps advisable. Specifically overdoing P.I.L. Metal Box one afternoon. I could've roasted marshmallows over the KT 88's. Or ribs...

McIntosh charged me $900.00 for a set of new KT 88's.

And I had a few issues with the meter, capacitors and resistors. The first go round I will allow was self inflicted, the second, nope.

Try as they might, I don't trust current production tubes to deliver the goods like tubes from the great manufacturers like Mullard/Amperex/Phillips/Tung-Sol/RCA/GE/Sylvania/GEC/Telefunken/Siemens and plenty of others. Unfortunately, matched pairs of GE 6550s will set you back a minimum of $200+, and GEC/Gold Lion KT-88s can easily triple that if you get really lucky. I was able to score nice pairs of Amperex 7308s for $70 or so maybe 4 years ago. Closer to $200 minimum is the going rate these days - part of the reason I don't pursue 45s. At least those Amperex 7308s are 10,000 hour rated tubes...

 

[howlin' hoosier]

I've got a sleeve of Hitachi 6V6 GTs heading my way. Japanese tubes are pretty underrated IMHO - Matsushita had Phillips tooling, and made some good stuff. The 6CA7/EL-34 is supposed to be good quality, too.

 

[howlin' hoosier]

Thought I'd wake this thread back up. I've accumulated a nice stash of EL84 6BQ5s (Mullard/Amperex/Tungsram/RCA/GE/Sylvania), some RFT EL34s, Mullard GZ 34, 6DJ8s galore, some 6922s - anybody in need shoot me a PM. I splurged on a Maximatcher and can match up power tubes properly...

 

[purple_pill67]

I have Croft Vitale SC and Series VC pre and power amps

 

[howlin' hoosier]

Just Maximatchered up a great set of late 50s to 1960 Philips/Amperex Xf4 type double D getter EL34s (gotta love double Ds) - truly a thing of beauty...

 

[howlin' hoosier]

Just got one of my Dynakit MK IVs to bias properly. After pulling my hair out after several failed attempts to solve the problem, I got a new bare driver board (after 50 years the traces had started to lift in a few spots), populated the board with new everything, including a pair of Wima coupling caps, and a NOS Sprague Vitamin Q, then yanked the sockets (they were wiggly, so I gritted my teeth and wired in NOS Belton octal sockets). Retouched all solder joints under the hood, and finally got stable bias. I've got about 50 hours on the rebuild and the caps are breaking in - the highs are starting to ring out as they should after a period of sounding rolled off.

 

[howlin' hoosier]

On the tube front, I lucked into 7 NOS Mullard xF2 EL34s rebranded for Sylvania in the old lightning bolt style boxes. Took me less than a week to sell them all (matched a quad and a pair to about 3% difference) - I wish I'd gotten my amp repaired before they flew out the door...