Review: Tube Audio Design TAD-60 Tube amp


Category: Amplifiers

I'll start by saying that I've been into higher-end audio for a few decades now, and quite a lot of equipment has been through my hands to this point (half the fun of this hobby). Somewhere around 12 years ago, I'd come to realize that I preferred tube amplification over solid state in terms of an overall involving presentation of the music, and ever since then have owned tube stuff (brief flirtations with various solid state devices only helped to enforce this notion).

Which brings me to the discovery of Tube Audio Design, the provider of components conceived by Paul Grzybek (of Bizzy Bee Audio fame), built to his specifications by a very reputable Chinese manufacturer, and then hand-finished by Paul in his shop located in Wheaton, IL. (His offerings are available exclusively online; detailed product info is found at http://www.angelfire.com/biz/bizzyb/index.html)

The TAD-60 amplifier is built like the proverbial tank; overall appearance and heft (not to mention its specifications) in my experience indeed belie the modest asking price. With its stainless steel chassis and almost 1/2"-thick black anodized face, the relatively compact package portrays a masculine but elegant stance (also included is a lift-off stainless steel tube cage). All function controls are easily accessible from the chassis top, as are the tube bias test-points and adjustment pots (a digital voltmeter is included too).

EL34-based, the TAD-60 is rated at 60wpc in UL-mode, and 30wpc in switchable-on-the-fly triode-mode. Other standard features include adjustable input sensitivity and adjustable global feedback, adding flexibility to a host of possible preamp and speaker combinations (the input sensitivity control may also be used as a volume pot in a single-source direct input configuration).

Listening to the TAD-60 after the recommended 30 hour break-in period and beyond, the music really began to open up, and along with the TAD-150 preamp, I was experiencing just about every CD I spun in a whole new manner - I'm particular to small-ensemble jazz and female vocals - there was an in-the-room conveyence of the music that I found startling at times - present is deep, tight bass, a glorious midrange, detail, depth, and an overall natural presentation that allows hour after hour of enjoyable listening. I've found that the feedback adjustment permits a fine-tuning of balance between dynamics and warmth, and was able to "lock in" the amp to my speakers for what sounds to be a perfect sonic match (just a tad of feedback along with the triode-mode setting seems to be the magic spot in my case).

Without attempting to describe every sonic attribute I'm hearing (though I'm happy to answer any particular inquiries), suffice it to say that the TAD-60/TAD-150 combination strikes a synergy and glow that is especially musical, and is among the finest I've had the pleasure of owning. The TAD-150 has already been highly praised in at least a few user and online reviews, and I bet the TAD-60 will soon be recognized as a similar standout. If you happen to be in the market for high quality, reasonably priced, excellent-sounding gear, just take a listen for yourself, and you will hear what these components can do for music. (Paul also offers a 15-day in-home trail period.)

Note: I have no financial interest or business relationship with Paul Grzybek or Tube Audio Design.

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The TAD-150/TAD-60 combo has been viewed quite enthusiastically in this thread. I have read elsewhere of a Cayin TA-30 integrated getting paired with the TAD-150 and receiving glowing reviews so the TAD-150 had fans in a number of camps.

I know there are other pre-amps out there I’ve seen suggestions of using:

-- Monarchy Audio M24 tube DAC/linestage
-- Quicksilver Remote linestage
-- Eastern Electric Minimax
-- Octal-based Mapletree Linestage 2A SE

Now that the TAD-150 plant has closed, has anyone heard from Paul G. whether he is going to find a substitute? Just curious now that the TAD-150 is no longer available, in addition to the above suggestions, what are people are thinking of matching to the TAD-60.
I decided not go for the 10M because of the cost and I wanted a more lively and dynamic sound. I read many reviews of the Mazda 12ax7 silver so that is what I purchased. The stock tube China 12AT7 had a wider soundstage, more gain and overall more pleasing sound than the Mazda tube. I noticed that the Mazda tube is generating a moderate hum audible from 20 inches away from my TAD-803 even with the preamp turned off. Did I get a bad tube?
Another X7 replacement to try rolling:
I have Chinese Triple Mica Mullard T7 knock-offs that are amazing! Yes, a T7 in the X7 socket. Only $10 + ship.
This is the same tube I supplied in the TAD-150 preamp that many seasoned tube rollers stated they could not top. Sounds better than the real Mullard triple mica T7! Paul, Tube Audio Design, Available on the Sale price page.
Scooby, the 10M was the first tube I rolled into the x7 slot (paid $150 on ebay, seems to be the going price) and overall I found it too be very warm and smooth, especially the mids. The low end was deep but not boomy, but the highs (while not bad) were not as sweet as you'd find in a Tele x7 or Raytheon 5751. Overall, a great tube if you're system is in need of a "warming" influence. If that's the sound you seek, you may want to save some cash and go for a regular Mullard short plate (which is what the 10M is only "hand selected for balance, yada, yada) and move on from there before laying out some serious cash. The GrooveTube x7 (a current production) that is supposedly modeled after the Mullard shortplate is a really nice tube (cheap too) but its much more dynamic and lively (not as warm and creamy) as the 10M. If you can get deal on one, I'd also try a Mullard longplate.

Lou
Bud,

I run my TAD 60 as an integrated. I only have one source so this makes things simple. Currently I am using a Mullard copy 12AX7 from Groove Tube in the middle position. This is a great new production tube. The 12AX7 that Paul shipped with my amp was a JJ. The JJ is good, but I prefere the tone of the Mullard copy. The 12AU7 tubes that came with the amp were EH, but am now using NOS Mullards. Got all these tubes from Upscale Audio.

Michael
I have owned the TAD-60 for six months and I am ready to tube roll. I adjusted the bias to single ended and noticed that the music is more smooth but not as dynamic.

I have read many tube posts and it seems that the most sought after 12ax7 is the Mullard 10M. Has anyone tried this tube in your TAD-60? I want to get some feedback before I spend $150 for the tube.

Thanks in advance.
My TAD-60 is on the way. I am moving my wonderfully satisfying Cayin TA-30 to the second system. Has anyone run the 60 without a preamp?

Thanks,

Bud
Hi Lou,

Where did you get those U7 RCA Cleartops? From reading about them it appears to be a good fit for my speakers. Vandy 2ce sigs. I have the Groove tube in the X7 spot and it seems to be a nice improvement over the Sovtec. More punch and air...
Just wanted to share a tweak that has made a HUGE difference; Herbie's Hal-o Dampers http://herbiesaudiolab.home.att.net.
Wasn't expecting much, but I couldn't believe how much microphonic smear and noise my tubes were emitting until I slipped these on the power and pre tubes. The sound stage went silent and clarity/separation were night & day. And talk about controlled tight bass. My jaw was on the floor. It's like having new gear. Seriously. Can't say enough good things about them. Best of all, they're affordable, and you get a 90 day trial. Some folks on the web have commented that dampers also dampen music, but I did not find that to be the case. Things are more musical and enjoyable than ever. Play some busy passages loud and be prepared to smile.
I use a Mullard 12AX7 in the A7 socket and a pair of GE 12AU7 in the U7 sockets. My TAD-60 came with some unknown U.S.A. made 5814A's and a Sovtek 12AX7WXT+. Changing out the Sovtek to a Mullard is a big improvement as one would expect. Also the very slight thump on power off is completely gone. This set up along with the VA KT88s results in a very tight bass, a beatiful midrange and slightly rolled of highs.

Eagleman, in the the u7 slots, Paul suggests keeping u7s. I'm using RCA cleartops, but have some Telefunken's i like to use as well. The greatest difference in sound comes from the swapping the x7 position. I'm currently using a GT "Mullard" reissue, but i've also tried a Mullard 10M (nice tube, but too bloomy & boomy for me), an RCA 5751 blackplate (really like this one and 5751 in general, yeah I read Joe's Tube Lore), and a Mullard x7 long plate, which has great warm mids, and nice bass. I've also tried a Tele u7 and Tele t7 in the center position, and find the t7 pushes the mids too forward for my taste. The u7 has nice seperation and clarity but lacks the presence of a t7 or x7. I also found the highs were rolled off a bit. One nice thing about the "relaxed" sound stage of the u7 was that you could turn up the volume and things didn't get messy; seperation and clarity remained. Have fun.

Lou
What is everyone using for the one 12AX7 and two AU7 tubes? Is anyone using alll 12AX7 or do you need to replace with the same type of tubes. I just put two GT AX7 in the preamp and while I am still evaluating I think the total system performance or net change may not be evident until I replace the AU and AXs in the TAD-60...
The standard power supply in the latest batch of 60's is smaller, producing 40 watts no matter what output tube type is used. This allows a lower initial price to help those on a tight budget. Power supply is the engine, tubes are the tires. Paul
I am a little embarassed. I fixed my image problem. I had my right woofer phased reversed. When I straightened that out the image was right on.
Armed with confidence I tried the class A bias and now I am in love with this amp. Paul's last e-mail suggested pushing the bias on V2/V4 to 600 which I will try in stages. I am at 500ma now and will start moving up. I am going to order some Pearl coolers. for the EL34's.
I have some NOS 12ax7 and 12au7 on the way.
I've been rolling the pre tubes and was wondering if anyone has tried an NOS BugleBoy long plate cause it's the one ax7s I haven't tried. Btw, if you haven't tried swapping the pre amp tubes, you're missing out. The change is HUGE. In fact, had I known I would have started there first instead of the power tubes. Lately, I'm running the 34s in Class A mode, but i have a quad of Penta solidplate 88s in waiting. Anyway, I tried quite a few NOS tubes in the center position, but found the ax7 variety to be best (just punchier and bigger soundstage) and settled on the Mullard sound; great mids, lush but not too much (imo), well extended, nice bass, and of course, warm, but not too tubey. The Mullard is a 10M, but I have a longplate coming tomorrow - I'll let you all know how it goes. Been wanting to try a Bugleboy long plate, but the eBay prices get crazy and rolling tubes in of itself can get crazy too, so I'm trying to ease up. In general, the TAD-60 out of the box is awesome (drives my Onix Ref 3s just right), but its nice to know that it can be tweaked, and the changes are more than subtle. Has anyone else tried rolling the preamp tubes? If so, please share :) Btw, if you'd like to try a nice NOS tube that won't break the bank, the RCA blackplate with the square getter ('50 - early 60s) was really nice. Great mids, mid/highs were very detailed, and bass was punchy but controlled. Overall, a great tube, but with my speakers it was little edgy. Oh yeah, as for the au7s, i settled on Telefunken au7s. For the most part i didn't notice much change in rolling here and I tried some RCA cleartops w/ gray plates, too. But i left the Teles in, just cause they're Teles.
I recently purchased a pair of Klipsch Fortes because of all the good buzz I've heard on the Net about them. When I first mated them to the TAD-60, I wasn't that impressed, but I was using the amp in ultralinear mode. So, I switche to triode mode. Boy, I was certainly impressed by the sound. With my old ScanSpeak speakers, triode mode always sounds too soft. With the Fortes, I heard the best balanced sound that I've every heard and vocals still retained the palpability that tubes provide, but now all the music, including orchestral has that 'just right' musicality.

The story doesn't end here. When I measured the bias, it was over 100 mV low on all tubes, so I readjusted and the sweetness of the sound became hard to believe.

Klipsch Fortes - try 'em with the TADs!
I think this amp is tremendous. The clarity (realism) was the big surprise for me. I am enjoying going through my record collection. It like everything is new again.
With all that I am reading about the JJ KT77 I guess I just have to try them. I do want to try some NOS 12ax7 and 12au7's
The amp has about 60 hrs on it and seems to be settling in so I can start evaluating. Paul has been very good with suggestions.
He was curiously quite about a request for a schematic.
I am finding the amp a little forward and the image is larger than my previous set up. My speakers are Vandy 2Ce's. The TAD-60 is in triode mode with little or no feedback. I have not tried the Class A bias yet.
I do have plans to glam up the TAD-60 a bit. I like adding exotic wood sides. I hate the silver cap on the power tranny as well as the tube shields on the 9 pins. I cannot hear any difference whether the shields are on or off. The feet have to go. I feel the plastic/hard rubber decouple the amp and trap mechanical vibrations in the amp. My music room is in the basement so I have thin carpet over concrete. I do my best to couple all my equipment to the concrete. For the TAD-60 I built a 4 inch thick wood block out of beech butcher block which have spikes to couple it to the concrete through the carpet. Right now the TAD-60 is on teak blocks that do not touch the plastic feet. This does a nice job coupling the amp to the 4 inch butcherblock base. I think the only thing better would be the Mapleshade brass footers.
I'm in the middle of purchasing with Paul and I'm curious to hear any feedback on the auricap upgrades.

Is there anyone out there that had their unit upgraded and felt that the unit outshines the stock one? If so, please indicate the areas in which you found the greatest gains and if possible, any other sonic differences between the two.

This info is highly appreciated as I'm impatiently awaiting the arrival of my new addition!

Thanks in advance for any info at all!

BTW, I will be running with a Quicksilver Audio Remote line pre-amp.

Regards!
I've tried the class A setup with a mix of 34s and 88s, but wanted to hear how they would sound with all 34s, so last night i made the switch. Gotta admit, i couldn't really tell the difference. The bottom was maybe a little softer (very subjective here), but better than the non-class a setup for sure. The mids and highs were very similar to the mixed tube setup, that is too say lush, airy and right on. At low volumes it was almost hypnotic; the definition and mids were that good. Most of my listening was on vinyl; genre was classic rock, blues & jazz. Overall, I think I like the all 88 setup best (albeit without the class A bias), but that could be because it was such a jump from the stock 34s at the time. I guess what impressed me most about the all 88 setup (too much tube rolling can be a bad thing) were the dynamics and balance of highs and lows. However, I do like the class A setup, and will stick with all EL34s (mids are the best) for now until I can afford (and my wife lets me) purchase 88 Pentas, or dare I dream, a quad of Telefunken or Genelax Gold Lions. Yeah, I got the bug.

PRE-AMP: TAD-150 Signature
SPEAKERS: Onix Ref 3
SUB: Rocket UFW-12
TABLE: MMF-7
Dave,

Place the EL34s in the V1 & V3 sockets (bias low, eg 175), the KT88s or other large tube in the V2 & V4 sockets (bias high >=500). Mine are set at about 705. I'll do some more critical listening over the weekend, but so far I like what i hear. I will probably live with it for a few days before trying all EL34s in the Class A setup.

Lou
Onotu2,

I was hoping this was possible. I could probably stand a bit of roll off in the highs. So, which tube and its corresponding bias level in which 'V' position? thanks.

Dave
Ok. So I rolled in the stock EL34s at V1 & V3 matched with my EH KT88s as suggested by Paul, and I've listened to about 20 songs (some on cd some on vinyl) that i know very well, and the first thing i noticed was that the highs were a bit rolled off; you could say a little warm or softer. Which isn't necessarily a bad thing because the EH KTs can sound bright. The bass has nice punch, and the mids are lush and defined (just like having all 88s in), but the added warmth of the highs makes for a different and pleasant setup. Its not better, just different. Also this setup makes for a friendlier volume control. I have the TAD150 pre, and set between 9-10:00 it has good definition now. With all 88s, I was at high volumes with the dial at 10-11:00. Not cool when the wife and kids are sleeping. Yeah, i sneak in late night listening. I'm going to try the Class A setup with all EL34s next, and then i think I'm going to get those Penta KT88s. After that I'm going to chill for a while cause all this new vinyl is killing my budget - got a an MMF-7 (first table ever) and I'm loving it.
I tried the Class A Bias with good results. Most noticeably the mids sounded great. I may even try & mix the 34's with the KT88's.

Jeff
I asked Paul the same question earlier today. Here's what he writes: "It appears the bias pots on the 60 do not swing low enough to do the class A mode with larger tubes.
Definitely try with 34's. So far all are really liking the A sound. Could try quasi-A mode - setting the bias low as possible on one 88, maintaining ~700 on the other. This will offer similar results, just not as ideal. Another twist - try running an 88 at 700 and a 34 at 175. Who knows this might even be better." Paul mentions a 700 reading in his reply because 2 of my KT88 are reading at 710. So it appears that you can't do it with KT88s unless you're willing to mix them in with a pair of EL34s. I'm going to try it tonight. I'll let you know how it goes. Btw, has anyone tried the Class A bias with all EL34s?
Dave,

From the bias levels it would be used for the EL34's. I did try it with my stock tubes & it did sound nice. Especially in the mids. Worth a try. Nice to have alternatives.

Jeff
Jeff,

I've got only about 15 hrs. on the Pentas but I really like what I'm hearing so far. From top to bottom they are an improvement over the EL34s with great balance and more articulate bass so I'm looking forward to what 50+ hrs. on them will bring. Do you know if Paul's single-ended class A bias is adaptable to the KT88s or is it just for the EL34s?
Paul has some new bias settings on his site that should be worth trying. The new settings will provide Single Ended Class A for the first 10 watts and Class A/B for 10-50 watts.
Dave, I'm using the Penta 88's also and find them to be a good sounding tube. What are your impressions?
Jeff
I've recently installed the Penta KT88s in my TAD 60 and had a similar experience with high bias readings. The V1, V2 & V4 sockets all rose quickly to the 580 range while the V3 went all the way up to 620. After about 15 minutes at idle, the V1,2 & 3 settled in at approx. 525, while the V3 settled at 585. I'm new to tube power amps so this was pretty scary since I couldn't get down to that recommended 200 starting point but I emailed Paul and he said not to be too concerned unless the readings hit the 700 mark. They never did and all seems well after a couple days.

Dave
Jeff,

Thanks for the reply. I am glad that you got the KT88s running. They are my favotite so far for this amp. I had never thought of adjusting the feedback before biasing the tubes. I used to keep my feedback at 10 o'clock but lately I have it at 1 o'clock. I just biased the tubes at what ever the feedback knob was adjusted to at the time. I really like the KT88's so I don't think I will be rolling in any different tubes for a while. I might start rolling the 12AX7s and 12AU7 tubes in the amp to see if it makes any difference.
New Finding on my oscillating problem. With speakers connected my Feedback knob will function full range with no problems. I read where it's best to have speakers connected on tube amps. Here's what I read, "An output transformer stores inductive energy, and a speaker load prevents this energy from being returned to the tubes in the form of high-voltage transients."

Jeff
Ldatlof,
I got the Penta 88's up and running but it took a little tweaking. I normally would Bias with the Feedback fully right but that was not possible. Actually the left channels, V1 & V2 run quite a bit hotter than the other side. V1 has a reading of 635 at its lowest point so that's where the quad is Biased at. If i turn the feedback all the way up the left channels will oscillate, run excessively hot, and shut the amp down. I had one happy fuse "blown". So I tested a lot, being more careful and finally dialed it in. Paul was helpful. I still may send it in in the future to get a bigger range with the Bias while using 88's or 6550's. Currently breaking in the new tubes and it sounds very good. Thanks for the reply. let me know if you have questions. I'm sure I'll have some.

Jeff
Meerp1: regarding the bias pots I can't get KT88s or 6550s to go much below 525. I noticed Paul changed the bias instructions on his website for the TAD-60. He used to want you to start at 200 (like the EL34) but that is not possible on my amp. I am no expert, but the remedy is probabaly to change the resistors on the bias pots. I'm interested in Paul's answer so keep us posted and good luck.
Ldaltof,
Thanks. I thought that was the case. I'm having a problem with my bias pots at this time so I'm kinda stuck at the moment. Left channel won't cooperate and is excessively hot. Not the tubes to my knowledge as I've rolled several with the same result. Any way to calibrate the bias pot? I did email Paul, hopefully not a painful remedy.
I also have the TAD-150. I'd like to try other tubes in that unit. Thanks.
Jeff
I biased my VA KT88s at 610. I think it is the same for all KT88s & 6550s regardless of who manufactures it. If you were looking for a less romantic sound with more bass - I am sure you will be pleased.

I just rolled a pair of NOS Sylvania triple mica gray plate 5751s into my TAD-150. Sounds real good right out of the box. Also the volume control has more play now because the 5751s have only 70% of the gain that a 12AX7 has.
Hi,
For those of you that have rolled the TAD-60 with KT88's what did you set your bias at? Paul's site states 600-625. Just wondering if this is the same with all mfg's. Just thought I'd give Paul a break and ask the forum. I imagine he spends a lot of time replying to customers. I'll post my thoughts on the Penta KT88's once they burn in a bit. Thanks!
Jeff
Thanks Eagleman. Found quite a few reviews and they all sound good. The folks at Underwood Hifi offer 2 mods, but they seem really expensive. I'm sure rolling in different tubes will probably do the trick. Thanks again.
Onotu2,

I have that set up and using an Eastern Electric Minimax CD with Amperex Navy Nos tubes. Check out the reviews. Will only set you back $900. I rolled in a quad of Tung Sol 6550 reissues. Definitely more punch and extention but, I may go after those Shuguangs...

Eagleman
Strongly agree with Metslp, the TAD-60 is a great piece of equipment. I too switched out the EL-34s for some KT-88s (Electro Harmonix) and I couldn't be happier. The 88s displayed an overall improvement right away, but sounded so much better after settling in - bass is totally on a different level now. However, Metslp has me curious, so I think I'll be trying a quad of Shuguangs soon. I'm new to the tube scene, but I love that you can improve or change the sound with a modest investment.
This is somewhat unrelated, but I would appreciate hearing from other TAD-60 owners as to what CD player or turntable they currently use or would like to purchase. I'm new to vinyl, but I was leaning towards a Rega P5 or VPI Scoutmaster; for the Cd player, a Jolida JD-100 or Shanling 100. I currently have no true cd player, I'm using an X-box - pls don't laugh - and Apple's Airport to stream my mp3s to my TAD-150 preamp.
Metslp, do your Shuguang KT88 plates have holes in them or are they solid? I replaced my Svet EL34 with Shuguang (Valve Art) KT88's and think it's a real improvement over the stock EL34s. I agree exactly with your assessment of the KT-88's I got the one with holes but there is a lot of buzz on the net that the solid plate Shuguang (Penta) are the ones to buy, so I was wondering which ones you have?
Metslp, how did you choose the Shuguang tubes? I just rolled in a quad of Tung Sol reissues with excellent results. More punchy music, stronger bottom end...

Eagleman
Just rolled in a set of Electro-Harmonix KT-88s this weekend and the difference IMO was an overall improvement. The most noticeable difference was in increased headroom and a tighter more controlled bass. There was also a nice seperation of instruments in the highs and mids, a welcomed plus, because I love the sweet tone of the EL-34s but the KT-88s were right there as well. In general, I thought the EL-34 could muddy the bass a little when volume levels were cranked, where the KT-88 really held things together at high volumes. You know you've found a good thing when new things jump at you (in a good way) on familiar tunes that you couldn't zone in on before. Always brings a smile to my face. I was running the TAD-60 in tri-mode with the EL34s because I liked the warmth in the mid-range over the UL setting. However, I did like the extra power and dynamics UL provided, but I was constantly adjusting feedback to find that elusive level of warmth. With the KT-88s I have the TAD-60 set to UL mode now, with the feedback knob set at 2:30 and haven't felt the need to touch it once; its a perfect blend of warmth & dynamics that I couldn't achieve with the EL-34's. Tubes were purchased from the Tubedepot, they arrived in 2 days and were very helpful on the phone. However, 2 of them were running a little hot (715-720 range), so I freaked and called Paul, who was very good about walking me thru the setup, tubology 101, and assuring me that they would run fine. As you can probably tell, I'm new at this stuff, so it's nice to have a real pro to call when you need help.
I also wonder how the upcoming TAD 803 speakers would fare with the TAD 60/TAD 150 setup. From the info listed on Paul's site, it sounds pretty impressive for $499. I just can't get that B&W image out of my head for a long time. Maybe I wait a few more weeks and see if any new 803 owners will chime in as the shippments are being filled this month.

Thanks for the suggestions anyways.
Interesting that you use MG 1.6 speakers...so do I. Some time ago I investigated whether I could use 60watt tube amps for my three MG1.6. In spite of the fact that my Maggies are crossed over from subwoofers, usually at about 80 Hz, voltage measurements at the speaker terminals revealed peaks that could only be achieved by a much more powerful amp. Mine are 600 watts into 4 ohms, and they just barely make it without clipping. Admittedly this was with very loud and challenging organ music, but that is sometimes what I listen to.

This TAD amp, and the model 1000 which would interest me appear to be excellent products at a very reasonable price. They remind me of the tube amps that I knew many years ago. However, the thought of the care and feeding of a dozen output tubes (for three TAD1000) puts me off! If I had a small system played softly these TAD amps would be in it.