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REVIEW: Dynaco Dynaco ST-70 KIT Amplifier (Tube)

66.185.1.21

Posted on March 18, 2009 at 17:55:07
kimjohns
Audiophile

Posts: 2
Location: Rural central Iowa
Joined: March 18, 2009
Model: Dynaco ST-70 KIT
Category: Amplifier (Tube)
Suggested Retail Price: $695
Description: An upgraded Dynaco ST-70 in KIT form
Manufacturer URL: Dynaco
Model Picture: View

Review by kimjohns on March 18, 2009 at 17:55:07
IP Address: 66.185.1.21
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for the Dynaco ST-70 KIT


I just turned 60 and have decided to simplify my life, smell the roses so to speak, and to do things that help relieve the stress and worries of our dismal national and global situation. I got rid of my home theater system (there is no hope for Hollywood) and decided to revisit simple stereo high fidelity and all of the pleasures that it used to give me. I never spent huge amounts of money on expensive stereo equipment, preferring to buy and build components that gave a lot of bang for the buck from the likes of Dynaco, AR, KLH, Grado and Hafler while hacking and tweaking all along the way. For me this was the true spirit of stereo, simple and relatively inexpensive (a lot of it built and serviced by myself). With that came much personal delight and satisfaction. This time around I thought I might try a valve amplifier, preferably a kit. Searching around on the net, I found a few kits. Most were priced more than I wanted to spend and fully assembled tube amps were mostly out of the question. One thing I noticed was that a huge part of the cost of this stuff is in the cosmetics and most of it is, in my opinion, just plain ugly. Not interested. Anyhow, upon further looking I hit upon Bob Latino's website and his modernized Dynaco ST-70. Everything about this rig looked good but I was a little apprehensive about spending a big chunk of change on an amp design that was almost 50 years old. More importantly there were just not a lot of reviews on Mr. Latino’s reissue of this amp. The ones that I did read were, however, very favorable. I bought one anyhow. Sometimes my least researched purchases turn into winners and I was hoping this would be one of them. The kit was a breeze and a delight to assemble, being pat Dynaco. Once assembled and work checked twice (remember I just turned 60), I set the output tube bias voltages, which took about 5 minutes. I then hooked up a pair of speakers, an old Harmon Kardon HD 8600ll CD player that has a volume control on the output (so I did not need a preamp). At this point there was dead silence, absolute quiet. I was worried. I gathered up my wife for the moment and then hit the play button. I immediately turned to my wife and said "holy crap, are you hearing this?” She said "yes"! To make a long story a little longer, this is one of the best stereo moves that my wife and I have ever made. I have no regrets whatsoever. It is exactly what I wanted in a valve amplifier. Since then (it was a Christmas present), I have scratch-built a preamplifier with phono inputs, designed and built a pair of two-way vented speakers tailored to this amp, bought a turntable, got out my boxes of records and have elevated my general quality of life significantly. The spirit of DIY lives again.


Pros: I am incredibly happy with the ST-70. Bob Latino is a nice guy to do business with.

Cons: It is 2009 instead of 1960.

Kim L. Johnson


Product Weakness: None
Product Strengths: Lots of bang for the buck and you get to build it yourself


Associated Equipment for this Review:

Amplifier: ST-70
Preamplifier (or None if Integrated): Scratch-built using ESP boards
Sources (CDP/Turntable): HK CD player, Rega P3
Speakers: Custom designed and built
Cables/Interconnects: inexpensive balanced
Music Used (Genre/Selections): Everything except rap
Room Size (LxWxH): 22 x 26 x 9
Room Comments/Treatments: Typical livingroom
Time Period/Length of Audition: 3 months
Other (Power Conditioner etc.): Triplite surge
Type of Audition/Review: Product Owner
Your System (if other than home audition): none


 

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Outstanding review and pictures, posted on March 18, 2009 at 19:12:15
kh6idf
Audiophile

Posts: 1047
Location: Texas
Joined: May 2, 2001
I enjoyed reading your review and looking at all the pictures. Reminds me of my old Heathkit building days.

 

Ahh, brings back memories of my college days experience with Dynaco kit, posted on March 18, 2009 at 19:35:09
rlindsa
Audiophile

Posts: 7232
Location: Fort Lauderdale
Joined: October 5, 2004
Nice review by the way.

Back in 1970 I built a Dynaco SCA80Q (the Q was for Quadrophonic, in the early stages of its short life then). Spent about 20 hours straight plugging, reading transistors, soldering, wire stripping, etc. I wasn't "electrically experienced", but I followed directions well. Felt like I was building a cyclotron or some such monstrous electronic gizmo - had a great time. Then the "bit moment" came when I connected my AR turntable and Dynaco A25 speakers and hit the power switch on the SCA80Q; a moment of pure bliss before a loud pop and FLAMES shoot out of the amp! I was crestfallen and figured I had completely destroyed the unit (which if I remember correctly cost about $75 or so - small fortune at the time).

My dad had one of his electrician buddies look at it and turns out I had put in a power transistor wrong. He replaced that and it ran like a champ for several years. Can't remember why I got rid of it

Wish I still had that old system (sniff, sniff).

rlindsa

 

I built a ST 70 in college,, posted on March 18, 2009 at 22:57:07
M3 lover
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Posts: 5127
Location: So. California
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Contributor
  Since:
July 4, 2007
along with a PAS-3 and FM-3. I hoped to learn something about electronics but all that came from it was the ability to solder and cut a green wire 6" long! Well, that and hours and hours of musical pleasure. I added AR speakers, and a Dual table with Empire cartridge. It was my first "stereo system".

That was in the '60s and I've gone through countless components since then, and more than a little money. But I've wondered sometimes if I ever had another system that gave me so much musical pleasure.

Glad you two are loving your new one so much.

 

Isnt that a hell of an amp for the money?, posted on March 19, 2009 at 00:14:06
Michael Samra
Dealer

Posts: 35887
Location: saginaw michigan
Joined: January 30, 2005
Contributor
  Since:
June 24, 2005
Where else can you get a literally 95% american amp with tubes with that kind of quality and power for that little money? We are talkng new here plus it has separate bias pots for each tube and,you can kt66s or 6L6gc and el34s and even kt88s.
If the power supply waveform isn't pretty,neither is the sound in most cases.

 

RE: REVIEW: Dynaco Dynaco ST-70 KIT Amplifier (Tube), posted on March 19, 2009 at 01:35:42
rgurney
Audiophile

Posts: 343
Location: Virginia
Joined: May 1, 2001
I agree. I built Bob Latino ST70 and ST120 kits. Both were a true joy to build and sound fabulous. Can't be beat for value.

 

RE: REVIEW: Dynaco Dynaco ST-70 KIT - preamp, posted on March 19, 2009 at 08:26:50
PeterI
Audiophile

Posts: 1359
Location: Colorado
Joined: October 17, 2006
It's always great to see the connection between projects, music, and personal happiness. That's a good-lookin ST70. What preamp design did you build?

Pete

 

Thanks, posted on March 19, 2009 at 09:47:09
WilHenry
Audiophile

Posts: 507
Location: upper midwest
Joined: January 21, 2003
Thanks, you made me smile ear to ear!

 

Groovy! Now you can have the joy, fun and pleasure of tube rolling!..., posted on March 19, 2009 at 10:48:48
musetap
Audiophile

Posts: 19346
Location: San Francisco
Joined: July 8, 2003
Contributor
  Since:
January 28, 2004
Believe me, it's a gas and a true learning experience.

The ST-70 design is a classic, and with the "better" parts available in the current kits, you now have a great amp that should last
a long time. I've read quite a few good things about the Bob Latino kit and am happy to read of your experience.

ENJOY!!!


"...You're all welcome to stay for the next set...we're going to play all the same tunes, but in different keys..." -Count Basie

 

RE: REVIEW: Dynaco Dynaco ST-70 KIT Amplifier (Tube), posted on March 19, 2009 at 11:06:08
Mick Wolfe
Audiophile

Posts: 1775
Joined: October 10, 1999
Contributor
  Since:
September 4, 2000
I already own Bob's ST 70 and I plan on adding the 120 soon. What sonic differences do you notice in these two amps? I'm assuming the 120 will get you better dynamics and a greater sense of ease while retaining the superb musicality of the 70. For the record, I'm using Gold Lion KT 88s ( re-issue ) in the 70 and would use the same tube in the 120. Thanks for your thoughts.

 

I used to have an unmodified ST-70, posted on March 19, 2009 at 14:12:59
DAT
Audiophile

Posts: 1400
Location: North Carolina, mountains
Joined: February 1, 2001
and while I liked it, I don't have the knowledge or skills that you possess. In fact, I barely trusted myself to set the bias without electrocuting myself.

Ultimately, I sold it on eBay, and, like most vintage gear I've sold, it wound up overseas. In this case Spain.

The only reason I got rid of it was I had a new toy, a badly neglected H.H. Scott 208, which I had professionally rebuilt, because I really didn't want to burn my house down.

 

RE: REVIEW: Dynaco Dynaco ST-70 KIT Amplifier (Tube), posted on March 19, 2009 at 15:17:38
rgurney
Audiophile

Posts: 343
Location: Virginia
Joined: May 1, 2001
Yes the 120, having more power, will get better dynamics and may better fit less efficient speakers. It is designed to use the KT88. I am using Ei KT-90 tubes in mine. The 70 can be used with a wider range of tubes - I'm using the new re-issue Gold Lion KT-66.
In both I replaced the stock output caps with the Russian K40y9 caps. A nice inexpensive upgrade even recommended by Bob.

 

RE: REVIEW: Dynaco Dynaco ST-70 KIT Amplifier (Tube), posted on March 19, 2009 at 16:06:19
Mick Wolfe
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Posts: 1775
Joined: October 10, 1999
Contributor
  Since:
September 4, 2000
Yes, my speakers are 88 db and although the 70 does a great job, the 120 might be a more ideal fit. That said, the 70 isn't going anywhere regardless. You'd be hard pressed to find its equal at a minimum of twice the price. I too am very curious about both the re-issue KT 66 and 77.

 

RE: REVIEW: Dynaco Dynaco ST-70 KIT - preamp, posted on March 19, 2009 at 17:41:26
kimjohns
Audiophile

Posts: 2
Location: Rural central Iowa
Joined: March 18, 2009
I built the preamp using boards from ESP (Elliot Sound products) in Australia. I used their “high quality audio preamplifier” (P88), "hi-fi phono preamp” (P06), and “preamp power supply" (P05) PC boards. They use Texas Instruments/Burr Brown OPA2134 opamps. My total cost of construction was maybe around $125. This is a very interesting company with a great website that has a lot of useful information. Rod Elliot claims that the performance of his preamps equal or exceed that of very high-end components. I tend to agree. This preamp is better than anything I have previously built. I am going to add his subsonic/rumble filter board soon. I will most likely build a tube preamp sometime in the not to distant future, but for now I am going to absorb what I have for awhile.



Kim L. Johnson

 

RE: REVIEW: Dynaco Dynaco ST-70 KIT Amplifier (Tube), posted on March 20, 2009 at 07:49:40
rgurney
Audiophile

Posts: 343
Location: Virginia
Joined: May 1, 2001
The ST-70 is optimized for 5881, 6L6, KT66, and KT77
The ST-120 is optimized for 6550, KT88, and KT90.

My personal preference for the 70 is the KT-66; for the 120, it's the KT-90.

Enjoy.

 

RE: I used to have an unmodified ST-70, posted on March 20, 2009 at 08:30:02
Mick Wolfe
Audiophile

Posts: 1775
Joined: October 10, 1999
Contributor
  Since:
September 4, 2000
The Latino 70 and 120 can be bought fully assembled at an equally reasonable price. The 70 ( and I'm sure the 120) are very user friendly and safe in regard to biasing. You will still need a meter, however.

 

Yes, but the Scott 208 sounds better (than my old ST-70), posted on March 20, 2009 at 11:46:55
DAT
Audiophile

Posts: 1400
Location: North Carolina, mountains
Joined: February 1, 2001
and doesn't have to be biased at all.

 

RE: Yes, but the Scott 208 sounds better (than my old ST-70), posted on March 20, 2009 at 13:50:27
Mick Wolfe
Audiophile

Posts: 1775
Joined: October 10, 1999
Contributor
  Since:
September 4, 2000
The Latino ST 70 is a completely different animal sonically as compared to the original. If auto-bias is a priority, however, you're right in that you won't find it here.

 

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