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Dynaco amp lovers!


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Many of us "of a certain age" had our first real hi-fi experience as a result of building dynakits. They were well-designed and, in kit form, cheap enough for a student or newly-wed to afford. The instruction booklets were well-written and illustrated. Darn near fool-proof.

My first project was a Dynaco ST-35 tube amp that cost $45 including the tubes! A few years later I stepped up to the ST-120 and although some would argue the ST-35 was a "sweeter" little amp the 120 was pretty ground-breaking in its day. I eventually sold both (along with a PAT-4) but a couple of years ago I decided to get a used ST-120 to restore.

CSP member John O'Hanlon helped me find some replacements for the big capacitors but the amp had other issues so I put it aside until a couple of weeks ago. I was looking for mods and upgrades (the 40+ year old design does have shortcomings) when I stumbled across a gold mine!

http://www.updatemydynaco.com/ is a great site that offers a load of upgrades and improvements for the ST-120. Long story short: I ordered every possible upgrade (the "Full Monty"), leaving only the original chassis, power cord, binding posts and transformer. I opted to spend an extra $10 for the amp modules used the AkitikA GT-101 power amplifier. The difference between those and the regular ST-120 replacements: 0.1% versus 1% gain setting resistors, 10,000 uF output capacitors versus 3300 uF output capacitors. I also bought the new heat sinks (very nice but unnecessary), power supply upgrade, power supply and C12 caps and a blue LED mod for the power switch (purely cosmetic). The prices were very reasonable IMHO (total was under $200). I installed new RCA jacks and new feet that I had on hand but those are also available on the site.

Delivery was FAST. All of the parts are high quality and the new printed circuit boards are well-made and clearly labeled. Instructions (available on the site) are as clear and complete as the original Dynaco manual. Best of all: The owner/designer Dan Joffe provides super-fast helpful tech support (I had made one bone-headed goof).

So today I finished the amp and after bringing it up on a Variac (just a precaution) I gave it the real test: Powering the AR-3a's. The 3a's are supposedly power-hungry and at 4 ohms they pose a tricky load. I played a variety of music: Jazz, Rock, Classical (including organ) at decible levels WAY higher than normal. They sounded great. And the amp wasn't stressed at all. The heat sinks got barely tepid and there was no hint of clipping. According to Dan, the updated modules put out more than 50 Watts, but a shade less than 60 Watts into 8 Ohms and nearly 90 Watts into 4 Ohms. I plan to take the amp to my favorite tech for testing but to my ears it's all good. A few photos below of before & after, and the amp being auditioned.

IMHO the updatemydynaco kits are true heirs to the Dynaco legacy and Dan Joffe may be the latter day David Hafler. And the tech support is incredible.

If you have a tired old ST-120 do yourself a favor and update it with one or more of these modules. Don't have an ST-120? The AkitikA GT-101 provides the chassis and a modern torroidal transformer. Updatemydynaco also sells some modules and upgrades for the PAT-4 preamp, SCA-80 integrated amp and the mighty ST-400. Makes me sorry I sold my old PAT-4!

I have no connection with this outfit--just a really satisfied customer.

-Kent

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  • 8 months later...

Update:

Dan at Akitika (it's a palindrome) has just announced the release of his preamp kit. I have not built it but it looks like a winner. Sort of a 21st century PAT-4. It has a remote and expansion panels for future additions and improvements. Not much is made in the USA anymore, and the hi-fi components that are cost a fortune. This is a return to high quality affordable kit philosophy behind Dynaco and Hafler.

btw--I get nothing from this--I just think it's a worthy product and Dan is a good guy.

-Kent

check it out: http://www.akitika.com/.

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  • 3 years later...

A follow-up:

AkitikA's power amp kit, the GT101, has been replaced by the GT-102. Dan Joffe tells me the GT-102 is very similar to the "full monty" Dynaco ST-120 rebuild I did using his updatemydynaco kits.

Now Stereophile has reviewed the ST-102 in their July issue https://www.stereophile.com/content/hot-shade-july  Dan says "they loved it" but the review isn't online yet. 

If you are looking to breathe new life into your old Dynaco, this is a good resource: https://www.updatemydynaco.com

-Kent

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When I saw this thread pop up again, I had forgotten that I had read the original discussion and was expecting to see a different topic. These upgrade options for the Dynaco ST-120 are quite interesting (does that transformer get rotated?), and this is a really helpful write-up - - - thx, JKent. It is good to know that this amplifier has an option for an affordable upgrade for the DIY-er. Years ago, I had my own Dynaco system with ST-120, PAT-4, and FM-5, and it served me well for many years.

What I had expected was that this thread title would lead to a discussion of a new Dynaco amplifier introduced a little over a year ago. Since this falls within the scope of "Dynaco amp lovers!", I'll just add it to this thread - - I don't think this product has been mentioned yet in this forum. 

The product is a contemporary reincarnation of the venerable ST-70 tube amplifier, now called the ST-70 Series 3. Made in Canada but unavailable in kit form (and soon to be followed by a ST-1 preamplifier). The ST-70 appears to have a rugged build quality and the renewed aesthetics are very much in the spirit of the original. Selling for about $2K, it's still beyond my budget, but I somehow get the feeling it might just be all the amplifier I'd ever need. 

Website info: http://www.dynaco.com/st70#0

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That looks pretty cool! But I did a little searching and it looks like it's $3,000! Yikes!

It's amazing the staying power of the Dynaco line. I've seen a couple of modern-day renditions.

Here's an ST-70 kit: http://triodeelectronics.com/st70buildkit.html

Here are some more: https://www.dynakitparts.com/product-category/dynakit-products/amplifier-kits/

And some more: http://www.tubes4hifi.com/bob.htm#ST70

And Bob Latino is pretty well known http://bob01605.50webs.com

Of course, those are ll tube amps. updatemydynaco is the only outfit I know of that focuses on the solid state. Dan's kits are very nice and affordable. 

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4 hours ago, JKent said:

But I did a little searching and it looks like it's $3,000! Yikes!

Yikes indeed! I wish I could find the original preview article I read that was predicting the lesser price. Geez, it must be those recent trade tariffs kicking in already! :lol:  

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  • 2 weeks later...

Here's the Stereophile review of the AkitikA GT-102 power amp:

https://www.stereophile.com/content/akitika-gt-102-power-amplifier

Here's the last sentence: "Super-highly recommended." Some people in the "comments" section say that Emotiva gives more bang for the buck. My original post was not about the complete amp kit per se but about my satisfaction with updatemydynaco.com. I love the instruction manuals, email support and all the clever updates for aging Dynaco gear. If you have an old Dynaco that needs updating, this is your source!

-Kent

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  • 2 months later...

An update (no pun intended) on this: When I did my ST-120 I bought all the individual kits. Dan now has a complete upgrade kit and complete instructions, AND a YouTube video. Wish I had this when I did mine because IIRC I made one mistake.

Check it out: https://www.updatemydynaco.com/storeindex.html#OPA1611X2

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  • 5 months later...

Almost 5 years after my initial "upgrade." As described above, it was a total rebuild. Only things left original were the chassis/cover, transformer and the heatsink for the power supply.

Recently Dan sent a high-pressure sales pitch: "You don't need this upgrade, but you might want it" ? He calls it The Really Big Heatsink and it replaces the flat original with a massive finned job that also includes a capacitor and resistor upgrade, increasing the current limit from 3 Amps to 3.5A for 36w more power. Cost: $22.

While I was under the hood I also installed his volume control kit ($10) and a pair of blue LEDs to replace resistors R9 ($1/pair). The blue lights serve no function whatsoever but make the amp glow with a cool blue light ;) The only other upgrade left would be the LED level meter but since my amp is hidden in a cabinet that would be a total waste of time & money.

I had a snag (was being stupid) and emailed for tech support. Got an answer within an hour.

Photo shows the new heatsink to the left and new volume control on the right, between the banana jacks.

Second shot shows the blue lights. The amp is in the rec room with a blu ray player and an AR-SRC as the preamp/remote.

Dan has upgrades for other Dynaco gear, and he also has complete amplifier and preamp kits. You can also find tips and other free resources on his site: https://www.updatemydynaco.com/index.php

I'll say it again: I get nothing for promoting this stuff. I just like what he does and how he does it.

-Kent

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  • 1 year later...

Well, I "did" have every mod offered for the ST-120 but updatemydynaco just released a speaker muting kit that "adds a relay that delays connection to the speakers until everything is completely charged and ready to go. On turn-off, it disconnects the speakers before the power supply sags enough to disturb the operating point." Dan is obsessed with providing updates. I may skip this latest mod, but for $25 maybe....

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  • 1 month later...

Stumbled upon this thread which may be the best thing I've done all year.

I've recently acquired a set of "Holophone Sopranos" and after recapping, sound amazing! The sound stage is quite wonderful.

With my trusty Lenco L70, I'm afraid that my 1990's pre/power amp combo "Cambridge Audio" is letting the side down.

Although it's the best listening experience I've had at home, I think going in the direction of a tube amp is the way forward considering the quality and vintage of the other units.

So then, Dynaco? I'm not willing to dive straight in with €1500, but tipping my toes in for €375, I am.

I've seen this on a local secondhand site and am very interested.

(Apparently it's new and hardly used, as it wont fit into his cabinet!!)

No refunds, so if I don't like it, I'll have too try and sell it on.

Any advice on adding this to my set up?

 

Many thanks,

Stephen

 

 

 

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That may be a nice amp, I don't know. It's definitely NOT a Dynaco. It's a Dynavox Tube Amplifier VR-70 E-2. If you google it you'll find some discussion. I think 375 Euro is about half the recommended retail price but I don't know how much they really sell for.

Kent

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