Dynaco MK IIIs

[Erik Mandaville]

This builder does some of the best work I have seen -- pristine, just as with the factory spec. Dyna 70s he does. Just in case someone might be interested in a time-tested circuit in the form of monoblocks at what are always reasonable prices.

Erik

http://cgi.ebay.com/NEW-DYNACO-MARK-III-TUBE-AMPLIFIERS-BY-AMPLITUBE_W0QQitemZ110169904368QQihZ001QQcategoryZ3280QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[Daddy Dee]

Beauty, eh!

I had a pair of the builder's Mark III's and thought they were very nice, like new from the factory. Also had a chance to take them down to a forum gathering in Hope a couple of years ago and quite a few forum members had a chance to hear them. They perform impressively. IMO.

[seti]

Beauty, eh!

I had a pair of the builder's Mark III's and thought they were very nice, like new from the factory. Also had a chance to take them down to a forum gathering in Hope a couple of years ago and quite a few forum members had a chance to hear them. They perform impressively. IMO.

 I heard Dee's MKIII's at the Goat Roper and I was very impressed. I never knew Dynaco's could sound that good. I could live with a pair and be very happy.

[scott0527]

This builder does some of the best work I have seen -- pristine, just as with the factory spec. Dyna 70s he does. Just in case someone might be interested in a time-tested circuit in the form of monoblocks at what are always reasonable prices.

Erik

http://cgi.ebay.com/NEW-DYNACO-MARK-III-TUBE-AMPLIFIERS-BY-AMPLITUBE_W0QQitemZ110169904368QQihZ001QQcategoryZ3280QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Chassis made by yours truly![]

[Erik Mandaville]

Dee:

Maybe you thought these were Autospec's MK IIIs? This is another builder who I, as well as a couple of others have mentioned here before. If not, I didn't realize you had once had a pair of Amplitube's amps. Pardon the confustion there. In any event, he also offers a great looking kit for the ST 70.

Scott:

Who is 'yours truly'? You supply the chassis?

Erik

[Daddy Dee]

Oh OK, my bad.

I was forgetting Will's Ebay ID. Is this the guy who, a couple of years ago, had rebuilt Mark III's on a plate type chassis mounted on a wood base?

Anyway, I don't after all, have personal experience with this builder. Just impressed with what I've seen.

[mark1101]

The price sure looks right.

[NOSValves]

The only problem with these Mark III repop's is nothing has been done to solve the over voltage at turn on design flaw on the power supply filter can. These modern twist locks made by AES are less reliable in a Mark III then the original were back in the 60's. I learned this the hard way I've had at least 8 of them fail in about 6 months to 1 year after being placed in service. In my rebuilds I even addressed the over voltage condition at start up VIA inrush current limiters and these cans fail anyway. You need a 600V or higher rated power supply in a Mark III. Other then that this looks to be a great deal.

Craig

[Guy Landau]

No offense,

They look quite ordinary to me.

[mark1101]

So....is it a simple mod to beef up the PS? How much would that cost? For $900 + the cost of a mod.

[scott0527]

Dee:

Maybe you thought these were Autospec's MK IIIs? This is another builder who I, as well as a couple of others have mentioned here before. If not, I didn't realize you had once had a pair of Amplitube's amps. Pardon the confustion there. In any event, he also offers a great looking kit for the ST 70.

Scott:

Who is 'yours truly'? You supply the chassis?

Erik

Erik,

Sort of. I had a bunch of ST70 and MKIII chassis made in my fabricating shop a couple of years ago. Chris(the builder of these) bought some from me. A few other fab shops started making Dynaco stuff so I haven't run any for a while. My shop is a production shop so I can only really run stuff that has a little bit of volume.

On another note, Holy Smokes, it's Craig. Must have resolved your computer problems?

[anarchist]

So....is it a simple mod to beef up the PS? How much would that cost? For $900 + the cost of a mod.

Keep it just like it is with the defective power supply or skip it.

You could beef up the power supply for $100.00 or so using great caps but it is simple. Then you want to beef up the bias. Then you need to put in new driver boards. Then you need to upgrade the chassis because the original Dynaco chassis are fugly (IMHO).

Not a great value proposition... now if the bias were done and you had great chassis to start with... driver boards and power supply are a no brainer. If you are going this route, start with a cheaper set of mkIII's and roll your own.

For value and no effort on your part, buy a set of used VRD's and be done.

[Erik Mandaville]

I agree, they are an extremely good value considering other available, far more expensive options.

If you want a fancy package, look elsewhere. Some put, and in my opinion correctly so, more value on performance than clever casework and expensive wood -- that does nothing other than improve appearance and add to cost, and only then if that's what one might prefer in terms of aesthetics. An all metal chassis with an actively grounded bottom plate will give much better performance in terms of shielding than any wood-only sided amp (including my own Moondogs and former Parafeed) in RFI/EMI prone areas.

The answer is simple: If you don't care for it, turn the steering wheel in some other direction.

Indicating that someone automatically has to put in new driver boards is premature. There are MANY people who are happy with the stock Dynaco circuits, and this one is put together better than many amplifiers I have seen on this forum. I know enough about this to make the judgement.

I've been interested in his ST 70 kit for a few years, and, despite the fact that I have the ability to take advantage of the heap of modifications available, would leave it stock.

The comment about great caps is also sort of a simple way of looking at this. A great cap is only great if it results in a 'great' sonic improvement. I've used very expensive capacitors that sounded worse. Many beginners tend to look at capacitors as THE deciding factor. It's simply not always the case. I've done enough building myself to know that. Many new to the hobby seem to get really bogged down with the coupling capacitor issue, which is easier to understand, I would say, than the circuit, itself. Some here have even suggested using very expensive capacitors in positions where the cheapest ceramic capacitor from Radio Shack (which are too expensive) would do just as well.

Very good cost/performance ratio.

Erik

[Erik Mandaville]

"For value and no effort on your part, buy a set of used VRD's and be done."

That would depend on the person, I would say.

Erik

[Erik Mandaville]

And Scott:

Erik,

Sort of. I had a bunch of ST70 and MKIII chassis made in my fabricating shop a couple of years ago. Chris(the builder of these) bought some from me. A few other fab shops started making Dynaco stuff so I haven't run any for a while. My shop is a production shop so I can only really run stuff that has a little bit of volume.

Then you have my compliments. Very nice work indeed! You did the plating, as well?

Erik

[Erik Mandaville]

Dee:

I figured you were thinking of Will, another artist and great builder!

I LOVE the ST-70 he did for us. No plans for Welborne Labs, AVA, or any other modification. I'm enjoying a classic design that still works extremely well.

Erik

[Erik Mandaville]

Lastly, to the few who contacted me about these: If a purchase were made and the power supply failed due to an inherent design flaw, I will repair for free. I am as able as any who have posted in thread to do the required work. However, Chris already offers his own warranty, and he is a nice person who has very high standards.

Erik

[anarchist]

Erik,

Of course, everything I said is my opinion and is based on my tastes. Some people like the stock Dynaco sound and the simple driver board it comes with. Some people like that nasty metal case. I don't, that is all. I would have bought a ST70 8 years ago if I could tolerate its looks. Others like 'em.

Different tastes for different folks. For me, its simple, the stock metal case can be improved dramatically and Will demonstrates just how awesome a set of Dynaco's can look. Others on this board produce amps using a wood case or metal cases that provide fantastic aesthetics. To each their own.

For folks who want a set of Dynaco's using stock circuits, these are very nice (a bit pricey but what the hell) and your offer to fix the power supply is mighty generous. Of course, that design flaw has existed for 40 years so I don't expect you will be replacing them very often and it shouldn't make a potential purchaser overly concerned. There are aftermarket cans available now that should handle the surge a bit better (according to their claims) and in fact one company produces a 600 volt can although obtaining one isn't the simplest thing to do.

[Erik Mandaville]

Erik,

Of course, everything I said is my opinion and is based on my tastes. Some people like the stock Dynaco sound and the simple driver board it comes with. Some people like that nasty metal case. I don't, that is all. I would have bought a ST70 8 years ago if I could tolerate its looks. Others like 'em.

Different tastes for different folks. For me, its simple, the stock metal case can be improved dramatically and Will demonstrates just how awesome a set of Dynaco's can look. Others on this board produce amps using a wood case or metal cases that provide fantastic aesthetics. To each their own.

For folks who want a set of Dynaco's using stock circuits, these are very nice (a bit pricey but what the hell) and your offer to fix the power supply is mighty generous. Of course, that design flaw has existed for 40 years so I don't expect you will be replacing them very often and it shouldn't make a potential purchaser overly concerned. There are aftermarket cans available now that should handle the surge a bit better (according to their claims) and in fact one company produces a 600 volt can although obtaining one isn't the simplest thing to do.

Absolutely, I agree with what you said above. Will takes great time with the Dyna chassis, but he is a master metal worker, with many, many years of professional work in that field. He is able to take a badly damaged chassis and turn it into something much, much nicer to look at it. And I think what he did with ours is really great. But that said, I guess I grew up learning to appreciate pure form and function in electronic equipment, and that's what the original Dyna Chassis portray for me. That kind of simplicity can be nice to look at for those who prefer it. The Baldwins are more like that than virtually any amp I have seen. Their appearance is based on the physiology needed to support transformers, chokes, tube sockets, and filter caps, and that's it. Function with no attempt at superficial ornamentation. Some people also like to use fins of clear acrylic plastic, glowing blue like spaceship wings in the light given off by hidden LEDs. Ugh. I don't like that in the least, but I am not one to tell someone else that his or her amp (or whatever component) lacks in any way whatsoever because of that. In fact, it may offer great performance despite the fancy light show.

And sure. As Craig said, if a problem arises, as with any product (which have surfaced here and there with a number of components offered here on the forum -- it happens to the best), something can be done to fix it at a small cost.

In my book, they are still a good deal. Look closely at the workmanship, wire connections, etc. They are well done, and that's important.

Erik

[Cornman]

Interesting thread Erick. I have no experience with the Dynaco's so I am asking - with all things being equal (condition & same upgrades) is the MkIII generally considered to have a better sound then the Dynaco st70?

Cornman