Dynaco MKIII - buy, build, or forget?

nasadowsk

nasadowsk

Bow:good, hunt:needs work
Ok, so, my current setup:

Pre: Sansui CA2000
Power: Fisher SA-100
Speakers: Klipsch RP-260F

It's good, but the power amp eats 7189s, it's a little wimpy, and, I'd like a bit better/more (who wouldn't? :) )

I'm thinking of a pair of Dynaco MKIIIs, and I'm not sure if this would acttualy be a worthwhile upgrade. I mean, let's face it, the Fisher's no slouch, but the Dynacos don't seem to be either.

So, the first question is really, is this a worthwhile idea?

Second - do I try to scrounge up a vintage pair then restore, or should I go to dynakitparts and just buy the kits for 2 new ones. Building it is no issue - I've resto'd TVs before. The thought is that 2 new ones are...new. But, will they match the original performance? A vintage pair is a gamble, is it more 'genuine'?

Any thought anyone?

Thanks! :thumbsup:
 
I would try some new speakers before changing power amps. If you like the Klipsch sound, some heritage line speakers like Fortes might blow you away with that SA-100.
 
Also maybe consider Dave's EFB setup for the SA-100. It should make it easier on the tubes and it gives a little extra power to boot.

http://audiokarma.org/forums/index.php?threads/improving-the-fisher-sa-100-with-efb-ii.476431/

just a thought.

I've heard that the repop Dyna trafos are actually extremely good. Frankly unless I got a really good deal on old ones, its tempting to just buy/build new rather than starting with something old and doing almost the same work to replace bad components.
 
You won't have any trouble matching the performance of the original Mk III with the kit. I've used the replica A430 transformers, they are extremely good.

I can't really advise on whether it's better to restore the SA-100 or get the Mk III kits. Just depends on what you are after. Don't underestimate the Fisher gear though. Properly restored and fixed so it doesn't eat those tubes (as per Gadget's recommendations) the Fisher will deliver world class performance, within the power range it's capable of.
 
I have listened to those speakers and they do have an anemic bass. Even with speakers that large you still need a subwoofer. As I've always said no matter what "magic" you use you are NOT going to get actual bass from a 6.5" cone. But that's a troll for the speaker forum.

Anyhow, I would go with the VTA monoblocks or simply the ST-120. By the time you buy a vintage amp, rebuild it, tweak it out, why not just start new. New sockets, wiring, components, your choice of tubes and tweaked up more modern driver board,etc...

http://www.tubes4hifi.com/

Just to complete the speaker troll, the 6.5 inch cone has been grossly misrepresented and sold off as a bass cone. IMHO (worth nothing) the best use for that cone size is a good quality monitor type speaker and a pair of subwoofers. Yeah, stereo subs!!!
 
Last edited:
Another 2 cents (at this rate I'll be broke by lunch) but for the 60 watt per channel level, I'd go Mark III rather than ST-120. Big stereo tube amps are annoyingly heavy.
 
I love my MK3's that I scratch built but knowing what I know now I would buy a kit. Buying a piece at a time isn't worth it and cost me more in the long run. Building kits are fun too. Make sure to get the 12au7 or the 6sn7 driver boards. The modern replacement boards are just so much better and most of them have bias points so you can adjust bias voltage in each output tube. I know the factory design had a balance pot but you couldn't fully adjust the bias if you wanted to run them a little cooler.
 
Go for the kit. Or maybe a vta70 ( you get twice the volume from the current amp) and half the price of two MkIII
There is no inherent value of an old amp as new production can keep the same level ( or even better)
 
However, if you're patient or lucky or both, you can find some real gems for cheap if budget is an issue like it can be for me. I paid maybe half of what I should have for my ST-70, dropped a VTA board in it, and it's right as rain! If you're already willing to do the work, you can save some money. But all else being equal, I'd probably have gone for a new kit over an older amp. There is something cool about kit-building on of these kit-amps.
 
Update:

So, I took the plunge and got the Dynakitparts kit. Well, two of them :)

I'm still putting them together - plus the tubes haven't shown up, but I have to say - this kit was packaged extremely well!

I went for 6550s, not KT-88s. Some say the KT-88 is the better way to go. I guess I can try them both...
Probably won't be finished till the end of the week (pesky work getting in the way ;) ), and the tubes might not show up till next week. So, I have to wait it out :(
 
I got the new Tung-Sol re-issue ones. One thing about flipping between 6550s and KT-88s is there's a one resistor change in the bias circuit that they recommend. I'm not exactly sure why. I don't think it's mandatory, and they give you the extra resistor, so I can just tape it under there for storage.

I think I should have one amp close to done tonight, then I can start on the other. I built both PCBs already. It kinda weird putting a kit together - it's like rebuilding an old amp but everything is nice, new, fits, and you don't have to mess with unsoldering stuff :)

Interestingly - the kits were delivered to my office - I'm only a town over from where they're based out of and they had to do a parts run into my area (we're apparently just down the block from one of their distributors). Therefore - instant shipping - order Sunday, on my dock at 10am Monday. Can't beat that!
 
Ok, the one tube vendor...didn't (so far). As a result, I ended up with a quad of EH KT-88s from a more reliable vendor.

A quick boot up and biasing...hey, they work!

Had a noise issue which was traced to my DAC and a ground loop. The DAC's manual suggested the ground lift switch on the back. That fixed it.

Initial impressions:

* These things are a hell of a lot ballsier than the Fisher was.
* Bass is a lot more solid when it needs to be.
* They double as space heaters :)
* Detail seems to be a lot better too. I haven't sat in the sweet spot to see what the imaging is like yet, though.

I have to rig up a master power switch so I can avoid wear and having to flip 3 power switches (they won't plug into the Sansui's outlets - no ground prong support. Also, a better spot for these, they're (very) temporarilly) on top of the Sansui, and they don't fit there. Not a big issue though.
 
I had a pair of mk3s, I regret selling them, especially to the non-friend who scammed me out of them by demoing them and low-balling the hell out of me.
 
I'd expect them to have more grunt than the Fisher. Its probably around 4x the power output.
 
If you build, I would suggest using a PA060( the St70's) power trans. A lot of the issues the Mk.ii/iii have are due to too high a voltage applied to the g2's. It will cost only a wee bit of output power. That and it will have enough heater current to run a proper front end's set of heaters( like a pair of EL84's ).
cheers,
Douglas
 
You must log in or register to reply here.

Similar threads

quadaptor
Dynaco MKIII Caps - Questions
Replies
2
Views
604
quadaptor
quadaptor
M
Dynaco MKIII Pair
4 5 6
Replies
109
Views
4K
Bill Ferris
Bill Ferris
W
Dynaco MKIII question..
Replies
8
Views
1K
Pio1980
Pio1980
A
Summer Loving.... the Revenge of the Dynaco MKIII and LaScala
Replies
13
Views
1K
ampsandsound
A
MRL_Audio
Dynaco MKIII - Fuse
Replies
15
Views
2K
AdamAnt316
AdamAnt316
Back
Top Bottom