NOSValves

Well under a 100 hours? Man you didn't use it much. Heck you never burned in one of the sets of tubes you have on hand for it or the amplifier itself for that matter. I think you should use it some more before selling it! Nice looking amp!

Those look to be original 1960-70's Dynaco Mark III's to me. They do look to be near original with little work done to them, the only thing I can see that has been replaced up top is the one single yellow colored cap on the circuit board per amp. The two black colored caps on each circuit board are original vintage caps that should absolutely be replaced. Pairs of original iron Mark III do not come up often these days and $900 is a good deal on the pair even if they do need refurbishment. I would want to confirm the output transformer have "cloth leads" which would means "made in the USA' the later plastic insulated lead transformers were made in China. But do realize this pair sooner or later will require work. A picture with the bottom cover off would really help.

Good grief....I do answer emails.... The NBS has nothing in common with the Peach. It is loosely based on the Merlin line stage but hugely upgraded. I stumbled onto the idea doing a mad scientist upgrade to a Merlin I owned. The phono section has allot in common with the Tercel phono stage. A schematic....If I say what I'd like to say in response to some comments in this thread would end up locked...I'll just say no complete schematic exists at this point. Schu...What was that last tube preamp you owned? Were you able to find a schematic for it?

Is that a boatload of crap between you and the music or what?

That Russian tube is tough as nails...I used them on and off 5 to 10 years ago. They use to cost about $3 each.......Like all things once the word gets out demand rises along with the price.

and the walk among us....

Oh and don't rule out a failed component on the crossovers... defective electronic parts do come up once in the blue moon.

After reading the entire thread I seriously doubt the MC275 has anything to do with the problem. I think it was just in the wrong place at the wrong time. Since everything possible has been changed except the speaker that leaves only the speakers to blame. I'd be looking over those crossovers and driver wiring real close. Loosen and re-tighten all connection screws for sure!

agree 100% somethings wrong

The receiver is not rebuilt...Any 50 year old cap testing good means it's good at that moment and nothing more. It could fail the next time the power is turned on. In my opinion your still listening to a tired near original vintage piece of tube gear.

Well it depends..... you use tubes that are for the most part not the norm for HiFi use which makes them inexpensive and not scrapping the bottom of the barrel. With more popular Hi Fi audio tubes the available "TRUE" NOS tubes at what most would consider affordable cost is pretty scarce. Just like anything it depends on point of view.. Now I read some comments stating the quality of vintage tubes was somehow inferior to today's modern production tubes....That is just plain stupid talk.

Schu, Give this gear a look see... https://hollowstate.netfirms.com/ either LINE 2C or Ultra 4C if you want phono.

WIKI pretty much got it right along with 5 wpc difference. I've rebuilt 100s of both models and if I had to choose one over the other with all other factors being equal it would be decided by cosmetic condition. My advice is always buy vintage gear in as nice as possible cosmetic condition. One more piece of advice..pieces this old should never be placed in use without electrical restoration. So plan on either doing it yourself or highering a pro.

Well in my professional opinion the pair of Mark III's is a much more robust setup. The output iron is larger and better suited to deliver good frequency response top to bottom in a 60 Wac amplifier. The iron used on the ST120 is a compromise to shoehorn them into the small available space on the original ST70 foot print. Then the advantage of dedicated power supply for each channel cements the deal..

Hmmm I thought SET or SEP amps would part your hair or the red sea with massively high SPL

Yes and it's not flattering to Klipsch brand name either IMHO...

McIntosh is sold at Best Buy now? What the hell is the world coming too?

I'm not offended...just remembered going over this before......geezzzz

Umm when I said "we" the op was included....he asked this same question previously and received multiple replies...

Didn't we cover all this long ago....

I'd pass...

Much common sense above. As far as getters and sound they have nothing really in common. I personally suspect most people realize that..the getter type or placement is an easy way to identify some tube brands and approximate production time frame...

You have all those speakers playing at once?

Contradictions! One clarification. That is not a SET amplifier. SET stands for Single, Ended, Triode. The EL34 is a Pentode type tube. Don't fret about it people make the mistake with the amplifier type all the time.

Hey you were the smart one! I sunk $ and countless hours into an HF85 and was never impressed.