First of all what great posts by all of you. So many of you continue to impress. I cannot tell you how much you all teach and how I myself love this sharing of knowledge. You've also reawakened in me what I have forgotten and how much I love this stuff.
I too am new to tubes and have chosen the older amps as a jumping off point.
I have just received a call from the shop I brought my Scott 299 to. It is ready and as Mechans, Atmasphere and others have said having the work done by someone else is not cheap. I have not seen the invoice nor know the total scope of work yet but the cost of restoration of this unit is approx $550. I can hear the collective gasp! May be expensive but I want it right. And this guy impressed me.
I will post the work done when I pick up the unit for scrutiny.
As Atmasphere and others have said there is the question of tube replacement if necessary. I've been doing a little research and the tubes used in these Scotts seem to be a little scarce. This unit and the 299B I have (awaiting restoration) and the 350 series tuners all have some Telefunkens and Amperex. Also the few NOS tubes I have seen are not cheap.
$75 is a great price for the unit. I haven't seen any at that price. I paid for mine, including shipping $386. The reason I paid so much is not only did they work but the cosmetic condition is excellent. It was first and foremost the most important thing to me. I feel the condition of the faceplate, chassis and all screening would be most difficult to restore. That the parts and working condition of the unit would be far easier to deal with.
So that put me in the neighborhood of $936. I can hear the guffaws! Yes, I could have probably bought something newer used here for the price. But these things look so darn good!
I've even sought out original wood cases, original metal cases with the leatherette covering, NOS feet, owners manual, schematics and photofacts. So if I factor this in the unit is now over $1000.
Why? Isn't that what an audionut extremist collector is supposed to do!? Please, correct me if I am wrong! :-)
And I wouldn't/didn't turn it on until you bring it to a tech. Great advice given to you by the others.
I'm going to say as far as reliability is concerned, if it lasted this long, after restoration, why wouldn,'t it last another 50 years?
Enjoy.
Best,
Dave
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Well understand that this unit, when repaired, would work well with a small pair of bookshelf speakers that are efficient. And by that I mean 88-91dB 1W/1m minimum. Generally, JBL's are efficient, but I'm not familiar with those models to know what their sensitivities are. The ESS AMT speakers, if there 1A's etc. are not very efficient and the bass would be rather sloppy and uncontrolled. |
First of all, thanks very much to all of you for your input. You obviously have far more knowledge and experience with this stuff than I do, and I'm glad I can rely on your input.
As a follow-up, there's the issue of what speakers are compatible with this. I have a variety of configurations I could use this amp in, depending on speakers and other components (I may elaborate on this later). For now, I have these to choose from: ideally, my set of ESS Heil AMT (or is that AMR?)1's; JBL L46's, JBL J216A's, or pairs of large-ish bookshelf '70's Advents or Polks (these are both in the garage, so I don't have the specific model numbers handy). Thanks again!
Dale. |
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possibly wrapping a band-aid around the bulging caps may buy some time... |
The process of re-forming caps does work; the problem you may well run into is the fact that quite often the caps have dried up over the decades as they are not perfectly sealed. In some cases if you look at the bottom of them, you may find that they are bulging- you can count on these to form up properly about as much as you can count on a bulging tire on your car. I would only attempt to re-form a cap that shows no sign of damage due to age or heat.
The half life of filter caps in round numbers is about 20-25 years, which is to say that in that time about half of them will have failed. In an amplifier like this that is more like 50 years old, harboring the idea that some of the filter caps might still be good after that time is simply asking for trouble. |
that should read The fact....LOL |
The face is as stated by Atmasphere, bad filter cans can damage a power transformer. Unless someone has run the thing and determined the caps are ok, which is doubtful given the age of the Scott, I would never power up a unit like that unless you can monitor AC ripple and voltage while slowly running it up on a Variac. Normally, I just replace the caps and if that unit has a selenium rectifier, plan on replacing that too as they all too frequently leak voltage. No one should ever turn an old tube amp on without knowing how long it's been off and when it was serviced last. Finally, the twist lock caps in that unit should probably be replaced with current production single axial or radial caps. They can be installed underneath if there's room for them. That will make a big sonic improvement. The twist lock caps needn't be removed. |
Sam, best of luck with it. That is a fabulous tuner indeed. A few years ago I had one in my main system for a while, that I had repaired for a relative.
Best regards,
-- Al |
Al
Thank you for the concise answer. Greatly appreciated!!! I've been given a McIntosh MR 71 tuner and don't want to ruin it as I think it's a decent tuner. I'll check the tubes first then power it up.
Thanks again.
Sam |
04-27-11: Samhar
How slowly ... ?
Minutes? Hours? Hours, perhaps 8 hours or even more, if the piece may not have been turned on for decades. That allows the electrolytic capacitors to "reform," and can often (depending on many variables) make it possible to avoid having to replace them. I've had many experiences with 1950's and 1960's tube audio components, as well as 1930's antique radios, where, having done that, it has not been necessary to replace those capacitors. During that process, temperatures of the power transformer and the electrolytic caps (the ones that are enclosed in cans on top of the chassis, only!!) should be checked by hand periodically, because of the damage possibility that Ralph mentioned. Ideally, ac current draw should be monitored during the process as well, with the voltage not being raised to the next increment unless the current draw is stable for some period of time at the previous increment. And of course before any of this is done, a check should be performed to verify that there is not a short between ac and chassis. AC leakage to chassis should also be monitored as full voltage is approached. All of these things can be done with an instrument such as this one, which is what I use. An inexpensive variac and a multimeter would probably be good enough in most cases, though. The OP may find this thread on vintage audio to be of interest. Regards, -- Al |
It's normally takes 3 min to 'fill up' caps. This much time I guess is needed. |
Frogman
How slowly are you suggesting?
Minutes? Hours? |
You need to be a-bit DIY to handle this amp. The cap banks that most-likely need to be replaced are not cheap and might cost more than you would pay for the amp, but $75 is a great price even for the partially functional unit.
I agree with Mechans that this amp is great for near-field, but should probably mention that built quality of this amp is superior to the modern tube amps. |
You did well on the price!- properly refurbished they can be quite nice sounding. However unless you have it on good information that the unit has been recently serviced, I would not run it until you have the power supply rebuilt with new filter caps and have the unit checked over, else the power transformer could be damaged.
With a new set of filter capacitors and other relatively minor service issues taken care of, you can expect the amp to be reasonably reliable for another 20 years or so.
We've been doing a lot of work like this in the last few years but anyone familiar with servicing tube amps should be able to take care of it. I would allow for at least $200 to get things taken care of, although it could go higher than that if the tubes have to be replaced. |
Respectfully disagree with Mechans; although his concerns are very well taken. But, $75 to get a taste of what tubes are all about? No brainer IMO! These Scott amps can be very sweet sounding, and will definitely let you hear what the fuss is all about; look cool too. But as Mechans mentioned, you should not try to drive anything other than a fairly high efficiency, easy load speaker. With an efficient small box speaker, the Scott can sound really good.
Sounds like cost is a conern for you. If you are reasonably sure that the amp has not been abused you are probably in good shape. Check to see what tubes are in there. Probably Telefunkens, which last a long time, and are probably worth more than $75 by themselves. Even if the amp is not working, it is worth much more than $75 for parts alone (transformers). I would buy or borrow a Variac and bring it up to full voltage SLOWLY, since it has not been turned on for a long time. Go for it! |
Probably not the best possible way to start tube audio. My reason is that despite the likely low usage the amp will need to be recapped and some tubes may be less than optimal. Unless you are willing and have a good tech familiar with vintage tube equipment who can give it a thorough check up and recap which can be costly. I would opt for either a reliably refurbished vintage or a relatively inexpensive modern amp. You will not find a good working modern amp for that money but if you are really interested in tube amplification you have to think in terms of much more money.That said, as a tube guy it's worth it.
I bought a recapped partly retubed Fisher 400 recently, that works great but I use it for nearfield only. My point is that there are other issues to consider. Such as, what kind of speakers and listening room preferences do you have. Most older amps work best with higher efficiency speakers.
My 2 cents vintage amps can sound very good but in all honesty of the several I own none compare to my modern tube amps. |
