Paoli 60M questions

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I have been on the lookout for a tube amp for some time, but know little about them.

As fate would have it, I stumbled across a pair of unknown (to me) monoblocks at an estate sale.  

I was able to ID them as a Paoli 60M, which I have come to understand is based on the Dynaco Mk. III, so hopefully someone might have some insights to share.



I found a couple of threads here that have given me a bit to go on, but a few questions remain (my apologies in advance if these are too basic):

1) In addition to the main panel binding posts, there are these on the extension chassis.  Does this mean that the main binding posts should not be used?



2) On the main panel, there is a connector to the right of the binding posts that it looks like the writing has rubbed off.  Should something be connected here?



3) is there any risk of damage from just plugging them in to a source and speakers and having at it, or should I have them gone through by a pro first?  (is there anyone that knows these well?)

Thanks for any comments or suggestions!

Yes, there is a risk just plugging them in. If you don't know anything about them, it would be prudent to take them to someone trustworthy. I see there is information about them on the web, so a decent vacuum tube tech shouldn't have any problem checking them out.
If you take the bottom cover off and take pictures we might be able to tell you what is going on with that added output jack, but please have someone knowledgeable check them over!

Thanks for the response - much appreciated.  

I pulled the panels, and it turns out that the output is just wired directly to the binding post.  

In looking at the componentry, someone has obviously done some freshening up in there - the datasheet on those diodes is dated from 2002.  Given that, I'm a little less hesitant to try firing them up.  

Here are more pictures showing the mods:











Thoughts?

You have all parts to make a pair of dynaco MkIII.
Strip them down, remove all added stuff and build according to the Dynaco manual.
As result you get another 10w of power and a more valued amps.

peterh wrote:You have all parts to make a pair of dynaco MkIII.
Strip them down, remove all added stuff and build according to the Dynaco manual.
As result you get another 10w of power and a more valued amps.

From what I've been able to gather, that would be a lot of work for what amounts to a downgrade in many respects. That's according to what few reviews there are of the Paolis.

So out of curiosity, why do you think that would be worthwhile?

FritoP wrote:

peterh wrote:You have all parts to make a pair of dynaco MkIII.
Strip them down, remove all added stuff and build according to the Dynaco manual.
As result you get another 10w of power and a more valued amps.

From what I've been able to gather, that would be a lot of work for what amounts to a downgrade in many respects.  That's according to what few reviews there are of the Paolis.

So out of curiosity, why do you think that would be worthwhile?

After restoral you will have a documented amp with more power and less unnedded parts that
might create problems. In addition, if done properly, it will be easier to sell at a higher price.

As you stated, you don't understand how to use your amp, if rebuilt to MkIII you have all the
documentation and knowhow to use it.
This is the problem with close to all "improvements". The original builder knows how it works but
since it seldom is properly documented this knowledge is lost forever and has to be
reverse engineered if some problems occurs after the first weeks.

I never listened to or measured a pauli but it does not impress me.

Thank you for the suggestions.  I get what you're driving at, but though I did say I was unfamiliar with tube amps, I do have a background in engineering and audio, so I'm sure I'll pick up the missing bits fairly quickly.  So I see no point in throwing time money at these only to end up with something far less rare and interesting, frankly.

Based on the evidence of a refresh, and what I was able to gather about the previous owner I decided to go ahead and fire them up.  They not only work, they sound absolutely magnificent.  So I'll just enjoy them as they are for now.  

[quote="FritoP"].

I have been on the lookout for a tube amp for some time, but know little about them.
----------------
This is far from an unknown amp.  It was built about 1974, a Dyna modification by one of the premium tube designers of the time.  It was my pleasure to have a pair in our store, Greenwood Audio, in Portland, Or.  It has an amazing imaging ability and a character than can only be described as delicious and liquid, far outperforming any tube amp at ten times it price.  Paoli believed in very stout power supplies as can be seen by the huge caps at the back of the amp.

Do not take it apart and salvage them back into its original Dyna design as you will be killing one of the few remaining examples of this superb amplifier and returning it to an inferior product.  
If you don't want them, let me know.

A proper slow graded initial turn on is important for any electronics sitting unused for a long time to wake up the power supply caps, plus checking the power supply output quality and signal pathway with a scope to insure all components are still within spec.

I have a pair of these, and take exception to any comments that they are ‘worth less than a stock MkIII’ or that they produce less power! Peter, I don’t think that’s accurate at all!! First, the improvements done to the amp provide essentially the same plate and screen voltages, as well as bias adjustment levels, using the stock power and output transformers. That alone should dispel the ‘reduced power’ concept. But, the modifications allow for individual tube bias for a cleaner wave formation in the push-pull OT, plus the bigger choke and added power supply capacitance permit the transient response of the amp to be greatly improved!! As to ‘value’, these are exceptionally rare!! An ‘estate sale’ is about the ONLY place you’ll find them as most people fortunate enough to own a set will usually plan an ‘until death us do part!’ strategy! Where a ‘stock’ set of MkIIIs in good condition might be worth $1200 to $1500 on a good day, a pair of these can bring nearly twice that if in equally good condition and sold to someone who knows what they’re buying! These are the Sunbeam Tiger of the amp world! I think the OP got really lucky here, especially if he bought them ‘cheap’ !! That said, the pics show mods that do go beyond that which were part of the upgrades done originally. I suspect further work was done which augmented the Paoli mods, but may render these amps as being even more unique. At any rate, the one thing I DO agree with is to NOT just plug them in and give them a try!! Rather, the initiation process should be done under controlled circumstances with full monitoring of critical voltages along the way. Perhaps even some preliminary ‘bench-testing’ of all the filter and coupling capacitors to pre-determine if they have any issues or are within spec, as well as to confirm power transformer outputs are also in line, and that bias levels match the tubes being used. Mine have old TungSol 6550s in them but I believe some had some other output tubes as well. Anyway, thats my $0.02 worth!! There may be further info still available on the web, incl schematics. I’ll poke around and see if I can put my hands on one myself. But there was some interesting background info as well as marketing material and even HiFi review write ups out there some 10+ years ago. Good luck finding it now!!! Tom D

Wharfcreek wrote:I have a pair of these, and take exception to any comments that they are ‘worth less than a stock MkIII’ or that they produce less power!  Peter, I don’t think that’s accurate at all!!  First, the improvements done to the amp provide essentially the same plate and screen voltages, as well as bias adjustment levels, using the stock power and output transformers.  That alone should dispel the ‘reduced power’ concept.  But, the modifications allow for individual tube bias for a cleaner wave formation in the push-pull OT, plus the bigger choke and added power supply capacitance permit the transient response of the amp to be greatly improved!!  As to ‘value’, these are exceptionally rare!!  An ‘estate sale’ is about the ONLY place you’ll find them as most people fortunate enough to own a set will usually plan an ‘until death us do part!’ strategy!  Where a ‘stock’ set of MkIIIs in good condition might be worth $1200 to $1500 on a good day, a pair of these can bring nearly twice that if in equally good condition and sold to someone who knows what they’re buying!  These are the Sunbeam Tiger of the amp world!  I think the OP got really lucky here, especially if he bought them ‘cheap’ !!  That said, the pics show mods that do go beyond that which were part of the upgrades done originally.  I suspect further work was done which augmented the Paoli mods, but may render these amps as being even more unique.  At any rate, the one thing I DO agree with is to NOT just plug them in and give them a try!!  Rather, the initiation process should be done under controlled circumstances with full monitoring of critical voltages along the way.  Perhaps even some preliminary ‘bench-testing’ of all the filter and coupling capacitors to pre-determine if they have any issues or are within spec, as well as to confirm power transformer outputs are also in line, and that bias levels match the tubes being used.  Mine have old TungSol 6550s in them but I believe some had some other output tubes as well.   Anyway, thats my $0.02 worth!!  There may be further info still available on the web, incl schematics.  I’ll poke around and see if I can put my hands on one myself.  But there was some interesting background info as well as marketing material and even HiFi review write ups out there some 10+ years ago.  Good luck finding it now!!!    Tom D

I agree. This is one of the most enjoyable tube amps ever produced.
If the owner does not want them. I'm willing to purchase them at the right price.

There are schematics available (I think I have them). They are very rare as Paoli only produced a small run of them. I am very sorry I did not buy the pair we had at our store.

LGilbert wrote:It has an amazing imaging ability and a character than can only be described as delicious and liquid, far outperforming any tube amp at ten times it price.

I believe it.  I've been listening to them for a few days now fed by a Parasound preamp through a set of KEF 104/2s and the sound is magnificent.  They are keepers for sure.

LGilbert wrote:
Do not take it apart and salvage them back into its original Dyna design as you will be killing one of the few remaining examples of this superb amplifier and returning it to an inferior product.

No worries, once I found out a bit about these, the idea of reverting them back to the base config seems... odd.  Kind of like stripping a RUF Turbo down to factory spec.  Well, maybe not that extreme, but a bit sacrilegious given their lineage.

Wharfcreek wrote:
Mine have old TungSol 6550s in them but I believe some had some other output tubes as well. Anyway, thats my $0.02 worth!! There may be further info still available on the web, incl schematics. I’ll poke around and see if I can put my hands on one myself. But there was some interesting background info as well as marketing material and even HiFi review write ups out there some 10+ years ago. Good luck finding it now!!! Tom D

These have 6550s in them.  One has GE markings on it, the rest I can't quite make out.  Idling and warm, I measure .57 on both TP on one amp and .59 on both TP on the other.  That appears to be right according to the schematic I found on blackdahlia.com /html/tip_84.html.  

Does that sound right to you?

I’d say that’s right on the bullseye!

At one time, mid-1970's I think, these were Gordon Holt's top dogs on his recommended list, beating out the Audio Research Dual 75 at something like twice the price.  

The accessory socket and the dinky terminal strip for the speakers are clearly Dynaco originals.  The chassis extension with the computer grade electrolytics is probably the Paoli modification.  I would guess the banana jacks labeled 4 ohms just go in parallel with the 4 ohm terminal on the strip.  But that guess should be verified with an ohm meter.  A tech would do that, and also hook it up to a Variac and ramp up the AC supply voltage slowly, and let it cook for a day or so.  If you're not familiar with electronics I echo the recommendation that you take it to one.  The main hazard in just plugging it in is if one of the power supply capacitors has dried up or shorted with age it could damage the rest of the power supply, including the expensive to replace power transformers.  There's probably at least a 50/50 chance you could plug it in and it would be fine, but it's an unnecessary risk.

FritoP wrote:.

I have been on the lookout for a tube amp for some time, but know little about them.

As fate would have it, I stumbled across a pair of unknown (to me) monoblocks at an estate sale.  

I was able to ID them as a Paoli 60M, which I have come to understand is based on the Dynaco Mk. III, so hopefully someone might have some insights to share.



I found a couple of threads here that have given me a bit to go on, but a few questions remain (my apologies in advance if these are too basic):

1) In addition to the main panel binding posts, there are these on the extension chassis.  Does this mean that the main binding posts should not be used?



2) On the main panel, there is a connector to the right of the binding posts that it looks like the writing has rubbed off.  Should something be connected here?



3) is there any risk of damage from just plugging them in to a source and speakers and having at it, or should I have them gone through by a pro first?  (is there anyone that knows these well?)

Thanks for any comments or suggestions!