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Advice for Mono Naim Nap 110 Build

hifiaf

pfm Member
Last summer, I was looking for a 32.5 and a Snaps, and ended up finding someone selling both who threw in a Nap 110 for free. Since I had CB 135s at the time, I didn't even try the 110 until a few weeks ago, in a moment of idle curiosity. And what do you know: I liked the 110 better than the 135s!

No doubt due in part to the peculiarities of my system. Based on advice from @YNWOAN I've gone to an active bass amplification system, so the Naim amps only drive the mids and tweeters on my Yamaha NS1000Ms. It seems the 110s are more than up to the task. I found them "airier" than the 135s, with a more expansive soundstage. They lacked the control of the 135s, but added excitement. It seems I prefer the sound of unregulated Naim amps.

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The 110 I got for free last summer (above) had been modified with an Avondale 110 PSU. It seems that one of the boards also had its output transistors changed: Naim 002 on one side, Toshiba 2SD552 on the other. As @nobeone put it, it seems to have "been through the wars."

Reading some threads here on pfm, I thought, if one 110 sounds this good -- imagine mono 110s! I put up a wanted ad on Canuck Audio Mart (I'm in Toronto), and a local seller offered a very nice 110 in original shape. It's got a very low serial number (3435) and the BDY56 transistors. It seems to be totally unmolested. That's it on the left below.

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This unmolested 110 doesn't sound as brilliant or airy as the modded one -- most likely down to the PSUs, or the fact it probably hasn't been serviced in 40 years.

My mono-ization plan is to make up matching Hackercap PSUs for both sides, recap the BDY56 boards, and then swap and compare when everything is in place.

My first question is about how to build up the Hackercaps for service in mono 110s. The Avondale MiniCap6 is CLCLC. Is that the best arrangement here? Any suggestions for particular values for the inductors? Particular diodes? Basically looking for a good Hackercap BOM for power amp use.

Thanks!
 
This unmolested 110 doesn't sound as brilliant or airy as the modded one -- most likely down to the PSUs, or the fact it probably hasn't been serviced in 40 years.
Check the components on each board of your recent purchase--at least one doesn't match. I'm not sure that that will have any bearing on it. Also, the feedback tants are the most likely candidate for servicing.

The transformer for the 110s changed over time. Yours look very similar, but they may not match.

My first question is about how to build up the Hackercaps for service in mono 110s. The Avondale MiniCap6 is CLCLC. Is that the best arrangement here? Any suggestions for particular values for the inductors? Particular diodes? Basically looking for a good Hackercap BOM for power amp use.
I've often heard it said that CLC (that Avondale 110PS) or CLCLC (in a HackerCap) is good for amps for the highs. Just a big capacitor (links instead of inductors) is better for bass. Given these will target higher frequencies, you're probably best with CLCLC.

Finally, I did the Avondale PS upgrade on mine (after swapping the amp boards for NCC200s), and I found that it was a big jump from the original rectifier and caps. You might want to consider just getting another Avondale PS.
 
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I don't like CLCLC supplies for power amps they have a similar effect to regulators on the sound more Hifi less music, just use new correctly sized single caps from a good supplier, I like Mundorfs best but there are other good ones to that are cheaper.Try shorting out the inductors on the avondale boards to see what happens its all a mater of taste who knows you may prefer them fitted.Have to say when I had a linn/naim system long time ago I went from a NAP140 to a 250 and ended up regretting it ,the effect was as much as you described better tighter bass but just not as enjoyable to listen to.
 
110s are a great amplifier. I have one with the SOA protection disabled and it sounds very nice. Can your speaker take a 4-pack? 4 mono 110s would be very good with the right speakers!
 
I'm about as locked into my crossover setup as a person can be: I built my own external crossovers... then potted them in epoxy!

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I do like the idea of a 4-pack of 110s... but not for now!

I do plan to experiment with disabling the SOA on the 110s. Currently in place on both 110s.

I'm looking for mismatched components on the unmolested (BDY56) boards but haven't found anything yet. Which did you see, @Mike Hanson ?
 
I do like the idea of a 4-pack of 110s... but not for now!

I do plan to experiment with disabling the SOA on the 110s. Currently in place on both 110s.

Disabling the SOA is easily done by sniping a couple of diodes in such a way that it can be easily put back with a bit of solder. It's been discussed on here many times if you have a search. Just be careful with the speaker cables if you go for it. It seems to free the amplifier and allow it to breath/operate better.
 
Nice to see You here again Adam. The 160 power amp board uses the 002/bdy 56 op devices but the rest of the circuit is the same as a 250/135 ,I think they throttled back the 110 boards so the ps was man enough for both channels but if mono ing you could mod the board to let it go . The 160 is better than a 110 by quite a margin and you only have to change a few resistors.
 
It’s probably an unpopular opinion but I’d leave the stock 110 alone apart from a recap/service.

Then compare again with the one that’s been messed with, using it as a control to ensure you’re not making retrograde mods.

It’s so very easy to make these amplifiers sound clearer, more dynamic and worse.
 
Nice to see You here again Adam. The 160 power amp board uses the 002/bdy 56 op devices but the rest of the circuit is the same as a 250/135 ,I think they throttled back the 110 boards so the ps was man enough for both channels but if mono ing you could mod the board to let it go . The 160 is better than a 110 by quite a margin and you only have to change a few resistors.

Thanks — I’ll have to look into that! Excellent idea and I don’t mind swapping a few resistors and listening to the effect.
 
It’s probably an unpopular opinion but I’d leave the stock 110 alone apart from a recap/service.

Then compare again with the one that’s been messed with, using it as a control to ensure you’re not making retrograde mods.

It’s so very easy to make these amplifiers sound clearer, more dynamic and worse.

David makes a valid point here. From memory, I have enjoyed the 110 over all the 140s that I have had (I sold the 140s on). The 110 is just a really musical amplifier, but mine does have the SOA disabled (it apparently allows the amplifier to operate "breathe" better). The 140 supposedly introduced a better power supply arrangement, but to me something is lost with that. The 140 might be technically better and measure better etc, but I don't enjoy them as much as a 110.
 
That's what set me on this lastest journey. I wasn't expecting to like the 110 in comparison to the 135s, but it just sounded special: airy and exciting. The first track I played through the system with the 110 in place was Can's "Future Days," and I could barely believe it: a massive, charged, tingling soundscape that just enveloped me.
 
I'm looking for mismatched components on the unmolested (BDY56) boards but haven't found anything yet. Which did you see, @Mike Hanson ?
I took another look, and I think it was just a trick of the light. What looks like a tant along the left edge of the boards (in your picture) seemed different, but they're probably the same.
 
I disabled the SOA circuitry on the "modded" (Avondale PSU) 110 this morning, but didn't hear any immediate difference. We'll see if my ears pick anything up with other records.

Semi-related question: Does anyone have a part source for the heatsink used for the NAPA boards on the 110, or one of the same dimensions? One of my plans for this round of 110 testing is to try out the Neurochrome Modulus-86 boards in the 110 (they're the right dimensions, they'll run on the same voltage, they should sound totally different, they're cheap to build) and it would work with the same heatsink.

Thanks again for all the thoughts! Current plan is to keep each of the 110s "stereo" for the time being and do a bunch of comparative experimentation. First I'll just recap and service the unmolested 110 so that I can make a fair comparison to the modded 110. Then I'll see about mono-ization! (And try popping in the Neurochrome boards!)
 
So you have nothing at all protecting your speakers from faults now the SOA is disconected bit risky with old amplifiers.
 
Easy to re-enable it with a dab of solder. I’ll listen for a while and see if I hear any difference, then re-enable if I don’t.
 
140 have different output transistors to 110/135s it could be the reason for the difference.

I have heard the difference between output transistors in my old 135 clones.

Pete
 


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