[Zachik]

Beautiful Keenan! Inside and out
Hey - what are the PCBs connected to the rear panel heatsinks?

 

[L0rdGwyn]

Beautiful Keenan! Inside and out
Hey - what are the PCBs connected to the rear panel heatsinks?

Thanks, Zachi, those are the CCS boards for the 45 output tubes. They dissipate a decent amount of power, around 7.5W, so they get their own exterior-mounted heat sinks.

 

[bcowen]

Okay the 45 parafeed rebuild is done, finally. Always takes longer than I think it will.

Here is the circuit first, there is a lot crammed inside.



Top.



Rear panel. Speaker binding posts sit behind the output transformers. Rear switch is for the headphone output.



Here it is with some tubes.



Bottom plate is perforated aluminum sheet for ventilation.



I like how compact this amp is, small footprint considering how much stuff is stuffed inside. It sounds great, spinning some vinyl.



Will have to go back in at some point to finely dial in the filament supply and I may better match the 45 CCS FETs, but overall it's done, I can mark it off the list! Will probably take some measurements later today.

841 amplifier is next...

Gorgeous! And you weren't kidding about the big huge monstrous coupling caps. Is that 2 of them stacked together on each side? Sweet!!

 

[L0rdGwyn]

Gorgeous! And you weren't kidding about the big huge monstrous coupling caps. Is that 2 of them stacked together on each side? Sweet!!

Yup, two 3.3uF in parallel! Luckily they fit gotta work for those PIO caps.

 

[Xcalibur255]

The perforated bottom panel is a great idea. I wonder why more people don't do that.

 

[L0rdGwyn]

I ended up swapping the 45 cathode bypass caps, they were Clarity Caps, now they are Audio Note Kaisei electrolytics. In this particular type of parafeed output stage, the cathode bypass caps are not "in the signal path" and do not affect the frequency response as a typical cathode bypass cap would, they provide an AC path to ground. For that reason, I thought I might be able to get away with a lower value film. Unfortunately, this left a significant degree of 60Hz noise at the top of the cathode of the left channel 45, so I had to add more capacitance, some experimentation showed that films weren't going to cut it.

A 220uF Audio Note Kaisei buried the 60Hz noise, so that's what it's gonna be.



I have found that the bypass caps in this setup are still somewhat audible, despite being out of the signal path, but to a much lesser degree than a typical cathode biased output stage. I'll take a small amount of bipolar electrolytic influence over a 60Hz noise, even if it is barely audible, would drive me crazy if left alone.

 

[whirlwind]

Okay the 45 parafeed rebuild is done, finally. Always takes longer than I think it will.

Here is the circuit first, there is a lot crammed inside.



Top.



Rear panel. Speaker binding posts sit behind the output transformers. Rear switch is for the headphone output.



Here it is with some tubes.



Bottom plate is perforated aluminum sheet for ventilation.



I like how compact this amp is, small footprint considering how much stuff is stuffed inside. It sounds great, spinning some vinyl.



Will have to go back in at some point to finely dial in the filament supply and I may better match the 45 CCS FETs, but overall it's done, I can mark it off the list! Will probably take some measurements later today.

841 amplifier is next...

Beautiful. Great idea to use the perforated aluminum bottom.

 

[L0rdGwyn]

Here is the 45 amp's final destination, back in the bedroom stereo with the Klipsch KG 1.



Just have a cheap Topping DAC and a Bluesound streamer right now, might upgrade the DAC to something fancy at some point. Sounds great though, very happy with the result.

 

[bcowen]

Here is the 45 amp's final destination, back in the bedroom stereo with the Klipsch KG 1.



Just have a cheap Topping DAC and a Bluesound streamer right now, might upgrade the DAC to something fancy at some point. Sounds great though, very happy with the result.

You need some Sound Anchors for the Klipsch's.

Looks great!

 

[CJG888]

Some of those old Klipsch speakers look like potential sleepers, underappreciated as they are not part of the “Heritage Series”, but sharing many of their characteristics: high sensitivity, flat 8 Ohm impedance, real wood veneer, mid-century style.

 

[L0rdGwyn]

Some of those old Klipsch speakers look like potential sleepers, underappreciated as they are not part of the “Heritage Series”, but sharing many of their characteristics: high sensitivity, flat 8 Ohm impedance, real wood veneer, mid-century style.

The KG series is highly regarded by many! Although many of the earlier models have a 4ohm impedance. The KG4 is a popular vintage model, 6ohms nominal, 94dB/W.



Sort of my 10 year hifi plan is to get a pair of full-sized horns, when I move into a larger home that can take them whether than will be something like the Klipsch La Scala, some vintage Altecs, or perhaps a DIY build using Great Plains Audio's new production 604 driver, not sure yet, just dreaming of giant speakers.

 

[bcowen]

The KG series is highly regarded by many! Although many of the earlier models have a 4ohm impedance. The KG4 is a popular vintage model, 6ohms nominal, 94dB/W.



Sort of my 10 year hifi plan is to get a pair of full-sized horns, when I move into a larger home that can take them whether than will be something like the Klipsch La Scala, some vintage Altecs, or perhaps a DIY build using Great Plains Audio's new production 604 driver, not sure yet, just dreaming of giant speakers.

Just get a pair of these and call it a day. 1 watt will get you to rock'n'roll levels, or make it 16 watts for best probability of structural damage.

(I wasn't even aware they were still making these)

 

[UntilThen]

What the heck is going on when there are 80+ guests viewing this thread? Are you people or robots?! It's a little disconcerting, in either case.

Wasn't me I was working hard. If I had been looking in that would count as 50 - just ask @bcowen .

 

[UntilThen]

Have you make my Auris Nirvana contender yet Lord Gwyn? If not I'll have to drop the Lord title and then camp myself in the 1101 thread instead.

 

[bcowen]

Wasn't me I was working hard. If I had been looking in that would count as 50 - just ask @bcowen .

Where have you been? You up and disappear just when we required needed wanted....well, we just wondered where you were.