What did you do to your stereo rig today?

marvda1

@dkfreebird sure you don't want to try a norma in there?

dkfreebird

@marvda1 I'd love to. Heard it at Skips.But at the stupid price I got this at it was a no brainer to me. Norma is a little out of my price range at this point. But....You never know.

hochpt21

I swapped my 2a’s back in for my 703’s in the man cave. It’s been awhile. Boy I sure do miss the SDA sound!!

nooshinjohn

Man cave, huh.... did the wife pick that color?

hochpt21

nooshinjohn wrote: »

Man cave, huh.... did the wife pick that color?

Lol, no I did. Got the color code off a former member a few years back who had it for his room. It’s more burnt orange than it looks.

I like the energy.

Tony M

I always liked how color on walls can affect our mood.

Tony M

gp4jesus

Gardenstater wrote: »

Interesting youtube video.....Does Polyfill Make a Box Bigger? - Tested and Revealed

https://www.youtube.com/watch?v=INM0g1JeMLY

In the motorhead world: there’s no replacement for displacement.

I’m a bit disappointed Polyfill seems to make less of a difference than I was lead to believe. YMMV w/the driver higher Qts versus lower Qts. Could help some w/BSC for a mid-woofer or fudge if the closure is a slightly undersized.

rooftop59

hochpt21 wrote: »

nooshinjohn wrote: »

Man cave, huh.... did the wife pick that color?

Lol, no I did. Got the color code off a former member a few years back who had it for his room. It’s more burnt orange than it looks.

I like the energy.

What Taylor is that? Nice room by the way...maybe someday when my kids are grown and I’m as old as @tonyb i might get one 😂

jdjohn

I posted a pic of this Phase Linear 400 power amp from my dad's collection a couple of months ago.

It didn't pass the dim-bulb-test on one channel, so I started researching whether it was worth fixing. These Bob Carver designed amps have a following of enthusiasts, and White Oak Audio https://www.whiteoakaudio.com/ actually has a few different upgrade kits for the PL400 and PL700 amps which improve upon the original design.

Having no money invested in this unit, I decided to buy a kit and re-do the main board as well as upgrade the power supply caps.

Here are the guts:


Here are the replacement filter caps (pre-assembled), and board (self-assembled):


I'm just about ready to do the final R&R on this, so wish me luck! I'll have to remove and re-install the outputs as part of the graduated start-up process. I'll be testing each of the output transistors (all 16 of them) as I remove them and prepare to reinstall, so it is entirely possible that some will be bad. Here's one side of the outputs (there are 8 more on the other side):

hochpt21

rooftop59 wrote: »

hochpt21 wrote: »

nooshinjohn wrote: »

Man cave, huh.... did the wife pick that color?

Lol, no I did. Got the color code off a former member a few years back who had it for his room. It’s more burnt orange than it looks.

I like the energy.

What Taylor is that? Nice room by the way...maybe someday when my kids are grown and I’m as old as @tonyb i might get one 😂

It’s an entry level...Taylor 110. Circa 2013. It certainly sounds good enough for my plinking around. Haven’t played much the last 10 years or so.

Thank you for the compliments on the room. If I made one smart decision in my life...when we bought this house 8 years ago, I negotiated with the wife. She got the master closet to herself and I got the 4th bedroom for whatever I wanted.

PSOVLSK

hochpt21 wrote: »

Thank you for the compliments on the room. If I made one smart decision in my life...when we bought this house 8 years ago, I negotiated with the wife. She got the master closet to herself and I got the 4th bedroom for whatever I wanted.

I can relate. When we moved into our current house I got the 4th bedroom as my music room. Up until about a month ago it had bed in it, but it’s finally gone. Closet space stinks in this house, so I’ve got clothes hanging in three different closets, but it’s worth it.

The room looks really nice. Though I can’t play, I wouldn’t mind a cheap guitar or two for decoration. They add to the room IMO.

Gardenstater

jdjohn wrote: »

I posted a pic of this Phase Linear 400 power amp from my dad's collection a couple of months ago.

It didn't pass the dim-bulb-test on one channel, so I started researching whether it was worth fixing. These Bob Carver designed amps have a following of enthusiasts, and White Oak Audio https://www.whiteoakaudio.com/ actually has a few different upgrade kits for the PL400 and PL700 amps which improve upon the original design.

Having no money invested in this unit, I decided to buy a kit and re-do the main board as well as upgrade the power supply caps.


I'm just about ready to do the final R&R on this, so wish me luck! I'll have to remove and re-install the outputs as part of the graduated start-up process. I'll be testing each of the output transistors (all 16 of them) as I remove them and prepare to reinstall, so it is entirely possible that some will be bad. Here's one side of the outputs (there are 8 more on the other side):

Good luck! Those prices on the website seem pretty reasonable too. I'm going to be attempting my first electronics repair, which will be my Martin Logan Dynamo Subwoofer. It blows the fuse and I hope it is just something with the power supply board but may extend to the amplifier board...who knows. If I can fix it I will have one for each channel.

Could you explain the dim bulb test? Thanks!

pitdogg2

You use a old incandescent light bulb to test and if done correctly it glows the bulb instead of smoking the gear.
Poor mans variac.

https://antiqueradio.org/dimbulb.htm

jdjohn

Yes, and we had a little discussion about here: https://forum.polkaudio.com/discussion/comment/2528821#Comment_2528821

Gardenstater

Thanks! Reading up now. I think the trick will be to come up with the proper wattage bulb that will indicate to me that their is a short still, without blowing the fuse. I have my known good ML Dynamo to determine minimum wattage that allows the thing to start playing, but that might not be the right one for testing the other one that I have attempted a repair on, to determine if there is still a problem without going through fuses.

motorstereo

Gardenstater wrote: »

OK cool. Looking forward to your further impressions. Not to be a wiseguy but there's no "backwave" at the sides either. I think it's more a matter of having the BH5 in the vicinity of the drivers because every surface of the back of the cone becomes a point source for a sound wave, in other words there are sound waves radiating out in all directions and bouncing all over the place within the cabinets and that can cause interference with the proper primary motion of the cones. I think the other key is amount of BH5 relative to total cabinet volume, along with keeping the area around the passive free of it. Just my 2c.

Thank you sir for giving me the kick in the a$$ to take them apart one more time for the install of side pieces of bh5. The side strips are in now and yes it was a worthwhile and significant overall improvement. Also while I had things apart I cleaned and treated all the speaker connectors. They were tarnished quite a bit but they're shiny now.

audioluvr

So on the I'd plate it will state either watt usage or amps (x120v). If it says it uses 480w of power then you need to use a 500w bulb.

Gardenstater

audioluvr wrote: »

So on the I'd plate it will state either watt usage or amps (x120v). If it says it uses 480w of power then you need to use a 500w bulb.

The lower the wattage bulb you use the more protective it is and 500W is way way up there. The subwoofer doesn't normally draw anywhere near that maximum rating, especially when powered up into standby mode. Respectfully I do not think that would be what I would want to use for troubleshooting a short circuit that is blowing fuses.

audioluvr

If it's blowing input fuses it's short circuiting. Period. The dim bulb test is for a device that has none.

Gardenstater

Regardless, 500W is too much because that bulb has a much lower resistance than a 50W bulb, for example. In a voltage divider, the higher resistance has the greater voltage drop. It may turn out to be more useful for when I get the circuit repaired to the point where it no longer blows fuses, but there is still something wrong. But I'm sure that 500W wouldn't provide very much protection.

mhardy6647

The DBT puts the bulb's filament in series with the AC input to the component under "test". [EDIT] What you want to do is limit current flowing through the component under test* with the resistance of the bulb filament. The filament takes up the load.

If the bulb's wattage is too low, it will light brightly even if your radio has no problems, and your radio won't play at all. We'll demonstrate this in an example below.

Your radio should play normally without fully lighting a bulb that is roughly 1.5 to 2 times the radio's stated wattage.

source: https://antiqueradio.org/dimbulb.htm
(this goes on to give some real-world examples for relative low current draw tube radios)

Remember that the most common use for DBTs is old vacuum tube equipment. Heating the tube filaments (and running the vacuum tubes) means those components draw a fair amount of juice even at idle. Solid state amplifiers (or receivers) draw very little current (more to the point, they consume very little power) at idle.

__________________
* if there were a short circuit in the component, the current flow would be dangerously high, and pop the fuse, or worse -- under these conditions, the bulb lights up bright(ly) and, in essence, 'protects' the component under tese from damage.

BlueFox

mhardy6647 wrote: »

Solid state amplifiers (or receivers) draw very little current (more to the point, they consume very little power) at idle.

Unless it is Class A.

Gardenstater

Thanks. So is it of basically little to no use for repair of a solid state amplifier that is blowing fuses? Can I use the dim bulb tester on my working amp and find the lowest wattage value that allows the good one to work and then use that on the one I am repairing? Will it be possible to determine that something is wrong still , ie. there is some limited short circuit that makes the bulb burn much more brightly than it did with the fully functional amp, and at the same time keep from blowing fuse after fuse after fuse, which can get expensive?

audioluvr

Put my Belles 350A Reference back in rotation following it's mod.

audioluvr

Had a loud buzzing and clicking sound coming out both channels of my Belles that I had to troubleshoot. Apparently these amps are very sensitive to electronic interference. I isolated some interference from the Bluetooth dongle for my Cambridge Audio 851N. Luckily I don't use it. Then I found out it HATES my left bank power outlet. Using it would produce an obnoxious low frequency buzz/ hum. The right bank thankfully was much better, producing only a low hum only heard when I got within a Foot or two from the speaker.

The upper mids and highs on this are sublime!

CH46E

Ground loop?? If I use my HTR as a source to my amp, say for usb thumbdrive playback i have to disconnect the hdmi from the TV. It creates a annoying hum.

audioluvr

Nothing else is plugged in. My amp is plugged into one circuit (the right bank) all by itself and the pre and streamer on the other (the left bank that the amp doesn't like) Never had any issues with the B&K's.

CH46E

What speakers are those? Just curious.

audioluvr

SDA 1C's