Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Stereomour => Topic started by: ebag4 on May 06, 2011, 04:47:57 AM
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Hi Guys,
I just ordered my Stereomour yesterday, I am certain I will be hitting you up for info when the build starts. This will be my first foray into SET/DHT and I am pretty excited to hear what all the fuss is about.
I am actually not completely new to the forum, I built a Foreplay II about a hundred years ago and did post a few questions on the old forum.
Since I have ordered my Stereomour and have started thinking through the build (no build documentation yet) I do have a few questions if you will bear with me.
I will be building my Stereomour as a straight amp, no volume control or input selector. I will also be building my own base out of Maple to match my other DIY equipment. I expect my kit will arrive late next week but there are a few additional parts I may need that I would like to get ordered and have on hand when the kit arrives.
Since I am not using the volume control it is my understanding that I will need to place a 249K ohm resistor across the input jack. This will be low level audio so I assume a 1/4 watt resistor should work. Are differences in the quality of this resistor going to be audible? What type of resistor is recommended here?
I understand that there are a series of components that need to be changed/removed from the circuit(?) when switching from a 2a3 tube to a 45. I would like to try both tubes at some point and be able to switch between them yet have the operating parameters as close to correct as possible for each tube. Can this be done with a switch or a switch and a series of small relays? How many devices need to be switched out or in?
And last but not least, while I wait for my kit I would like to get started on my base. To do that I need to know the actual size of the mounting plate. Is it actually 10"x 12", if not can someone give me the actual dimension and how much it overlaps the standard base (how wide is the notch for the lip?)?
I would like to thank Inferno (John) and Jim Rebman for sharing with me their thoughts regarding the Bottlehead amps and their sonic attributes.
Thanks guys and I look forward to the build.
Best,
Ed
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Ed,
Funny meeting you here :-). As I said, I think you've made a great choice, but since you already know most of what I have to offer on these questions, I'll let some of the other folks chime in.
Welcome again,
Jim
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Chassis plate is 10" wide, 12" long and .125" thick.
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Hey Jim! Thanks for the welcome.
Doc, thanks for the info, much appreciated.
Best,
Ed
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Ed,
Sorry, I could have answered the top plate question for you, just forgot to type it. Also, the width of the rabbet should probably be no more than 3/16" as the area around the IEC inlet can get a bit crowded.
I like to have my top plates bolted down in lieu of the gravity mount, so I install some cleats along the bottom edge of the box on the inside that I can drill some holes in for the bolts. On my stereomour I have the cleats on the front and back inside edges, and then use some 3 inch socket head bolts and threaded brass inserts in the cleats. A bit of overkill, but it works great.
I have these on my stereomour, Crack and s.e.x amps but the crack and s.e.x. amps have the cleats along the side edges (with notches cut out for the plate chokes on the s.e.x.
I bought the longer length socket head stainless bolts from bolt depot, which is he place I was able to find them the easiest.
-- Jim
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Welcome to the club (again), Ed! I think you will enjoy your Stereomour very much....have fun with the build.
John
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There are six places where the wiring is different for the 45 vs. the 2A3. Four of them are simply inserting or removing a resistor which is in parallel with another resistor, and the other chooses which wire is used. If I were to do it, I would use three DPDT switches - one for the power supply voltage, one for the cathode bias resistors, and one for the plate chokes. Because high voltages are being switched, I would install those switches under the chassis to make sure that they are not actuated while the amp is in operation. There is no provision in the design or layout for mounting and wiring the switches.
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Hey John, thanks for the welcome!!
Paul, thanks for the info. Once I dig into it a little further and have a better understanding of the build I will decide whether or not I want to do it via switches it or just make the change when i get the 45s. I appreciate your response.
Best,
Ed
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Since I am not using the volume control it is my understanding that I will need to place a 249K ohm resistor across the input jack. This will be low level audio so I assume a 1/4 watt resistor should work. Are differences in the quality of this resistor going to be audible? What type of resistor is recommended here?
Thanks for the responses so far. much appreciated.
As I have gone through some of the other threads I noted two different values quoted to be used when the volume pot is eliminated, 100K and 249K. Can someone let me know which is correct and what type of resistor is best suited for this position?
Thanks,
Ed
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Ed,
I think there is a typo on the product page that is a throwback to the paramour II amps in that the input impedance is 100k for the stereomour, not 249k. Took me a while to figure out what you were talking about, but this must be it. The normal pot is 100k, so I'd sub 100k resistors for the pot, and it would just go across each inputpair from signal hot to ground, and I'd keep it as close to the grid stopper as is practical -- in other words, not at the input jack. That would work, but could possibly make the signal cable inside the amp more prone to picking up hum. I say possibly because it is shielded, but I still prefer to keep loads like that closest to the tube input.
As for type, any good metal film, tantalum, or such should be fine. I'd use the vishay dale metal films or if I wanted something more exotic, maybe a caddock mk132, and a nude bulk foil if I wanted to get carried away. I'd also get them matched fairly closely if it were me.
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Ed,
I think there is a typo on the product page that is a throwback to the paramour II amps in that the input impedance is 100k for the stereomour, not 249k. Took me a while to figure out what you were talking about, but this must be it. The normal pot is 100k, so I'd sub 100k resistors for the pot, and it would just go across each inputpair from signal hot to ground, and I'd keep it as close to the grid stopper as is practical -- in other words, not at the input jack. That would work, but could possibly make the signal cable inside the amp more prone to picking up hum. I say possibly because it is shielded, but I still prefer to keep loads like that closest to the tube input.
As for type, any good metal film, tantalum, or such should be fine. I'd use the vishay dale metal films or if I wanted something more exotic, maybe a caddock mk132, and a nude bulk foil if I wanted to get carried away. I'd also get them matched fairly closely if it were me.
Thanks Jim, that is exactly the info I was looking for. Now to get a few items ordered...
Best,
Ed
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My order has arrived at the house! Can't wait to get home to get started! Thanks for the quick shipment Doc & Eileen!!
Best,
Ed
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My order has arrived at the house! Can't wait to get home to get started! Thanks for the quick shipment Doc & Eileen!!
Best,
Ed
Yea!!!!!!!
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So Ed, is it built yet? :-)
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So Ed, is it built yet? :-)
Of course Jim, isn't yours?? ;-D
I hope to get a good start on it this weekend as I have a break in my son's wrestling schedule (YAY!!). I ordered a quilted Maple board from ebay, it arrived as did my tube sockets and resistors to go across the inputs. I want to get the chassis sprayed tonight and maybe get started on the circuit boards.
I will update this thread on my progress.
Best,
Ed
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I have my chassis components mounted and am currently wiring everything. I have a question concerning the wiring from the IEC to the switch and to the power transformer. Is there any benefit to using a larger conductr here? If so, does it have to be overall shielded or will twisted the conductors eliminate the electrical noise?
Thanks,
Ed
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Twisting reduces magnetic fields. Shielding reduces electric fields.
Noise on the power line is going to be high frequency, so it will radiate into nearby circuitry by capacitive coupling, i.e. electric fields, and the shielding is important. A magnetic field is generated by the 60-Hz current in the wires, and will mostly induce hum by magnetic coupling - hence the twisting is also important but for a different noise mechanism.
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Twisting reduces magnetic fields. Shielding reduces electric fields.
Noise on the power line is going to be high frequency, so it will radiate into nearby circuitry by capacitive coupling, i.e. electric fields, and the shielding is important. A magnetic field is generated by the 60-Hz current in the wires, and will mostly induce hum by magnetic coupling - hence the twisting is also important but for a different noise mechanism.
Thanks for the reply Paul. OK, so stay with a shielded cable for the AC input to the amp, do you believe increasing the size of the conductors to the switch and power transformer would be a benefit or are the lengths so short it just isn't an issue?
Other than my humpots which i believe may be on backorder the wiring is complete, now on to the base!!
The kit is basically stock. I have used Azuma tube sockets instead of the stock units, since I did not use a volume control I have added a 100K resistor across each input, and I used a couple of 2.2 uF Obbligato caps I had instead of the stock 3.3 uF Solens that came with the kit.
Best,
Ed
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The wire has more than enough current carrying capacity, and its resistance is a tiny fraction of the primary winding DC resistance, so there is absolutely no known technical reason a fatter wire would have any audible effect.
Of course, there are always effects unconnected to known technical reasons. Whether they are because of mass hysteria, or unknown technical effects, or something else we've never thought of, is unknown and unknowable. So I hardly ever say "never". :^)
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The wire has more than enough current carrying capacity, and its resistance is a tiny fraction of the primary winding DC resistance, so there is absolutely no known technical reason a fatter wire would have any audible effect.
Of course, there are always effects unconnected to known technical reasons. Whether they are because of mass hysteria, or unknown technical effects, or something else we've never thought of, is unknown and unknowable. So I hardly ever say "never". :^)
Thanks Paul, I'll stick with the known factors for now. Much appreciated.
Ed
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My base is not finshed but I got the Stereomour up and running today. All the measurements were right on with the exception of the 230VDC reading which read consistantly low across the board. A quick call to Dan "Doc Bottlehead" and he told me they have seen this here and there and that it appears to be due to differences amoungst 12AT7 tubes, not an issue. So I fired it up and out came music!
This is a great piece of kit, the instructions are outstanding!
A big thanks to Doc, Eileen and Paul Joppa. Thanks to Jim Rebman and Inferno (John) for making their recommendations.
More to come as I complete the base and let the unit burn in a bit.
Best,
Ed
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Ed,
Congrats! Can't wait until you get some time on it and can give us some more impressions.
-- Jim
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Wonderful, Ed!
I found the burn in made a difference but the overall character showed from the beginning. I don't recall: what did you select for your various caps (stock, Mundorf silver/oil, Auricaps, etc?????). Did you post photos yet? You know it didn't happen if there aren't photos....
John
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Wonderful, Ed!
I found the burn in made a difference but the overall character showed from the beginning. I don't recall: what did you select for your various caps (stock, Mundorf silver/oil, Auricaps, etc?????). Did you post photos yet? You know it didn't happen if there aren't photos....
John
Thanks John. Right now I have a pair of 2.2uF Obbligatos PIOs in the amp. I also have a pair of large (think red bull can size) Ampohms that are currently residing in my modified T-amp that I may switch out for the Obbligatos. But I will probably listen to it this way for now.
My unit is primarly stock except i am running it as a power amp and I used Azuma tube sockets.
I hope to get the base completed by this weekend.
BTW, I am pretty certain it happened, here you go!
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fnormal_Circuit_Boards.JPG&hash=c60631830c5429fc8c5ba68f170c54de857a3d17)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fnormal_front_parts_installed.JPG&hash=721364e4bc5299c7197669b283077ef277d5da6e)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fnormal_wiring_complete.JPG&hash=9efc0ee9bde9e094bf4982b5688ab4a1de41352b)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fnormal_base_front_unfinished.JPG&hash=973f449086c88b97275bea74318fca92c06af037)
Best,
Ed
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Someone on another forum recommended that I bolt the pillars on, I have always glued everything but in this case I thought bolting them on was a good idea so here you go!
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fnormal_Legs_Bolted.JPG&hash=495823030f6cdec1a34945028f907f5ecff64134)
Yes, the rear right corner brace is smaller, there is less room here due to the IEC socket.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fnormal_Legs_Bolted_all_frame.JPG&hash=97608c0b8a64b8f9abad2584fad47f9a89509361)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fnormal_amp_and_base_unfinished.JPG&hash=a57e62c452d6ccbcc779baf508436e85ad833e52)
If the amp looks a little swayback that is because I haven't installed the braces for the chassis yet.
Best,
Ed
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Very nice, Ed! I guess it DID happen after all. Those Obbli's should be a nice fit...I have been thinking about a nice set of Mundorf Silver in Oil 2.7uF caps instead of my Auricaps just to compare.
I like the "legs" and I bet it sounds nice without the extra switches for the inputs and without the pot. Congrats again!
John
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Very nice, Ed! I guess it DID happen after all. Those Obbli's should be a nice fit...I have been thinking about a nice set of Mundorf Silver in Oil 2.7uF caps instead of my Auricaps just to compare.
I like the "legs" and I bet it sounds nice without the extra switches for the inputs and without the pot. Congrats again!
John
Thanks John. I have a big pair of AmpOhms I am considering trying in this amp. The highs are sounding a bit muted on some material to me, I am hoping that clears up with some burn in or perhaps I need to roll some tubes. I am considering starting out with an in expensive tub like that JJ 12A7T you tried. Any other recommendations are welcome.
Best,
Ed
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. . . I have a big pair of AmpOhms I am considering trying in this amp. The highs are sounding a bit muted on some material to me, I am hoping that clears up with some burn in or perhaps I need to roll some tubes. . . .
No surprises here. I'm going to suggest adding a 0.1uF (or0.22uF) @600V KK Teflon in parallel with those AmpOhm caps. But... always a but, you have to break them in first. The relatively painless breakin instructions I have used for years are in this thread:
Relatively Painless Capacitor Break In Instructions (http://www.bottlehead.com/smf/index.php/topic,80.msg286.html#msg286)
Teflon caps take a long time to break in, 300-400 hours. But you get 89-90% of the way there in 100 hours, 4 days.
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Grainger,
Thanks for verifying that what I am hearing is not unique and the tip on burn in. I will try installing the ampohms which are already burnt in and if that doesn't bring up the highs by itself than I will try the bypass. I have a unused solid state amp sitting here ready to burn in some caps for me!
Thanks again for the burn in procedure.
Best,
Ed
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Ed,
If the AmpOhms are burned in then you can clip them in with jumpers, you ought to have a dozen, just to check easily and quickly.
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Ed,
If the AmpOhms are burned in then you can clip them in with jumpers, you ought to have a dozen, just to check easily and quickly.
Hi Grainger,
I should have been more clear. The Ampohms are 2.2uF caps that are about the size of a red bull can. I would install these in place of the 2.2 uF Obbligatos that I am currently using.
Best,
Ed
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Hey guys, I have made some progress on my build. I have also ordered a JJ ECC81 Gold pin matched triode tube and a pair of Mundorf .1 uF caps for the coupling cap position.
Here are some pics of the build, now I need to take it apart and put a finish on it.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Famp_complete_unfinished_top.JPG&hash=78bdf742025e54a1df7473512119ee3ac9ead077)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Famp_complete_unfinished_top_front.JPG&hash=c98d89b280ab8487e7e9ca8dd03e250e8a070b43)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Famp_complete_unifnished_side.JPG&hash=1d17ece986c926f54fce8529859b7e7149d7f6ff)
Best,
Ed
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Ed,
That cover is really looking good. Very creative and excellent craftsmanship. I like the clever use of the BH logo to cover the volume pot hole, too! I can't tell what the little wood part is on the left covering the selector switch hole (old eyes).
This is really coming together. I noticed a pretty big performance swing or two during burn in...more than I had found with the SPUD project. It really settled down for me after about 120 hours and is even smoother after about 250 hours (YMMV).
Thank you for posting photos of the progress as you go!
John
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Thanks John. I started applying the finish today, it shuld really bring out the character in the wood. The lttle block was something I was experimenting with, I am trying to figure a way to engrave or apply the words "Bottlehead Stereomour" on it but I don't think my woodburning skills are up to the task.
With regard to the sound it is really starting to smooth out today, much better with a little over 60 hrs on it.
I'll post again once it is complete.
Best,
Ed
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That makes sense on the piece of wood. How about the piece of wood but with a pilot light so you can tell from a glance it is powered on?
Enjoy the music....
John
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Hey guys, the amp is complete! I have about 90 hours on it now and it is really coming into it's own, it is really sounding fantastic! I have swapped out the stock 12A7T with a JJ E81CC gold pin, that made an improvement but I really think the hours are starting to add up and the amp is setteling in. I have some Mundoerf Silver/Oil .1 uF on the way that I will be switching into the coupling position.
Here are a few pics of the amp and system:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2FBase_and_cover_finished.JPG&hash=90bf24b4f41a6e639ac6f669b00e9e9c5da6bb12)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Ffinished_amp_front_1.JPG&hash=745f227bae593effb9d541c6061181f1f5714fa5)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Ffinished_amp_side.JPG&hash=2e34a04b62b1ba80dbad801bcedc191377ceee27)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Ffinished_amp_top.JPG&hash=7ef4d84d8f59dc5c165a18350c207781c1b6ddb6)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fequipment_front.JPG&hash=93a9acaf9583ff654fe1f63f4286030da056c5da)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fsystem_2.JPG&hash=24446b276f74a43d2559ded0c30177b65399cb81)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fsystem_3.JPG&hash=99b24ea53f6d668e732072dbdd6efca967b793df)
Please excuse the mess and unfinished acoustic treatment projects.
Best,
Ed
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Gorgeous! And like those speakers. And the Dodd Audio. And the curved diffusion wall. And the gnome....
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Gorgeous! And like those speakers. And the Dodd Audio. And the curved diffusion wall. And the gnome....
Thanks John. The speakers are GR Research V1's, full OB. Each speaker has 2 12" servo woofers and a servo amp for 200 Hz and down. The Stereomour is hi-passed at about 140 Hz feeding the coax. 3.5 watts is PLENTY of power for these speakers!
That's not just any gnome, that is a University of Louisville Cardinals gnome!!
Best,
Ed
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It's funny, I have a set of Danny Ritchey designed (box) speakers that I use with a P-P Jolida on my HT set up (two channel old school). I don't care what folks may say, I love Danny's taste in crossovers and speakers. I guess it just works for me.
And it's even funnier that I have been in a gnome war for about 8 years with a former co-worker and we are still at it even both having moved to different cities. No lawn or office is safe between the two of us!
John
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Guess I haven't heard what folks say but the V1 is my third (second actually, my first was a hybrid of Danny's OB MTM and an Augie for bass duty) speaker build designed by Danny. The second was a pair of his N3s for my sister, excellent speakers. I really enjoy the speakers I have heard that were designed by Danny, the V1s are outstanding and incredibly dynamic which is a great segway to my next point regarding the Stereomour.....low level dynamics! I have never heard an amp sound this good at low levels. You still get the entire sound spectrum even when you are playing at levels less than 60dB, incredilble!!
Best,
Ed
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Yes, that low volume level tonal balance and resolution is a strong characteristic of parallel feed single ended triode amps.
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Ah, Doc, just posted almost exactly the same thing but it got eaten. Anyway, I said something very close to the following:
Ed, yes, those low-level dynamics are very nice, and what I feel is the combination of great engineering, but also the parafeed topology, right-sized iron, and the magic of 2a3s and DHTs in general...
Then I went on to say:
I told you this BH stuff was addictive, didn't I? :-)
And Ed, when you get those JJs in there andsome time on them, fasten your seatbelt -- IMO they can make things just that much nicer.
I'm really glad to hear that you're liking this so much -- one never knows how somebody else is going to react to a piece of gear in their own system.
BTW, are those the same coax drivers Danny used in the Super Vs I heard at RMAF last year? Those were some really nice speakers, as was the rest of the system.
-- Jim
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Well the low level dynamics are icing on the cake for me, I had no idea.
Jim, the speaker I built is the V1 which was the first of this series Danny designed. The diference between the V1 and Super V is the P-audio coax used, the V1 has a 1" tweeter and I beleive the Super V has a 2" tweeter. Both coaxes are 12", of course the crossover for the coaxes differ from each other with the Super V being considerably more complex I believe.
Well, I have felt the amps I have been using were the bottlenecks in my system but no longer, I am really starting to love the sound I am getting from this amp!
Best,
Ed
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One last set of pics with the chassis holes covered.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Famp_complete.JPG&hash=1749875b8cf6ccbfb4aef310b3755071a2572d2e)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Famp_nameplate.JPG&hash=7a645e270ffccb8984a871c9e52dedbc0aa87548)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fsystem_final.JPG&hash=3a9ef013d5ae2ea11814782026fa580e46dc248a)
Best,
Ed
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I received my parafeed bypass caps (Obbilgato Premium Gold) within two days of ordering them (Thanks Diana!!), great service. I added them to the amp, no big change like there was going from the Sovtecs to the JJs, of course the caps have zero hours on them. More as things develop.
*UPDATE*
5 hours on the new caps. I sat down to listen and I found that things are sounding quite a bit better, soundstaging and imaging are better, music has better separation between instruments, music seems to have gained texture for lack of a better term. A worthwhile upgrade! Of course everything on this amp is still breaking in so I can't be certain this is all due to the caps but the improvments are a bit different than the improvements I experienced when I changed to the JJs.
Edit 2*Nice improvement in the sustain of cymbals!!
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fparafeed_bypass_caps_2.JPG&hash=7523f5e236736bf39ad8f33136919d065b79e264)
Best,
Ed
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My Mundorf's finally arrived!!
I have installed them and they are currently playing with zero hours on them. No huge improvement like there was with the JJs but I am hearing a bit more clarity and more air (could definately be in my head )! More as they burn in. Here is a pic:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.hawthorneaudio.com%2Fphotos%2Falbums%2Fuserpics%2F10060%2Fmundorfs.JPG&hash=25b7132529085290d253262f61d481ce3506265a)
This is the last of the upgrades I am currently planning. The amp has been sounding really great for the last day or so.
Best,
Ed
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Question:
If you look at the pic in the previous post you will note that all of the caps are labeled from left to right. I just realized that these two halves of the amp are actually mirror images of each other which means I have the (non-polarized) caps installed in two different directions between left and right as far as the circuits are concerned. So what do you think, is it worth taking the time to swap the parafeed and coupling caps around on one half of the amp? Although they are non-polarized one of the leads is the in-going lead and the other is the outbound lead, also keep in mind that I have 20+ hours on the Obbligato Premium Golds and over 200 hours on the Obbilgato Copper, the Mundorfs were just installed about an hour or so ago.
Thanks,
Ed
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The known technical reason for directionality of non-polarized capacitors is to minimize pickup of hum and noise through electrical fields. So if you can't identify a difference in hum and noise between channels, it not important.
I'm not saying that nobody will ever hear any other difference, and I'm not intending to pre-judge whether they are imagining it if they do :^), just that this is the only one I know of that is based on known physics.
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Thanks for the response Paul. No disproportionate hum between the channels so I guess I am good to go. And yes, they are imaging and presenting a very satisfying soundstage, I am really loving this amp.
edit: Whoops, you said imagining, not imaging....nevermind!
Best,
Ed
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I'm pleased to see you have made your mods and that they are starting to burn in. I would give the whole setup at least 100 hours, 200 would be better still, before I made up my mind. That means leaving it alone and listening to LOTS of music!!! Should be a labor of love....
Congratulations and I'm really excited to see the Mundorf's in the coupling cap position.
John
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This is the best amp I have owned. I am getting amazing sound now that it is starting to get a few more hours on it. Sounds very even and accurate but musical with great textures and tone. I am really loving it!! Playing Deacon Blues the opening cymbals are in the room, perfect.
Best,
Ed
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Ed,
That's especially gratifying to hear! Funny, I was thinking about my desert island discs, and Aja was right up there. Just love that album, and have since the day I bought it home when it came out. Of course you've got some really nice speakers there too :-).
-- Jim
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Jim, this thing just keeps getting better. The cymbals and chimes just stand out, I have never heard them so accurately recreated, ever. The bass is outstanding, the textures, detail, everything, I am a very happy camper.
Best,
Ed
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I'm so happy for you, Ed. You are right, it just keeps getting better. Now you see why I had to get those Radian's and the Mundorf/alpha core crossovers started. Congratulations!
John