Hi guys, I've been 'offline' for a while - very busy at work - but hopefully there'll be some faces I'll recognise still around. With all the work stuff I decided on a change in direction and packed up the job just before Christmas. I planned to take a break with some audio projects on my list of things to do; unfortunately the break wasn't the type I had planned - I had a fall before the new year and fractured my hip so I've been laid up unable to get to the workshop ever since!
Anyway, enough of my woes.
I'm still using my Bottlehead Paraglow 2 amps but am planning a fresh rebuild, mainly focussing on the power supply, where I plan to incorporate a regulated supply courtesy of Paul Hynes.
I've also just taken delivery of one of Bruce Rozenblit's Single-ended Output Transformerless kits;
http://www.transcendentsound.com/singleended.htm
I'll post occasionally as I get the projects underway.
Ray
SE-OTL
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andrew Ivimey
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#3
Hi Ray, still using those Lowthers, too?
The bottlehead ...oh, surely a stabilised PSU will only complicate the beauty of what is simple... but then, maybe. You must come to Owston, I know you are thousands of miles the other way.
And I'd really like to hear a Rosenblit OTL. I have an OTL but its the onlyone I've ever heard and I'd like to hear more.
The bottlehead ...oh, surely a stabilised PSU will only complicate the beauty of what is simple... but then, maybe. You must come to Owston, I know you are thousands of miles the other way.
And I'd really like to hear a Rosenblit OTL. I have an OTL but its the onlyone I've ever heard and I'd like to hear more.
#4
Ali, I purchased the kit sans transformers and paid around £600 including delivery. Her Majesty added around another £100 to the bill. I dispensed with the normally supplied transformers as I have a thing about aesthetics and safety and I don't do exposed transformers - I've ordered some potted toroids to replace them.
Andrew, good to 'speak' again. Yes, I'm still using, and loving, my lowthers and it'll be interesting to see how they work with the Transcendent. I take your point about the simplicity of the Paraglow but nothing ventured, nothing gained and I can always revert.
Ray
Andrew, good to 'speak' again. Yes, I'm still using, and loving, my lowthers and it'll be interesting to see how they work with the Transcendent. I take your point about the simplicity of the Paraglow but nothing ventured, nothing gained and I can always revert.
Ray
Sorry, I couldn't resist!
#6
Hi Ali, no, not the cheapest project around - I reckon it'll cost me around £900 all in to get it working and including the changes I want to make. There is a clear mark-up on the kit as the components could be purchased for a lot less but the guy is making his living from his kits and I don't begrudge him that.
By reputation the amplifier should sound excellent so I'm positive about the prospects.
Ray
By reputation the amplifier should sound excellent so I'm positive about the prospects.
Ray
Sorry, I couldn't resist!
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andrew Ivimey
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#7
Aha! I 'member... Dave the vinyl junkie (where is he now?)
He had a 'Transcendant'. Anyone any (un)reliable memoirs on this hamplifier???
He had a 'Transcendant'. Anyone any (un)reliable memoirs on this hamplifier???
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andrew Ivimey
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#10
ooooo I know the one, with all those russian 6S19s?! Sweet, I hope! My otl uses 4 6AS7s (two per channel), so it is a bit more powerful. It is the amp that SWMBO prefers; the glow of filaments reflected in the copper chsasis top, ah! but I never use it.
makes a note - 'give OTL a severe 'do'!'
makes a note - 'give OTL a severe 'do'!'
#11
Well, finally I've made a start on the Transcendent SE-OTL....
As some of you may recall, I've been nursing a fractured hip and haven't been able to get to my tools etc. - until today.
Bruce Rozenblit is very specific in the build instructions that you must build exactly as per the instructons and any modification will reduce the performance; what was the first thing I do?
I reasoned that if you want to minimise any hums, buzzes etc. then running 240V AC wiring across the amplifier sections so you can have an on/off switch on the front panel isn't such a good idea so today I've relocated the switch to the rear, next to the mains inlet and fuse. It's just taken me nearly two hours to cut the whole for the switch with mini grinding disks in my Dremel and an assortment of diamond files - don't you just love working with stainless steel! Unlike a Mr I chassis though, the hole is rectangular,the chassis isn't smeared with blood and I still have all my digits intact.
BTW, the chassis provided is all very nicely laser cut so when I remove the protective plastic film and give it a good polish it should look nice.
Rather than get a new front panel I'll just leave the old switch as a dummy - it might be fun to see if some of my audio friends will be able to tell the difference with it in/out of circuit - I wonder if I can complete it before April.
As I have chosen to ignore Bruce's instructions I've purchasing a few replacement parts too, Schottky and Hex-Fred diodes, some nice Jupiter caps for coupling and a few other bits and pieces.
I'm hoping to start the actual build next week - still waiting for some of the bits at the moment.
Ray
As some of you may recall, I've been nursing a fractured hip and haven't been able to get to my tools etc. - until today.
Bruce Rozenblit is very specific in the build instructions that you must build exactly as per the instructons and any modification will reduce the performance; what was the first thing I do?
I reasoned that if you want to minimise any hums, buzzes etc. then running 240V AC wiring across the amplifier sections so you can have an on/off switch on the front panel isn't such a good idea so today I've relocated the switch to the rear, next to the mains inlet and fuse. It's just taken me nearly two hours to cut the whole for the switch with mini grinding disks in my Dremel and an assortment of diamond files - don't you just love working with stainless steel! Unlike a Mr I chassis though, the hole is rectangular,the chassis isn't smeared with blood and I still have all my digits intact.
BTW, the chassis provided is all very nicely laser cut so when I remove the protective plastic film and give it a good polish it should look nice.
Rather than get a new front panel I'll just leave the old switch as a dummy - it might be fun to see if some of my audio friends will be able to tell the difference with it in/out of circuit - I wonder if I can complete it before April.
As I have chosen to ignore Bruce's instructions I've purchasing a few replacement parts too, Schottky and Hex-Fred diodes, some nice Jupiter caps for coupling and a few other bits and pieces.
I'm hoping to start the actual build next week - still waiting for some of the bits at the moment.
Ray
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Mike H
- Amstrad Tower of Power
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- Joined: Sat Oct 04, 2008 5:38 pm
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#12
I am intrigued by the "fully Class A, single-ended mode"
Suggests to me one half of the output is a 'passive' current source? I.e. not signal driven
+ has anyone else noticed DC blocking cap to feed the speaker load?
Suggests to me one half of the output is a 'passive' current source? I.e. not signal driven
+ has anyone else noticed DC blocking cap to feed the speaker load?
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
#13
Mike, my understanding of amplifier technical design is very limited but what I can tell you is that the output stage is very simple, just four paralleled low power triodes(6C19Pi). Have you seen the schematic?
Yes the output is capacitor coupled, Bruce's argument being that it is 'a thousand times less damaging than output transformers'. The proof of the pudding will be in the eating as I'll be able to compare it to a Bottlehead Paraglow 2 (2A3 SET, complete with Cobalt output transformers).
Ray
Yes the output is capacitor coupled, Bruce's argument being that it is 'a thousand times less damaging than output transformers'. The proof of the pudding will be in the eating as I'll be able to compare it to a Bottlehead Paraglow 2 (2A3 SET, complete with Cobalt output transformers).
Ray
#14
Ray et al,
The SE-OTL intrigued me so I looked up 6C19P then I found these, even more intriguing they do not appear to have a getter, least not this version does not.
http://cgi.ebay.co.uk/Vacuum-Powerful-T ... 58856c25e7
-- Andrew
The SE-OTL intrigued me so I looked up 6C19P then I found these, even more intriguing they do not appear to have a getter, least not this version does not.
http://cgi.ebay.co.uk/Vacuum-Powerful-T ... 58856c25e7
-- Andrew