DCAudioDIY.com

DC Area Audio DIYer's Community
It is currently February 20th, 2019, 5:20 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 41 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next
Author Message
 Post subject: Re: Musician's Amplifier
PostPosted: October 14th, 2018, 12:19 pm 
Offline
User avatar

Joined: July 24th, 2015, 4:17 pm
Posts: 825
Location: Parkville, Maryland
Jim G wrote:
Grover Gardner wrote:
.... I'll have to measure the taps and see if it's still good. Sigh. Wonder if I can find another one....

Don't worry about a pair. Time to set up a 1st rate mono system. People tell me mono is making a comeback. I still have my father's first corner cabinet with a University coax inside.

Maybe the club should do a mono demo at CAF sometime?



But -- do not play mono LPs with a stereo cartridge. Last year one the vendors had a TT set up with teo arms one with a high-end Ortofon stereo cartridge and one with an Ortofon mono cartridge. They played some nice vintage mono LPs first with the stereo cartridge, and then with the mono cartridge. To say there was a major difference in the reproduction was a gross understatement. The true mono cartridge playing those LPs was a revelation! The sound got bigger and more open! Nothing in the system was changed other than going from a stereo cartridge to a mono cartridge. For me it was definitely a "GEE-WHEEZ!" not to be forgotten.

_________________
Walt


Top
 Profile  
 
 Post subject: Re: Musician's Amplifier
PostPosted: October 14th, 2018, 1:04 pm 
Offline

Joined: June 4th, 2013, 2:39 pm
Posts: 137
Jim G wrote:
Grover Gardner wrote:
.... I'll have to measure the taps and see if it's still good. Sigh. Wonder if I can find another one....

Don't worry about a pair. Time to set up a 1st rate mono system. People tell me mono is making a comeback. I still have my father's first corner cabinet with a University coax inside.

Maybe the club should do a mono demo at CAF sometime?


Ha! That's a thought. The gentleman who built it was a one-time cartoonist for Disney and inventor. He had a single three-way horn system built into a console in the living room of his hand-built ranch-house. He ran a pear orchard, maintained an enormous machine shop next to the garage and played around with single-person flying machines. Among the items in the shop was a bicycle with a jet engine attached to it. The property was littered with old Heinkel bubble cars. Apparently he used the engines to make one-man open-frame helicopters.


Top
 Profile  
 
 Post subject: Re: Musician's Amplifier
PostPosted: October 15th, 2018, 4:53 pm 
Offline

Joined: June 4th, 2013, 2:39 pm
Posts: 137
Further listening has led to disappointment with the KT66's. They are "richer" but lack ambient detail, which is very clear with the 1625s. And they have an unpleasant harmonic signature. I suspect the cheap Chinese build quality. I have some Gold Lions coming shortly and will try those--they are supposed to be very good. But I think I may stick with the 1625s. They have some real magic.


Top
 Profile  
 
 Post subject: Re: Musician's Amplifier
PostPosted: October 15th, 2018, 7:05 pm 
Offline
User avatar

Joined: July 24th, 2015, 4:17 pm
Posts: 825
Location: Parkville, Maryland
Grover Gardner wrote:
Further listening has led to disappointment with the KT66's. They are "richer" but lack ambient detail, which is very clear with the 1625s. And they have an unpleasant harmonic signature. I suspect the cheap Chinese build quality. I have some Gold Lions coming shortly and will try those--they are supposed to be very good. But I think I may stick with the 1625s. They have some real magic.



Don't waste your time or money. The Gold Lions are Russian "wanna-be" KT-66s. The Chinese tubes are actually quite nice despite the rumors. But then there is nothing on this earth equal to the Genelec KT-66s with the carbon coating inside the glass envelope. When I had an amplifier modeled after the Williamson design I tube-rolled beyond reason. Then I took the plunge -- genuine British made Genelec KT-66s. ZOWIE! They're rated for a minimum of 8,000 hours MTBF at about 50-ma cathode current but sound best biased for about 36-ma. Compared to EL-34s, KT-88s, Chinese and Russian KT-66s, and Bendix Red Bank 6384s it was not even a contest. The big surprise with the Genelecs was that they really came on song set up as triodes.


Attachments:
Genalex-KT66-1.jpg
Genalex-KT66-1.jpg [ 16.19 KiB | Viewed 779 times ]

_________________
Walt
Top
 Profile  
 
 Post subject: Re: Musician's Amplifier
PostPosted: October 15th, 2018, 7:11 pm 
Offline
Site Admin
User avatar

Joined: February 28th, 2013, 10:38 am
Posts: 1028
SoundMods wrote:
But -- do not play mono LPs with a stereo cartridge. Last year one the vendors had a TT set up with teo arms one with a high-end Ortofon stereo cartridge and one with an Ortofon mono cartridge. They played some nice vintage mono LPs first with the stereo cartridge, and then with the mono cartridge. To say there was a major difference in the reproduction was a gross understatement. The true mono cartridge playing those LPs was a revelation! The sound got bigger and more open! Nothing in the system was changed other than going from a stereo cartridge to a mono cartridge. For me it was definitely a "GEE-WHEEZ!" not to be forgotten.


And remember, the Denon DL-102 is not a proper mono cartridge, it was specifically designed to produce a mono signal from stereo records for use in AM broadcasting....

Roscoe


Top
 Profile  
 
 Post subject: Re: Musician's Amplifier
PostPosted: October 15th, 2018, 11:16 pm 
Offline

Joined: June 4th, 2013, 2:39 pm
Posts: 137
SoundMods wrote:
Grover Gardner wrote:
Further listening has led to disappointment with the KT66's. They are "richer" but lack ambient detail, which is very clear with the 1625s. And they have an unpleasant harmonic signature. I suspect the cheap Chinese build quality. I have some Gold Lions coming shortly and will try those--they are supposed to be very good. But I think I may stick with the 1625s. They have some real magic.



Don't waste your time or money. The Gold Lions are Russian "wanna-be" KT-66s. The Chinese tubes are actually quite nice despite the rumors. But then there is nothing on this earth equal to the Genelec KT-66s with the carbon coating inside the glass envelope. When I had an amplifier modeled after the Williamson design I tube-rolled beyond reason. Then I took the plunge -- genuine British made Genelec KT-66s. ZOWIE! They're rated for a minimum of 8,000 hours MTBF at about 50-ma cathode current but sound best biased for about 36-ma. Compared to EL-34s, KT-88s, Chinese and Russian KT-66s, and Bendix Red Bank 6384s it was not even a contest. The big surprise with the Genelecs was that they really came on song set up as triodes.


Yes, there were about 8 of those too in the grandfather's stash. ;-) They tested from very good to okay. I felt obliged to return them to my friend to sell on eBay. About $800 worth--I figured he could use the money.

The point here is to reduce my costs of maintaining a sweet PP triode amp. I picked up five NOS 1625s for $25 including shpping on eBay. I figure I'm good for two or three years now. ;-) I have a few dozen military 12J5's I bought some time ago for peanuts. That's what I'm going to use.


Top
 Profile  
 
 Post subject: Re: Musician's Amplifier
PostPosted: October 16th, 2018, 12:19 am 
Offline

Joined: June 4th, 2013, 2:39 pm
Posts: 137
About twenty years ago, I attended a listening session that featured Lowther speakers in fancy plywood boxes driven by single-ended 300B monoblocks built entirely with vintage Western Electric iron. About $12,000 there. Acoustic guitar sounded wonderful, Mahler not so much. The wine was flowing and in the middle of the session, our host for some reason plucked a $2000 1950's WE 300B out of one of the amps--he was going to make some point about the construction, I believe--and bobbled it. The rest of us watched it fly into the air...and drop on the hardwood floor. And I thought, that's not's going to be me. ;-)


Top
 Profile  
 
 Post subject: Re: Musician's Amplifier
PostPosted: October 16th, 2018, 10:29 am 
Offline
User avatar

Joined: December 14th, 2013, 2:19 pm
Posts: 636
Hey Grover,

I'm putting together a set of Class A amps that can use any of the common octal output tubes: KT100, KT90, KT88, KT77, KT66, EL34, 6L6, etc., just so long as the pinout is the same.

My application will have two channels used from ~100Hz to 3.5kHz, the other from 3.5kHz up.

I can use different tubes in each of the four "channels". With the larger set of tubes, ~ 25WPC, the smaller ones ~15 WPC. I think even the 15WPC will be more than adequate.

Given your expertise, and what Charlie tells me are a great set of ears, what would your tube recommendation be? Price is an issue!

Thanks,

Stuart


Top
 Profile  
 
 Post subject: Re: Musician's Amplifier
PostPosted: October 16th, 2018, 2:20 pm 
Offline

Joined: July 17th, 2016, 6:24 am
Posts: 570
Stuart Polansky wrote:
Hey Grover,

I'm putting together a set of Class A amps that can use any of the common octal output tubes: KT100, KT90, KT88, KT77, KT66, EL34, 6L6, etc., just so long as the pinout is the same.

My application will have two channels used from ~100Hz to 3.5kHz, the other from 3.5kHz up.

I can use different tubes in each of the four "channels". With the larger set of tubes, ~ 25WPC, the smaller ones ~15 WPC. I think even the 15WPC will be more than adequate.

Given your expertise, and what Charlie tells me are a great set of ears, what would your tube recommendation be? Price is an issue!

Thanks,

Stuart


Since your amp can take EL34, try Russian 6n3CE tubes if you can find them. I are not as soft was EL34 in the bass and they are better than most KT88/66 etc.

_________________
Shashi


Top
 Profile  
 
 Post subject: Re: Musician's Amplifier
PostPosted: October 16th, 2018, 7:08 pm 
Offline
Site Admin
User avatar

Joined: February 28th, 2013, 10:38 am
Posts: 1028
Grover Gardner wrote:
About twenty years ago, I attended a listening session that featured Lowther speakers in fancy plywood boxes driven by single-ended 300B monoblocks built entirely with vintage Western Electric iron. About $12,000 there. Acoustic guitar sounded wonderful, Mahler not so much. The wine was flowing and in the middle of the session, our host for some reason plucked a $2000 1950's WE 300B out of one of the amps--he was going to make some point about the construction, I believe--and bobbled it. The rest of us watched it fly into the air...and drop on the hardwood floor. And I thought, that's not's going to be me. ;-)


I watched Vu's (ex I believe) wife pick up a boxed NOS 50 once and the bottom of the box came open.....

Roscoe


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 41 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group