First of all sorry about the Noob questions, This is my 1st SET. I have built many SE, UL, and PP amps, HiFi and Guitar, but this is my first with regulated fil and thought best to ask questions here first.
I have been gathering components togather for this build.
List as follows...
For output
2- matched NOS Kenrad 45 st's
OPT James JS-6113HS
For input
2-matched NOS RCA 27 st's
What would you recomend for a driver?
I intend on regulating the filaments for graveyard quiet transients, but still working on that.
I still have to order the power tranfo yet any Ideas? preferably James for matching appearance. and chokes...
Yes, this is still a little vague, but I will fill in the blanks as build continues.
Thanks
I have been gathering components togather for this build.
List as follows...
For output
2- matched NOS Kenrad 45 st's
OPT James JS-6113HS
For input
2-matched NOS RCA 27 st's
What would you recomend for a driver?
I intend on regulating the filaments for graveyard quiet transients, but still working on that.
I still have to order the power tranfo yet any Ideas? preferably James for matching appearance. and chokes...
Yes, this is still a little vague,
but I will fill in the blanks as build continues.Thanks
I and a good many of us around here have found the 27 to be somewhat unreliable, and inconsistent in terms of sound quality - some are very good, and some surprisingly are rather the reverse.
You could consider a single 6SN7 which has enough gain to drive a pair of 45s if you are contemplating cd level signals - the purist in me would use a 270H plate choke from Lundahl such as the LL1667 configured for SE operation with the 6SN7 biased for 10mA or so.. B+ of about 200V.
A combination I particularly like is the 5842/417A with 100H choke load and this provides about 7dB more gain than the 6SN7 option described previously. Run this at around 15mA and B+ of about 125V..
http://www.lundahl.se/pdfs/datash/1667_68.pdf
I like fixed bias on my 45s as well, and found an operating point of 250V/38mA pretty nice.. A 5K primary Z will give you roughly 2Wrms out at < 5% thd. Grid bias would be somewhere around -45V (pot range approximately -40V to -50V) or so depending on the specific tubes. Fixed bias gets rid of the inevitable colorations introduced by a cathode bypass cap and gives you a lot of flexibility to optimize the operating point. The down side of course is that a very simple but well filtered bias supply is required. Measure cathode current with a single 1 - 10 ohm resistor in the "cathode" circuit. (I usually use center tapped filament transformers)
I have found the 45 to be extremely quiet even with AC heating, but a simple DC supply with a CCS will eliminate IM sidebands due to the AC heating and result in better measured performance. (Which in some cases may also be audible - George of Tubelab can elaborate on this further.) Antek makes inexpensive toroids that are suitable for powering a CCS based heater set up..
The 45 is a GREAT tube to cut your SE teeth on.. I have loaned my original prototype recently to a friend, but it remains one of my favorites. IMHO It is one of the best sounding power triodes out there period.. (I also like the 300B and GM70)
Link here: 45 S.E Stereo Amplifier
I think you could do even better than this design, and hopefully my suggestions are helpful.. And yes I do like regulated B+.
You could consider a single 6SN7 which has enough gain to drive a pair of 45s if you are contemplating cd level signals - the purist in me would use a 270H plate choke from Lundahl such as the LL1667 configured for SE operation with the 6SN7 biased for 10mA or so.. B+ of about 200V.
A combination I particularly like is the 5842/417A with 100H choke load and this provides about 7dB more gain than the 6SN7 option described previously. Run this at around 15mA and B+ of about 125V..
http://www.lundahl.se/pdfs/datash/1667_68.pdf
I like fixed bias on my 45s as well, and found an operating point of 250V/38mA pretty nice.. A 5K primary Z will give you roughly 2Wrms out at < 5% thd. Grid bias would be somewhere around -45V (pot range approximately -40V to -50V) or so depending on the specific tubes. Fixed bias gets rid of the inevitable colorations introduced by a cathode bypass cap and gives you a lot of flexibility to optimize the operating point. The down side of course is that a very simple but well filtered bias supply is required. Measure cathode current with a single 1 - 10 ohm resistor in the "cathode" circuit. (I usually use center tapped filament transformers)
I have found the 45 to be extremely quiet even with AC heating, but a simple DC supply with a CCS will eliminate IM sidebands due to the AC heating and result in better measured performance. (Which in some cases may also be audible - George of Tubelab can elaborate on this further.) Antek makes inexpensive toroids that are suitable for powering a CCS based heater set up..
The 45 is a GREAT tube to cut your SE teeth on.. I have loaned my original prototype recently to a friend, but it remains one of my favorites. IMHO It is one of the best sounding power triodes out there period.. (I also like the 300B and GM70)
Link here: 45 S.E Stereo Amplifier
I think you could do even better than this design, and hopefully my suggestions are helpful.. And yes I do like regulated B+.
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45SET build
Thanks, Kevin
Before I decide on the 27's, I will breadboard out the amp for a good listen.
I do have many 6sn7's of sorts and a half dozen of the CCCP 6H8S t plate.
I guess I will be bread boarding for a few days to find out what may sound the best.
My list of tubes on hand is over 2500 strong, yes been at it for a few years.
Too many choices, and I haven't tried all the options yet.
I was hoping to stick with ST's, just for looks.
My other optionsmany each)
76
6c6G
6ae5G
6f8G
6a6G ect.
I was looking into the 27 because a local friend considered it his "holy grail input".
Back to (fun) work again
Thanks again,
Michael
Thanks, Kevin
Before I decide on the 27's, I will breadboard out the amp for a good listen.
I do have many 6sn7's of sorts and a half dozen of the CCCP 6H8S t plate.
I guess I will be bread boarding for a few days to find out what may sound the best.
My list of tubes on hand is over 2500 strong, yes been at it for a few years.
Too many choices, and I haven't tried all the options yet.
I was hoping to stick with ST's, just for looks.
My other options
many each)76
6c6G
6ae5G
6f8G
6a6G ect.
I was looking into the 27 because a local friend considered it his "holy grail input".
Back to (fun) work again
Thanks again,
Michael
Thanks, Kevin
Before I decide on the 27's, I will breadboard out the amp for a good listen.
I do have many 6sn7's of sorts and a half dozen of the CCCP 6H8S t plate.
I guess I will be bread boarding for a few days to find out what may sound the best.
My list of tubes on hand is over 2500 strong, yes been at it for a few years.
Too many choices, and I haven't tried all the options yet.
I was hoping to stick with ST's, just for looks.
My other options
76
6c6G
6ae5G
6f8G
6a6G ect.
I was looking into the 27 because a local friend considered it his "holy grail input".
Back to (fun) work again
Thanks again,
Michael
Take a look at the 76, should work reasonably well with choke loading at 5mA and about 250V with a 270H plate choke and 220K grid resistor at the 45 grid.. A little over 2.5Vrms would drive it to the required levels for full output.. IMHO..
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While digging for parts, to my suprise I found a nice filament tansformer.
I think it is manufactured by Thordoson, but not in a box the part number is T16F09 stamped on one side and 2.5V 10A on the other. This should be adequate for the 45's it is center tapped. Now to dig through the half ton of power transformers...
I think it is manufactured by Thordoson, but not in a box the part number is T16F09 stamped on one side and 2.5V 10A on the other. This should be adequate for the 45's it is center tapped.
Now to dig through the half ton of power transformers...
While digging for parts, to my suprise I found a nice filament tansformer.
I think it is manufactured by Thordoson, but not in a box the part number is T16F09 stamped on one side and 2.5V 10A on the other. This should be adequate for the 45's it is center tapped.
Very similar to the filament transformer I used in mine.. Fixed bias of course.. Very quiet overall.. Has always been used with HE speaker systems good down to at least 40Hz..
Just another possible brain fart of mine, How about an srpp 6sl7 in first then a 6ah4 driver for the 45 output? Just throwing some ideas around, what do you think? Could be very transparent.
I have many of the 6ah4, 6bl7, 6bx7's on hand also that I wasn't thinking about at the time of starting this thread.
The reason for all this is to figure out what will give the best solid frequency response across the board. We listen to all types of music styles from classical to modern hip hop (kids). I prefer instrumentals though...
I have a supply of 6an4's, 6t4's, 12a4's, 12b4's ect. I have basicaly whatever type that are favorites on the net. and then some.
I ask for help on frequency response, because I do not have a o-scope at hand yet. I did have, but it was pushed off bench by kids (accident).
I promise when this get's started it will become interesting, indulge me for a few days, some components are in transit still so pics at this time won't show enough.
Found a NOS Mullard GZ34 for rectification...!
I have many of the 6ah4, 6bl7, 6bx7's on hand also that I wasn't thinking about at the time of starting this thread.
The reason for all this is to figure out what will give the best solid frequency response across the board. We listen to all types of music styles from classical to modern hip hop (kids). I prefer instrumentals though...
I have a supply of 6an4's, 6t4's, 12a4's, 12b4's ect. I have basicaly whatever type that are favorites on the net. and then some.
I ask for help on frequency response, because I do not have a o-scope at hand yet. I did have, but it was pushed off bench by kids (accident).
I promise when this get's started it will become interesting, indulge me for a few days, some components are in transit still so pics at this time won't show enough.
Found a NOS Mullard GZ34 for rectification...!
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With the 45 set, it will be powering a pair of vintage RCA speakers that rock with even 1.4w se 6an5. They originally were powered by 6v6 UL amp out of an early 1940's tall boy record player and complimenting them with 4" Audiophile full range and pair of super tweets. Quite a home-brew mix, but sounds fantastic.
A 6SL7 SRPP running at 2mA will drive a 45 to full power very nicely. I think you loose something when you add unneeded stages...
The James Mod. JS-6113HS opt came today.
Awaiting other components for some tube porn here.
Then Assembly will commense
I must admit these transformers are sweet looking.
I think you will find the James to be quite nice..
45 SET build
Happy day, the pair of James JS 5-200's arrived today!!
This is a nice pair matched in size and shape to the opt's.
I am separating the power supply with filtering to each chanell, just for overkill.
Now awaiting a special ordered potted power tranfo from hammond model 370DXP, should arrive 1st or second week of Aug.
This build is a little extravagent, but I always wanted one this nice, and building these ourselves creates a product that will be passed on.
Now for the signal caps, I have a lot of black spragues that sound really nice in circuit, but if you were building a one off special unit what would you use in terms of sound quality and reliability?
I am waiting on chassis choice once everything has come togather, just to make sure everything fits. (I am looking at the new wood sided hammonds)
I like the full wood wrap ones, but the have a new chassis that has wood enplates that I am leaning toward 10"X17"X3" .
Pic's will be published here when all components have arrived. I promise the drool factor will be here...
Have a great DIY day!!!
Happy day, the pair of James JS 5-200's arrived today!!
This is a nice pair matched in size and shape to the opt's.
I am separating the power supply with filtering to each chanell, just for overkill.
Now awaiting a special ordered potted power tranfo from hammond model 370DXP, should arrive 1st or second week of Aug.
This build is a little extravagent, but I always wanted one this nice, and building these ourselves creates a product that will be passed on.
Now for the signal caps, I have a lot of black spragues that sound really nice in circuit, but if you were building a one off special unit what would you use in terms of sound quality and reliability?
I am waiting on chassis choice once everything has come togather, just to make sure everything fits. (I am looking at the new wood sided hammonds)
I like the full wood wrap ones, but the have a new chassis that has wood enplates that I am leaning toward 10"X17"X3" .
Pic's will be published here when all components have arrived. I promise the drool factor will be here...
Have a great DIY day!!!
Happy day, the pair of James JS 5-200's arrived today!!
<snip>
Now for the signal caps, I have a lot of black spragues that sound really nice in circuit, but if you were building a one off special unit what would you use in terms of sound quality and reliability?
<snip>
Have a great DIY day!!!
My choice (all teflon) in order of preference would be:
- Vcap
- REL TFT
- Ex Soviet FT3 Teflon
All save the Russian Teflon are costly, but as you need only a couple I'd go for it. My choice is the Vcap despite its high price, I just haven't heard a less colored, more transparent cap than this.. All that said the other two choices will be very good as well.. Try to stick to values of 0.1uF or so for cost and capacitor HF performance.
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45 SET build Re: Caps filter and signal
I am building this 45SET with overkill in mind.
It started as a simple project, but escalated with my DIY mind.
Looking for your personal suggestions for filter and signal caps.
I won't say money is no object here, but if there is enough proof of mfg quality and sound quality it will be on order.
On a different note, drifting off cap subject....
My budjet has been blown out the door so far, but its for an audio amp right!
The 45's were a little spendy also but they are NOS Kenrads and measure as a very close match on my Simpson tester. They are in the 90% range with perfect getter flashing. Not gassy at all. They look brand new even though over 70yrs old.
For the vol control I have very nice set of NOS AllenBradley 100k MONO's (hot molded carbon with carbon wiper pad). (very quiet contol)
I was looking at a step vol control, but the AB's have been a mainsay on my bench, and have never sounded bad.
The 27's remain as input, for now, because along with the solid plate RCA's that I have, I bought a very nice pair of globes 227's Mesh plate RCA radiotron's that measure very similarly. I have high hopes, and I know I will have them working flawlessly in the end.
Excitement building....
Have a great day
Michael
I am building this 45SET with overkill in mind.
It started as a simple project, but escalated with my DIY mind.
Looking for your personal suggestions for filter and signal caps.
I won't say money is no object here, but if there is enough proof of mfg quality and sound quality it will be on order.
On a different note, drifting off cap subject....
My budjet has been blown out the door so far, but its for an audio amp right!
The 45's were a little spendy also but they are NOS Kenrads and measure as a very close match on my Simpson tester. They are in the 90% range with perfect getter flashing. Not gassy at all. They look brand new even though over 70yrs old.
For the vol control I have very nice set of NOS AllenBradley 100k MONO's (hot molded carbon with carbon wiper pad). (very quiet contol)
I was looking at a step vol control, but the AB's have been a mainsay on my bench, and have never sounded bad.
The 27's remain as input, for now, because along with the solid plate RCA's that I have, I bought a very nice pair of globes 227's Mesh plate RCA radiotron's that measure very similarly. I have high hopes, and I know I will have them working flawlessly in the end.
Excitement building....
Have a great day
Michael
Kevin,
I have 3 crates full of NOS US military oil in paper metal can caps that I nearly forgot about.
They range from .25uF600v- 8uF1000v. Many sizes to choose from
Have you used these? I have been holding them for special projects, but they slipped my mind. My basement is a virtual warehouse of goodies...
Michael
I have 3 crates full of NOS US military oil in paper metal can caps that I nearly forgot about.
They range from .25uF600v- 8uF1000v. Many sizes to choose from
Have you used these? I have been holding them for special projects, but they slipped my mind. My basement is a virtual warehouse of goodies...
Michael
Purchased capacitor samples...
Russian FT-3 .1 600v teflons
Solen .1 630v
Clarity Cap ESA .1 630v
and
Clarity Cap 2.2mF 630v snubbers
I couldn't decide, so I'll try a few versions.
They will get used with this project or the next anyway.
I also found many Sprague Black Beauty's in a box and along the way found a large batch of Sprague Bumble Bees .005, .011, .022, .05, .12, .15 and .5 in 400 and 600v. Nice basement find, I must have bought them years ago.
Suprising what you find when you clean out the storage area.
Have a good day
Michael
Russian FT-3 .1 600v teflons
Solen .1 630v
Clarity Cap ESA .1 630v
and
Clarity Cap 2.2mF 630v snubbers
I couldn't decide, so I'll try a few versions.
They will get used with this project or the next anyway.
I also found many Sprague Black Beauty's in a box and along the way found a large batch of Sprague Bumble Bees .005, .011, .022, .05, .12, .15 and .5 in 400 and 600v. Nice basement find, I must have bought them years ago.
Suprising what you find when you clean out the storage area.
Have a good day
Michael
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