NOSValves
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Posts posted by NOSValves
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In many ways it is....they may work okay in that amp or they may not. In the end my advice is to investigate never assume. It all depends on how the amp is biased and how much adjustment is available.
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On 2/28/2018 at 12:36 PM, mopardave said:
Yes i noticed that will measuring things. Im now looking at the Dared vp20 i think is the model. Takes 6L6 and should be able to use the kt66 in them.
That not a sure thing 6L6 require less negative bias voltage than 66 too
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Dave,
It's not totally unusual for KT66's to not bias in an amplifier designed for EL34's. EL34's bias with -34 to -45 volts applied to pin 5 control grid while KT66's usually take well over -50 volts. Oh and realize the more negative (higher number) you adjust the pin 5 control grid voltage the cooler the tube is biased (pin 8 will go down).
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Dave slow down and read more carefully. I never said measure at pin 5. I was explaining why changing then 10 ohm resistor would not work....I did tell you to return the tubes they bias to hot in your amp.
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On 2/25/2018 at 12:38 PM, mopardave said:
Thats good to know because i was thinking about going that route.
Before ruling the route out you might want to ask Schu how much cheese he has invested in his digital rig. DAC's have come a long way since the 333ES there is no magic in a spinning disc
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Dean,
Sorry I don't allow forums to alert me of replies to my posts I found doing that saves me a boat load of time.
I use a little Chinese made dac similar to the one Grant Fidelity rebrands. http://shop.grantfidelity.com/grant-fidelity-tubedac-11
It does a decent job. Realize I don't use digital sources for serious listening. When I want to really listen I drop a needle. I listen to music while I work and either listen via my fm rig or my digital music server.
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No absolutely not..... if you have a set of tubes that will not bias most likely you have a set that bias way hot. Many modern production tubes bias excessively hot.
When you adjust the bias you are actually adjusting a negative voltage that enters the tube via the control grid which on your amp is pin 5. The measurement you are taking on pin 8 is the current the tube is drawing through that 10 ohm resistor from ground. We use a 10 ohm resistor so the voltage translates into how much current it equals. .50 VDC = 50 mA and .75 VDC = 75 mA and so on... to make a set of tubes run cooler you have to be able to apply more negative voltage to pin 5...
Rather than modify the amp I'd return the tubes and request a cooler biasing set of tubes. With some tubes it might be impossible to get a cool enough running set.
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I thought I had good luck with cleaning when my 333ES started acting up. Good to hear it helped you out!
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57 minutes ago, mopardave said:
I have had this 333 for 15+yrs and has had trouble reading from time time, but no big deal til now. Just bought 2 new cd's, one RB and one SACD. Player reads SACD perfectly and will not read RB at all. Any ideas?
Have you tried one of those laser lens cleaner disc? I seem to recall extending the use of my 333ES players by using one of those. But at some point both of my 333ES players would almost never read a redbook CD. I don't use any players these days I have everything put on the server and run it through a little DAC. Well except my SACD collection...
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15 hours ago, USNRET said:
Arranged to keep power cords from crossing other wires / cables. At least that is how I remember it from Craig when I got mine.
Yup
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That looks like a EL34 to me. Your not going to destroy your tube tester by placing a tube in it and setting it to what you think the tube is and then check it for shorts and so on....if it passes those tests then and only then hit the test button. If you have a blatant mismatch that will harm the tester it will show up in the shorts test. Or the tube will glow brightly as soon as you plug it in and if that is the case just promptly take it out. Unless careless this will not hurt the tester but it could fry the heater in the tube.
I use my tube testers all the time to confirm what I think a tube might be. I have tube testers that have been continually used this way for almost 20 years without harm. Heck I have one I inherited from my father that has been in use for about 50 years this way and never been damaged from it. Sadly it's about wore out though!
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The lower the bias number the cooler the transformers should get.... lower number = less current...less current = less heat
Something strange
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On 12/1/2017 at 11:56 AM, derrickdj1 said:
Thanks for the explanation. So, an amp can use a switch to go from triode to pentod without being ultralinear. Ultralinear is a design or amp topology thing.
Pretty much that's the jest of it.
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Ultra Linear has to be built into the output transformer with the special tap usually at around 40% to power the screens of the output tubes. Pentode powers the screens directly from the B+ power supply. Many folks like to describe Ultra Linear has having nearly the power and punch of Pentode with the mid range of Triode.
So it's pretty easy to implement a switch to allow Triode/Pentode or Triode/Ultra Linear, but an ultra linear tap would first have to be available in the output transformer.
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20 hours ago, mike stehr said:
Those sure look like Hammond output transformers.
Good eye! Those surely are Hammond labels. Surprised they would be that careless leaving those in place for the photo.
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Severe cosmetic flaws can not be easily, inexpensively and in many cases fixed at all... I've rebuilt thousands of vintages pieces and rarely have to replace controls and switches to achieve great results.....
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On 10/2/2017 at 7:10 PM, ksquared said:
OK, think of me as just landing from Pluto, not knowing much of anything about the tube amps/pre-amps. I've done some research, and it seems the 299C is rated mighty excellent. Now, not to debate, but I have a few questions.
1) Why is the 299C so spectacular? And is the 299D even better? Why didn't they keep going with the 299E?
2) Is the 299C a pre-amp, and thus needing an amp, or can it work on its own?
3) Will the 299C work with only two speakers, or can you have the center speaker and a subwoofer with it too?
4) Are there any Klipsch speakers it wouldn't be good with or work properly with?
5) is there a modern tube amp/pre-amp that is just as well-respected?
6) Are the tube amps only used with playing vinyl records?
Hopefully there are some patient people out there, as I know these are ridiculously basic questions, and I appreciate any help.
1) If you were to take a pole of all vintage scott owners you'd find just about all of them prefer the model they own. In the end the basic sound of all models is more similar then different (IF ALL THINGS ARE EQUAL). I usually advice folks to choose the model by the cosmetic condition not the model number. For example if you have to choose between a 299A in near perfect condition or a 299C in rough condition with both being similar in price buy the 299A.
2) 299C is a integrated amplifier. All you need to do is add source like CD players, tuners and turn table.
3) The amplifier can power your 2 main left and right speakers. It also has a mono center channel output signal that can be sent to any powered speaker you choose like a center channel with its own mono amplifier to power it or a powered subwoofer.
4) it will power just about any Klipsch speaker vintage or modern.
5) Lots of them..
6) Tube amps are used for everything under the sun sound wise.
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On 9/29/2017 at 2:00 AM, joshnich said:
New reissue c22. This is an awesome preamp and the phono section is to die for
Pretty amazing how close they made that reissue look like the original C-22 which was always a nice looking and great sounding vintage tube preamp. What is the tube compliment of the reissue?
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I hate to state the obvious but I'm fairly sure Josh was not at all being cryptic...he was politely naming you without actually naming you by quoting your post. While you may not come out very often and openly bash me or my business but you do go out of your way to recommend competitors of mine that YOU personally have zero experience doing business with whenever someone recommends me around here. It's not like it's some secret that you have an attitude when it come to NOS Valves........
Josh and everyone else bothered by his axe grinding I'd suggest just ignoring him IMHO he's just not worth the effort. I do appreciate all the praises you folks give to my work and service. Its nice that you give it so freely from your OWN personal experience.
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The service technician is confusing the 7868 tubes the Fisher 400 uses for the 7591. None of the modern production 7591 made today have a pin size issue like the 7868. There is one modern 7591 that has a really large glass bottle size both tall and fat. You have 3 modern production 7591 to choose from the EH 7591(really fat and tall), JJ 7591 (1/2" tall), Tung-Sol Reissue 7591 (1/4" tall). I personally prefer them is this order
1)Tung-sol
2)JJ
3)EH
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Muel is most likely correct. What brand are the two far left 12AX7's and is this noise in both channels? Try tapping the tops of the two far left 12AX7's directly you might find its just one tube.
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On 7/11/2017 at 10:39 AM, alzinski said:
If you ask me having a power amp that asks 6v to reach full output power is wimping out and passing the buck in order to boast low noise specs.
Wow someone gets it!
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On 7/11/2017 at 8:30 AM, tube fanatic said:
Most noise in tube amps originates in the gain stages which precede the output stage. Mike's approach in using a very low input sensitivity is a wonderful way to deal with the noise issue when the amp is to be used with very high sensitivity/efficiency speakers. And, the measured performance of these amps is truly outstanding and far better than the majority of tube amps out there (including my own).
Maynard
Oh gosh Maynard disagrees with me what a surprise... on a clear day is the sky blue?
I'm BLOWN AWAY! K-Horn / Dynaco discovery!!!
in 2-Channel Home Audio
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I haven't read the entire thread yet but had to ask about this 13 volt bias setting. Where are you measuring?
After giving it some thought I bet your 13.0 volt is a typo error on your part and you're setting it to 1.3 volts which makes perfect sense.