Sometimes I miss the KT77's

[Snake Aces]

About 7 years ago I had bought two Traynor YCV40 amps so I loaded one with KT77's. I had to sell a lot of my gear when I moved a few years ago but it really was a beautiful sounding amp and some days I really miss it. There is nothing wrong with my current amp situation and I have really become a big fan of EL84's since those days, but there was definitely something special about the KT77's loaded in a YCV40. There was clean sparkle but a great sounding gain as well that was rich, mean and articulate. Perhaps we will meet again one day Katie Seventy Seven.

That's my rant.

 

[Demanic]

Re: Sometimes I miss the KT77's

I have a Carvin XV-212 that I loaded with two JJ's 6L6's and two JJ's KT-77's. I know you're supposed to make sure that they are balanced and all, but I've run the combination in that amp for about 5 years now and nothing's blown up yet. Love the sound of the KT-77. Nice bottom with that perfect top sizzle that doesn't get fizzy. If you like it by itself, paired with the 6L6, the two produce even more top and bottom. I've run one by itself in my Jet City Picovalve 5 watt. The only tubes I like better are the 6CA7 and the KT-88 witch I currently have in it.

 

[Snake Aces]

Re: Sometimes I miss the KT77's

That's a combination I would love to try, I did not know you could do that to be honest (6L6 pairing with KT77). I have never tried KT-88's, but I almost bought some once.

Yeah, I agree with the KT-77 assessment. Great low end with nice sizzle. Good tone for sure.

 

[zzmoore]

Re: Sometimes I miss the KT77's

I will not argue your appreciation of the KT77.
But.......that Traynor YCV series were some decent amps.....especially the 20 and 40.
Too bad you had to cut it loose.
You should (IF you feel like it) probably send me a PM, but.....how are things going for you in Greece.?
good luck my friend

 

[Snake Aces]

Re: Sometimes I miss the KT77's

I agree, the Traynor amps are amazing! I have also owned a Custom Blue 50 in the past. Great stuff indeed. I wish I could find some of their amps here!

PM in the works.

 

[TimmyPage]

Re: Sometimes I miss the KT77's

I have a Custom Blue 50 back in Canada, such a great amp. When I move back home I'm tempted to sell it off for one of the YCV 20s or 40's, just to get a slightly fenderier clean tone, I've heard some amazing clips of what it can do.

 

[Demanic]

Re: Sometimes I miss the KT77's

In amps with four tubes in the power section, you can mix tube types if their resistance is similar, but you have to do so keeping the inside pair and outside pair done with the same type of tube.

 

[Snake Aces]

Re: Sometimes I miss the KT77's

I have a Custom Blue 50 back in Canada, such a great amp. When I move back home I'm tempted to sell it off for one of the YCV 20s or 40's, just to get a slightly fenderier clean tone, I've heard some amazing clips of what it can do.

Yeah but it would be tough to give up the CB 50. Sure, the fender clean tones are great but the crunch of the CB 50 is also great... ideally, it would be great to be able to have both kinds of amps!

 

[Snake Aces]

Re: Sometimes I miss the KT77's

In amps with four tubes in the power section, you can mix tube types if their resistance is similar, but you have to do so keeping the inside pair and outside pair done with the same type of tube.

Did not know this but that's pretty cool

 

[GuitarStv]

Re: Sometimes I miss the KT77's

I have a Custom Blue 50 back in Canada, such a great amp. When I move back home I'm tempted to sell it off for one of the YCV 20s or 40's, just to get a slightly fenderier clean tone, I've heard some amazing clips of what it can do.

I emailed and asked customer service at Traynor a long time ago about plugging EL-34s into the YCV40WR. Turns out it's just a single resistor mod to change a YCV50 blue into a YCV40WR or vice versa:

Hi Steven.

It is safe to install EL34s in a YCV40, but the bias point needs to be adjusted to optimize it for the EL34s. The power transformers can handle the extra filament current of the EL34s since this was a consideration in the original design. The 6L6 family of tubes wants to see more negative bias voltage than the EL34 tubes. If the EL34s are substituted without bias change there will be more crossover distortion. The negative bias can be turned down by changing the value of R78 from 39K to 22K however you won't want to plug in 6L6s after making this mod since they will be biased very hot and will have a shortened lifespan. I would recommend running EL34s for anybody that is always using an extension cabinet since the EL34s have a slightly lower output impedance as well as putting out a little more power.
Thank you for your enquiry,

Mike Holman
Yorkville Sound

So, you can just switch the resistor if you want to dabble with 6l6s, then switch it back if you don't like it.

 

[Snake Aces]

Re: Sometimes I miss the KT77's

That's some great info GuitarStv! I wish I had found out about that a few years ago!

 

[GuitarStv]

Re: Sometimes I miss the KT77's

Yeah, I was kinda blown away when he emailed me that . . . I had never heard of an amp accepting other power tubes.

 

[Edgecrusher]

Re: Sometimes I miss the KT77's

In amps with four tubes in the power section, you can mix tube types if their resistance is similar, but you have to do so keeping the inside pair and outside pair done with the same type of tube.

Yeah this is absolutely NOT a rule. Some amps can handle this many cant I dare say most. This is a good way to fry a transformer. Who matches tubes for resistance anyways or do you mean bias? Even if you match bias it doesnt mean that all other specs will be in range. Even an amp like a Dual recto that you can change the bias between EL34's and 6L6's wouldnt like it if you installed a pair of each. The problem is nothing happens in the short term. But over time you do damage.

This is just plain bad advice.

 

[zzmoore]

Re: Sometimes I miss the KT77's

I think what he is saying is that if you have two different power tubes....and both have a similar rp, they will (running in parallel) share their side of the OT in a reasonable manner.
Tubes and tube amps run over a fairly wide range. A pair of 6L6 can look at an OT where the primary will vary by several thousand Ohms.
What he is suggesting (IMO) lies at the very heart of running a mismatch with a speaker.
Standard "wisdom" tells people it is OK to run an 8 Ohm tap at 4 or 16 Ohms.....and you will be OK.
But that is never a given...you need to know what the OT primary IS. A given OT may already be running its 8 Ohm tap well into the preferred Impedance of a 16 Ohm speaker.....on the high side. So switching to a 16 Ohm speaker would be way out of spec, but a 4 Ohm would not.
You need to know how the amp is set up before you can make definitive statements.....but if the OT is running close to "optimum" levels, the 100% mismatch is usually acceptable. Depends on the build quality of the OT.
As always.....it depends.

 

[Edgecrusher]

Re: Sometimes I miss the KT77's

You need to know how the amp is set up before you can make definitive statements.....but if the OT is running close to "optimum" levels, the 100% mismatch is usually acceptable. Depends on the build quality of the OT.
As always.....it depends.

Umm ok so you just reiterated what I said. His original comment was that amps with 4 power tubes all can run 2 different types of tubes. Say someone takes is advice and bias's in a pair of EL34's to their favorite 6L6... Just the fact that EL34's draw 1.5 amperes of heater current vs .9 amperes for a 6L6 is alone enough to cause problems. Sure some might take it but others might not. Lets not forget that not all amps have their sockets wired the same. EL34's use Pin 1 where 6L6's dont pin 8 also needs to be grounded with EL34's.

My exception to his comment was that he made it sound like it was a universal truth and it just isnt. It all depends. I would hate for someone to stumble upon the advice and think its ok without any warnings that maybe no it might not be so easy or so healthy for your amp.

 

[zzmoore]

Re: Sometimes I miss the KT77's

Fair Enough.....and you are correct, of course .....many things to consider when swapping power tubes...especially between the 34 and L6 types.
Fender (and many others) often used Pin 1 as a tie point for the circuit.....the filament draws.....etc etc.
You would hate to get that mixed up in a tube swap with a Pentode/Tetrode change.
Your caution(s) is well taken.....

 

[Demanic]

Re: Sometimes I miss the KT77's

Never meant to imply that it's a "universal" truth. However, I didn't just come up with the idea on my own, I did some research first. The caveat being that, yes, every amp is different. However, some of them with four tubes in the power section can indeed run two different pairs. As I said, I've been running my Carvin like this for about five years now and nothing's blown up yet.
The mod that GuitarStiv mentioned can also be accomplished by adding a pot in parallel to the original resistor which will allow you to adjust the bias accordingly. At some point I may even do such a mod to my Carvin.

 

[zzmoore]

Re: Sometimes I miss the KT77's

Never meant to imply that it's a "universal" truth. However, I didn't just come up with the idea on my own, I did some research first. The caveat being that, yes, every amp is different. However, some of them with four tubes in the power section can indeed run two different pairs. As I said, I've been running my Carvin like this for about five years now and nothing's blown up yet.
The mod that GuitarStiv mentioned can also be accomplished by adding a pot in parallel to the original resistor which will allow you to adjust the bias accordingly. At some point I may even do such a mod to my Carvin.

No Probelm-O.......
I think you and I were talking about something very specific.....he was just pointing out, for the less experienced, that there are other considerations. "Do not try this at home on your own".......:fingersx:
best

 

[Demanic]

Re: Sometimes I miss the KT77's

^^
Well, I can't really object to that disclaimer. Which brings to mind the joke: "What are a redneck's famous last words?" "Hey ya'll, hold my beer and watch this!"

 

[tubecrunch]

Re: Sometimes I miss the KT77's

I put kt77's in a dr z 6545. You described them perfectly