Guys .. I was contemplating about swopping the Tesla E88CC for a RCA 6CG7 in my SE KT88 amp. Will it sounds any better?
I'm confussed about the dissipation of 4W for 6CG7 against E88CC's 1.8W !? Is that the total or per triode?
Please advice, Sir .... thanks!
zekk
I'm confussed about the dissipation of 4W for 6CG7 against E88CC's 1.8W !? Is that the total or per triode?
Please advice, Sir .... thanks!
zekk
They're different tubes, so there's likely to be going a change in sound. Dunno what will sound better, but at first glance, I'd be careful putting a 6CG7 in a circuit optimized for E88CC. The operating point will be rather different, and I suppose there's a risk in running the 6CG7 beyond its maximum ratings. Just speculating here though, perhaps someone who's actually tried this could give his 2cts.
BTw, any chance of posting a schematic?
BTw, any chance of posting a schematic?
They are both twin triodes, with the same pinout. Apart from that, they are very different: gm, mu, bias - just look at the data sheets. Swapping them in a circuit correctly designed for one of them could turn it from an amp into an effects box.
You cant put 6cg7 instead of E88cc, anyway u should change anode and catode ressistors.
6cg7 sound more..analytic, but without soul...hard to explain, anyway its just my opinion.
6cg7 sound more..analytic, but without soul...hard to explain, anyway its just my opinion.
From the data sheet 4W each plate, 5.7W both plates together.
Note the difference in heater currents between E88CC and 6CG7. You will be taking an extra 1/2 amp for a pair of tubes.
Last edited:
ImageShack® - Online Photo and Video Hosting
Guys ... above is my handdrawn,cut & paste circuit of the amp.
It's copied from various designers and if you found anything familiar to your's, please forgive me ... ya!?
I'm a newbie, a retired 68 yrs old structural engineer, trying to build a sweet sounding amp that'll see me thru my twilight years.
And until than, my grandsons will continue to remarks..'grandpa is with his LEGO again.. he.he.he!
Reluctantly used a 35uf oil cap after the #83 mercury rectifier to acheive a 450vdc B+. It's already into 100hrs of services, but no fireworks!
Any forecoming advices will be greatly appreciates.
Regards, Zekk
Guys ... above is my handdrawn,cut & paste circuit of the amp.
It's copied from various designers and if you found anything familiar to your's, please forgive me ... ya!?
I'm a newbie, a retired 68 yrs old structural engineer, trying to build a sweet sounding amp that'll see me thru my twilight years.
And until than, my grandsons will continue to remarks..'grandpa is with his LEGO again.. he.he.he!
Reluctantly used a 35uf oil cap after the #83 mercury rectifier to acheive a 450vdc B+. It's already into 100hrs of services, but no fireworks!
Any forecoming advices will be greatly appreciates.
Regards, Zekk
In that circuit the 6CG7 would give you less gain (around half?). It might give slightly higher distortion, as I think its anode impedance is higher. You might need to adjust the cathode resistor to get the right bias.
Assuming the circuit was designed for an ECC88, why do you want to redesign it (or, even worse, simply substitute a different valve without redesigning)?
Assuming the circuit was designed for an ECC88, why do you want to redesign it (or, even worse, simply substitute a different valve without redesigning)?
The 6CG7 is just a noval version of the 6SN7. Seems to me it will work fine, tho u will have a little less gain.
Nice copy-paste work, we don't get it like that much anymore these days 😉 Does the trick nicely though.
Note that you're running the #83 beyond its limits. I'd replace the 35u with something of 8uF or smaller to stay below the 800mA or 1A maximum rating of the rectifier. I understand you're aware of this, so maybe it's a calculated risk and you have a couple of spares lying around.
Are you runnin both halves of the ECC88 in parallel? Since you stated the parameters per triode, but the schematic shows the second triode unconnected.
If you replace the ECC88 with a 6CG7 without changing anything else, it seems you'll end up with about 10mA running through it with a grid voltage of somewhere around -4V and maybe 160V on the plate. So pretty much in the same general area as the ECC88 is running, and not too far away from the load lines suggested in the GE datasheet at first glance.
So in any case, ignore my earlier remark about potentially running the 6CG7 beyond it's maximum ratings; in this circuit, you won't. I'm no judge if the operating point would be wisely chosen, because wisdom, that's one thing I don't have too much of.
Note that you're running the #83 beyond its limits. I'd replace the 35u with something of 8uF or smaller to stay below the 800mA or 1A maximum rating of the rectifier. I understand you're aware of this, so maybe it's a calculated risk and you have a couple of spares lying around.
Are you runnin both halves of the ECC88 in parallel? Since you stated the parameters per triode, but the schematic shows the second triode unconnected.
If you replace the ECC88 with a 6CG7 without changing anything else, it seems you'll end up with about 10mA running through it with a grid voltage of somewhere around -4V and maybe 160V on the plate. So pretty much in the same general area as the ECC88 is running, and not too far away from the load lines suggested in the GE datasheet at first glance.
So in any case, ignore my earlier remark about potentially running the 6CG7 beyond it's maximum ratings; in this circuit, you won't. I'm no judge if the operating point would be wisely chosen, because wisdom, that's one thing I don't have too much of.
Yes, it's a calculated risk by using 35uf instead of 4uf regularly used by the some of the gurus on this forum. But then, the B+ will drops to 385v unless, I resort to using the original 5AR4, which is very good.
Half a Tesla E88CC (not ECC88) is used per channel.
6NIP is the original driver. Then I swopped to a 6DJ8, and then a 5687 and finally a E88CC. Off-course, needs to re-adjust the parameters to that sweet spot.
We're all here because of the passion in us to explore the magic tonality of vacuum tubes.
Greatly appreciates all the responses.
Cheers!
Half a Tesla E88CC (not ECC88) is used per channel.
6NIP is the original driver. Then I swopped to a 6DJ8, and then a 5687 and finally a E88CC. Off-course, needs to re-adjust the parameters to that sweet spot.
We're all here because of the passion in us to explore the magic tonality of vacuum tubes.
Greatly appreciates all the responses.
Cheers!
hi
I have builded tube preamp by Andrea Ciuffoli im using it like gain stage for PF99, the first tube in my setup is PCC88. I was trying many different tubes, but pcc88 gives higher gain and i really like how it sound, there is more music with this tube, better 3d image and great midrange.
I would like to hear some opinions from people on this forum (im going out of topic here), i have 3way speakers and would like to build active crossover using Pf99 for mid and high. For bass i need some powerfull amp. The problem here is gain. PF 99 doesnt have gain. I need a help, how to bias the gain to all 3 amps.
PS: very satisfied of sound of PF99 in midrange and high
I have builded tube preamp by Andrea Ciuffoli im using it like gain stage for PF99, the first tube in my setup is PCC88. I was trying many different tubes, but pcc88 gives higher gain and i really like how it sound, there is more music with this tube, better 3d image and great midrange.
I would like to hear some opinions from people on this forum (im going out of topic here), i have 3way speakers and would like to build active crossover using Pf99 for mid and high. For bass i need some powerfull amp. The problem here is gain. PF 99 doesnt have gain. I need a help, how to bias the gain to all 3 amps.
PS: very satisfied of sound of PF99 in midrange and high
Not me! I designed and built a solid-state amp but could never get the thing to stop oscillating. I always seem to have more success with valves, but I do my best to avoid "magic tonality". I want to listen to the music, not the amp.
Yeah, something similar going on here...tubes seem easier to make an amp with that sounds halfway decent. They can take a beatin' once in a while without going belly-up at slight mistreatment as silicon tends to do. And tubes glow and look all nice. Silicon always glows very briefly, and then stinks the place up.
Im impressed you are able to design an amp. Is it push-pull design? Send schematic maybe we could make it to not oscilate 🙂
It would be rather OT for this forum, and I don't want to hijack the thread.
Anyone who has read and understood Doug Self's book can design a conventional SS amp. My CFP outputs were unstable, and there were hints of global NFB instability too - I think the low noise input devices were too slow. I'm sure I could have fixed it, but I eventually got bored and gave up. My valve amp (modified 5-20) works fine.
Anyone who has read and understood Doug Self's book can design a conventional SS amp. My CFP outputs were unstable, and there were hints of global NFB instability too - I think the low noise input devices were too slow. I'm sure I could have fixed it, but I eventually got bored and gave up. My valve amp (modified 5-20) works fine.
Sure, i understand.
Have you ever tried the SE designs?
As i wrote above, i would like to build an active system, using 4 SE amps to drive middles and highs and 2 push-pull for bass. Maybe you can help, my problem is how to change the gain of push-pull amplifier (marantz PM 44 SE) to be equal to my SE amplifiers.
Gain stage for SE amplifiers is tube preamp (gain about 30)
Have you ever tried the SE designs?
As i wrote above, i would like to build an active system, using 4 SE amps to drive middles and highs and 2 push-pull for bass. Maybe you can help, my problem is how to change the gain of push-pull amplifier (marantz PM 44 SE) to be equal to my SE amplifiers.
Gain stage for SE amplifiers is tube preamp (gain about 30)
Thanks anyway.
By the way, the reason for oscilations on you self designed amp are not the low noise input devices for sure, speed doesnt have nothing with.
By the way, the reason for oscilations on you self designed amp are not the low noise input devices for sure, speed doesnt have nothing with.
This section of diyAudio is classified for Tubes/Valves right?
Or, have I posted on the wrong department?
This section of diyAudio is classified for Tubes/Valves right?
Or, have I posted on the wrong department?
You are on right place, its me who is changeing the subject asking about push-pull, I apologize.
I have tube preamp and i would be gratefull if someone here can tell me how can i change the gain of preamp
- Status
- Not open for further replies.