'80's style high plate classic....

[ayan]

True... Note I mentioned mids. I felt the low mids had a more natural dense quality when comparing slopes in the classic stack.

I think it is a very worthwhile change to try. Especially considering 100K is the value in that stack. AFAIK.

I believe you've seen 135... classic stack and 150K slope. There are a few of those around and AFAIK all of them (w/150K slopes) have high plate load resistors.

Gil

[dogears]

Interesting. Did not know that there were real classic stack amps aith 150K slope....

True... Note I mentioned mids. I felt the low mids had a more natural dense quality when comparing slopes in the classic stack.

I think it is a very worthwhile change to try. Especially considering 100K is the value in that stack. AFAIK.

I believe you've seen 135... classic stack and 150K slope. There are a few of those around and AFAIK all of them (w/150K slopes) have high plate load resistors.

Gil

[tubedogsmith]

Another thing I've noticed with this circuit is this, on the skyline it can be hard to get enough boost when switching from clean to overdrive if you keep the OD dialed fairly clean. On this amp you can get a big boost easily with the OD channel controls even dialed quite low. This circuit has a lot going for it, I can see why you dug it for nine years Gil.

[swt]

any chances to take a look at a schem of a classic? or...what's different comparing to a nonhrm skyliner? i've used the search...but with classic, no pointers appear...thanks a lot!!

[tubedogsmith]

Here's a thread with a lot of stuff. On a quick glance, differences in mine are no filter on the loop jacks, 5uf cathode caps on all four stages, and I used 330pF caps on V2.

https://tubeamparchive.com/viewtopic.php?t=4382

[swt]

wow that was fast!!! thanks a lot, interesting reading...will really dig it.

[ayan]

Another thing I've noticed with this circuit is this, on the skyline it can be hard to get enough boost when switching from clean to overdrive if you keep the OD dialed fairly clean. On this amp you can get a big boost easily with the OD channel controls even dialed quite low. This circuit has a lot going for it, I can see why you dug it for nine years Gil.

Well, the thing is this: when in PAB mode, both Classic and Skyliner sound identical. With PAB off, the Skyliner can be made to sound very phat... So, that implies than the boost will be more dramatic in the Classic case, since there is "less" to begin with when the boost if off.
In the Skyliner, depending on your settings, you can "lose" a lot of the meat when switching the PAB on.

Gil

[two tone]

what about classic tonestacks with 100k plates,
were there any?

[tubedogsmith]

Another thing I've noticed with this circuit is this, on the skyline it can be hard to get enough boost when switching from clean to overdrive if you keep the OD dialed fairly clean. On this amp you can get a big boost easily with the OD channel controls even dialed quite low. This circuit has a lot going for it, I can see why you dug it for nine years Gil.

Well, the thing is this: when in PAB mode, both Classic and Skyliner sound identical. With PAB off, the Skyliner can be made to sound very phat... So, that implies than the boost will be more dramatic in the Classic case, since there is "less" to begin with when the boost if off.
In the Skyliner, depending on your settings, you can "lose" a lot of the meat when switching the PAB on.

Gil

Gil, when I mention boost in that paragraph I was actually referring to the volume increase going from clean to overdrive channels, not hitting the boost relay. It's easier to get a good volume spread between CL/OD in the classic than it is in the skyline. I should have said it that way in the firstplace

[bluesfendermanblues]

FWIW I tried the classic stack on my 50w, 100k amp and liked the clean sound a lot, when playing on my own.

However, I a band/gig situation, I felt that the Clean and OD (without PAB) were too different aminals with the Clean being nice n' fendery and the OD (without PAB) much too much midranged.

Changed the stack to Skyliner (with 47n mid cap for strat) and got a 'better' balance between cleand and OD (without PAB).

The preamp is now close to #124 - Just sayin

[ayan]

Another thing I've noticed with this circuit is this, on the skyline it can be hard to get enough boost when switching from clean to overdrive if you keep the OD dialed fairly clean. On this amp you can get a big boost easily with the OD channel controls even dialed quite low. This circuit has a lot going for it, I can see why you dug it for nine years Gil.

Well, the thing is this: when in PAB mode, both Classic and Skyliner sound identical. With PAB off, the Skyliner can be made to sound very phat... So, that implies than the boost will be more dramatic in the Classic case, since there is "less" to begin with when the boost if off.
In the Skyliner, depending on your settings, you can "lose" a lot of the meat when switching the PAB on.

Gil

Gil, when I mention boost in that paragraph I was actually referring to the volume increase going from clean to overdrive channels, not hitting the boost relay. It's easier to get a good volume spread between CL/OD in the classic than it is in the skyline. I should have said it that way in the firstplace

Ah... I udernstand now. Replaced the 150K output resistor and 100KL pot for the overdrive volume with a wire jumper at the board (i.e., no 150K resistor) and a 250KL volume pot. If you have anything greater than a 150K output resistor, you will be losing volume (and I do know a couple of amps had that to tame the OD brightness).

Gil

[ayan]

what about classic tonestacks with 100k plates,
were there any?

You know? I have seen pictures of some "silverface" amps with classic stacks and 100K plates. However, some of those amps had a different pre overdrive network. The early 80s amps, blackface, I have seen that had a classic stack all actually had 220K/150K plates and the 150K slope resistor.

Gil

[tubedogsmith]

Well, the thing is this: when in PAB mode, both Classic and Skyliner sound identical. With PAB off, the Skyliner can be made to sound very phat... So, that implies than the boost will be more dramatic in the Classic case, since there is "less" to begin with when the boost if off.
In the Skyliner, depending on your settings, you can "lose" a lot of the meat when switching the PAB on.

Gil

Gil, when I mention boost in that paragraph I was actually referring to the volume increase going from clean to overdrive channels, not hitting the boost relay. It's easier to get a good volume spread between CL/OD in the classic than it is in the skyline. I should have said it that way in the firstplace

Ah... I udernstand now. Replaced the 150K output resistor and 100KL pot for the overdrive volume with a wire jumper at the board (i.e., no 150K resistor) and a 250KL volume pot. If you have anything greater than a 150K output resistor, you will be losing volume (and I do know a couple of amps had that to tame the OD brightness).

Gil

cool, thanks, I'll try that in the skyline.

[mdroberts1243]

Here's a thread with a lot of stuff. On a quick glance, differences in mine are no filter on the loop jacks, 5uf cathode caps on all four stages, and I used 330pF caps on V2.

https://tubeamparchive.com/viewtopic.php?t=4382

Coincidentally, I just revisited this schematic recently while planning for a variant I plan to build soon. I noticed that it didn't include a pre-OD network (0.005uF & 4.7Mohm).

I wonder if anybody (Gil?, Scott?) could comment on whether that network was part of an 80's Grail-tone non-HRM or not?

[two tone]

what about classic tonestacks with 100k plates,
were there any?

You know? I have seen pictures of some "silverface" amps with classic stacks and 100K plates. However, some of those amps had a different pre overdrive network. The early 80s amps, blackface, I have seen that had a classic stack all actually had 220K/150K plates and the 150K slope resistor.

Gil

Gil,what OD entrance did those amps have?
220K/500pf to ground, 1.2M in series, 33k to ground?
Do you remember if those late silverface amps
already had the feedback loop on the second stage?
Regards Hanno