VHT amps

[Dmoney]

Yes. The Vox AC30 is a cathode biased output stage isn't it? I can't recall at this second but that leads to a decision to not use NFB. That is why the Vox uses a Hi Cut. Its a good alternative and I use that control in the amp I built, since my amp has variable NFB, which would make a normal depth and presence sometimes ineffective.

The Cathodyne... I did recognize it, and I've seen some sketches too. It means you're output is pretty much always balanced but you need a gain stage to drive it. I do own the Merlin Blencowe book that details its use but I haven't read up on the Cathodyne for a while. I didn't know about adding the NFB into the driver stage. The effect probably varies from one type of PI to another. I'm sure it's harder to get good results using certain combinations of phase inverter and NFB circuits than others. That is why I asked the question about how it sounds.

There is no real equivalent non-NFB reliant depth control that I've found. I really like the sound of the 'standard' depth circuit used in an SLO or Marshall. I added one to a friends Laney GH100TI and it sounds MASSIVE!

I was toying with the idea of a new build project using the Cathodyne (and a few other things) but wondered how well the NFB related controls worked with the Cathodyne.

I think MDV answered the question.
If it had a LTP phase splitter and SLO style pres and depth... those control would probably sound different, though do the same thing. well... the controls are probably doing exactly the same thing... more or less... but the tone of the Cathodyne vs the tone of the LTP probably has something to do with the difference too.

At least thats my conclusion.

Interesting!

Phaez Daisycutter and the Vox night train uses a Cathodyne as does the Peavey Valveking I think.

[Shag101]

Not really on topic here, but the new VHT Special 6 combo I bought for 199 usd is amazing for a nice tube driven hand wired bedroom amp.  Very easy to play around with inside to get more of what you want..

[MrBump]

the screamer is great amp for the price, very versatile and the only thing i don't like about it is that the tube sockets
are pcb mounted(weaker structurally) .
sometimes i have the urge to change or more like 'upgrade' but the problem for me is to find something with a great
CLEAN, crunch and overdrive(with chassis mounted sockets)
i've looked at the supersonic fender 22 which seems great but maybe not enough poke for you?
i've looked at the cornford mk series which is in another category.
i don't think there's much better in the price range of the screamer without giving something up( eg less great cleans traded off for a better overdrive etc).
the koch twintone's worth a look too.
just to remember how good it can sound(even on youtube)
"http://www.youtube.com/v/BCHueoawVsc?

That's a bloody EXCELLENT demo of the Screamer!!!

[darkbluemurder]

There is no real equivalent non-NFB reliant depth control that I've found.

Me neither.

Phaez Daisycutter and the Vox night train uses a Cathodyne as does the Peavey Valveking I think.

You are correct on the Daisycutter and Night Train. Not sure about the Valveking but the Classic 50 does have one. I played the Night Train once and liked it. Good sounding inexpensive amp. The other guitarist in the band I used to play plays a Classic 50 and gets a good sound with it. So far I have built 5 amps but all have a long tailed pair PI - I guess I have to convert one to a cathodyne PI :D

[Dmoney]

So.
I just stumbled onto this link.

http://www.framus.de/media/manuals/Amps/Cobra/Cobra_V1-2.pdf

Take a look at page 8.

the top right hand corner. There is a little non NFB reliant 'Deep' control.
Is this just rolling off highs?

[ericsabbath]

So.
I just stumbled onto this link.

http://www.framus.de/media/manuals/Amps/Cobra/Cobra_V1-2.pdf

Take a look at page 8.

the top right hand corner. There is a little non NFB reliant 'Deep' control.
Is this just rolling off highs?

the deep is not a true depth
the cobra already has a fixed depth, which is a 2,2n cap in the negative feedback with no parallel resistor or pot (that's a HUGE bass boost)
the deep knob is some sort of reversed bass cut
edit: actually it always leaks the mids, some low mids and highs (so you're not exactly wrong), and then you control how much bass will be cut along with the other frequencies
I hated that control in the cobra
it should be wired to the 2,2n cap, Soldano style
it was impossible to lower the huge low end thump, even with the deep at zero, unless I dialed the bass knob under 2 (and that killed a lot of the thick preamp tone)
negative feedback can be used for the preamp too
the VHT deliverance has some sort of NFB based presence control in the preamp
my Zambelli Hyperdrive has something similar as well

[Dmoney]

gah oh well.
I didn't think it would be that effective.
I didn't spot that it had a fixed "depth" control in the nfb. I saw it had a typical NFB style presence circuit though.

meh... back on the lookout i suppose.

[hunter]

Thomann stock VHT, so just order there and if you don't like you got 30 days free return I guess?

http://www.thomann.de/gb/fryette.html

[darkbluemurder]

negative feedback can be used for the preamp too
the VHT deliverance has some sort of NFB based presence control in the preamp

Eric,

That is absolutely correct. I guess SF took the preamp NFB from Fender (see 5E5-A Pro, 5F4 Super, 5E8 Low Power Twin). The "Edge" switch decouples the NFB in the high frequencies. I have never tried either NFB on the tone amp nor the Edge switch so I cannot comment on how it sounds. Unfortunately I never got to play a Deliverance either.

I actually modded one Marshall to a preamp close to the Deliverance (only one gain control, slightly different cold clipping stage, no NFB on the tone amp). I intended to do it completely but since I like it so much as it is now I decided to not further mess with it.

Cheers Stephan

[Dmoney]

i have a deliverance 60 schematic somewhere. I hadn't noticed the NFB further into the preamp. It is a sketched schematic though and that always makes it less easy to follow. takes a bit more concentration when dealing with peoples handwriting.

I'll take a look cos it sounds interesting at least. I know you can use feedback in various ways globally/locally around the amp. I guess thats putting it really simplistically.

[darkbluemurder]

BTW has any of you ever played the Memphis or had one on the workbench? From the descriptions and manual on the website it appears that the drive channel has 3 gain stages (4 with the boost on) and the clean channel has 3 gain stages. So it could be twice the Deliverance preamp only with one gain control, plus the cathodyne phase inverter.

I wonder whether SF used negative feedback in the power amp. All the website says about the power amp is that it's cathode biased EL84 tubes. The absence of any presence/depth controls suggests that the amp does not have any negative feedback in the power amp.

Cheers Stephan

[northlane.josh]

I absolutely love VHT/fryette amps.

At the moment I own a fatbottom cab & 2/90/2 poweramp. On my axefx i use the D60 model.

They aren't for everyone, and have a very unique sound but if you can make them work for you they're second to none. They are also among the most rugged, reliable and well-built units you can buy.

Might be worth noting - my cab is badged as a fryette on the front, but on the jack plate on the back its badged as a VHT, i'm pretty sure the dealers were sent badges to rebadge their amps when the name change happened but i may be wrong.