talbany wrote: ↑Wed Nov 13, 2019 11:06 am
...
AFAIK Dumble used a mix of both 6PS and (NTE) MPP type caps in some of his HRM amps.The MPP's are a bit darker and have a tighter bass response and can be a bit more scooped in the mids. Either cap is any better than the other they are just different and depends on what direction you want to take it. Dumble obviously never used these MPP caps in his 2nd and 3rd generation amps so IMO Brandon liked the sound of them in that design and was going for a slightly different vibe. 2nd gen's are a different beast and can be a challenge. As you just found out they have a raw-ness to them that is not for everyone,(perhaps Brandon was trying to smooth the amp out some)
...
Tony
Don T., the NTE caps Dumble used are Mylar (polyester), just like the 6PS ODs. Xicon has (or had) similar looking caps that are MPP, that I think Fender uses or used on their guitars for the tone caps. I used the Xicon MPPs in a couple of amps and remember liking them better than the 715 ODs I had used early on. Then I moved on to the 6PS type and stayed with them.
talbany wrote: ↑Wed Nov 13, 2019 12:16 pm
Marcus
Did you do the standard Skyliner stack or a 2nd gen stack? Also do you have plenty of range control on T M B?
Tony
yes, I did as Martin said but I used the single 0.002uF and 10k resitor on the bass pot. To be honest the tone range is quite small indeed, Also I used high plate values on V1 .
I'm not a huge tone adjuster guy, it's usually rolling a bit of bass depending on room so not a big deal as it is, however......I'm open to trying things.
M
Last edited by norburybrook on Wed Nov 13, 2019 4:31 pm, edited 1 time in total.
talbany wrote: ↑Wed Nov 13, 2019 11:06 am
...
AFAIK Dumble used a mix of both 6PS and (NTE) MPP type caps in some of his HRM amps.The MPP's are a bit darker and have a tighter bass response and can be a bit more scooped in the mids. Either cap is any better than the other they are just different and depends on what direction you want to take it. Dumble obviously never used these MPP caps in his 2nd and 3rd generation amps so IMO Brandon liked the sound of them in that design and was going for a slightly different vibe. 2nd gen's are a different beast and can be a challenge. As you just found out they have a raw-ness to them that is not for everyone,(perhaps Brandon was trying to smooth the amp out some)
...
Tony
Don T., the NTE caps Dumble used are Mylar (polyester), just like the 6PS ODs. Xicon has (or had) similar looking caps that are MPP, that I think Fender uses or used on their guitars for the tone caps. I used the Xicon MPPs in a couple of amps and remember liking them better than the 715 ODs I had used early on. Then I moved on to the 6PS type and stayed with them.
Gil
(West Coast Chapter of TRM)
Gil,
I thought I'd give these a go , I tend to try different things each build hoping for lucky accidents as I've said. I've got 6ps caps I can swap out but I'm liking the inital sound of this amp. It's different, which is good as I have 3 other ODS amps now!!!!
it's a moving target though so as i'm waiting for a new relay board and the amp is open I'm going to try a few ideas people can throw at me ..as long as the component isn't a PIA to get in and out
talbany wrote: ↑Wed Nov 13, 2019 11:06 am
...
AFAIK Dumble used a mix of both 6PS and (NTE) MPP type caps in some of his HRM amps.The MPP's are a bit darker and have a tighter bass response and can be a bit more scooped in the mids. Either cap is any better than the other they are just different and depends on what direction you want to take it. Dumble obviously never used these MPP caps in his 2nd and 3rd generation amps so IMO Brandon liked the sound of them in that design and was going for a slightly different vibe. 2nd gen's are a different beast and can be a challenge. As you just found out they have a raw-ness to them that is not for everyone,(perhaps Brandon was trying to smooth the amp out some)
...
Tony
Don T., the NTE caps Dumble used are Mylar (polyester), just like the 6PS ODs. Xicon has (or had) similar looking caps that are MPP, that I think Fender uses or used on their guitars for the tone caps. I used the Xicon MPPs in a couple of amps and remember liking them better than the 715 ODs I had used early on. Then I moved on to the 6PS type and stayed with them.
Gil
(West Coast Chapter of TRM)
Gotta correct that, it is now the (TRACM) (The resistor and capacitor mafia)
Thanks
I thought so then glancing over his amp he had the single .002 hanging off the bass pot (ala Skyliner) instead of the typical james config on the 2nd/3rd gen amps. So . So Marcus did you leave the 1M bass pot or did you change that as well?
Tony
" The psychics on my bench is the same as Dumble'"
That stack has a rather limited range due to the higher value bass pot (load) marcos whom also has an actual Dumble 2nd gen amp had the same issue. I don't have the PAB in mine however I would think this is why your PAB boost is less effective.. So there are a few options. You can change the stack to a standard skyliner or Classic. Option 2 re-wire the PAB circuit and lift the mid pot with a fixed value resistor(ala Mega-boost). IMO the 3 resistor OD network cuts a lot of low end so with the standard lift the bass pot out of circuit style PAB makes for a rather thin sounding OD.IMO this is more than likely why Dumble didn't use that PAB in his 2nd gen amps. Doesn't sound very good I recommend lifting the mid pot!. That way you are boosting everything.
Hope this makes sense!
Tony
Last edited by talbany on Wed Nov 13, 2019 11:20 pm, edited 1 time in total.
" The psychics on my bench is the same as Dumble'"
talbany wrote: ↑Wed Nov 13, 2019 11:06 am
...
AFAIK Dumble used a mix of both 6PS and (NTE) MPP type caps in some of his HRM amps.The MPP's are a bit darker and have a tighter bass response and can be a bit more scooped in the mids. Either cap is any better than the other they are just different and depends on what direction you want to take it. Dumble obviously never used these MPP caps in his 2nd and 3rd generation amps so IMO Brandon liked the sound of them in that design and was going for a slightly different vibe. 2nd gen's are a different beast and can be a challenge. As you just found out they have a raw-ness to them that is not for everyone,(perhaps Brandon was trying to smooth the amp out some)
...
Tony
Don T., the NTE caps Dumble used are Mylar (polyester), just like the 6PS ODs. Xicon has (or had) similar looking caps that are MPP, that I think Fender uses or used on their guitars for the tone caps. I used the Xicon MPPs in a couple of amps and remember liking them better than the 715 ODs I had used early on. Then I moved on to the 6PS type and stayed with them.
Gil
(West Coast Chapter of TRM)
Gil
Yeah I remember that a long time ago where we went through that phase of trying those different caps and everyone voicing their opinion. I remember trying both Xicon's and NTE's and Panasonic and Nichicon also had their Mylar variants. I generally find all those pressed caps to have a tighter bass response/scooped mids and smooth. The Panasonics were some of my faves along with the Nich's (Brandon uses). I actually prefer them in the Dumbleator over the PS caps myself.
Tony
" The psychics on my bench is the same as Dumble'"
That stack has a rather limited range due to the higher value bass pot (load) marcos whom also has an actual Dumble 2nd gen amp had the same issue. I don't have the PAB in mine however I would think this is why your PAB boost is less effective.. So there are a few options. You can change the stack to a standard skyliner or Classic. Option 2 re-wire the PAB circuit and lift the mid pot with a fixed value resistor(ala Mega-boost). IMO the 3 resistor OD network cuts a lot of low end so with the standard lift the bass pot out of circuit style PAB makes for a rather thin sounding OD.IMO this is more than likely why Dumble didn't use that PAB in his 2nd gen amps. Doesn't sound very good I recommend lifting the mid pot!. That way you are boosting everything.
Hope this makes sense!
Tony
thanks Tony, I had a hunch that the PAB was because of the tone stack.
I'm slightly reluctant to change anything tone stack wise at the moment as it's going in a combo so any tonal changes will need to be made with the amp in it's intended cab with the speaker, again this is an unknown variable too, so I'm going to have to wait a week. Actually all I need to swap to get a full skyliner stack is a 500k on the Bass and a 250k on the treble (I have a 0.02uF orange drop in there already) so an easy experiment
thanks for the thread link, a good read.
My amp has a 100k drive and level pot , which are NOS Allen Bradley they're perfect values (thanks Erwin)and the balance between OD and clean is whatever you want it to be. Obviously my high plate V1 affects the V2 OD so again I'm reluctant to mess with that as the OD is really good.
Marcus I think you may have something miss-wired in your PAB. It should have about the same effect as in a Skyliner stack. The larger value Bass pot doesn't make much difference to the PAB, and it actually increases the bass range by about 1dB.
martin manning wrote: ↑Thu Nov 14, 2019 12:21 pm
Marcus I think you may have something miss-wired in your PAB. It should have about the same effect as in a Skyliner stack. The larger value Bass pot doesn't make much difference to the PAB, and it actually increases the bass range by about 1dB.
If I've wired the PAB wrong would that affect the tone stack range though as well?
I'm going down the studio later I'll check. I have no jazz rock so perhaps I've don something the wrong way round. Also my relay boards are different to the layouts so I'm having to pay close attention to which is NO1 NO2 NC1 NC2 etc
In my 2nd gen hybrid the pab boost is less compared to the skyliner.
The mids increase and should be the significant change when using the pab. Works like a charme on single coil bridge pup with drive.
talbany wrote: ↑Wed Nov 13, 2019 6:36 am
Marus
Glad everything fired up ok
Let's do a real test With the loop jumped out with a patch cord only the master all the way up send set at noon and the return set at noon. At those noise levels could you play a show or would everyone be looking over at you?
Also at those settings is it at all buzzy or do you just hear just a little hiss in the background?
Curious as to what you found!
Tony,
Just done this test, it's fine noise wise,I'm testing in a quiet studio and there's some hiss like you'd expect on stage no one would notice.
. So Marcus did you leave the 1M bass pot or did you change that as well? 
I recommend lifting the mid pot!. That way you are boosting everything.
