102 Feedback City

[Max]

OK.. Cool got that out of the way

I'm sorry to have been in the way here. Got the message. So indeed now back to Franken102.

A nice weekend to all here!

Max

[talbany]

Max
Sorry you took that the wrong way.. I thought everyone has said there Peace concerning the clone issue!! If you like to continue the discussion please by all means..BTW..What is it exactly that bothers you about using this term to describe a copy.. Were you referring to it's sonic characteristics or just didn't think an accurate clone could ever be achieved in which case I agree with you!! Personally I don't see how someone could confuse my amp with the Ford 102.. But this is my opinion..

All The Best!!

Tony

[brentm]

OK.. Cool got that out of the way back to the amp..
Things that has little to do with the sustainability

Filter Caps
Tubes
Speakers
LNFB V1
Snubbers
PI Trimmer settings
Direction of coupling caps were not tested on this one
Sustains/feedsback without PAB in OD
Does it on both clean (PAB) and OD
OD channel sustains/feeds back with either single coils or Humbuckers
Amp does not need a D-lator to sustain bloom feedback
Amp does not need to be played at loud volumes
Does not need Formica circuit boards..
Amp uses standard ODS voltages
Amp does not need FET to Sustain/Bloom
Amp does not need 100uf on the plates
The wire used in the Preamp is cloth covered wire so so much for needing Teflon for good tone
BTW.. one of the OPT secondary wires were even spliced..Could that be it.

The meatball surgery approach (cut it in half and see which side it's on) seems like a good approach. But I thought I read that mismatched power tubes would sometimes cause some increase in second order harmonics and clipping.

I do like the cloth wire!! What's the current consensus on teflon wire? It seems like all the mojo is in cloth covered and possibly pvc covered. Heck, even vintage throwback guitars have cloth wire under the pickguard...

[talbany]

The meatball surgery approach (cut it in half and see which side it's on) seems like a good approach. But I thought I read that mismatched power tubes would sometimes cause some increase in second order harmonics and clipping.

Dumble design leans more tword a balanced output section and minimal THD!!

I do like the cloth wire!! What's the current consensus on teflon wire? It seems like all the mojo is in cloth covered and possibly pvc covered. Heck, even vintage throwback guitars have cloth wire under the pickguard...

Merely poking fun at the purists..

[wokkel]

Tony,

Things that has little to do with the sustainability

Filter Caps
Tubes
Speakers
LNFB V1
Snubbers
PI Trimmer settings
Direction of coupling caps were not tested on this one
Sustains/feedsback without PAB in OD
Does it on both clean (PAB) and OD
OD channel sustains/feeds back with either single coils or Humbuckers
Amp does not need a D-lator to sustain bloom feedback
Amp does not need to be played at loud volumes
Does not need Formica circuit boards..
Amp uses standard ODS voltages
Amp does not need FET to Sustain/Bloom
Amp does not need 100uf on the plates
The wire used in the Preamp is cloth covered wire so so much for needing Teflon for good tone
BTW.. one of the OPT secondary wires were even spliced..Could that be it.

on the list you say LNFB V1 has little to do with it. Do you state that because you left it out on this build?

From your 102 thread:

Personally I like the LNFB when in OD but don't care for it at all in clean so I opt out.. I also do not care for the snubbers if I don't have to go there..

And now from a famous note flipping thread http://ampgarage.com/forum/viewtopic.php?p=144905 :

How can something bloom or feedback without speakers?

This can happen if the circuit is setup so that the magnitude of the electrical feedback in the circuit is unity or more and 180 degrees out of phase for some frequency. This is the concept of phase margin. Sounds like the second harmonic in this case. I believe this is BobW's thought about feedback control theory.

Give this man a cigar! no two cigars!!
Dr.Ika (pickmaster or Eric Lee) is here and I'd like to defuse some skepticism about upper mentioned sound samples.
As I've mentioned before (and nobody noticed) this "bloom'n flip" phenomenon is a combination of several factors: amp, guitar, speaker etc.
First of all, clips were recorded direct to the PC from the amp's effects send out !!! not surprising that tone is harsh, but in this experiment tone was not a concern, "bloom'n flip" was.
Before I continue let's do other experiment - get a guitar with a neck pickup very closer to the strings (in my case PAF humbacker. Well spoted dear vibratoking). Plug it to the nice compressor.To avoid acoustic feedback listen via the headphones. Turn compressor's GAIN up and ATTACK down. Play sustaining notes on all fingerboard. Some notes on some frets will "Bloom'n flip" much more then others, especially when note fades out. Obviously different guitars will have blooming notes on different frets.
Compressor is an AVC device and it amplifies weak 2nd harmonic on the end of the note. If you do this with a speaker you also can get acoustic feedback and infinite sustain.

Now about amp. Just for experiment sake I've removed V1 NFB and lowered V1's 150k slope resistor down to 57k which added compression and lower mids. From input to the V1 and almost all internal shielded cables were changed to RG 174 28pf/ft coax. Tweaked a tone stack for my taste/touch and tweaked PI tube. That's it, no rocket science.
This effect is much more evident without speaker but it is much more complex end pleasant with nice speaker at the gig volumes where you have guitar, amp, speaker etc, interaction.

Now, Tag's "fast note phase flip" is a different phenomenon. It is evident from his clips that Tag has a strong pick or finger attack . If amp's PI tube is not ideally symmetrical you will have amplitude dependent frequency phase shifting on each note, faster on high and slower on lower notes.
So, Tag open your amp and tweak the PI trimmer, you might enhance the "flipping" effect.

Cheers

What do you make of that? Is the absence of LNFB a factor?

Harald

[Max]

Max
Sorry you took that the wrong way.. I thought everyone has said there Peace concerning the clone issue!! If you like to continue the discussion please by all means..BTW..What is it exactly that bothers you about using this term to describe a copy..

Tony, IMO you took a lot of trouble to draw up and post the layouts of the 2nd and 3rd generation amps and the layout of the "classic" version of #124. And AFAIR one of your intentions for this has been, to stop the sloppy and confusing talk here about e.g. the "seventies classic amps" by making clear all the differences between a typicial 2nd and 3rd generation amp from the seventies and a "classic" amp from the early eighties.

Now in my opinion the same kind of sloppy talk starts again, when we label amps with e.g. no snubbers and a rather different power supply etc. etc., like your amp that's the topic of this thread, "102".

And what - IMO: consequently - happens?: New memebers here indeed seem to be confused - at least to some extent - and seem to wonder about all the differences between your amp that's the topic here and your layout of #102:

On a side note, on the layout of 102 I see two snubbers on V2. But it seems you don't have them on this amp.
I'm I wrong?

And in my opinion a label like "102" should be precise and definite, otherwise it's IMO not functional as a tool of communication, as it might lead to misunderstandings just like this nonsense talk about "70ies classic amps", that you did end with your layouts of a 2nd and 3rd generation amp and of the "classic" version of #124.

And considering all the labour when drawing up these layouts, I think it's a pity that now all this kind of sloppy talk sarts again - just on a new level.

That's what bothers me.

IMO it would perhaps be less confusing to introduce an amp like the one discussed here e.g. just as some personal interpretation, or version, or clone - or however you want to call it - of the non HRM skyline design e.g., than to introduce it with the "102" label on it.

What would be wrong with just introducing such an amp here in some manner like this e.g.?:

"Here’s a clip of my newest amp. Here are some of its more important ingredients: ..."

What do you think are the advantages of this "102" label?

All the best,

Max

[talbany]

Max
Sorry you took that the wrong way.. I thought everyone has said there Peace concerning the clone issue!! If you like to continue the discussion please by all means..BTW..What is it exactly that bothers you about using this term to describe a copy..

Tony, IMO you took a lot of trouble to draw up and post the layouts of the 2nd and 3rd generation amps and the layout of the "classic" version of #124. And AFAIR one of your intentions for this has been, to stop the sloppy and confusing talk here about e.g. the "seventies classic amps" by making clear all the differences between a typicial 2nd and 3rd generation amp from the seventies and a "classic" amp from the early eighties.

Now in my opinion the same kind of sloppy talk starts again, when we label amps with e.g. no snubbers and a rather different power supply etc. etc., like your amp that's the topic of this thread "102".

And what - IMO: consequently - happens?: New memebers here indeed seem to be confused - at least to some extent - and seem to wonder about all the differences between your amp that's the topic here and your layout of #102:

On a side note, on the layout of 102 I see two snubbers on V2. But it seems you don't have them on this amp.
I'm I wrong?

And in my opinion a label like "102" should be precise and definite, otherwise it's IMO not functional as a tool of communication, as it might lead to misunderstandings just like this nonsense talk about "70ies classic amps", that you did end with your layouts of a 2nd and 3rd generation amp and of the "classic" version of #124.

And considering all the labour when drawing up these layouts, I think it's a pity that now all this kind of sloppy talk sarts again - just on a new level.

That's what bothers me.

All the best,

Max

Max
Although I see your point..
Perhaps you should approach it from this angle.. If someone uses the word clone IYO incorrectly call them on it.. Put simply hey I interpret the word clone as being precise and definite yours is not..Your amp does not fall under (by definition) a clone for whatever reason!!..Perhaps you could help them by better identified it as a hybrid or a combination of 2nd gen amp with a classic stack etc. Like you did with my #13 hybrid..That was great!!
If someone does not use the word clone and simply states here is my 102 then points out any changes or modifications posts pictures then I don't see it as being sloppy..Personally I don't give a rip what I call it.. I simply tried to label the amp the best I could so people would have an idea of what it is so I don't have to spend an hour typing up a spec sheet then another hour answering questions like, what kind of Dumble amp is it?, why did you use this part? here or why is this amp different..I know many here including me appreciate the fact that you clarified all the different generations for us wonderful..Thank You BTW..

IMHO There is no precise and definite in our world when it comes to the building of 2 amps that are exactly alike is impossible.. especially one that has 25 + years under it's belt..IMPOSSIBLE!!..
For this reason I don't use the word clone anymore..

BTW.. My amp does share the same ability to feedback on itself like the original 102.. So I must have gotten pretty close..

All The Best!!

Tony

[Max]

... here is my 102 then points out any changes or modifications posts pictures...

Tony, what I've difficulties to understand is this:

When considering all these "changes or modifications":

For what technical reasons precisely do or did you think, that it's more appropriate to label your "Feedback City" amp "#102" than to label it "#124"?

I ask, because looking at the layouts of the skyline version of #124 and of RF's #102, I think to see more or less the same amount of differences between your "Feedback City" amp and #102, as the amount of differences between your "Feedback City" amp and the skyline version of #124. Or is this wrong?

And when comparing the layouts of the skyline version of #124 and of RF's #102, it's at least not completely obvious for me, if #124 isn't perhaps even less different from #102 than your "Feedback City" amp?

Thanks for your patience and have a nice weekend,

Max

[talbany]

... here is my 102 then points out any changes or modifications posts pictures...

Tony, what I've difficulties to understand is this:

When considering all these "changes or modifications":

For what technical reasons precisely do or did you think, that it's more appropriate to label your "Feedback City" amp "#102" than to label it "#124"?

I ask, because looking at the layouts of the skyline version of #124 and of RF's #102, I think to see more or less the same amount of differences between your "Feedback City" amp and #102, as the amount of differences between your "Feedback City" amp and the skyline version of #124. Or is this wrong?

And when comparing the layouts of the skyline version of #124 and of RF's #102, it's at least not completely obvious for me, if #124 isn't perhaps even less different from #102 than your "Feedback City" amp?

Thanks for your patience and have a nice weekend,

Max

Max
For me it really depends on where you draw the line!!
For instance...Say if I were to build a #102 version..BUT did not have access to some of the parts used in #102.. I use alpha pots Xicon Carbon films instead of Phiers Xicon caps etc etc ...but stuck to the layout I did of #102..

On the flip Side!!.. Say I use all the correct parts in the layout CTS pots period correct resistors (Pihers and KOA Speers etc).. BUT did not use the snubbers and lowered the filtering like I did in my #102..
Which amp do you think will sound closer to the original #102? or which amp would you think be best suited to wear the 102 distinction??

I know naturally in order for it to be classified as a clone you would need both correct parts build technique and stick to the layout exactly..

Also to be fair since we do not know exactly the types of parts used in 102 (things like which resistor types which brand bypass caps..Which type of coupling caps etc) it is by definition impossible to do an exact clone of 102 without some detailed pictures..

The main reason for my labeling it 102 instead of 124 was because I used the schematic/layout for my build, minus the changes of coarse..124 is a low plate with different bypass caps and a different GNFB circuit A 250k drive and 340k od trimmer as well..I believe these changes in 124 to have a greater impact on the timbre/sonic qualities than the changes made to my amp..

Generally when I build an amp for myself I make various changes to the circuit before I build the amp..As I stated I do not care for the LNFB on V1 and lowered the filtering due to the larger iron and didn't want the amp to be too stiff.. Had I of built the amp and thought it was too loose I would have upped the filtering and perhaps added the LNFB loop on V1.. But as it turned out The amp performed perfectly for my needs so the changes were left there..That is kind of how I go about it when building an amp for myself.. Naturally if someone wanted an exact replica I would have added these changes..

The Feedback City distinction is just a nick name since the amp likes to feedback.. Kind of like the Velvet glove nickname!!

Hope this better explains my thought process for the post!

Tony

[andyhardy]

Getting back to the feedback business

What is the measured value of the gnfb resistor hard to tell in the pics. Just wondered about that area of the amp since it takes off even at low volume.


I do love a good amp mystery
Cheers

[talbany]

Take a look through this thread as it has info about GNFB and other questions that have been answered already

http://ampgarage.com/forum/viewtopic.ph ... 11&start=0

Tony

[stevlech]

Perhaps the question to be asked is "what makes a #102 build a #102?"
Is it the presence cap? The filter caps? The pot sizes/tapers? What's unique to #102 and does Tony's amp retain those differences?

Just poking my nose in where it doesn't belong...

Good day to all.

EDIT- FWIW, a build w/o LNFB and small snubbers (maybe none) sounds more like #183 to me. But what do I know????

[talbany]

Perhaps the question to be asked is "what makes a #102 build a #102?"
Is it the presence cap? The filter caps? The pot sizes/tapers? What's unique to #102 and does Tony's amp retain those differences?

Just poking my nose in where it doesn't belong...

Good day to all.

EDIT- FWIW, a build w/o LNFB and small snubbers (maybe none) sounds more like #183 to me. But what do I know????

Exactly!!.. I think its safe to say that one of the defining qualitys within 102 is it's ability to sustain bloom and feedback easily..Judging by the clip my variation does the same with several modifications and still the bloom feedback exists..So its safe to say that if this is a quality you like and want in your 102 variation the changes I have made will not effect the amps ability to bloom feedback etc, like the original 102..This is my whole point

Thanks ...Tony:D

[lovetone]

Hi Tony did you post the layout for this amp on the other discussion?

i cant find it although i thought i had seen it.

Thanks Geoff

[talbany]

Hi Tony did you post the layout for this amp on the other discussion?

i cant find it although i thought i had seen it.

Thanks Geoff

http://ampgarage.com/forum/viewtopic.ph ... 73&start=0