Members gusfinley Posted February 13, 2005 Author Members Share Posted February 13, 2005 here are some pics of the tip jacks / pin jacks that I installed to monitor the bias without having to take the amp apart... I think I'll put them in all my projects from now on - you just plug your leads right into them!! Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 13, 2005 Author Members Share Posted February 13, 2005 and the other Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 14, 2005 Members Share Posted February 14, 2005 Originally posted by gusfinley I haven't got any terminal strips yet, to tell ya the truth I don't even know what to look for!! Look here- http://www.cinch.com/view_item.cinch?item_id=98§ion_id=28&sub_section_id=35§ion_title=Barrier%20Blocks&sub_section_title=Accessories%20-%20Lug-Type%20Terminal%20StripsI was thinking about some singal row barrier strips... Like these- http://www.cinch.com/view_product_line.cinch?id=28 could you post a link to a few good examples of terminal strips... I have seen the kind with the screw terminals - this would be nice for testing purposes.. Maybe but they are costly. I did it once for a Hiwatt clone, sure they worked great but almost broke the bank. Consequently I have also been looking at how to build the amp and test it first before commiting it to a chassis.. I went to the hardware store and found that the puchouts in electrical sockets are 7/8" so I could probally mount preamp tube sockets in them for the time being.. You will prolly end up with a mess of wires. Just buy a chassis from Weber SVT, the rejects(minor flaws) for dirt cheap.Best to work with what you are going to ideally want. Any time working with make shift items is prolly time wasted I also found some octal relay socket that have octal sockets and then screw terminals to the "pins" - it will be great to get it up and working before I throw it in a box... I saw some guy do this on his website although he did have to punch holes for the preamp tubes... IMO just get a hole saw. About $20for a good one, you need two at most. One for 9 pin miniatures, and one for Octal and big caps like the JJs I need to see if anyone in town will punch the chassis for me - I'm on a budget being a student and don't went to $pend lot$ of ca$h on punches - especially the non-round ones that run $200+!!! As above, should be no more that 20/each also what kind of wire with I need to hook this up - I know that I'll need stranded 600V, but some wire isn't rated - is there a safe gauge that will work in the same setting. Stranded??? Use solid because it stays in the shape you make it, is way easier to solder...The only stranded wire I use is 3 conductor double shielded for sensitive areas in th preamp. It is not the gauge as much as the insulator that is crucial for voltage. PVC is fine, Teflon is better, cloth looks nice. Use 20 gauge for the heaters and 22 @ 600V for everything else. Use the wire that comes with the trafos as much as you can in the power supply... once again thanks for all the help..... Just get the lug type terminal strips and some Solder Wick...Have fun, always remember safety first.RE Lee Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 14, 2005 Members Share Posted February 14, 2005 Originally posted by gusfinley just got my new digital camera today... here a pic of the fried resistor.... still reads 100 ohms, too!! Cool, if I were you I would redo the DSL stock just to get it working. Then think about making your own super amp. The DSL is not bad but you could do better if you took your time and did it right, without those tone sucking anode caps! Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 14, 2005 Author Members Share Posted February 14, 2005 Thanks for the input on those anode caps - I wondered what all those extra caps were for, and I especially wondered why I could never get my amp to feedback!! I've determined that I will also put in some headers were the caps go also, Then I can experiment with having them in/out and see what I like. I've been wanting to play with some good feedback for quite some time now!! I'll be using this amp for recording in my apartment (yeah, I know not the best, but it does have a great tone after a few touchups) and the nieghbors have been very willing to deal with the noise becuase the say they enjoy hearing me play - but they might not like the feedack - so it would be handy to be able to put them back in... This is turning into quite the good project!! And it will be very easy to swap caps / transitors with the headers I will install - and I could put it all back to stock by just putting the right value of caps back in and hotgluing them in place - no one would ever know the difference - well excpet for the whole I drilled in the front panel for the "right swtiches" better make those functional I guess.... seriously, Guitarzan, you have been a great help and I'm gathering some good info for my upcoming DSL401 website... I'll be sure to give you credit - although i am not sure how you would want that done.... (guitarzan from the HC boards) Thanks again!! Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 15, 2005 Members Share Posted February 15, 2005 Originally posted by gusfinley Thanks for the input ... Thanks again!! You're welcome. I was suggesting you build your new amp without the tone sucking anode bypass caps. The DSL may need them to keep out noise for some reason. As long as you are careful it could not hurt to try without them. It will feedback easier without them but you may get some surprizing parasites... IMO if you want to experiment you should get started on your DIY and spend the extra effort on that. The DSL will always be limited to mods by the PCB. Nice to have good neighbors. One of the reasons I live in a house! Give credit to Robert E. Lee if you like. No real need, just remember tone is in your head and my opinions may differ from others. There is no perfect tone, it is a individual experience. Electrical Laws are another thing. Get an ARRL handbook for easy understanding & quick reference to those equations if required. The 2002 Ed. I have even has a chapter on the benifits of tubes and how to use them properly. Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 15, 2005 Author Members Share Posted February 15, 2005 Yeah, I won't be putting anode caps in my DIY - its going to be based off a marshall JMP 1987 - except is gonna have A LOT of switches on it to make it really CUSTOM. I am currently working on a USA/UK switch, which is gonna take some crazy "trickery" to get to work - might have to consult a professor on this one... So far its gonna half to use a 5PDT switch!! and they don't make those in the ratings that tubes are going to need!! What does ARRL stand for - something to do with ametuer radio I'd guess... I'll see if I can find that book, still waiting to hear back about "The ultimate tone" I ordered it over a week ago and have recieved nothing!!! As far as wiring goes, you suggested not getting stranded wire - does this include the AC heater wires that will be twisted to reduce interference? I still plan to mod my DSL while I am getting ready to build my DIY - at least I will be modding something thats sound I am familar with the see, how different compenents, etc effect the tone.... Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 15, 2005 Members Share Posted February 15, 2005 Originally posted by gusfinley ...effect the tone.... I have no idea why you would need a 5P/2T just to switch to UK volts. Are you trying to re-invent the wheel? If you use the right power trafo, see here-http://www.hammondmfg.com/300series.htm it will have the right windings so all you should need is a 2P/2T. The components that effect tone are many. Pretty much everything in some way, from the layout to the type of Rs you use. The big contenders IMO are the size of blocking caps, higher values yeilding lower FQ roll off and the cathode bypass caps that boost the gain of different FQs. Yes the heater wires can be solid core. Those are usually thick twisted wires. ARRL= American Radio Relay League. I have two copies, 1952 and 2002. Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 15, 2005 Author Members Share Posted February 15, 2005 Originally posted by guitarzan I have no idea why you would need a 5P/2T just to switch to UK volts. Are you trying to re-invent the wheel? Yeah, I am probally trying to reinvent the wheel here in a way - the USA/UK isn't a voltage switch, its a preamp thing- I am also planning on putting a Vox/Marshall switch in there to see if I can get an AC30 kind of tone. Like I said - this amp is gonna be crazy and its gonna require a lot of planning for it to work right, but its gonna be sweet when it is done!! Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 15, 2005 Members Share Posted February 15, 2005 Originally posted by gusfinley Yeah, I am probally trying to reinvent the wheel here in a way - the USA/UK isn't a voltage switch, its a preamp thing- I am also planning on putting a Vox/Marshall switch in there to see if I can get an AC30 kind of tone. Like I said - this amp is gonna be crazy and its gonna require a lot of planning for it to work right, but its gonna be sweet when it is done!! The biggest difference between Vox & Marshall tone IMO is brought about with Marshall using global feedback but Vox using no NFB, aka open loop. There are way more than 5 things I can think of that are also different; Tone stack, cathode Rs & bypass Cs, Blocking caps, phase inverter, master volume, topcut/presence... Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 15, 2005 Author Members Share Posted February 15, 2005 Originally posted by guitarzan The biggest difference between Vox & Marshall tone IMO is brought about with Marshall using global feedback but Vox using no NFB, aka open loop. There are way more than 5 things I can think of that are also different; Tone stack, cathode Rs & bypass Cs, Blocking caps, phase inverter, master volume, topcut/presence... It's true - there are a lot more variables at stake than just one switch... the Vox/marshall switch would just change the filtering in the tonestack really.. I will also have switching on the feedback circuit, and a cathode/fixed bias switch. I'm hoping that it will be possible to get close enough to almost any amps tone by tweaking the switches in the preamp and power amp to closley match the circuitry of the amp I want to "dial in." I could also math it precisely if I wanted to by just swapping cap values and such. (This is why I wanted to go with screw terminal strips - EASY modification) Yes, its crazy, yes its complicatied. But I want to be able to hear the difference that different circuit comtribute to "tone", and in many cases A/B them, without having to buy 7 amps!! (Although I have been thinking alot about the Vox AC30CC head...) Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 16, 2005 Members Share Posted February 16, 2005 Originally posted by gusfinley It's true - there are a lot more variables at stake than just one switch...the Vox/marshall switch would just change the filtering in the tonestack really.. I will also have switching on the feedback circuit, and a cathode/fixed bias switch. All those switch wires could bring about some scary noise issues and others will reap few rewards. Why not build a 2 channel amp or a power amp and play around with different preamps. I'm hoping that it will be possible to get close enough to almost any amps tone by tweaking the switches in the preamp and power amp to closley match the circuitry of the amp I want to "dial in." I could also math it precisely if I wanted to by just swapping cap values and such. (This is why I wanted to go with screw terminal strips - EASY modification)Without digital switching and some serious knowledge you may end up with just a noisy bunch of dangerious wires, if you do try this better stick to a Hiwatt layout and spacing. Just line up the screws where the turrets would be Yes, its crazy, yes its complicatied. But I want to be able to hear the difference that different circuit comtribute to "tone", and in many cases A/B them, without having to buy 7 amps!! (Although I have been thinking alot about the Vox AC30CC head...) That is why Orange used a FAC switch. The DC30 second channel has one as well. Easy designs for effective preamp voicing adjustment. This changes the low FQ roll off by just switching the value of the blocking cap. Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 16, 2005 Author Members Share Posted February 16, 2005 Originally posted by guitarzan All those switch wires could bring about some scary noise issues and others will reap few rewards. Why not build a 2 channel amp or a power amp and play around with different preamps. Without digital switching and some serious knowledge you may end up with just a noisy bunch of dangerious wires, if you do try this better stick to a Hiwatt layout and spacing. Just line up the screws where the turrets would be That is why Orange used a FAC switch. The DC30 second channel has one as well. Easy designs for effective preamp voicing adjustment. This changes the low FQ roll off by just switching the value of the blocking cap. I've been thinking about the two channel amp due to the complexity of the USA/UK switch... The premp is still in the design stage. I am really wanting to get the poweramp section done soon so I can used the DSL401's preamp and run it through some EL34's. This is really a two step process and this is why I don't want to commit it to a chassis yet.... its may be one noisy amp when I get done, by I am really doing this for experimentation/ experience more than I am searching for "the tone", but hopefully I will find it along the way!! by the way whats, a FAC switch? Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 16, 2005 Members Share Posted February 16, 2005 Originally posted by gusfinley by the way whats, a FAC switch? Check out vintage Orange amps or the DC30 B channel.Besides a FAC switch the best way to alter tone IMO is to add stages. Easier said than done. In my amp I have the options of an extra stage before the tone stack, after the tone stack, or both. Also you could use an adjustable sweep control feeding the mid and bass like on the newer Marshalls and Krank advertises like they thought of it first. A CF fed tone stack keeping a middle value treble cap(250pf) works best IMO. Too small a value like Vox just is too thin, too big like some newer highgain amps has too much mids. edit,The most important thing after safety and getting the right parts is layout. Without a good layout it will be too full of noise to hear any good tones, or you will need to use tone sucking anode caps to make up for it;) Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 18, 2005 Author Members Share Posted February 18, 2005 reguarding the "USA/UK" switch, If I remove the cathode follower that is typical in a UK preamp setup, then I could use a 4PDT switch, which is produced and would be able to handle the current/voltage present in the preamp... I am just wondering how much you think the cathode follower effects the tone of a UK type preamp. How similar would it be if the tonestack in a UK type preamp where fed from the anode of the second gain stage rather than from the cathode follower? Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 19, 2005 Author Members Share Posted February 19, 2005 installed the new master volume dual pot and it sounds great!! No more hum!! took out the anode caps and its feeding back like a real amp!! put in the larger value coupling cap in the cathode follower and it rumbles!! Thanks for all the advice.... now as soon as I get more parts I can get back to those bright switches........ Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 19, 2005 Members Share Posted February 19, 2005 Originally posted by gusfinley reguarding the "USA/UK" switch, If I remove the cathode follower that is typical in a UK preamp setup, then I could use a 4PDT switch, which is produced and would be able to handle the current/voltage present in the preamp.... I am just wondering how much you think the cathode follower effects the tone of a UK type preamp. The CF is not a British thing, Fender used it in a Bassman to feed the stack before Marshall, Laney or Vox did. IMO a CF improves the impedance match greatly when feeding a Fender style tone stack. This allows the stack to simply work better . Why not have individual adjust on the perimeters rather than switching all 4 or 5 at once?Originally posted by gusfinley How similar would it be if the tonestack in a UK type preamp where fed from the anode of the second gain stage rather than from the cathode follower? IMO the best amps use more CFs to match up stages, not less. If you use a CF you do not have a phase shift. The CF can usually be connected without to many extra components. It is well worth having as the output is greatly improved over that which is possible by an anode output. The advantage IMO of doing DIY is that you don't have to deal with cost factors like you would if you were selling them. My amp even has one CF driving each output tube after the PI. This would not be cost effective in a production amp or even most boutiques. Just my .02 other's milage may vary... Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 19, 2005 Members Share Posted February 19, 2005 Originally posted by gusfinley i took out the anode caps and its feeding back like a real amp!! put in the larger value coupling cap in the cathode follower and it rumbles!! Thanks for all the advice.... You are most welcome. Dang those tone sucking anode caps:mad: So glad taking them out was good for you. Better bass now with the larger blocking cap too! Haha, gald I could help but lets maybe talk before you attack the bright switch. Looks like you're winning the battle so way to be, Mang! Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 19, 2005 Author Members Share Posted February 19, 2005 Originally posted by guitarzan Haha, gald I could help but lets maybe talk before you attack the bright switch. Looks like you're winning the battle so way to be, Mang! Here are my plans for the bright swtiches - first I'll install some headers and swap in different cap values - I think I have 5 or 6 ranging from 100pF-470pF - then when I find one I like in that particualt channel I'll wire up a switch and plug it in the headers.... Since I've already drilled the wholes for the bright switches - I might as well put them in, or I'll have to find something to plug the wholes!! Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 19, 2005 Author Members Share Posted February 19, 2005 When I talk about headers I am talming about these: You can just break them to whatever size you need. The components in my amp need three pin sockets, but I have to break the lead off of the middle one as there are only two holes in the pc board. After this is installed you can EASILY add or remove components without desoldering and resoldering.... which I have found to be quite detrimental to PC boards!! Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 21, 2005 Members Share Posted February 21, 2005 Originally posted by gusfinley Here are my plans... Ok so which caps(#s from schematic) on your amp are you fiddling with? Marshall typically hard wired some treble caps in the circuit that Fender uses in their Bright switch. I would start with those. Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 21, 2005 Author Members Share Posted February 21, 2005 The bright caps that I am messing with are C97 on the clean channel and C 100 for the distotion channel.... actually looking back at the schematic... again which is a bit confusing... I'm not sure what c100 is doing!! The schematic that I posted does not really follow the circuitry of my amp. My amp is somewhere between the one I posted (issue 9) and issue 4.... Mine would appear to be like issue 4, but with the transistors for A/B ducking in place... except for the fact that I took them out... So this schematic better follows my amp.... http://cc.usu.edu/~davbradshaw/imghost/dsl401.pdf in this issue C87 looks to be the bright cap for the gain channel.... but I can't find c87 in my amp.... I see a C86 and a C88, but there is no C87 in between them..... so that is good... SO in this case what would be the "bright cap for the gain channel? would there one I could simply replace rather than just putting one across R107 in the tone stack? hmm, glad you asked.. looks like I need to track down the REAL schematic that goes with my amp... Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 22, 2005 Members Share Posted February 22, 2005 C97, definately a bright cap bypassing high FQs around VR1. Note that when VR1 is maxed this cap has no effect. This would be a good cap to use a switch on, like a Fender somewhat. C100 is simular but uses R122 to limit the level of high FQs bypassing R121. If you use this as a bright switch maybe try changing the value of R122 so you can adjust the level of highs allowed to bypass. Link to comment Share on other sites More sharing options...
Members guitarzan Posted February 22, 2005 Members Share Posted February 22, 2005 C87 seems to be the same idea but across VR5. according to your latest link. If it is not in your amp then I would not concern yourself with it. Hope that helps. Link to comment Share on other sites More sharing options...
Members gusfinley Posted February 22, 2005 Author Members Share Posted February 22, 2005 Originally posted by guitarzan C97, definately a bright cap bypassing high FQs around VR1. Note that when VR1 is maxed this cap has no effect. This would be a good cap to use a switch on, like a Fender somewhat. C100 is simular but uses R122 to limit the level of high FQs bypassing R121. If you use this as a bright switch maybe try changing the value of R122 so you can adjust the level of highs allowed to bypass. Finally, I see how C100 is affecting the frequency response!! I didn't notice that it was being fed into the other section of the tube from the other anode. Rather than adjust R122, I think I will play with a few different values of capacitors in this location... I already know that 470pF sounds too shrill... Then when I find the one I want I'll give it a perminant install.. I believe the orignial owner of my amp modded it too a 100pF which sounded pretty good... if I don't find something I like than varying R122 will be the next step... Oh, and another question - what exactly is C68 doing? It is between the anode and the cathode on the first stage of V1. I don't think I've ever seen a cap connected like that in any other preamp schematics.... Link to comment Share on other sites More sharing options...
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