Fender frontman 25R o something else?

[madapj]

hi everyone...
I got a 18-0-18 120VA toroidal transformer that i want use to build a guitar amp.
I saw the circuit of the fender frontman 25R, i think its easy to build, cause the amp stage is with only a TDA1514 and the pre-section seems easy to understand...
i wanna know, if with my toroidal i can build something with more watt, if there's some schematic that you can suggest me instead the frontman?
i'd like something with a IC in amp stage, and maybe easy to build. :-)
I'm able to do good board, i got everything necessary to print board.
Please nothing like lm3886 or lm1875, i've already done. :-)
There's maybe some fender or marshall schematic amp that i can build?
Thank you...
Marco
 

[J M Fahey]

Please nothing like lm3886 or lm1875

¿¿¿???
Well, then search for any amp you like and build it.
Do you like the Frontman 25? Go for it.
Or any other amp you like, with the caveat that it must be powered +/- 25V, which is what you've got.
*That*, more than anything else, defines the power you'll get.
I've been replacing scores of hard to find TDA1514's (Valvestate 8040) with LM3886 mini boards, but if you can get one, it will doubtlessly work.
Search Ampix where you will find tons of excellent commercial guitar amp schematics.
Good luck.
PS: your relatively low voltage but ample VA rating means you can build a stereo guitar amp.
Even if you don't build a chorus, the typical stereo amp effect, you can make a stereo effects loop, and hook a stereo multi-effects unit there, or even use it as a preamp; in that case your "guitar amp" will need only a PSU and two power chips (and 2 speakers, of course), think about it.

[madapj]

good, thank for answering me back.

So, im going, this morning,to check if i can find the tda1514 on my electronic shop.

If i do, im going to build this little marshall.

If i dont.....
The main problem in the post before is that:
For this project i dont wanna try and esperiment anything. I just wanna build a complete
amp, already designed and tested.
So my question was if there is a schematic, something about 30W, that you can raccomand me.
Something that you have already listen and you think sound good.
im not interested in a good distorted channel and no in particolar effect.
Something that sound clean and "pure".
I got a good fender acoustic guitar and a original telecaster.
An Amp that can sound good with both would be perfect.

About the two streo channel:
Im not really interested. the idea is play music, a singer and an two guitar player, in small pianobar.
i hope that i cleany explain what im looking for.

thank again....
Marco

[tron1]

Speaking of the Fender Frontman 25R, the TDA 1514 is supposed to be a 50W Hi-Pref HI-Fi ic, what can be done to bring out a bit more from this amp?

[madapj]

i was thinking....just some question...
i didn't find the tda1514.
if i want more watt with my toroidal.... 18-0-18 (120VA).
my toroidal have not power enough for the lm3668
i want use two lm1875 that i have home, each one connected with a single speaker. (but not stereo needed!!!)
but, if is possible i wanna use only one preamp.  I dont wanna make two preamp, i dont wanna double plot and more simple as possible.
How i can do this?
I have to connected simply the two input of lm1875 (with the "normal" chipamp schematic) with the output of the preamp?
and, another question: which one can be a simple pream, maybe only with tone stack and no second channel like distortion needed. Just a clean preamp!!!!
any suggestion?

[J M Fahey]

Hi madapj.
I suggest you check
http://www.ssguitar.com/index.php?topic=1379.msg8745;topicseen
where the user madapj asked all of this before and received  lot of answers.
The only "new" answer is: 1 preamp can drive many power amps, each of them with its own speaker(s) .

[madapj]

im sorry, i know....
Of course i know what i had write and your answer back. i check this forum often and with passion !!!
Thanks to you, i built the last project and i was "happy" of the result. lm3886 + esp pages (preamp), (i still have to buy some new plot cause i used the standard (not good enough), plot).
In this case, the will of new build is like a drug for me, i wanna build something different.
Like i said i was thinking about two lm1875 with one speaker each and a different preamp, just for try.
That's all.

Thanks. Marco

[J M Fahey]

OK Marco/madapj , congratulations on your build.
Yes, you can drive 2 or more chipamps with that preamp.
It's the only easy way to get more power from your actual power supply, because it's output voltage is not very high.
Of course you have an excellent current capacity on hand.
Good luck.

[tron1]

Speaking of the Fender Frontman 25R, the TDA 1514 is supposed to be a 50W Hi-Pref HI-Fi ic, what can be done to bring out a bit more from this amp?

Didn't mean to break up the "conversational momentum". I'll go somewhere else, I get the message.

[madapj]

Didn't mean to break up the "conversational momentum". I'll go somewhere else, I get the message. Embarrassed

sorry tron...

here we go:
the tda1514, i learn, is a good chip, but really difficult to find...
so, before to start a deep conversation about that, is better that you find first one...
about the 50W....
I got the same problem... i want some more watt
But, i think, that if the fender designed this chip in that configuration, for 25W, was because, they knew that this configuration was the better for a good sound...
So, if you wanna "more watt", the first things to talk about is which transformer you have...
if you find this chip, and you got a big transformer you can decide to use two tda1514 for two different speakers.
Like J M said, you can use the same preamp and pilote the two tda1514.
If you wanna more watt, the solution can be the lm3886, that everyone here, for wath i read, have built one.

But the question is:
you wanna build cause you wanna have fun or only for money?
cause, i think, i learn reading and checking for prize of  speakers and transformer, that buy a used frontman is really cheaper that build one....

[tron1]

I decided to stand back, take a look at the "big picture", and put my focus on the pre-amp section. Swapped out a TL072 for a NE5532 (U1). A welcome difference. Smooth gain, nice tone & not as harsh. Did the same for the drive channel (U2), but used an OPA2134PA. More edge, a bit cleaner & slight increase in gain. You are right about the transformer thing, Madapj. I kinda figured that would be the way to go at first, but getting one of those for that particular amp is worst than trying to get a TDA1514A. I'll leave it alone since it sounds better now. :tu:

[jordileft]

I decided to stand back, take a look at the "big picture", and put my focus on the pre-amp section. Swapped out a TL072 for a NE5532 (U1). A welcome difference. Smooth gain, nice tone & not as harsh. Did the same for the drive channel (U2), but used an OPA2134PA. More edge, a bit cleaner & slight increase in gain. You are right about the transformer thing, Madapj. I kinda figured that would be the way to go at first, but getting one of those for that particular amp is worst than trying to get a TDA1514A. I'll leave it alone since it sounds better now. :tu:

Hi, I'm planning to build a Frontman 25R and do any upgrades if possible. I don't know too much about electronics, so I hope you could help me with some questions I have. In order to get a suitable transformer, I know it should be 230V/ 20-0-20, but how many amps should it withstand? I've seen you have replaced U1 and U2 for NE5532 and OPA2134PA with sound improvements, is it necessary to change the schematic? or are it substitutes? Replacing U3 or U4 for any of those two IC could improve the sound even more?
I was going to replace TDA1514A for LM3886 ('cause I can't find TDA1514 anywhere), what schematic changes should I do?
Do you think I could improve this amp with any other modifications?
Thanks for your help!